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YOUR RESEARCHWRL Race at HPR Aug 7-8
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Disconnect air oil separator
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Performed · outcome unconfirmed · Original poster
Chad disconnected the AOS from the intake which means it can't have smoking events.
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Suggestion · Original poster
The driver's role is to make sure that the car is set up right in practice, to not make mistakes and damage the car, and to adjust his driving to the conditions so the car can run the fastest average lap times thru his stint (and hopefully in the process not take away the next driver's ability to do the same).
Leading evidence: 'Disconnect air oil separator' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'car may have a mechanical problem' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Adjust driving' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Performed · outcome unconfirmed · Original poster
The axles are stock but disassembled and blueprinted and the CV joints filled with very expensive grease.
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Performed · outcome unconfirmed
Oil temp initially was an issue so Chris installed an auxiliary water to oil heat exchanger last year which drops the engine oil temps another 10-15F (this was not installed in this video) and helps keep the oil temps below 270F even on the hottest summer days with track temps at +120F.
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Performed · outcome unconfirmed · Original poster
Chad has installed Boxster S/996 center cooling pipes.
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Performed · outcome unconfirmed · Original poster
I recently repaired a failed GT3 engine that had a claimed 30000 DE track miles that had failed an exhaust valve.
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Adjust driving
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Suggestion · Original poster
The driver's role is to make sure that the car is set up right in practice, to not make mistakes and damage the car, and to adjust his driving to the conditions so the car can run the fastest average lap times thru his stint (and hopefully in the process not take away the next driver's ability to do the same).
Discussions that performed work without a confirmed outcome
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Performed · outcome unconfirmed
Oil temp initially was an issue so Chris installed an auxiliary water to oil heat exchanger last year which drops the engine oil temps another 10-15F (this was not installed in this video) and helps keep the oil temps below 270F even on the hottest summer days with track temps at +120F.
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Rennlist: 1 discussions
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Outcome without a verified action link
There is a good chance we'll get that fixed for tomorrow's race.
It looks like I will be able to update during the race.
The race actually starts at 9am. I thought it was going to be 8am and I mistakenly said that in the oil pressure instability thread. Tomorrow's race is 8-4.
Our Plan A race strategy:
The car gets extremely good fuel economy and we hope to complete the race on 3 pit stops, which means we'll need to run a little less than 2 hours between pit stops. I suspect we will be a little short of this, so unless there are extended yellow flag periods, which are rare in WRL, we'll need to have a short pit stop for a little extra fuel at some point during the race. We will likely run the first stint see how many laps the car does before running out of fuel. Our target number is 57 laps for the first stint, which means we pit on lap 55 because there will be two pace laps. We expect to be the last car in the race to pit, but it won't surprise me if some of the slower GP3 cars can go longer. Our target average lap time is 2:05.5 and I expect there will be 2:04's in the first stint before it gets hot.
This all assumes that the fuel system works properly. This is tough to get right. The system has been tested at low altitude and cooler temps but today will be a real test for it. The main issue is that the last few gallons of fuel are very hot due to having been recirculated through the engine bay for two hours. The hot fuel boils in the fuel pump inlet and the lower atmospheric pressure at high altitude further reduces the boiling point.
Yesterday in practice the car handled well at 95% pace but had oversteer at the limit in the fast corners. This may mean that the rear tires will limit our pace later in the race. We have an untested tire setup for this race so we don't really know what will happen. The new tire setup is certainly an improvement but we don't know if the tires will remain strong throughout the race. The car is equipped with race TPMS so the driver is kept aware of the tire temps and pressures and can adjust the driving accordingly. Our car is quite fast but the time is made in the corners so we have to drive it very hard. We will have less power than any of the other GP2 cars. This is compensated by also having less weight.
Penalties are a big issue. It's easy to get a penalty for passing under yellow or for breaking the fueling rules. WRL enforces those penalties consistently. Normally the penalty is having 1 lap deducted from your current total, which can be devastating. It's like being stationary for 2 minutes. The livestream will show how often we are passing. It is normal to pass several cars every lap.
I think the car owner will be starting the race and I will be driving from about 11 to 1pm, so no updates from 10:30 until 1:30 or so. The current plan is for me to drive only the 1 stint in today's race. I will be heading home around 2 in order to make a social engagement.
I would like to race for the overall win today. Our car is not fast enough to win overall (the GTO cars will be running around 2:00 lap times on average) but I think we can get into the top 5 overall and beat all the GP1 cars. The car owner may decide to reduce the pace in order to save wear and tear because of the upcoming 24 hour Sebring race is going to require an enormous amount of prep work, which the car owner does himself.
I have 3 hours to kill now so any questions or comments are welcome.
Chris Cervelli
Racher Renstall #211
Whooops, I was just informed that I am starting the race so adjust expectations of updates accordingly. This is nice for me because it won't be so hot. The car owner told me the car's ambient temp sensor was saying 107 degrees yesterday afternoon. It feels like about 65 right now.
Chris Cervelli
Racher Rennstall #211
He also told me that the practice results say we are 6th fastest overall. We start 22nd due to how WRL sets up the grid by class (it actually makes sense) so I will have a busy stint. Should be fun.
Chris Cervelli
Racher Rennstall #211
Adding in the live stream that was linked to in the other thread:
You Tube
Track Map
Chris,
What tires is the team running for the race ?
The strategy involved in multi class endurance racing really adds a fun aspect, leveraging the strengths and weaknesses of your car, and the other car you'll be racing against to develop a path to the best finish position possible - very cool.
I just gave a quick scan through the WRL Class system - I like it from a freedom of modification standpoint and PWR/WT with power modifiers.
What cars in your class do you view as the top sprint performers Vs. endurance (reliability)
Kick some ***
ETA... Cool suit for driver comfortable discomfort ?
We are running Cooper tires. I am not sure of the model. WRL mandates 180 TW tires, which is the best thing that ever happened. Fast, sticky, short lived tires are miserable.
WRL is great overall. Classing is common sensical etc.
I don't think we will be paying attn to GP2 for this race. At Daytona we had a super tight GP2 race.
The car has a Chillout system which is a freon based driver cooler. It works well enough.
Chris Cervelli
Racher Rennstall #211
Nice pass on the 240 !
ETA.... That little boxster motor really putting in work on the uphill !
He's running right at 2:05... every lap. Super consistent even with the traffic. By my timing, last couple laps I watched:
2:04.98
2:05.22
2:04.74
2:04.96
They're up ^13 positions, so we're in (virtually) the very car that's done the most passing!
Really cool
Edit: now ^14 for position. 8th overall. Very smooth
Edit: ^16 6th overall - so in a groove!
Edit: ^17 5th
(if you can't tell, I'm really enjoying this sitting in my RV lol)
Stream buffered on your last lap, so I didn't get to see you enter the pits or how long it was in.
But you went in the pits 4th overall, got back on the track 7th.
Amazing, for me, to ride along. Thanks!
Super fun stint there, we are right there in the thick of it.
The car stayed consistent with the oversteer in the fast corners and slight understeer in the slow ones. Most importantly, it did not change thru the stint which means the tires will last the whole race.
I have not seen the live stream yet so I don't know what you see there. I hope it is obvious how much corner speed we have vs the other cars. This particular track really rewards good handling and does not punish low horsepower that much.
I made a pretty big error in turn 11 about 3 laps from the end. I'd love to see the replay of that so I know if I need to apologize to anybody.
Chris Cervelli
Racher Rennstall #211
I was driving as fast as I was comfortable with the whole stint. I never backed off at all. The lap timer was not working and they were not asking me to slow down on the radio so I went for it.
There is not really a case to be made for taking it easy, except occasionally it makes sense to save fuel.
A quali lap would be the same except it would take advantage of a cold car and tires. The track is very inconsistent so its hard to estimate what the car could do in its current configuration, but I figure with new tires tmrw am I could do a 2:03 if I got serious about it.
This whole sport is about risk management. I have cultivated a more conservative driving style and I don't consider myself able to rip off a fast lap like I could when I was young. I just don't have the risk tolerance anymore.
Chris
No worries as far as I'm concerned. I thoroughly enjoyed your stint. The livestream was actually fantastic!
A couple of pictures of my tablet in my lap
Oh, and yes! The corner entry speed was by far the biggest advantage that was seen from the camera. And the car often held a tighter line, especially right handers. Or at least it seemed like it.
We have literally thousands of laps here in Boxsters, so everything is well optimized. The tight line into Turns 2 and 11 is worth about .6 sec on each entry. Normally you give back .4 on the exit but that does not apply when you are passing.
Early turn in with early apexing is very useful for endurance racing, especially with an underpowered car.
ABS failure, going off…. Know all about that.
I would be interested in the advantage of early turn in / apex specific to endurance racing.
The car looks very sorted, looked a little easier to drive when you were driving than driver 2 though. Setup characteristics suiting one driver better than another or just experience… or I’m off base.
I'm no racecar driver, but I am an old dinosaur who raced on 2 wheels for decades. So just my opinion in an effort to apply the same logic..... But the first stint did look less busy in the cockpit and so either it was, as you stated, a setup that suited the driver, but you could say the driver drove (adapted to) the car with the setup it revealed?
The second driver just has a technique in places that the setup doesn't match up with?
Or we would say driver one is running what they brung.
We have pitted so now we have only one more stop. That should move us up a little.
Driver 2 says the car is understeering heavily now and driver 3 has confirmed this. I did not expect this to become a problem.
Possibly Driver 2 was trail braking less than I was and got the front tires hotter, or his slower pace allowed the rears to cool down and grip more. it is also possible that the track temp dropped a lot because a cloud of forest fire smoke came over the track right when my stint ended. We should be able to figure all that out by looking at the TPMS data tonight.
I got faster back in 2003 when I figured out that the entry speed was the key to the whole thing. I kept working on that for years and have been comfortable entering the corners faster than optimal for a while now. By doing that, I can be out of synch with the other drivers which makes it much easier for me to pass them, and if I have to defend (which I normally won't do in endurance racing, but anything goes in the last 15 minutes) the hard entries make it very tough to pass me.
It looks like our pace has deteriorated badly. This highlights the importance of consistent and tough tires and making sure the handling balance does not change much as the tires age.
I suspect the car may have a mechanical problem that is affecting the handling. The rear sway bar may have failed early in driver 2's stint. We will find out tonight. I have all the necessary parts at the shop so we will fix it for tomorrow if that's the case.
I think tomorrow we revert to the well tested Hankook RS4 tire setup. The Cooper setup used wider tires and was better overall, but if there is nothing wrong with the car and the front tires did indeed give up than we will have a faster overall pace on the Hankooks.
At the end of the race, with in this case 8HRS of data to review….
What is your strategy for choosing what to review, in what order, and to what extent ?
With another race tomorrow, you have limited time to digest and get changes made, so I would imagine the analysis has to be very strategic to yield the best opportunities for improvement with sufficient time for implementation.
The tires had to be changed on Lap 145. It looks like the camber is not quite right but even with that optimized these tires are not going to last 8 hours and don't seem to be faster than equivalently sized Hankooks so that's probably it for the Coopers.
Now that we know the tire issues are not really fixable thru set up changes, data tonight will likely be limited to making sure the oil pressure was ok at the end of the race. It will have used some oil by then and the OP will be worse.
These WRL weekends are incredibly tiring so I always tried to limit the Saturday night work to what was absolutely necessary: tires, brake pads, oil level, and fixing any obvious problems.
Great to see the durability of the engine with a wet sump at the pace you carried for 8 hours. Looking forward to tuning in to your stint tomorrow. Congrats on today and a successful tomorrow.
We did attempt to make 60 laps for the final stint but did not make it and had to make a 4th stop. 7th place today and the car is still 100% for tomorrow. We shoot for 4th overall tomorrow.
Really enjoyed following along and getting your perspective - hard to imagine how gassed I’d be a after a day on track like you guys had and can’t even imagine a 24HR… huge respect and thanks for sharing as much as you have both technical and perspective, impressive doesn’t cut it.
What specific challenges would a 996 non GT/turbo face in endurance racing - I would think there’s a really good reason only caymans and boxsters representing the brand.
Thanks again man ! Look forward to following tomorrow.
No a 911 would be better. There was a 997 at Daytona that did well. If you can get a suitable rear tire, no other car can beat a 911 at a given power to weight ratio, unless manufacturer level aero is allowed.
I actually purchased a 997 for a WRL build but decided that I just could not afford to do the build the way I wanted.
Race starts at 8 tmrw and I am doing the 2nd stint. Hopefully we get the livestream going again.
Chris
I'd like to see that build sheet haha... What would you say like a Cayman build to be competitive runs for cost ? Not in the market, just curious.
Yeah... Hope you fix the live stream, that was awesome and great way to watch FUN racing. Not as good as being there... but really good !
My concept was to build the best WRL Cayman I possibly could. Later I switched to a 911 because 987.2 Caymans are impossible to find and 997.2 C4S's are plentiful.
It was gonna be a $200k car, but it would have been the ultimate customer race car, much better than GT4CS. My concept is that the car has AI so it would set itself up and be in a constant state of self diagnosis. This type of thing is possible with the pro level Motec displays and ECUs. It's just more than I can do with my current time, money, and motivation. If I ever win the lottery, I will build it.
Chris
No offense but we just watched an amazing showing by a 986 Boxster with the little 2.5 singing its heart out all day long. I know that we don't know what all is actually in the setup of that car but why wouldn't a 987.1 Cayman with the 2.7 be just as good to build from as that boxster? I mean the GP1 class, whatever it is compared to GP2, watched that boxster put laps on them. (not to take anything away from the great driving, of course)
Looks to me Yaw were the smart money. And having a blast doing it.
My team won the GP1 and overall championship in 2017 with 2.7 Boxsters. Winning the GTO championship and beating all those factory built cars is the next thing up from that.
But your point is well taken.
Chris
I'm just spitballing and really don't know squat about what you obviously have many years of experience with, but I really appreciate your generous responses.
So those 2.7 Boxsters (plural?), I assume were 987.1's?
And is there a reason for Boxster over the Cayman of the same drivetrain?
By the way, I have a little Base Boxster 2.7 and I way underestimated how much fun I was going to have in it. So yea, you've peaked my interest all day today.
No need to reply tonight. Get some sleep and go slay them tomorrow.
I messed the live stream, but I got to re-live it through the play-by-play comments. Very nice !!
I hope to catch some live stream tomorrow !!! Good luck !!
I just arrived at the track. I think the 12 place drop was because we started the race based on the finish position from yesterday and there were many faster cars behind us.
I am told the different tires are working well and the driver is happy.
Chris
Chad appears to be short shifting and saving some fuel. I think he is concerned about getting worse economy than yesterday. The current rear tires are shorter than what we ran yesterday and the avg rpm is going to be a little higher.
The gearbox has had a scratchy 4th gear since Daytona. It never seems to get any worse. I shift ever so slightly slower than I otherwise would and it seems ok. It will get a build after this race.
We should complete a few more laps today compared to yesterday and it looks like the winning GP1 car has had trouble already.
Chris
I am getting suited up now. The gearbox should not be an issue.
I am feeling a little fatigue from yesterday due to the fact that I don't drive regularly anymore. That will disappear for the first half of the stint but I will feel it again towards the end.
I will be driving at 100% unless I am told to conserve. That will be obvious because I will be using 3rd gear in Turns 2 and/or 11.
Chris
Just watched about 20min. One day ill be that smooth.
It apears to be a slower track but technically difficult. Not a lot of visual clues for braking and turns.
That was a harder session than yesterday. The car has less grip but it's more nimble and better balanced overall. It also brakes quite a bit better, like the front tires are sticking better under braking.
I got very tired about 9 laps from the end and had to slow down a little. That's embarrassing but to be expected since I don't drive much anymore.
It looks like all the cars have lost grip, the GTO cars especially. Them passing me was really awkward at times, because they have to slow down more for the corners.
Our tires held up during the a stint and the balance did not change at all. I think we'll be ok tire wise but I thought that yesterday too. We'll see how Adam is doing in a few minutes.
I was asked to drive the last stint but I don't really want to. I will see how I feel in an hour. I am super glad it is not as hot as forecast.
The oil pressure thread guys are probably curious about temps. On average I saw 200 coolant, 240 oil, and 255 trans. The trans is hotter than I expected it would be. Feels like a dry and breezy 85 out here.
Chris
Chris, nice job. You could definitely see the difference in grip. I saw you up to lap 112 and then my reception cut out on my phone. Appreciate you sharing the race with us. Certainly adds a little wind to our sails as we discuss M96 durability.
Just a point of interest, we ran my yellow Boxster (with 3.4 engine) in GTO at the 2019 24 hour race at HPR. We DNF'd after 4.5 hours when the clutch release bearing failed.
In the first stint of that race it was hotter than today and I was able to run at a 2:01 pace very early in the race. At that time there were not a lot of fast GTO cars so we made the decision to run at reduced pace for the remainder of the race. The first stint lasted something like 57 laps because of the fuel savings running at a 2:04 pace.
Anyway, the point is, heavily modded Boxsters still can be competitive for the overall wins in WRL. It is much more work and money than running the GP2 car though.
That car had gotten ridiculous due to budget constraints. It still had smaller tires than what we are running on the GP2 car and PSS9 Spec Boxster shocks. It did not handle well and was pretty much a rodeo to drive fast.
Chris
Chris
That was pretty much a flawless day. We found that the car uses more fuel when it's hot. We'll have to look into that.
The rear tires were a little hurt at the beginning of my stint so I had to avoid sliding the whole stint. The balance would have been better thru the whole race with the front bar one hole stiffer.
Chris
I admit that I got a little smitten watching that little M96.20(?) take that flogging and happily take it without missing a beat. And after reading up on the GP2 class, I assume it's not putting out a whole lot more RWHP than a stock Boxster of the day?
I can see where it would be tough to not get bumped to GP1 with even the later 2.7, unless you left some weight in it.
I was really impressed with the cornering speed, and the sustained consistency - the Boxster won some points with me over the course of the weekend and your whole crew looks like they really have their **** together tight, from driving to having the car prepared to run 16HRS over 2 days. For a guy like me that just runs DE's, the thought of that kind of strain on the equipment is pretty daunting actually.
If you could share some general info on the component choice : Mileage and general state of the motor, Dampers, any rubber left in the suspension, Safety - I think some of that stuff could certainly carry over to us 996 guys.
Also, hoping once you have had a chance to review some data you wouldn't mind sharing anything you find interesting - I'd be interested to know if there were noticeable shifts in the oil pressure in line with consumption, and, what the consumption looked like overall.
And big thanks for letting us tag along with you for the weekend, for a guy who was as busy as I could only imagine you were, you did an awesome job keeping up with the stuff coming in from this thread and responding with info I know I have, and will learn from.
And...Great Finish !
It makes about 195 rwhp which is about normal for these engines once you open up the exhaust and make sure everything works right. The engine is stock and it's a factory build. I doubt the valve covers have ever been off it.
We are at the limit for GP2. The car badly needs better shocks and we can't do it.
A nice 2.7 makes about 20 more rwhp, but offers much better real world performance. The extra 20 hp comes with another 500 rpm of usable power band. On the other hand, a dry sump becomes mandatory to get thru a season. HPR is not bad for oil pressure problems but other tracks kill a 2.7 fast. The extra RPM is the difference.
The 2.7 also feels much more like a race engine. More fun to drive and sounds better.
Chris
The prep level is indeed much higher. EVERYTHING has to be attended to or it will break. There is no part of the car (other than the engine proper) that has not been replaced or upgraded. The suspension arms etc are all GT3 or 997 Cup type stuff with monoballs, which is why we just don't care about running on the curbs all day. The axles are stock but disassembled and blueprinted and the CV joints filled with very expensive grease. This is mandatory. Wheel bearing life is about 2500 miles. The transmission will need a build prior to Sebring so it will have about a 30 hour life. My cars use Cayman S 6 speeds because they are strong and don't require so much attention. I always use Boxster S axles too (the 2.7 eats the puny Boxster 5 speed pretty quick, and the 3.2 pretty much instantly). The fuel system has a ton of work in it as well. Racing clutch and light flywheel which actually are pretty trouble free. The street clutch discs fail pretty quickly. We use Boxster S brakes and they work well until you have a 3.4. This car has MCS Spec Boxster shocks and they are a liability for us. They have been reliable though.
This particular car is not old yet. There is a bunch of stuff that happens once the chassis gets 25000 race miles on it. The seat mounts rip out and the rear suspension mounts crack. More work.
Overall though, they are incredibly tough cars and almost all the stock nuts and bolts and brackets are very suitable for this job. There are a few problem areas but it's amazing how much abuse they will take.
Safety stuff:
I use only Recaro seats, Brey-Krause side brackets (which I modify to get the seat lower), and stock sliders. This car has a Cobra seat and it seems ok, but I flop around in it. The belts are Schroth Enduro and they are best belts made by a wide margin. I use 996 Cup electronic kill switches on all my race car builds. The manual switches are not reliable. Normal electronic fire system. I like Safecraft window nets because they mount solidly and they are easy to use. Our pit stops need to be fast so getting the driver change done quick is really important. I am much bigger than Adam so there are many details that have to work right to do that change quickly. Chad is closer to me in size so that was easier.
So I was not at all busy this weekend. I had zero responsibility other than driving and that is far too good to be true. I have to thank Chad and Adam for that. Chad does the car prep all himself, except for some machining which I did. I will also do the upcoming trans build. He is amazing for a hobbyist (hah). Adam and his wife Angela help with the at the track stuff like setting up the pit box and handling all the fuel logistics (We burned 150 gallons of fuel this weekend. This is a big job). We also had a hired mechanic named Brandon who was the fuel man and handled some stuff on Friday. He did a great job.
I should have the data in a couple days. Sunday's data will be good but Saturday's will be a mess due to the Motec GPS not working right. I am sure the engine had oil pressure dips on every lap of both races. They just are not that severe I guess. I will find out about the oil consumption. I know at Daytona it only used .5 quart or some small amount.
Thanks for riding along,
Chris
**** Yeah ! Go Chad ! Representing us hobbyist's with dignity, class and skill. I like Chad
Wait just a minute.... if someone of that level is a Hobbyist - It would seems like I have a **** ton or ladder rungs to go before I can claim to be a hobbyist... Whatever.... I take back liking Chad
So much good stuff to unpack in the rest of the post... Thanks man !
Chris you are a pretty good driver and you know your tech stuff to. You said you guys burned 150 gals of fuel. What grade was that? Also if you don�t mind me asking what was the cost. Over here I can get 104 for about $9 a gallon. I don�t track my p car but when I was tracking my twin turbo r32 I ran 104, yes I had cats on it.
The engine we raced last weekend runs an LN 2 qt deep sump. Chad disconnected the AOS from the intake which means it can't have smoking events. It is then run overfull. I am not sure by how much. I regularly ran my wet sump engines a couple quarts overfull.
This car ran a normal 3 radiator setup with extra fancy ducting, such as a top outlet for the center radiator like a GT3. It also has fender top outlets for the side radiators. This stuff helps a little but is not a game changer.
The cooling system was sufficient for yesterday's race in 90+ degree weather. The transmission was a little hotter than optimum. It was over 250 for the second half of the race. This is not fatal, but indicates that with more power an upgrade will be required. This car has my Gen 1 cooler. I had to double the cooler size for my cars once I started running 3.2s and 3.4s.
Keep in mind HPR is at 5000 feet elevation. This lowers the cooling system efficiency quite a bit. At sea level everything would have been cooler.
Chris
Wow. There I is a huge story here on a number of things that we should all think about.
1. Chris demonstrates with his Boxster 2.5 that it's not all about horsepower on the track, it's more about suspension set-up, weight and driver skill if you want to go faster. And he did.
2. The engine has many miles of longevity including two back to back 8 hour races without a dry sump. Instead he used a non-fabricated 2.5 water cooler engine and attached a 3rd radiator, LN 2qt Deep sump and his gen 1 cooler but did fabricate the air ducts. Speaks volumes about our engines and their durability capability.
Chris, you may have mentioned this in the past, but can you tell us about your Gen-1 cooler?
Lastly, every engine needs a rebuild, water cooled and mezger. After how many hours of racing would you recommend to your clients to rebuild a M96 engine, 996 GT3 engine, 2.5 and 2.7 Boxster engine?
So I am home, had my coffee and eggs and got some sleep last night and thought it would be fun to participate in this thread.
Chris is right, I am a hobbyist. I don�t do this for a living, actually just the opposite, all I do is spend money on it
, and I haven�t race consistently in the last couple years. This effort to go run Sebring is funded mostly by me and I have only 1 goal: to complete the race, and be the top finishing GP car. Same goal as this weekend and every weekend. If I couldn�t demonstrate that the car, or the driver group, could achieve the goal I wasn�t going to bother, its a total waste of time and money. I take all of this very seriously and I have spent my time as a driver/mechanic trying to be exceptional at both driving and engineeering/mechanics because that is what racing is, man and machine. Chris has been a mentor to me for most of my racing career (10 years), I try to be a good mentee, and I deeply value our relationship. I was fortunate to have driven for him in two 25H Thunderhill races and many WRL events in car 481 with lots of wins, including the Daytona 14H. He is the only person I know who knows how to develop race cars properly while being a pro level (and former pro) driver. I work hard to innovate myself in developing the car but I usually run my ideas by Chris before going down whatever rabbit hole I am pursuing because his views are invaluable. At the same time I don�t like bing a pest either, he has to make a living and I am not a good customer because I work on my own cars. I spend a lot of time reading racing engineering journals, learning data tools, trying to think like a race engineer, and develop cars with an engineering mindset, but this is my hobby.
My car car was a very nice and quick SPB that I raced occasionally in PCA. Chris built my cage in 2016 and my Motec system and I modeled many aspects of my build on his WRL race cars with the exception of the power train. In 2020 I missed endurance racing so Adam and I took it, in basically SPB trim, to the WRL Championship race at COTA, with some fuel mods, and finished 2nd on Saturday and 4th on Sunday in a competitive GP2 field with Robert Ames as our third driver. What we learned from that race was that the 2.5 platform could be a potent GP car because of how efficient it is on fuel while still being quick enough in the right hands. I like big races so I set sights on Daytona. Adam and I do this sort of thing very well together and have been close friends for a long time but I needed another driver. There are lots of fast amateur drivers, but very few that can be consistently fast under extreme pressure, not mechanically destroy the car, stay out of incidents while still being ultra aggressive passing, and still have the bandwidth to participate in race strategy and car optimization both in and out of the car.. I can�t have someone write off the car because it would all be over, I don�t have the time to deal with that kind of program, I am a one man shop. All work has to go into improving the performance of the car and making it more reliable. I was thankful Chris agreed to participate because he was the top choice for obvious reasons. When I approached him about being the third driver for Daytona it was in the context of using the Daytona and HPR races as a 30H test for Sebring. I would build the car and not re-prep it between races, and only make improvements to develop the race potential in the car.
Daytona proved to me that the 2.5 could run at the front of both GP1 and GP2, in the right hands, even on a high horsepower track because of low fuel consumption. Had we not experienced an air pressure loss problem in both rear tires (TPMS stem problem), in separate events, requiring late pit stops (costing two laps), and a couple of teething penalties (another 2 laps), we would have been the top GP car there too, even on what was not a fully optimized tire setup. Between Daytona and HPR I changed the engine oil, added a catch can to the vented to atmosphere AOS (just to keep the bay cleaner and monitor escapement) and cut the car for more tire/setup freedom. HPR would be our race to start to test tire packages and optimize that part of the package. The differences in the Coopers and Hankooks are significant in terms of construction and setup so I had to make compromises there to run both in the same weekend. We had too much camber in the front for the Coopers and were a bit under cambered for the Hankooks. After HPR I believe there is more performance to be had out of tires and we have more to explore there before settling on a package for Sebring. As Chris has mentioned dampers are also a problem and we have to complete development there before Sebring.
I am now convinced this car, as developed, can complete the WRL 24 at Sebring, so we are going. We are looking for our fourth driver which isn�t easy, because on top of all the other requirements I want a financial participation from the fourth driver and no �arrive and drive� mindset. The prep is insane for me, not to mention the logistics for the race. I basically have to take the entire car down to the tub and nut and bold the whole thing, evaluate every part, and replace and rebuild everything. I take a clean room approach to this process so the time commitment and organization is high. I have already done this once this year before Daytona so it is truly insane, 30 race hours later to do it all over, but that is the deal. Chris is going to rebuild the gearbox (and fix that 3-4 issue), and work on our damper package. What to do with the motor for Sebring is not completely decided, I�ll let Chris deal with that discussion here. I will share this about the motor. It is a factory build, 66K street mile engine, with approximately 8K race miles on it. It has always been a great motor and makes good power. I haven�t pulled the data from Sunday yet but the Saturday oil histograms looked really good. Daytona wasn�t bad but I ran more oil in it this weekend at HPR than Daytona and the pressure drops were almost non-existent, much better than any time before.. I have employed a ton of thermal management strategies to keep the motor in a happy place its whole life and it has not been abused. I�ll get Chris the Sunday race data and he will make the call on what we do, wet sump or dry sump, rebuild or no rebuild.
I take back my take back…. Chad, Boss work amigo.
I’d like to take the time for a proper reply and will do so when I’m out of the office.
Thanks for joining the thread, allowing us to ride with you and sharing such a detailed post.
Great finish, I’ll be back.
1. Cornering speed is king on a road circuit. Horsepower is a big contributing factor but along with power comes weight (big brakes, sturdy transmission and axles, fuel consumption) and drag (for the necessary cooling) and tire wear. For endurance racing, getting the car balanced right so it does not wear out the tires allows it to be consistently fast. This is what wins races. The driver's role is to make sure that the car is set up right in practice, to not make mistakes and damage the car, and to adjust his driving to the conditions so the car can run the fastest average lap times thru his stint (and hopefully in the process not take away the next driver's ability to do the same).
2. As I stated in the oil pressure thread, I found that the engines do not have any weak areas other than the oil starvation and the inherent weakness in the main bearings, which is easily worked around by using a heavy oil and keeping the temps under control. The 2.5 allows you to mostly ignore the oil starvation and cooling but I must stress that the larger engines do not allow this at all.
My goal was to have a 10000 mile rebuild interval. At the avg speeds we were normally running at, this would be around 125 hours. At that point I would expect to do a quickie rebuild with bearings, chains, and rings and run it another 10000 miles. I never quite achieved this due to not solving the main bearing problem soon enough to try. I don't know what would fail on an engine raced that long. I suspect maybe thermal fatigue on the pistons. Nothing else in there is working hard at all. I had a couple engines reach 8000 miles before they failed main bearings (which happened due to specific conditions, not due to accumulated wear) and they appeared to be in great condition except for the point of failure. There is no way for me to predict the piston life though. I should point out that all my endurance racing engines were built with entirely stock internal parts. The 2.5's made 190-195 rwhp, the 2.7's made about 215, the 3.2's about 250, and the 3.4's about 260. The 3.4s underperform on the peak power because the airbox and exhaust system are too restrictive. The 3.4 has a much better power curve than a 3.2 otherwise.
The Gen 1 cooler I refer to is a transmission cooler. See details here:
https://irp.cdn-website.com/e112be6e...laminova21.pdf
I also use these for oil cooling.
I recently repaired a failed GT3 engine that had a claimed 30000 DE track miles that had failed an exhaust valve. All Mezgers have very short valve guide life and that beats up the valves. I would recommend a 10000 mile life on the Mezgers as well but that would be only for very intense use. DE use isn't that.
Chris
is it because that is regulated? I run v power 93 and that was $3.10 with my shell discount, I can get Sunoco 104 for $9. When
i used to track I would run anything from 98 to 104. Huge difference at Hennessy Motorsport in Sealy Texas dyno my car made
655 at the wheels with 93 v power. 695 with 104. Sold in 2013.
our track races and the need for speed tour were a little different kind of racing. In need for speed , twin turbo lambos 1500 hp spitting fire from both exhausts doing over 200 mph on i 10 after midnight. Not even the ninja motorcycles could keep with that. But they we�re able to film some good footage. Clandestine autobahn.
Fantastic thread. Great insight and contribution by Chris and Chad.
I was drafted into a team to run the WRL race at Road Atlanta last month in a new team's Boxster S in GP2 and can attest it was a fun experience and a very well organized weekend by the WRL. I'll definitely do it again and am considering rental options with a few teams running in GTO at VIR next month.
Thank you Chris and Chad for sharing your endurance race adventures with the 996 crowd as well as information on car setup and maintenance. Very surprised at the longevity you expect from your stock motor. Look forward to more adventures with the Boxster.l
I got to say dude, I really admire the task you have taken on the development side on such a difficult task and based on what I saw over the weekend, have done a very good job. I also can relate to trying not to be a pest and not being a good customer - I really enjoy the making the car better side as well and through those efforts have been fortunate to develop some really good relationships with people who have the knowledge to let me skip some failure steps along the way - but I try to exercise them as sparingly as I can and accept that learning from mistakes is learning, and I know, I have a long way to go on that front. From what I have read and had the opportunity to discuss with Chris - your word of invaluable would certainly be fitting. He has gone well out of his way to share what he likely learned through hard experiences with those of us trying to push for more reliable M96's in an incredibly candid way - I really appreciate it.
The breadth of disciplines in endurance racing is so cool, and you touch on the makeup of those who can put the team in a place to be successful, treatment of the equipment, decision making and consistency, traits you can look for in successful people in a lot of different disciplines, certainly a group of skills not possessed by all. Chris touched on it early in the thread, risk management. As I was thinking about how I take that phrase as it relates to what you guys are doing it gained depth in my head. From the risk management as you begin to prepare the car, to when time for prep get short, to the strategic goals and planning set for the race, to the start when traffic is bunched and on through the meat of the race and maintaining as best you can the strategy plotted and then the push for the end. It's very dynamic and interesting.
I hope that the prep for Sebring and the driver search goes well for you, I think a bunch of us 996 DE, and even street guys are now eyes open to what you guys are doing with our cousin cars and see the value in stealing some of the innovation you're implementing in such a grueling endeavor to make our own cars better. I think I remember Chris saying, if it works for you guys - it will work for the rest of us. I would love to follow along with you guys forward going. I keep beating the drum - we have some really great platforms (really, until watching you guys, I was never much of a boxster guy - I'm converted) and especially with regards to the 996, because of the expense and consequence of a failure ($20K motor rebuilds, I'm looking at you), a lot of folks will just not stomach the risk to exercise them on track where they are so capable. I definitely see what you guys are doing and what can be taken away from it from a development side as a way that the cars (996) can be made better, we just got to steal ideas from people who are actually really pushing the reliability envelope - the Boxster guys.
Zbomb, did you really just give props to The Boxster? 😉🤣
I've really enjoyed, from the sidelines, this forum and the folks that give it value currently.You are one of them as well. I'm a newbie to the Porsche thing, which is a little weird for me because I'm too old to be the new kid at anything. And I can clearly see that there are YEARS of history here and there's not enough time in the day to go back and start at the beginning. Regardless, I'm having a blast.
I said all that to be an opportunist and point out that my little 2.7 Boxster is ALL Porsche, as it turns out. 😎 Recent acquisition, of course, and I didn't know what I didn't know.
Chris is a friggin' animal behind the wheel. He's been a mentor to me for many years. Congrats Chris and Chad on this past weekend! Chad's Boxster is the most beautiful example I've ever seen.
Since this is a 996 forum, here is Chris at High Plains in my 996 that he prepped for track use. At this stage, it was still street legal but has since been gutted and is currently being prepped by Chris for full race status.
You Tube
Holy cow does it sound good, and the speed Chris is carrying a lap at 1:48 is incredibly fast.
Gotta ask, what have you done to the engine and how are you addressing oil pressure stability, starvation and cooling?
That's a 996 Turbo, so cooling is the only issue. You can see it's a wee bit faster than Chad's Boxster. It's not far off from 4X the horsepower so 155 on the straight instead of 112.
That car is in the midst of a very ambitious overhaul and I think it will be another 5 seconds per lap faster when it's finished.
Chris
Chad sent me an email to correct and clarify a few things I said about his car:
1. The engine is equipped with the 996 oil cooler. I think the larger than normal Coolant to Oil Temp delta is due to the placement of the oil temperature sensor in the sump rather than in the oil cooler itself as I have been doing for a few years. The sump temp will be higher.
2. Chad has installed Boxster S/996 center cooling pipes. These are much larger than what 2.5 (and 2.7 manual trans) Boxsters came with. I don't know whether doing this results in better cooling. Porsche does not do stuff like this for no reason though.
3. Chad spent a fair amount of money and effort wrapping up the exhaust system. This may have a small effect on HP and cooling.
4. The sump is not a 2qt LN as reported but instead a .75 quart FVD sump plate with X51 baffle. The oil pressure data looked good even at the end of the race. The oil level was run at max plus 1.5 liters.
We did some preliminary data analysis yesterday. The big mystery is why we wound up with oversteer in the final two stints on Sunday. The tire wear, as well as the tire temp and pressure data, does not correlate with this. I think the oversteer cost us a second a lap for around 115 laps, so nearly a full lap all told. The rear shocks got really hot and this may have contributed to the oversteer.
We also have some inconsistency in how full of fuel we are getting the car when it is red hot. This cost us at least another 60 seconds due to having the splash stop at the end even after I slowed down to try to conserve fuel.
Chad can simply add these complaints to the short list of work he has to do before Sebring.
Chris
As Chris said, It's a dry sump twin turbo Mezger so there are no issues with oil pressure and we are using the dual pick up GT3 oil pump along with the latest generation dual oiled 991.1Cup crank and RSR IMS. Engine is a 4.0L. Oil temp initially was an issue so Chris installed an auxiliary water to oil heat exchanger last year which drops the engine oil temps another 10-15F (this was not installed in this video) and helps keep the oil temps below 270F even on the hottest summer days with track temps at +120F. The oil cooler is mounted on the coolant pipes in the tunnel ahead of the gearbox. It's a slick set up. We will be using the car for 30-60 min sprint races so cooling should not be an issue as it's been well tested at this point.
If I'm not mistaken, Chris uses this same exact set up to cool the gearbox on the endurance Boxsters. My car has the GT2 gearbox which has it's own OEM liquid to oil cooler so temps are not an issue there.
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Part of the reason I am staying in class in GP2, running a 2.5, and keeping the car light is to see how far I can actually go with optimization. It is a much easier task to keep these cars together without the additional problems that come with additional HP. Heat, fuel consumption, drivetrain stress, oiling, you name it, everything gets worse, almost in an exponential way, as Chris said here. The rules in most of the endurance racing sanctioning bodies like WRL permit similar type of development for nearly every class so what is possible to develop in GP1 is also possible in GP2. Its simply a choice that many teams do not optimize their platforms to the full extent of the rules.
On Saturday the top finishing GP1 (250hp or 50-60 more than us) car put up 224 laps in what appears to be an almost perfect race for that car. It ran a fast lap of 2:02 in the race and the drivers were pretty consistent. The race had no FCY. On Sunday they had mechanical issues and didn’t finish. Our car on Sunday put up 221 laps in what is our best performance in a race so far. We may have put in one more lap if we didn’t have to dump the last can of fuel at the end. It was hotter on Sunday and the lower temps Saturday would have helped, maybe one lap, but we would have still been a lap short of finishing ahead of the GP1 car. So we have work to do. There will be many cars in GP1 as good or better than the #44 BMW at Sebring.
We know there is more to be found in tire packages and optimizing the setup to be more balanced for the whole race. A balanced car= Driver confidence= quick laps. We have cooling issues to resolve with the dampers, we have damper issues generally, we have some protocols to work out on fueling so we have complete verification of the mass of fuel that went in the car, and so on. What we don’t have are significant reliability issues, and I attribute that in some significant way to restraining ourselves to the 2.5l motor and gearbox, and keeping everything cool (a much easier task on a small motor).
This goal to be the top GP car at Sebring is purely personal to me and the other drivers. There is no award for it, and only the best racers even recognize what it means. Still, this is what we want, top finishing GP car at Sebring for the 24. We have to get our package (combination of average lap times and fuel distance) to at least draw even in total distance with the fastest GP1 cars, considering the fuel consumption over at least a 6 hour distance. I say that because there are bound to be at least 3 FCY at the 24 and when that happens we lose the advantage of fuel efficiency because the GP1s get a free stop. If there are more FCY then we need to hope they have mechanicals and we don’t because we cannot quite match their fast lap pace. In my view mechanical reliability works in our favor at Sebring over higher powered production cars, (as long as we don’t have oiling issues which I think we are getting on top of), because we are all working within the constrains of similar production car platforms and for us less HP related problems. So we do need a bit more outright pace, and that means more optimization, mostly in the areas of handling and grip. I am confident we have the tools and knowledge to get there.
There will be pro teams at Sebring, most will be GTO, but the level of competition in every class should be at the top of WRL competition, most average teams are not going to bother. Too much pain and misery. I wish we had one of two more 8+8s to test but I think we will be ready and bring our A game.
Just an amazing thread. So much more than what first was a YouTube link for entertainment, which absolutely was FANTASTIC.
But then the thread morphed. It's chock-full of YEARS of racing experience from a drivers, mechanics, and owners strategy.
Big fan now.
Will be following as closely as I can
It's obvious you have spent a lot of thought on the compromise between reliability and outright pace - working to inch the pace potential up with well thought out and engineered optimizations that are identified through the testing you have done. I would guess with regards to pushing the envelope of the rule book, budget and the specific platform with its inherent strengths and weaknesses would be a big factor in deciding what rules you have to take to the edge of the book and what can be minimized for better resource allocation elsewhere.
Are you running a stock ECU ? If so, is it still in a stock state of tune or have you optimized for your use ? I would be interested if it has been tuned, or run on an aftermarket ECU (I believe Chris likes Motec, who doesn't) the strategy and goals. I would think with fuel management being so important, even small changes to the fueling run out over 24HRS could provide meaningful gains. I see switchable maps seem to be prohibited (any device that alters tune cannot be within reach of driver...). But what about crew ?
I would be interested if you wouldn't mind sharing the data collection strategy - what sensors logging what data ?
As far as your goal - Any car that can take a beating for 24HRS at Sebring says something in and of itself with regards to the attention to detail and preparation it has received, to be at the top of GP there seems to be a goal that would provide a huge sense of accomplishment. Playing to the reliability on such a punishing track, it would certainly seem a race that those with the best development success with regards to reliability would have an advantage vs outright speed there, more so than at somewhere like Daytona.
