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YOUR RESEARCHUpdate on the LNE 4.0
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Replace few things
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I changed a few things from stock other than displacement...
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The 3.6 cylinder heads have MORE potential than the 3.8 heads, and often times I use 3.6 castings on the Carrera S engines that I build to 4.0, as the 3.8 heads are factory crippled, and suck to modify.
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Not only was this a bad design for many reasons, they used the same heads and intake and exhaust as the 350s.
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Happy to report it was "squeaky clean" and that is what i was expecting.
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The 3.6 cylinder heads have MORE potential than the 3.8 heads, and often times I use 3.6 castings on the Carrera S engines that I build to 4.0, as the 3.8 heads are factory crippled, and suck to modify.
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Engine has just under 10k km now. Its been running great but still have issues to sort out that aren't engine related. Pretty happy with the car and how its been running.
Im not the best driver by any means. I go out there to really drive the car how i want to drive it and not get arrested
I misspelled motorsport, i know.
https://www.youtube.com/watch?v=Azck...ature=youtu.be
I kept traction control on. This is my 1st time lapping a car with TC. Is it supposed to be that intrusive? Or do I just need work on the smoothness of my lines?
Epic, really curious if you have had a chance to dyno? do you notice a difference from the original 3.6? I don't need an engine rebuild yet, but I might pre empt a rebuild if it gave me something closer to GT3 power.
I really don't notice the traction control on the PSM. Maybe you have a lot of additional torque?
never dynod it. don't really give a **** about numbers. it's not anywhere near gt3 power.
do you track your car?
everytime I went over the turn "Candy Mountain", it would light up like a xmas tree and just kill power right away. I tried a few lines throughout the night and it didn't make a difference.
I have tracked my C4S, and the PSM doesn't interfere very often. Usually only tells me I have had too much in sweepers where I have the throttle wide open.
I am disappointed to hear that you don't think your 4.0 is making "GT3 Power" considering the 3.6 made 325 and the GT3 was 380. I would have expected a 4.0L to make close to 400 with the proper intake, exhaust and tune...
that might be so but I don't have any mods. the car is completely stock. it still pulls very nicely and I am happy with the power.
once I sort out the rest of the car, I'll start optimizing things. better exhaust, plenum, intake and tune.
Glad to hear the car is running well after the 4.0 upgrade. First thing I do when leaving the pit is turn PSM off. I've found it will intervene at times when I'm not expecting it. This is very spooky in high speed sweepers, rather just control the car myself.
OT: How did you mount the Camera? what camera is it? I am ready for my track day in 2 weeks and was thinking to get one of those dash cam but tech says i need it to be tethered. So looking at solutions.
Sorry I don't know how PSM works but back in the day... my S2k didnt have traction control. I would say try turn it off for a lap and see how it feel?
Remember, AWDguy added displacement, but didn't add additional port work, and etc. Displacement alone doesn't make the power, its the whole combination.
I'm sure his engine is a brute, but there's more than one way to skin a cat. Anytime I do a 4.0 I add over 20CFM of port flow at minimum, in fact every engine gets port work thats above a Stage 1 combination.
To many times I see people paying way more attention to displacement than they should. Hell, I have built a 5 chain 3.4, and kept it stock bore and stroke, making over 300WHP with a stock intake, and no bolt- on components... Just old fashioned internal hot- rodding.
Its not how big you make it, its how you make it big that counts. Its all in the combo.
Yes, exactly. GM learned this the hard way when they did 400 cubic inches in a smallbock format. Not only was this a bad design for many reasons, they used the same heads and intake and exhaust as the 350s. More torque, but at the expense of horsepower.
There are times I leave PSM off because I can't stand its habit of retarding the timing when one rear wheel breaks loose. If you're losing power and you're seeing the PSM light flash, that's what is happening.
I've built these engines to 4.3 liters. Big has proven to move the power band down so low, that the RPM range become narrow. Head work is a near necessity, and when studying VE tables we see the efficiency drop way down beyond 4 liters. I do have a new CNC head profile that makes the 4.3 viable.
That said, its only being done for the "bigger is better crowd" and to keep the copy cats in their places. Meanwhile my 3.5L R51 combination is making more power with less displacement. I've been making some engines smaller than stock, yet making 80 HP more at peak. Try that one on for size!
Yep. We used to see better efficiency in GM V8s with longer rods compared to stroker engines with shorter rods (but higher displacement). The piston sits at TDC longer and builds a hair more pressure. And then might have some ways to get a little more RPM. If the pressure on the crank is the same but at a higher RPM, that equates to more horsepower. And less peaky engines can cause greater area under the curve so that a flatter torque curved higher up in RPMs can create more average horsepower over the range. Which means faster if driven properly.
Rod ratio matters a lot with these engines.. Its unfortunate that the case decks stayed the same from the 2.5, to there 3.8.
That means when the factory wanted to add displacement via stroke, they had to use a rod that was way shorter than optimum for an 82.8mm stroke.
With everyone just keeping things the way they were, its been really easy to pound them into the sand. Just takes some effort, and not being stuck on what the factory did :-)
Waking these things up is combination dependent, and displacement really doesn't matter.
I had minimal port work done on the heads while it was being decked. they recommend it since i was going with a larger displacement.
I'm not a "bigger is better" guy. I'm a "the 3.6 to 4.0" was the same price as staying 3.6 kind of guy.
What do you recommend in terms of bolt-ons for this Jake? IS there an intake & plenum combo this 4.0 should be using?
This is what I try so hard to keep my purchasers from thinking. Why? Because when optimized, this isn't true. The additional displacement may be free, but that does not equate into more power for free, or more efficiency for free.
Since head work was not done in the form of port enhancement, then outside of an IPD plenum you won;t find any other gains that are worth the expenditure. Its a lot like a water hose, you can connect a larger hose to a smaller one, but all you'll end up with is the maximum flow volume that the smaller hose can move. The 3.6 cylinder heads have MORE potential than the 3.8 heads, and often times I use 3.6 castings on the Carrera S engines that I build to 4.0, as the 3.8 heads are factory crippled, and suck to modify. In stock form the 3.6 head will remain efficient for a 3.8, but above that the losses in efficiency become apparent, if you can can compare things scientifically.
I'd bolt on an IPD and roll with it.
but you don't sell nickies. LNE does, and they were the ones who pushed me in that direction. I have emails basically saying "no issues using a 3.6 head with our 4.0, no modifications necessary"
yeah there's no issues but maybe they should have spent sometime explaining to me what you just said.
ah well. what is done is done. I don't know if I ever will open up this engine again but if I do, I'll make sure to get the head work done.
right now I'm just going to continue driving the **** out of it.
break pad light came on while I was on my way to the track but I still ended up doing ~40 minutes of track time. Surprising how much pad life you have left when those lights light up. I still had just under the thickness of the pad plate itself when I took them off.
I just did the front brakes pads and rotors with sensors for under $470 CDN. My parts guy ordered the wrong pads (regular 996) so i had to spend an hour driving back to his shop to get the right pads but otherwise, this was one of the easiest brake jobs I have ever done in my life. I think the Subaru Justy was the only one that has been easier than this. Took me no more than an hour per side to do. super simple install.
Now, I met a guy who tunes cars, and is a whiz with NA cars. Said he's done a few Porsche NA 3.8 tunes and said he wouldn't have any issues tuning my car also. I'm going to reach out to a few of his customers to get their idea on his tuning skills but it looks promising.
Tuning a 3,8 is a bit different, the bore size of the 4.0 is 101mm, Vs 99mm on the 3.8, so the engines tend to like a much different ignition curve when being tuned. He may try to start with an NA 3.8 file, which tends to be a mistake for me when I've tried it.
Make sure he isn't the kind that just raises safety thresholds and removes limiters without altering tables. Also make sure that he doesn't alter the adaptive learning of the arrangement.This is what most tuners do, and it causes more problems than anything else.
Keep the rev limiter where it is stock!
After he does this work, watch fuel trim VERY closely for the first few hundred miles. I'd capture fuel trim values before he does the work for at least the final 100 miles before its tuned, then compare that to afterward.
BTW- We typically see that with displacement increases the fuel economy goes up, not down(dependent upon the driver!). This is of course something that's efficiency driven, and since I bump CR at least 1 point over stock on all builds, which helps.
The car is dumb, it doesn't know what engine is installed. The more powerful engine motors the vehicle along at cruise using less of it's net energy, which helps add to the fuel economy. I have had some engines get over 35 MPG, with the right driver, on the right gas, but with today's ethanol enriched fuels, we will never see that again.
Cool, thank you very much for that info in regards to tuning, I will watch him and challenge him on these points.
I am pretty sure I can get even better mileage than that. That was with half a tank left after the track day and a 1.5 hour drive home....
I'm close on a 4L project... first fire was yesterday. I changed a few things from stock other than displacement... high flow cat x-pipe, & Len Hoffman did the heads (knowing it was an LN 4L build). We don't have peak dyno numbers yet because it's not even broken in but it was hitting 300 WHP without even really trying. I'm not sure if those were altitude corrected numbers or not - we're > 5,000ft. We expect to hit about 385 at the crank, maybe a bit more. My builder said maybe 10hp from the x-pipe and the rest of the gains are a pretty even split betw displacement & headwork. Len told me he was quite pleased with how my heads came out.
I can't wait to get this project done & drive it! It's been about 10 months since I blew it up. I hope to post dyno numbers when I'm done.
I will start a new thread... but since I'm not doing the build (not the skills nor the tools nor the time), I selected a guy who specializes in Porsche engines and has done quite a bit of work on 996s including several 3.8 total rebuilds. This means I have very limited pics, and no real knowledge of the how things were done. All I can do is really talk about what happened, what we did, and the end result.
new front brakes this month - this is expected, especially since i track the car.
Low oil pressure light briefly flashing at me while idling in traffic. weather was crazy hot and the gauge was bouncing all over the place. going to 0, then shooting to 4 and back to 0, back to 5 then to 1. The new sensor gives a more consistent reading and is very steady. Took it to the Calabogie track for fathers day and did a few laps with it, drove back in the crazy heat and oil pressure was good.
Now an airbag light is on. lol. ugh.
"The car IS 15 years od, The car IS 15 years old, The car IS 15 years old." I need to keep telling myself this.
The airbag light might just be your seat belt buckle contacts.
I watched the video from Calabogie (I haven't been there, though I'm now in Ottawa and I really should go) and apart from some mid-corner adjustments that are provoking your balance when you get close to the M3 (look past him to get past him!) I think the main reason for the car intervening is probably a mix of throttle pedal impatience and the loss of feel you're suffering from swaying back and forth in the seat.
Try to stay planted with your left foot pushing hard on the dead pedal, the way your instructor is. It's hard to keep from moving in a street car seat, but the benefit to staying as stationary as possible in the seat (with your head straight, not leaned) is that you have a far better feel for the weight transfer that's happening, enabling you to make little corrections early, rather than bigger ones later.
Is there a way to clean those properly? I tried using electrical contact cleaner and compressed air, that did nothing.
Thanks for the track tips! One of the guys recommend I get some CClip, or Glock or something like that for my seat belt,. It apparently keeps the belt from moving and keeps you planted better in the seat without having to go full out race mode.
I have the CG lock for when I take my DD to the track and have been pretty happy with it. Especially since you can't pull the seatbelt all the way out and lock it on my '99.
CG Lock Performance Add-On for Your Seatbelt
Amazon
Amazon
Getting her ready for winter storage.
Before putting in fresh oil, I asked my friend to remove sump plate and take a peak inside. Happy to report it was "squeaky clean" and that is what i was expecting.
My knock turned out to be nothing in regards to the axles. I guess when I had put one of the suspension arms back, I cross threaded it and my track days made it back out. Had to tap in a new insert and a new bolt....no more knock
The new engine mounts and the transmission mount insert from function-first really made the car feel more solid. The transmission mount did increase some cabin vibrations though but its not too bad. Glad I went with the soft one and not any harder.
Also sent some oil away for a sample...
