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YOUR RESEARCHTrack doods - brake cooling mod (pics)
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also switching
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Reported cause · Original poster
Compounding the problem was also switching to more agressive pads (PFC 01/06/07) from Pagids.
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Reported cause · Original poster
For my application, the best upgrades for stock calipers using aggressive pads turned out to be:
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I have a friend who installed identical looking ducts on his 996 C2, and swears they were around $60 for both.
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I ran my car slightly lower with a bigger front spoiler which was keeping more air from getting under the car and to the brakes, I was running standard 997 GT3 ducts and not the cup ducts, pagid black pads, smaller 17" wheels AND all of that on a warm day when I had my brake heat issue last year.
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FWIW I run the GT3 ducts on my 996 and the Cup ducts on my 986.
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I ran my car slightly lower with a bigger front spoiler which was keeping more air from getting under the car and to the brakes, I was running standard 997 GT3 ducts and not the cup ducts, pagid black pads, smaller 17" wheels AND all of that on a warm day when I had my brake heat issue last year.
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Suggestion · Original poster
The track was a bit funky (dusty and slick), and I was running a second or two/three off my previous pace, but my caliper temps never got above 430 as indicated on my caliper heat stickers for a 15+ minute session.
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Suggestion
Also, you say GT3 fender liners, but it appears to me that you're running stock C2 liners that are trimmed by the frame rails, which then feed another set of ducts, which a stock C2 does not have, and I'm guessing this is what you're referring to when you say the GT3 fender liners?
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I have GT3 brake ducts, but was still having a brake temp issue at one track that is hard on brakes.
I have GT3 brake ducts, but was still having a brake temp issue at one track that is hard on brakes. I tried to use GT2 brake ducts, but they extend a full inch lower, and woud simply scrape everything from driveways to speedbumps. The next course of action was to upgrade to internal GT3 scoops. This is (close) to the same setup as the GT3, and uses GT3 parts. The scoops normally snap mount onto the cooling lines, so we added a few zip ties to keep them from falling off, and cut off some of the useless plastic bits as well.
Just like it looks, air comes directly through the front radiators, and instead of venting down, passes through the air hole, across the scoops and directly onto the rotors. One track day down, and so far, so good. They stayed attached and functional. As you can see, the front rotor temps didn't brake 350, but granted, the track is pretty easy on brakes. This weekend will be a real test as I'm back at the track where I boiled Motul 600 a few times in one weekend.
So far, the only downside is with my 8.5" track wheels running 245s, I can't use full lock. With my 8" wheels I have no issues.
Other results to follow.
-td
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Cool. I didn't know about this one. Is that black piece that is zip tied 2 parts or one part. Can you list the part #s.
So you also need to trim a little bit of the liner. I guess that extra hot air from the radiators is still better than less air? Any way to punch all the way to the front to grab cold air? Looks like a great path for some cooling ducts to run.
The entire black piece is one part. It's actually bigger and hangs lower. The bottom part was cut off as it didn't direct anything to the rotors.
Part numbers:
996-575-232-30
996-575-231-30
Ambient air might add some additional cooling, but only a little since calipers run hundreds of degrees hotter than your coolant will (should) ever be. Getting 200 degree "hot" air on 600-700-800 degree calipers is like a frickin AC unit right on them
There is some direct airflow back as well, but most of the air is passed through the radiator. A side benefit to this is better airflow through the radiators, which has brought operating temps down slightly as well.
-td
It's a decent compromise since I still street the car as well. I like it 100X better than stock and 10X better than my ROW M030. When it becomes a full on track car, I'm getting remote 3-ways, but for the price and functionality, PSS9 works.
-td
Nice job.
You don't use data acquisition, do you? Being able to analyze brake pressure and deceleration G forces may teach you ways to be more efficient on the brakes - that may help keep temps down, too.
Ok enough said that sells me right there
I have cut way too many track sessions right in the middle of the action because my car was about to go past the point of no return.
I too got to the point last season where I was boiling Motul 600. I was planning on just running cup car ducts and installing them / removing them at the track so I didn't break them off on the street. this might be another good addition.
Thanks for the tip.
I saw a car last year at NASA Nationals that had a really great setup running cup car ducts AND 3" hose through the front trunk area, through the tub and directly onto a backing plate on the rotor. However I'm not going to be drilling holes in my tub anytime soon so this looks like a better solution.
Andy
p.s. That wheel well is supposed to be silver just like the rest of the car
I'm surprised at the brake overheating issues. I used to have them on my '87 track car, but have never had any hint of them on my 996 even at CMP, which is very hard on brakes. Perhaps it's a pad issue - which pad are you using? Some pads seem to transfer more heat to the calipers than others. Also, as one poster suggested, it could be an issue of technique. No one wants to hear that, of course, but it's definitely something you may want to look into.
For me it was a combination of things I think. I ran my car slightly lower with a bigger front spoiler which was keeping more air from getting under the car and to the brakes, I was running standard 997 GT3 ducts and not the cup ducts, pagid black pads, smaller 17" wheels AND all of that on a warm day when I had my brake heat issue last year. I think with a fresh set of pads and cup car ducts my situation will go away.
However if this cooling mod is effective and doesn't take much money or effort I don't see how more cooling will hurt anything.
Andy
Agreed. And it sounds like the items you listed could all work together to lead to some overheating. It still might make some sense to have another experienced driver ride with you during your next track event to make sure there aren't any issues with technique. I did this several years ago and found it worthwhile. In general, I always try to get another instructor to ride with me once during a track weekend - always nice to get another perspective.
Sorry for the off-topic. I just had to ask since I saw the setup and it seems you're at the border of street and full-time track, especially since you're having brake cooling problems.
I have been using dataAq for more than a year. Although i don't use a brake pressure sensor, I have plenty of LongG data. I have evaluated my data against other "better" drivers driving my car. My braking points, distances and LongGs are pretty close to the "better" drivers when the drive my car.
Of course, the issue may still be technique, but assuming that I'm not a retard (all the time) the overheating issue still had to be addressed. The overheating problem primarily manifests itself on one particular track with 5 heavy braking zones with little cooling time - this track is notorious for killing brakes. Compounding the problem was also switching to more agressive pads (PFC 01/06/07) from Pagids.
This is a good suggestion for anyone as they progress, even when they are in the "fast" group. As for me, I have hired an actual pro coach more than once (i.e., someone who coaches pro drivers, NOT just someone who simply coaches for money - he was the lead instructor for Panoz school, lead instructor for Porsche Driving Experience, lead instructor Bondurant, etc, and currently coaches for Ferrari Challenge). I have also had a few other ex-pro drivers and and a slew of "normal instructors" ride with me. And I am also an instructor. Not saying my technique is perfect, but so far nobody has screamed beat me up about it
Paul, I also have the 3rd radiator. Down here in Texas, you kinda need it
-td
You could also try the cup brake ducts. They will collect more cooling air than the GT3 ducts. They have worked very well on my 986 and I don't have issues with them draging over curbs on the street.
Oh, yeah. I was supposed to update, doh!
I went back to the track that used boil my fluid [Motul 600]. I was using the same pads as before (PFC 06(F) / PFC 97 (R)), with Castrol SRF - just to be safe. The track was a bit funky (dusty and slick), and I was running a second or two/three off my previous pace, but my caliper temps never got above 430 as indicated on my caliper heat stickers for a 15+ minute session. Now that is some serious cooling improvement! Even with more speed and longer sessions, I should stay in the high 400/low 500 temp range. [I still have the stickers on, so I will confirm an post all temps later tonight]. I'm going to flush with Motul 660 since I have a couple bottles left over, but then I'm going back to the cheap Motul 600 since it looks like I have the heat under control. *fingers crossed*
Also, I didn't have any rubbing on the track, but it is very easy to rub against the ducts when using too much steering input in the paddock. With my street tires, I can go full lock with no rubbing (whew!).
Lastly, my yellow student had an Audi R8! Now that was fun
-td
Your "yellow" student??? I think that is a little racist, don't you? Oh wait..... you meant the student in the Yellow group, not the yellow.... oh never mind!
Sorry Tom, I couldn't resist!
This can also be cuased by the caliper pistons hanging in the bore. Rebuild kit fixes it. Just happened to me last week. Never had brake problems before.... last week I was melting the brakes. Turns out my calipers needed to be rebuilt. Evidently common on older 996s.
no, just the gt3 ones. i had no need for the cups at $240ish a pair. (rediculous for pieces of plastic) i'm sure anyone could fabricate basically the same thing for a few bux if you have the skills and the need.
99634111790 AND 99634111890
from:
http://e-partssales.com/Merchant2/me...AND99634111890
they are calling them euro model gt2 ducts now. previously called gt3 cup ducts.
The ducts at the bottom in that picture do not look like the GT3 ducts to me, possibly cup? I'm currently running what I thought were 996 GT3 ducts which look similar to the ducts at the top, and the 997 GT3 ducts look like the ones in the middle. If the ducts at the bottom indeed are GT3 ducts (996?) available for about $30, I'll have to get those! Anyone can confirm?
I think this has the skinny many of us were looking for - regarding the "duct spoilers"
6 Speed Forum
I've sent over for a quote for the following, to my shop:
Rear:
996 (GT2?) rear brake ducts are 996.331.127.90 and 996.331.128.90
(I'm guessing these are like $130/set)
Front:
996 gt3 cup brake ducts are 996.341.117.92 and 996.341.118.92
(I think $250/set)
996 gt3 brake ducts are 996.341.117.90 and 996.341.118.90
(I think $30/set)
Sorry if there's any mistakes here - doing my best to get my arms around it - I noticed I was frying my calipers at the last DE and this seems like a simple, effective mod...
the ones at the top are just like the oem ones that came on my 02 c2.
the middle are what i bought at the local dealer for $11.41 ea. those are the gt3.
the ones in the bottom are the expensive gt2 euro or gt3 cup depending on who you ask. they are reported to be extremely effective but more than what i needed for my dd with occasional track days.
see link:
http://e-partssales.com/Merchant2/merchant.mvc?
needed or not, why wouldn't everyone buy and install in 10 min the gt3 ducts for that price?!
It looks like the top are 996 stock (which are the same as MKI GT3), but I haven't run them in so long, they might actually be 996 GT3 MKII ducts. The second one looks like 997 GT3 ducts to me. I don't know what the bottom ones are, but they are close to the 996 Cup ducts, but are not the current ones. Maybe they are older versions.
Here are all the part numbers for those that are interested:
Brake Ducts [Front]
996 Stock
- 996.341.483.01 996.241.484.01 [also .02 for MY01]
996 GT3
- 996.341.483.01 996.341.484.01 [also .02 for MY01]
996 GT3 CUP
- 996.341.117.90 996.241.118.90 [GT2 2002+] [also .91 for GT2 from 03) (GT3 04-05)]
996 GT3RS Street
- 996.341.117.92 996.341.118.92
997
- 997.341.483.xx
997 GT3
- 997.341.483.xx (MY 07)
997 GT3 CUP
- 997.341.483.xx
997 GT3RS Street
- 996.341.117.92 996.341.118.92
997 GT3RS race only
- 997.341.483.xx
Brake Ducts[rear]
996 Turbo/GT3
- 996.331.127.90 (left) / 996.331.128.90 (right)
As for brake cooling, you will get some additional cooling from the front GT3 ducts, but your front nose will affect air flow to them. As you can see, there ins't a huge improvement in size between #1 and #2. But, the GT2 ducts are HUGE. Almost twice as big, extending a full inch lower than the GT3 ducts. You will definitely rub on speed bumps and anything low. AND if you go off track, they turn into shovels, grab dirt, rocks, and grass and snap off. A really quick way to lose $250. IMO, you should stick with the GT3 ducts.
Also, you won't benefit (much if any) from rear brake ducts. IIRC, your undercarriage will not flow air to them (and I think they evantually took them off the GT3 and Turbo, and only recently put them back on the 997s). Note: if you look at the undercarriage cover for a turbo, you will see air guide slots for the rear brake ducts. Without them, the air simply passes by (instead of into) the rear ducts. Also, given the size differential between front and rear, you will gain more by cooling the fronts a lot more, than by cooling the rears a little more.
For my application, the best upgrades for stock calipers using aggressive pads turned out to be:
GT3 air scoops [GT2 are too big]
GT3 liners
PFC dimpled rotors
Castrol SRF [or Motul 600/660 if bled frequently]
For endurance pads, there is little need for the GT3 liners.
I haven't visited my brake setup in a while, so this info may be outdated or just plain mixed in my head
-td
That makes it sound like the bottom duct is a GT2 part? I have a friend who installed identical looking ducts on his 996 C2, and swears they were around $60 for both. If that were the case, I'd order them today... Also, you say GT3 fender liners, but it appears to me that you're running stock C2 liners that are trimmed by the frame rails, which then feed another set of ducts, which a stock C2 does not have, and I'm guessing this is what you're referring to when you say the GT3 fender liners?
All this makes me wish/wonder if I should just pick up a GT3, the upgrade/part swap game gets old quick...
I took this picture and the "ducts" in it are mine. To clear up the confusion they are......
* Stock 986/996
* Stock 996 GT3
* Stock 996 GT3 Cup
FWIW I run the GT3 ducts on my 996 and the Cup ducts on my 986. I can't remember the pricing for all of them but I do remember that the Cup pieces were stupid expensive...
I have heard (have not had to try this yet) that the 997 Cup versions are much less $$ that the 996 version but will fit the 996. This is an internet rumor that I have not verified.
If you read the entire thread, you will get the gist of the parts and install. There are separate air guides for the GT3 that reside in the fender. You have to "configure" the fender liner and radiator guides to work [which could be done with the GT3 fender liner].
The mega-brake-ducts pictured (bottom of the 3) are not stock for the 996 C2, they actually appear to be the GT3 RS street version to me [PN 996.341.[117/118].92]. The GT2 version looks more like the stock duct with another piece riveted on. The middle ducts have a corresponding 996 part, but there is no reason to pay the extra premium when the 997 part works and are cheaper. [This is the part virtually everyone is using now]. FWIW, Pelican shows the 996 GT3 part as $30 per side, whereas the 997 part is $11 per side.
-td
I did this a year ago, put 997 GT3 ducts on the front.
I noticed that the wheel weights to balance the wheels do not fall off anymore. I used to tape them on but now there is no need to.
I have the 996 GT3 ducts in my C2 (along with the rest of the suspension). I actually don't have any issues with the brakes on Pagid Yellows and ATE Super Blue fluid, but if those ducts really were under $100, that's what I would've gone with. Even at $250, I have to wonder if they'd be worth it considering how much they may save on rotor/pad life...
The radiator pass through modification was particularly appealing, as I like the idea of keeping some of the air going through the radiators from ending up under the car as well.
Anyway, I think I'll stick to keeping things as they are. If I could sell my 996 at a reasonable price, I'd like a GT3, though I have to say the C2 is a marvelous car, and I'm enjoying it thoroughly for the time being.
BTW, Ray and Td, thanks for all the part numbers and pictures. I appreciate reading about different set ups and comparisons.
Okay thread revival...
This past weekend at Thunderbolt I was talking to a guy with a GT3 cup, within the convo we got into brake ducts and he said get a set of the 997 cup ducts which are 20 dollars a piece, since the 996 variants were like 250 or something crazy... He said it was not a mistake and they still sell them?
Later on that day I ripped off my rear brake duct hitting a gator too hard (I guess one wheel went off into dirt a tad and the height difference caught it) so now i'm looking for options... I'm seeing my stock GT2 rear ducts are actually the best of the best? Or one of them but just hang low from the research i've done.. So are these indeed the gt3 cup ducts? I'm so confused lol
And the 997 cup ducts I was going to pick up for them being so cheap, but it seems as if the stock 996 gt2 ducts are really good , and that there is no need to switch? I never once had any brake fade or issue though..
The bottom duct in that photo is what comes stock on the GT3.
The Cup duct is the same thing, but with an extra section riveted on that makes it deeper.
There are threads & photos about this on the GT3 board.
I got mine from sunset for a little under 10.00$ each side
#997.341.483.92
#997.341.484.92
BTW I'd like to see pictures of your car. Like the 007 theme
Hmm, well I did read it, but I share Ahmed's confusion. In the first post, it sounds like you configured the stock liner. In other posts, there is some mention of GT3 liners. I'd like know if I can add these ducts (the upper ones mentioned in your first post) to my C2 without getting a new liner. Did you succeed in doing this?
Thanks for letting us know!
Come to think of it, has anyone reading this thread done this? With the original wheel well liners? Or ... ? On a 996.1 or 996.2?
And the other big question: Some say venting air into the wheel wells reduces drag and lift, at least that's been claimed of adding vent holes in the wheel well liner similar to those in a Turbo. Has anyone who has done it as shown here noticed any effect on lift or drag?
Thanks again!!
RS10 - You need to modify the radiator cowls that side behind the wheel arch liners to realize any benefit.
The cowl collects air that has passed through the rads and then directs in 90 degrees downwards to under the car.
Some say this causes air stacking through the rads and front end lift, I would agree.
You need to cut/modify the rad cowl so as some air can pass straight through onto the back of the wheel arch liner, you then vent, slot, cut the wheel arch liner so as the air passes straight through into the wheel well.
Porsche obviously realized that the 996 design was flawed, as all future model (Including 996 turbo) ducted the air straight through into the wheel well, these models have wheel arch liners with vents manufactured in them, however they will not fit a 996.
I have pictures of mine if required.
Cheers
