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Discussion Starter #1 (Edited)
I am preparing my PDK-equipped Cayman S for a swap to a BGB Motorsports 3.8L X51 Powerkit engine (engine is on order, but it may be a month before the engine gets to BGB). I have read threads on other forums about heat being a problem in the 981 engine bay. Side effects are reduced reliability of the PDK transmission and lowered horsepower due to heating of the intake air. I already have the third radiator installed and if the GT4 side air scoops are retrofitable, I will install them to increase RAM air effect. My engine bay is hot now, and the additional output of the X51 engine will likely make things worse.

I am looking into ways to insulate hot and cold things in the engine bay while the motor is out and things are easy to get at and am looking for recommendations from anyone who has tried to mitigate this problem. My first plan of attack it to use thermal wrap on the headers; but I hear it is bad to wrap the catalytic converters. I assume you can wrap the pipes to the rear mufflers and one company is offering a muffler thermal wrap. I have purchased some thin polished stainless steel sheeting to create a heat shield for the catalytic converters. This should reduce the heat in the engine bay by at least 1/3 (the rest radiated by the engine and transmission).

For the intake system , I think insulation could help here, too. There are two choices that I see: An adhesive backed insulating thermal wrap about 1/4 inch thick and a thin metallized heat reflective tape. The heat reflective tapes also come in sheets that could be applied to the intake air filter box and hose, or use the thicker thermal wrap similar to the muffler product. Question is, do you go so far as to wrap the plenum and intake runners or is that going too far? The plenum has to be removed to flip it around for a 981 installation, so it would be an ideal time to get something on the bottome of the plenum and have reasonable access to the intake runners. The idea is to insulate the intake air from what heat is left over in the engine compartment after doing as much as can be done to limit heat radiation from the exhaust. Can't do too much for the engine case itself as it probably relies on thermal radiation into the environment to keep the oil at a reasonable temperature, even though there is an oil to water heat exchanger.

Another concern is the proximity of my Fabspeed sport headers/catalytic converters to the rear brake lines. I am surprised the brake lines don't melt. At least the cats must heat the brake fluid, excaberating the tendency for the rear fluid to boil. The heat shield is meant to help this and if thin reflective thermal tape is flexible, I may wrap the brake lines for additional thermal protection, as I think anything here will help brake fade.

I am willing to listen to anyone's ideas or experiences, especially things that are known to work or don't work. I am trying to get every HP out of this new engine and just don't want to cook anything and make the car last a long time. I don't want any heat-induced mechanical failures.
 

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I am preparing my PDK-equipped Cayman S for a swap to a BGB Motorsports 3.8L X51 Powerkit engine (engine is on order, but it may be a month before the engine gets to BGB). I have read threads on other forums about heat being a problem in the 981 engine bay. Side effects are reduced reliability of the PDK transmission and lowered horsepower due to heating of the intake air. I already have the third radiator installed and if the GT4 side air scoops are retrofitable, I will install them to increase RAM air effect. My engine bay is hot now, and the additional output of the X51 engine will likely make things worse.

I am looking into ways to insulate hot and cold things in the engine bay while the motor is out and things are easy to get at and am looking for recommendations from anyone who has tried to mitigate this problem. My first plan of attack it to use thermal wrap on the headers; but I hear it is bad to wrap the catalytic converters. I assume you can wrap the pipes to the rear mufflers and one company is offering a muffler thermal wrap. I have purchased some thin polished stainless steel sheeting to create a heat shield for the catalytic converters. This should reduce the heat in the engine bay by at least 1/3 (the rest radiated by the engine and transmission).

For the intake system , I think insulation could help here, too. There are two choices that I see: An adhesive backed insulating thermal wrap about 1/4 inch thick and a thin metallized heat reflective tape. The heat reflective tapes also come in sheets that could be applied to the intake air filter box and hose, or use the thicker thermal wrap similar to the muffler product. Question is, do you go so far as to wrap the plenum and intake runners or is that going too far? The plenum has to be removed to flip it around for a 981 installation, so it would be an ideal time to get something on the bottome of the plenum and have reasonable access to the intake runners. The idea is to insulate the intake air from what heat is left over in the engine compartment after doing as much as can be done to limit heat radiation from the exhaust. Can't do too much for the engine case itself as it probably relies on thermal radiation into the environment to keep the oil at a reasonable temperature, even though there is an oil to water heat exchanger.

Another concern is the proximity of my Fabspeed sport headers/catalytic converters to the rear brake lines. I am surprised the brake lines don't melt. At least the cats must heat the brake fluid, excaberating the tendency for the rear fluid to boil. The heat shield is meant to help this and if thin reflective thermal tape is flexible, I may wrap the brake lines for additional thermal protection, as I think anything here will help brake fade.

I am willing to listen to anyone's ideas or experiences, especially things that are known to work or don't work. I am trying to get every HP out of this new engine and just don't want to cook anything and make the car last a long time. I don't want any heat-induced mechanical failures.

Only thought I do have is that I think it is amazing that while Porsche has insulation on the over axle pipes, none of the aftermarket companies even bothered to consider it.

I have a feeling that the impact on heat from the 3.8 is not going to be that bad
 

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Maybe some undertray ducting of cool air from under the car to shoot up into the engine bay to circulate cool air up and out of the compartment. Something similar to little air scoops under the engine bay
 

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DEI sells titanium exhaust wrap, insulated wraps for your lines, and other insulating products. I plan to wrap my over the exhaust pipes like Porsche did on theirs. Rear brake heat is a major problem at the track. Ask john about wrapping the headers. Not sure if that will cause any problems such as warping due to the increased heat in the pipes. Adding some naca ducts to blow some air into the top of the engine bay would cool the intake area and generally get rid of some of the heat at the top of the engine chamber.

In regular driving I don't think you will have many problems, but the track will be another story. We know you aren't adding this motor to loaf around town so I think all of you concerns are warranted to make your car the best and most reliable.


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Found this post from a year ago, and thought it worthwhile to pull it forward. Thanks Matt at Dunlap.

**Disclaimer - I'm a 987.1 Cayman S owner and exercise my car at the track frequently. I found this thread while doing a search for 3rd radiator info**

"I saw some information in this thread that concerned me, and wanted to point this out to my 981 brethren...sustained 270*F engine oil temps at the track are TOO HIGH!! At that temperature, certainly the factory fill Mobil 0w40 is going to have a hard time maintaining sufficient film strength to keep internals properly lubricated. Yes, more stout racing synthetics are "good" up to 300*F -- but "good" might mean something different to a racing team who only needs their motor to last a few hundred miles vs. the Cayman owner who is hoping to get many miles out of their car. As someone mentioned earlier in this thread - heat is the enemy of durability and longevity for most anything mechanical.

The factory 3rd radiator (Suncoast
has a kit now) will absolutely help address these issues. The engine oil and PDK
/gearbox fluids all go through separate oil/water heat exchangers on these cars. The more capacity you have to dissipate heat (as RobVN mentioned), the lower your oil temps will be. You're coolant temps won't likely change much, given that they're controlled by the Thermal Mgmt System, but that extra radiator will give you more capacity to dissipate the heat exchanged from the oil/PDK exchangers. 987.1 and .2 owners have seen oil temps drop as much as 20*-25*F at the track by adding the 3rd radiator.

If you take your car to the track without a 3rd radiator, you're putting yourself at risk for overheating the engine oil to the point where engine components are at risk. This should be everyone's first mod for a track driven car.

Two other tips for track driven vehicles...(1) make use of the cool down lap. Drive at moderate speeds to get plenty of air over the radiators in a gear that allows 3-5k RPM to keep coolant circulating at a good rate, and (2) don't shut the motor down as soon as you get back into the paddock. Let it idle to continue circulating coolant/oil/etc. Fans my cycle on and off, and that's fine.

Also, if it's a hot day at the track (90*F +) and I don't have someone in the passenger seat, I'll close all of my vents except the passenger side vent. I leave that open, aim it out my open window, and turn the heat/fan up to full blast. This is like a *free* 4th radiator!! I'm effectively using the heater core as an additional air/water heat exchanger to further help control coolant and oil temps. Since the vent is blowing all of the hot air right out of the window, I don't notice any discomfort. According to measurements from my OBDII sensor, this "mod" is worth 5*F lower coolant temps in my car.

Oh -- one last thing. Change your oil after every 2 track events (4-6 event days). Heat takes its toll on oil and shortens life. This is cheap insurance.

This is what works for me. My 987.1 motor has 45k miles on it, about 3,500mi at the track. I'm sharing this because I'd hate to see a bunch of 981 motors going south at the track because of cooling issues.

Hope this helps!! "


I particularly love the 5th radiator option. Five degrees for zero dollars. Amazing! A 6th option that I have always done is to drive off the track, go down the highway in 7th gear at 70 mph, and let a bunch of fresh air run through the radiators and cool off the brakes. At low revs, you are making the least amount of new heat from the motor and dumping the most out the cooling system. With no braking to speak of the rotors and calipers also cool down significantly. I roll down the road a couple of miles and return which only takes about 5 minutes. It is like adding 2-3 cool down laps for your session. Time that is too valuable to be wasting on the track of course.​


 

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Discussion Starter #6
DEI sells titanium exhaust wrap, insulated wraps for your lines, and other insulating products. I plan to wrap my over the exhaust pipes like Porsche did on theirs. Rear brake heat is a major problem at the track. Ask john about wrapping the headers. Not sure if that will cause any problems such as warping due to the increased heat in the pipes. Adding some naca ducts to blow some air into the top of the engine bay would cool the intake area and generally get rid of some of the heat at the top of the engine chamber.

In regular driving I don't think you will have many problems, but the track will be another story. We know you aren't adding this motor to loaf around town so I think all of you concerns are warranted to make your car the best and most reliable.
Yeah, I have some of their stuff on hand and more on order. I didn't want to mention product vendors by name for a non-forum sponsor. I plan on wrapping the headers and exhaust pipes with the Titanium wrap and the two mufflers with two of their muffler kits. The intake plenum, intake runners, air filter boxes, and Y hose are what I am considering using their floor and tunnel insulation (with good heat insulating properties) or the gold reflective tape and sheets. I probably will wrap the rear brake lines with small segments of the gold tape to reflect exhaust heat off of them, yet allow for flexibility of the brake line as the suspension/wheel moves up and down. Wrap not like a header, but in multiple 1 inch loose segments, sticking to itself on one side so it can flex without restriction.
 

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Discussion Starter #7
I have the 3rd radiator and still regularly see 234F oil temperatures driving on the interstate!

Note: many track-specific oils will take the heat, but have an additive package that wears out in 400 miles or so and needs to be changed after each event to keep the anti-wear additives in plentiful supply. For an occasional track use, you need to swap back to street-compatible oil after the event and the street oil needs to be chemically compatible with the track oil or the engine has to be flushed. Mis-mash of incompatible additive packages can be bad for the engine (per a Mr Jake Raby, on another forum). These high levels of additives in racing oil can also contaminate your catalytic converter.

The break in oil I want to use on the new engine is rated only for 300-400 miles as the additives get attached to the internal parts and come out of suspension in the oil. I haven't cleared it with BGB, but I am providing 20 quarts of break in oil and 10 quarts of a compatible street oil. One set of break-in oil will be used for the first 30 minutes and thrown away to get rid of gross machining particles. The second fill will be the oil used for dyno testing and working out the bugs in the suspension setup. When the car is ready, I will require street oil put in as my trip home will be 1000 miles and I can't do that on the break-in oil.

The problem with the mid-engine design is that the exhaust headers, catalytic converter and piping run very close to the PDK oil coolers and I am not sure how protected the engine oil cooler is. Again, that is why wrapping the exhaust is a no-brainer. The other option is a ceramic coating on the exhaust, but the better coatings require the parts to be sent out; it doesn't come in a can that can be sprayed on by the car owner.
 

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Discussion Starter #8
I received news that my 3.8L X51 engine will be in by mid-next week, so I have to drive down to BGB Motorsports the first weekend of May. Car will be transformed in an incredible way. Many of the ideas listed here will be used to cool the exhaust and intakes.
 
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