NSXavier

Just seeing who has had first world experience with utilizing both factory RS and any aftermarket intercoolers. As the summer approaches and ambient temps rise, I find my car succumbing to some heat soak and power loss. I am in the market for some upgraded intercoolers, and am interested in factory GT2RS / TurboS intercoolers, but also don’t want to limit myself and end up having to upgrade later.

goals:
-reliability over anything
-power increase with supporting mods (Cobb AP, free flowing exhaust, GT3 TB, IPD plenum and Y-pipe and a custom tune)
-highway pulls street car and don’t plan on going to the track

pros/cons

*RS intercoolers are the most cost effective option.

*I’ve read that the RS intercoolers are prone to cracking and leaking but have not read about exactly what causes them to crack.

*I would imagine aftermarket intercoolers to provide the most consistent performance.

*All aftermarket intercoolers are expensive.

Thoughts?

strato58

I believe I read the GT2 coolers are an awesome low cost alternative and perform on par or better than the high cost customs

djillusion

I don’t have direct experience with the RS IC’s but I have AMS IC’s in my 997.2T. They reduce heat soak a ton, but I don’t have track experience to confirm.

I will try to log IAT’s but as we all know Turbos get hot really quick after a few aggressive WOT runs/pulls. I have yet to feel any heat soak (ie loss of power) even with my Cobb tune and Europipe. I would strongly getting upgraded IC’s if you plan on adding more power to the car via tune & exhaust.

wcarson

I had 3.5" core GMG World Challenge intercoolers when I was running 68mm VTG's on my 3.8L built motor. These are likely pretty similar to the GT2 coolers performance-wise, and are a big upgrade compared to the stock 997.1TT coolers. I extensively data logged the IAT's with these at the time- IAT's were good for 2-3 consecutive third or 4th gear pulls, but IAT's would start to rise after a couple pulls pretty quickly. Of course, even during the first of several pulls, IAT's would rise to maybe 15F above ambient. But after a couple pulls, IAT's really shot up. But overall, these were very good IC's. Undoubtedly way better than stock.

I then upgraded to the big AMS coolers- they are definitely better performing. IAT's never got up more than around 10F above ambient no matter what I did, even after 5, 6, or 7+ pulls. Certainly the data logging showed a definite improvement in IAT's with the big AMS coolers.

I am now running Xona XR1000 turbos on the 3.8L build and also methanol injection..... so my AMS coolers are probably a bit overkill but it's nice to know I have ample intercooling. The AMS units were straightforward to install and I highly recommend them. You can throw any mods on your motor in the future and you will be happy to have great intake temperature control.

A418t81

I had both. The GT2 units are great and OEM. They work fine on the street for 10 second runs of wide open throttle. After about 8-10 seconds intake air temps start to destabilize and increase quickly. Hugely better than the factory .1 turbo intercoolers in flow and function.

Had the DO88 bigpack which is an AMS equivalent. On the street, fairly similar until you do a run that’s more than 2nd and 3rd gear WOT. The intake air temps basically peg 10 deg F over ambient and stay there for anything short of a half mile run in an E85 VTG setup. The DO88 and AMS setups also increase the piping size to 3 inch and get rid of the restrictive quick disconnect couplers the factory uses.

On my 656 whp stock turbo E85 setup, the logs were cleaner on the Do88 kit. Perfect logs actually. Intake air temp supression was excellent.

Hard to go wrong with any of the 3 depending on your usage of the car.

NSXavier

Thanks for the input guys. I'm still debating on what route to take, but as of right now I'm leaning towards aftermarket units. Though the car is strictly a street driven machine and will never see track, I'd rather overkill it than be limited. Is there any reason as to why the RS cores leak? I've read posts about them having to be re-sealed with JB WELD...

bondjockey

The 997.2 I/C’s have plastic end caps and there have been a few reports of leaks in high HP cars. There are a number of forum members running them (including me) and I never hear of complaints. The do88 and AMS use aluminum end caps so presumably less risk of cracks / leaks. On the flip side they are heavier. If you are planning to do modest mods and don’t plan to constantly track it or drag race it the 997.2 I/C’s are a much better value. It’s only worth paying the extra $$$ if you are going to run E85, do a 3.8 build, track it etc. My opinion fwiw.

nzskater

I'm running the cheaper DO88 ICs. These logs are from a midday track session in New Zealand in March. Ambient temps were mid to low 20's (celcius). Under full load it shoots up pretty quickly to about 20 degrees above ambient: https://datazap.me/u/nz911tt/turbo-levels?log=0&data=3

NSXavier

Nice, thanks for sharing that log! As far as I know, Do88 only has one intercooler kit available, correct?

nzskater

They have three options available: https://www.do88.se/en/artiklar/hose...971/index.html

TheDeckMan

One of my .2's stated leaking after 3k miles on my 996. Have AWE's in the car now and very happy.

bondjockey

What hp were you running at the time?

Torque-less

I agree 100% with your pros/cons. It seems that in order to go bigger power, you must get one of the big money brands.

Although I do not have any data yet, once my engine is reassembled and put back in the car my good friend and fabricator will be making my intercooler's for the car. He has made numerous parts for me for other cars I have owned and he even made the exhaust that's currently on my 997. One of the benefits for you as well is hes located in Cecil County, MD close to the Harford County line. His instagram name is jchutch and you can see some of the work he has done which includes other p-cars.

JoeFromPA

So forgive me for recommending something a bit....low end.... from my past. When I was into Subaru their stock intercoolers would sometimes split at their plastic end-tanks as power/pressure was ramped up. The "fix" was to JB weld the plastic to the metal and using a pair of metal strap tie-downs - none of those who had had that done split, even just with JB weld. And they were running much higher PSIs than most of these tuned 997's.

From the data above it sounds like the stock intercoolers can handle 1 decent pull for street driving before performance starts to deteriorate IF AIR FLOW DROPS. I.e. It'll heat soak if you are pulling hard then coming to a stop OR if you are doing multiple pulls in a row and you want rock solid IATs. But if you fall into that camp of "I want to tune the bejeesus out of my Mezger but don't want to drop $1500-$3000 on new ICs and I'm afraid of my stock ICs leaking..." perhaps some JB weld is on the table?

ECB

One problem is you probably don't want to tune the bejeesus out of your Mezger with the stock intercoolers. I'd imagine the temps are a bigger problem than the potential for leaks. But I do like some JB weld.