Re: High performance intercooler for tt/GT2
What I was worried about with getting a typical RS Tuning tune on the GT2 was basically having too much torque. The way RS likes to tune he gives as much area under the power curve as possible by bringing on the boost early, this will also limit the unltimate maximum peak power as the early boost onset heats up the IAT to the detriment of maximum peak power however it does make for a very fast car IF the car can deploy the torque to the road.
This IF is the important bit. For a 4WD turbo no problem. I have scanned in my power curve for my 993tt 3.8litre 8.4:1 CR
You can see it has over 550hp from 5000rpm until 7000rpm. This was difficult to achieve and involved specific cams and timings. The result is a very fast car but the power (torque) from 5000 to 7000 is very savage and puts the 4WD system right at the limit of grip even in the dry. I did try and run the 993tt in 2WD mode for a while and it proved just too dangerous with this power curve.
I felt that for the 997GT2 I didn’t want to upset the car’s power delivery as it felt really “right” with the factory settings.
I knew roughly how much torque and power one could expect from various components and especially since I now had the special intercoolers. I actually got hold of an RS engine dyno torque diagram and plotted my own torque curve to what I felt would be right for the car. It basically had lower peak torque ~820NM but then keeping that level as far up the rev range as possible which basically results in a 45 degree straight line power curve with power rising in a linear manner and peaking right at maximum revs.
I left my hypothetical dyno diagram with explanatory notes to why I wanted said curve and truly expected to be ignored since RS usually DO know best.
As mentioned in posts above my intercoolers were tested and were deemed to be virtually as good as Secan, controlling the very high GT2 intake temperatures effectively.
Once I had indicated that I would go with the bigger turbos (the lure of 650hp was simply too great) RS tried their two offerings on the dyno. They have a unique design of compressor wheel which apparently was designed by a student who works for KKK Race dept, they had the wheels made in three sizes and the biggest size did not work causing a stalling at specific revs. My engine ended up with the bigger of the two effective wheels which fits inside a new bigger compressor housing.
The engine was on the engine dyno for two days for programming. This programming should not be read in the same way as the chassis dyno tuners, this is done as the manufacturers do it with ALL the maps being altered and is very meticulous and can only be done with the correct tools and the experience of turbo race engines and focuses on making the engine completely like standard to drive with no hiccups or holes or surges or silly noises (I was intrigued that Cannaga likes to switch programs – why on earth would one need to on a properly programmed engine ?).
RS use a water cooled intercooler for the tuning and he uses this device to replicate on road intake temperatures so he knew that my intercoolers had Secan like effectiveness so could use lower IATs for the tuning (for standard intercoolers it would be pointless using lower IATs as the timing would be pulled immediately once on the road).
Bottom line is that RS did as I asked !!! 827NM max at 3000rpm then a straight 45 degree line as a power curve peaking at 6880rpm and 660hp.
The car is perfect on the road driving just like standard, no noisier than the 200cell cats (wears 100 cell now) and response in lower revs feels very similar to stock. The torque (apart from not breaking the rods) is perfect in the dry with the smooth delivery allowing the rear tyres to maintain traction, the engine revs up the range like factory curve but just a lot faster with the power just “pouring” on as the revs rise.
Driving back through Germany I did lots of logging of IATs and in the 30degC ambient the maximum intake with prolonged blasts up to 300kph never rose above 54degC. I couldn’t find the conditions to do a proper 100-300 run although from the stuff I did I am confident that this is a 25 second 0-300kph car.
Back to the topic of the thread. It looks very likely that RS will be using these intercoolers and discussed the possibility of getting one made for a Ford GT which they have their, apparently they are attempting to tune to 700hp and the IATs are the problem, it needs proper (Secan style) intercooling.
I will share some more acceleration numbers etc as/when I do them but for now am enjoying the engine in all driving.
BTW the uprated clutch is a joy to use as a DD, it doesn’t feel heavier than before yet somehow seems smoother to use than the stock one !
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2009 997 GT2 659PS/827NM DIN
