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I dint find now official info regarding gt2rs turbos, but I am quoting Sam from another post:
"The RS is a a completely different animal. Compression is 9.0 vs 9.8 and it runs up to 1.7 bar! Injectors and charge intake revised. Water is sprayed on the Intercoolers for cooling and they make about 680hp to the wheels stock. It may be very challenging to get the parts from it but we are working on it for observation. Part numbers available but parts not so much haha. The compressors are 67mm with a larger turbine and exhaust. The .2 cars all do have better heads, more fueling capacity and even updated turbine aero and metal composite. We have a few 991.2 TTS cars running full E85 finally!"
I dint find now official info regarding gt2rs turbos, but I am quoting Sam from another post:
"The RS is a a completely different animal. Compression is 9.0 vs 9.8 and it runs up to 1.7 bar! Injectors and charge intake revised. Water is sprayed on the Intercoolers for cooling and they make about 680hp to the wheels stock. It may be very challenging to get the parts from it but we are working on it for observation. Part numbers available but parts not so much haha. The compressors are 67mm with a larger turbine and exhaust. The .2 cars all do have better heads, more fueling capacity and even updated turbine aero and metal composite. We have a few 991.2 TTS cars running full E85 finally!"
Thanks for sharing.. Must be true then they seem quite longer, this IC is not what most aftermarket ICs are in terms of density and material, which goes back to my initial point, a bigger is better only as long as fin density and quality are there or it becomes a heat sink in racing. We will soon find out if the core is from the same supplier as the stock TT/GT2RS or they went back to the old 993GT2 times with Marston or Secan cores.
I mentioned the larger compressor size and improved plastic intake and ports earlier, I doubt the turbines are larger than the 991.1 or 991.2, more efficient yes. Maybe Kevin can shed some light here.
I reached out to Randy Pobst through a track buddy that races with him and got the reply that around Laguna Seca that he noticed no obvious reduction in power doing a few laps at a time...and added that he loved the car!
He also discussed it with a GT3 Cup champ who said based on experience at the Nurburgring that the Turbo should be able to handle anything I throw at it, and may not notice any small power loss.
Starting to think it might not need to be relegated to winter beater status after-all!
Happy New Years!!! May all your 2019 track events be bright and your IATs low
I reached out to Randy Pobst through a track buddy that races with him and got the reply that around Laguna Seca that he noticed no obvious reduction in power doing a few laps at a time...and added that he loved the car!
He also discussed it with a GT3 Cup champ who said based on experience at the Nurburgring that the Turbo should be able to handle anything I throw at it, and may not notice any small power loss.
Starting to think it might not need to be relegated to winter beater status after-all!
Happy New Years!!! May all your 2019 track events be bright and your IATs low
To follow up on the Water sprayed intercooler, confirmed some data regarding this setup, its benefits and trigger points..
- Temperature reduced by up to 20 C Degrees more than conventional airflow cooling
- Spray system is triggered when intake temps reach 50 C, throttle is pressed more than 90%, and engine speed is >3000 RPM
Exhaust is Titanium, 7Kgs lighter than the turbo, short cats dumping the exhaust gases faster, and has an electronically controlled valve to reduce back pressure under load..I already discussed the Intake earlier, shorter runners, smaller diameter, larger ports, and unlike a traditional system, it has an air expansion rather than air compression suction system that accelerates flow, the air expansion cool the air further and the cooler air in the combustion chamber improves ignition for better performance.This keeps torque in check yet delivers all the high RPM HP required to protect the PDK. Definitely sounds like na interest upgrade to do to a 991TT.
Lager turbos and reduced engine compression by 0.5 CR.
All of this to improve efficiency and reduce operating temperatures. I will give this a try, provided I can find someone who can build a similar system for me, and then will compare datalogs.
Jean thanks for reminding me/us the trigger points for injection. I am more and more into keeping things simple, as simple as possible and maybe use the windshield tank for my aquamist system, seems big enough and we have also for free a low level system in the dashboard. The OEM gt2rs tank is crazy expensive imo and doesnt make sense anymore for me.
Running some shielded lines from there and till the intake shouldnt be a big problem. Also will have to hide the Aquamist controller somewhere in the cabin.
I am coming to the final requirements, how much should I inject and where/how should I inject?
The first question that comes into my mind is if we can use sagely the plastic? oem intake to drill some holes to install the injectors, or do we need metal type aftermarket Ypipe like IPD or some others? And if we need IPD, can we still use the OEM TB or do we need to upgrade Ypipe+TB?
Secondly, I am debating if having 2+2 very small injectors (2 before ICs and 2 after ICs) instead of 2 bigger injectors after ICs, would protect the engine better from rising IATs on the ling run.
Guess 2 bigger injectors are still the better way, but maybe you have some other experiences.
And finally, do you guys use only pure water sometimes instead of mix of water-meth? I am not going to squeeze everything from my engine, so no need to push things, I want a reliable track oriented tune, with lower middle torque to keep things happy, dont mess the grip, cluthes, IAT etc from overspinning the turbos at mid rpms
My guess is that even by using pure water only and stil no meth, the car will do consistent and reliable 700hp crank like a gt2rs. Of course we can push even more, but that might mean a price to pay after first fast lap or in other departments.
My car was able to do 5.1-5.2s 100-200kmh (5.97s 60-130mph) in COLD weather and with "COOL" engine on the highway, after few pulls I can see 5.3-5.5s
Now, at the track the car is doing only 5.5-5.8s when engine is cool (a bit warmer weather), but only 5.8-6.2s after few laps... the performance decrease is HUGE, guess these cars need the lower IAT like air and fuel
Hope by implementing water injection to be able to hit high 4.x 100-200 in optimal conditions and the decrese in performance after few laps (read HP) will be just minimal (5s flat 100-200)
Jean thanks for reminding me/us the trigger points for injection. I am more and more into keeping things simple, as simple as possible and maybe use the windshield tank for my aquamist system, seems big enough and we have also for free a low level system in the dashboard. The OEM gt2rs tank is crazy expensive imo and doesnt make sense anymore for me.
Running some shielded lines from there and till the intake shouldnt be a big problem. Also will have to hide the Aquamist controller somewhere in the cabin.
I am coming to the final requirements, how much should I inject and where/how should I inject?
The first question that comes into my mind is if we can use sagely the plastic? oem intake to drill some holes to install the injectors, or do we need metal type aftermarket Ypipe like IPD or some others? And if we need IPD, can we still use the OEM TB or do we need to upgrade Ypipe+TB?
Secondly, I am debating if having 2+2 very small injectors (2 before ICs and 2 after ICs) instead of 2 bigger injectors after ICs, would protect the engine better from rising IATs on the ling run.
Guess 2 bigger injectors are still the better way, but maybe you have some other experiences.
And finally, do you guys use only pure water sometimes instead of mix of water-meth? I am not going to squeeze everything from my engine, so no need to push things, I want a reliable track oriented tune, with lower middle torque to keep things happy, dont mess the grip, cluthes, IAT etc from overspinning the turbos at mid rpms
My guess is that even by using pure water only and stil no meth, the car will do consistent and reliable 700hp crank like a gt2rs. Of course we can push even more, but that might mean a price to pay after first fast lap or in other departments.
My car was able to do 5.1-5.2s 100-200kmh (5.97s 60-130mph) in COLD weather and with "COOL" engine on the highway, after few pulls I can see 5.3-5.5s
Now, at the track the car is doing only 5.5-5.8s when engine is cool (a bit warmer weather), but only 5.8-6.2s after few laps... the performance decrease is HUGE, guess these cars need the lower IAT like air and fuel
Hope by implementing water injection to be able to hit high 4.x 100-200 in optimal conditions and the decrese in performance after few laps (read HP) will be just minimal (5s flat 100-200)
Hi,
Not sure if you bought the Aquamist kit or not, but if you want to keep it simple go with the Snow Performance kit with all the SS braided lines...I mix 10% of distilled water per 1 gallon of VP M1...
Years ago I previously used the windshield washer tank with an Aquamist system, and bought a supply of winter grade washer fluid that contains methanol. Windshield and engine both loved it!
An intercooler is most efficient with a large delta between ambient air temp and charge air temp So the hotter the charge air and cooler the air passing over the intercooler fins the better. So extra jets would be better to cool the fins of the intercooler as done on the GT2RS instead of the charge air running through it. But once the charge air has been cooled by the IC, and just before the air enters the throttle body, the injection will further reduce charge temps and also EGTs.
I had a rough way to determine the nozzle size but have long forgotten, but monitoring IATs using different size nozzles would seem like a good method. When IATs stop reducing as nozzle flow rates are increased then you know when to stop enlarging. Smallest spray would be best so as not to lean out the air-fuel ratio, and to help your mix last longer.
So moving forward from Kevin's idea (thank you Kevin!) we used an Aquamist pump (just like the OEM sytem from 991GT2RS Clubsport) installed near the LiteBlox battery as both are fitting in the place of the old oem battery.
Cost of 8 "injectors" and hoses was less than 50$ But seems 4injector/IC are too much, so we are going to use only 2 and see from there.
We added also a Honeywell Hobbs (20$?) and considering to use a remote control relay - Radio or maybe even BT and use it with my Iphone, so can turn on/off without using an in-cabin swithc or opening the frunk. (20$)
Aquamist pump is pretty expensive but had one here from an old kit... Intalling the hoses still work in progress, but just to have an idea of what we did..
Testing will start soon, cant wait... Also check this
you should really check in with Mike at TPC. He developed a system very similar to the GT2 but controls it through the DSC box. All dependent on loads, heat, acceleration etc. His done a lot of work on it and done a lot of work on the track as well. Worth discussing your setup.
Thanks for that link ! I’m researching a system like the GT2RS but with a plastic tank instead of a $2,500 carbon fiber tank. I researched the factory part number of the pump in the link, it is a standard Porsche windshield washer pump. Is that a mistake or do they really use that pump ?
Their Motorsports car uses an Aquamist pump from the pics I’ve seen.
12-31-2018, 02:02 PM
they seem quite longer, this IC is not what most aftermarket ICs are in terms of density and material, which goes back to my initial point, a bigger is better only as long as fin density and quality are there or it becomes a heat sink in racing. We will soon find out if the core is from the same supplier as the stock TT/GT2RS or they went back to the old 993GT2 times with Marston or Secan cores.
