So, basically, the 997tt.2 ICs are superior to just about any AM IC?
That's eye opening. I must admit, I initially misread this thread, now I'm subscribed!

 

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Short of Secan or CTR and based on *available data*, that is correct.

I've seen logs of popular 5" coolers and at 300k/hr and on a 12C day, the temp was 40 over ambient and still rising.

 

George,
Here's your data graphically, please let me know if you have an issue with me using it. This is great data -I'm a little surprised myself! Thanks for collecting and sharing it!

 

GT-TT , I have a few questions ,

What fuel are you using on those runs?

What horsepower is the engine producing?


Dosent it look a little bit lean for the amount of boost on 3rd gear on both runs? especially near midrange? or is it a race fuel map??

My Car is behaving almost the same as this car regarding lambadas in 3rd gear , i posted my datalogs on another thread here and most people thought it was running dangerously lean for the amount of boost ??

What i thought that it might be is an overboost that is activated in low in gear acceleration that outruns the lambadas for a while t hen it settles down?

 

When I first logged George's car i had the same questions...It seemed lean to me...However Sportec (the engine builder and tuner) said that AFRs are ok and we wont have to worry about it...Fuel was euro 100oct +octane booster...exactly same conditions on both runs,we even put fuel on the same gas station...We run approximately at 105 euro octanes...(ron)

 

Well had endless discussions on the AFR issue but they insist this is the way to do it. Car has a lot of torque and is running with the GT2 intake which apparently is a total b..ch to tune beyond 680hp. Car is rated at 730-740hp/ 950nm on a custom tune on a chassis dyno. I have no idea how accurate those numbers are, there are tuners that claim they can get 850hp on stock engines and others that say that it is impossible to get more than 680hp on vtgs..
Regarding the octane levels I guess dimitri has more info on the effect of that booster, i am more cynical with these things and my guess is more around 102 octane at best.. Also having the experience of driving this car around europe it is obvious to me that currently the quality of fuel around here is worse by quite a margin to begin with vs say 98 pump gas in germany. So lets say that fuel used for the test was probably equivalent to 100-102 real octane.
We tried to control as many variables as possible to produce accurate results. I think the main piece of data here should be the 200-300kms time which is more consistent than the 100-200kms (I hear this is the case with most 997tt cars). Notice also that the boost is a little bit lower at certain rpms with these coolers. I am not sure if this is just a flow difference or just the ecu changes the parametres for some reason. ECU is running with all safety parametres on so many variables can affect boost. (including those stock BRVs that keep breaking in my car )
I think with these ICs it is probably feasible to get some more power at high rpm with some more aggressive ignition timing maybe.

 

How can you tell if an i/c is limiting flow for the engine? I understand that if the temps rise the timing will get pulled but how about if flow was the issue? I think there was some discussion about these i/cs being slightly more restrictive than other i/cs. I did notice that on the stock programming with these 997.2tt i/cs that I didn't hit 15psi/17psi (overboost) but must say that the car feels fine. I'll pbox my times on standard programming and then on Proto tune.

 

Yeah i guess logic says that the most sensitive point would be at spooling and overboost. With the 2RS ICs i did not feel much difference but for example with some other ICs i tried a few months ago the difference was so noticeable that i did not even try to log any numbers, i took them off immediately.
Having said that everything is depending on the tune one has. Those other coolers have been reported to work very well with a large turbo (GT30 etc) as all you would need to do is just compensate with the boost. With vtgs there is a only narrow band of boost efficiency before temperatures start rising stratospherically so you cant really sacrifice too much back pressure. I guess P did their homework with those coolers to optimise those parameters for high boost vtg application, aka GT2RS..

here is the video http://www.youtube.com/watch?v=msLPtGaKoHA
and the vbox file as promised

 

It's interesting to see these logs. The most recent two logs and RUF QTRs seem to run on the lean side. For instance, the AM IC log shows lean conditions >.9 lambda, even 0.99 lambda and then timing drops to 6.75 with a fuel dump to 0.87 lambda. Probably some knock issues going on. I would say this tune is also on the edge. I don't know if this is common for Euro tunes or what. It's a little unnerving to me.

 

Yes I have an engine guarantee, car has done 10k+ with no mechanical issues (except sensors etc). Actually it is still getting faster the more i drive it.
The reduction in timing in the mid range is a feature of the GT2 expansion system i believe. It is tuned to go to 9 degrees and we have tried to get rid of it but it has been pretty difficult, its 90% perfect now. The perception is a small flattening of the torque curve after a surge at low rpm and then power comes again hard at 6.5k until 7.8k limiter. This is the compromise of the expansion intake i guess; good low end and very good high end - like NA engine really.
The power curve of this tune is crazy; 3k to almost 8k and this is what I aimed for. With GT30s i would have another 100hp for sure but did not want to go down that route (maybe i was wrong!).
On the AFRs the tuner says that those in the "know" i.e race engine tuners are always programming at 0.87 lambda. Don't know what to say as opinions differ on the subject but this tune looks very reliable mechanically so far. Dimitris can also comment on engine response as he has also driven the car.
Actually i will look to increase ignition timing now in the mid range and in the high rpm with these new coolers.

 

Thanks for the feedback. That's interesting. I just noticed from your 2IC and the AM IC logs that only a 7 deg change (11 to 18 deg), your timing is being pulled and fuel is dumped which is why I said it was on the edge.

 

yes but this is not timing pull, it was programmed that way (9degrees at that rpm range).
I also thought that it was because of the lean AFR just beforehand and i asked and they told me that this is how you get the torque (which i like ). If you make it richer there then you lose some of the torque.
The GT1 engine is prone to torque at around 4.5 to 5k rpm beyond a certain torque level (I have over 900nm) so its at the limit there. The cams, ported heads etc improved that point a lot but then we raised the torque everywhere..
Now with these ICs we can probably try to get it a bit higher - around 11-12 degrees at that point and hopefully 27 at top end.

 

Yes, I agree that leaner generally means more torque but in your .2IC log your tune seems to hold around 9 deg around 4347 but in the AM log it drops to 6.75 around there. So it seemed to me that the AM IC causes you to pull timing a little even with just a 7 deg IAT difference.

PS I should add were these runs where done on the same fuel? That is did you refuel in between?

 

won't most people ECU tunes just use an IAT table to account for the change when using these I/Cs?