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The benefit of official lap attempts is that you're the only car on track and you know for a fact there's no fluid spill around a blind corner. Worth a couple of seconds on its own but that kind of luxury is unavailable to amateurs.
Maybe you can check with Porsche Club Nürburgring, they organize track days with only members of the club so probably less traffic and you might even be able to be the first car to start a session so no one in front of you at least for the first lap.
I had a tuned and built turbo motor in my last track car (3.0L 951) and did some tuning. I ended up with reliability issues mostly due to sloppy execution from the engine builder and install. The lesson for me is to not lose track time chasing small improvements in power by messing with the engine.
this is obviously a different situation as you havent messed with the internals (or externals -yet) on the car and are seeing gains from tuning in a way that you understand. Since the stock tune is trying to stay lean for fuel efficiency it seems that the risk to reliability and longevity of the motor should be minimal - ie this tune will not shorten engine life. Is that your expectation? Since it maybe runs a little richer and therefore cooler could it be neutral or even beneficial (less knock?) for engine life?
Im not skeptical of the power gain as you have explained well the rationale but if you add power could you over-stress an already high-strung engine and shorten engine-life?
of course Im trying to consider how this sort of tuning might translate to my 991.1 G6 engine where I think my ideal tune after the warranty is out will add power but provide a new 8800 redline but that can wait for another thread.
I have some aero ideas for you when you go for your next record.
if you add power could you over-stress an already high-strung engine and shorten engine-life?
Thanks for the valuable contribution!
While the added stress is not going to be zero mathematically speaking, it should be neglibible for all intents and purposes... the same engine makes 20 HP more in the RS which has the same rev limit and is not known to be any less reliable than the GT3. People have strapped superchargers to these engines and increased output by 150-200 HP and I would definitely say doing THAT would significantly impact the lifespan, but 5% on an NA engine is nothing. Especially one that is built to rev to 9K because the hard part there is making it reliable at 9K RPM as the forces on the rotating parts are pretty wild regardless of power output.
The exhaust side modifications will increase power output without adding any stress at all as the gains are basically achieved by reducing the losses caused by the stock exhaust system.
I haven't owned a car yet that I didn't end up modifying and I've made topics in the past about my 981 and 982s with emperical data gathered first hand (in contrast with various manufacturer's claims) so now it's time for my 991.2.
Somehow I get easily bored without goals and my biggest goal of '23 was go sub-7 mins BTG on the Nurburgring, but that came a little too easy so I stepped it up trying to beat the 2017 OEM lap time and managed that as well on the final track day of the year. The car had minor track mods but it was on stock suspension and stock exhaust headers/center muffler since I didn't want to cheat too much. But to continue in 2024 without any changes would be, again, boring, and mods are fun to test and document so here we are.
I imagine that there is no mechanical way to deceive the original ECU to change its limits and values while being undetectable? (you never know, it is not forbidden to believe in Santa Claus, even aif almost 50 years old )
I imagine that there is no mechanical way to deceive the original ECU to change its limits and values while being undetectable? (you never know, it is not forbidden to believe in Santa Claus, even aif almost 50 years old )
Unfortunately not, there's a MAP sensor in the intake manifold... theoretically a piggyback device for the ECU might be possible but those are never as good as a tune and there's no incentive for anyone to spend a ton of money developing one as there's not much of a market. I think I've only ever seen them made for turbocharged cars.
Yes, I saw ton of them on modified Subarus and Evos when I was a turbo guy.
I never really liked them, I never had one by myself (I prefered first OEM ÉCU, then MoTec (Map instead of Maf)
Last edited by Lolo La Torche; 01-30-2024 at 03:04 AM.
Did a new stock run, 30 minutes apart from the tuned run on a level road.
Stock ECU
Tuned ECU:
If there was any doubt that a decent ECU tune is tremendous value on the non-RS GT3's I think we can put it to bed. Going by some other data posted elsewhere, this is a bigger drop in time than going to a full 10K+ Dundon package.
It could've been faster had I been able to run a day earlier, I didn't have the dragy with me but the car felt quicker with DA below zero where it was about +800ft today.
Did a new stock run, 30 minutes apart from the tuned run on a level road.
Stock ECU
Tuned ECU:
If there was any doubt that a decent ECU tune is tremendous value on the non-RS GT3's I think we can put it to bed. Going by some other data posted elsewhere, this is a bigger drop in time than going to a full 10K+ Dundon package.
It could've been faster had I been able to run a day earlier, I didn't have the dragy with me but the car felt quicker with DA below zero where it was about +800ft today.
Who tuned it? 93 octane I assume? Be interesting to see how much faster long tube headers add...
98 RON / 93 US fuel yeah. Tuned by Ehresmann in Germany. If things go well the headers might go on tomorrow but the weather isn't playing nice. I'm back on the stock ECU after that testing so with headers I'll test it on both maps.
98 RON / 93 US fuel yeah. Tuned by Ehresmann in Germany. If things go well the headers might go on tomorrow but the weather isn't playing nice. I'm back on the stock ECU after that testing so with headers I'll test it on both maps.
Thinking about using Jens again for stage 1 on the 718. Was very happy with the job he did on my 981.
Headers are on... about 3 hours of leasurely wrenching since we didn't even had to take the bumper off as there was plenty of space after the side muffler delete last year.
Performance TBD but the sound was captured pretty well on this smartphone recording.
The improvement from the tune is pretty staggering. That's a big increase in performance. It's hard to know how much better your custom tune would be than an off-the-shelf tune. I'm also going to assume that, at best, the gain would be reduced by 5% for the 991.1 with the 3.8L. Maybe I should be excited for the end of my engine warranty, I'll get a tune to celebrate.
It will be great to see you repeat it with the headers just to get a second set of data. I am not familiar with the device - does it also give you some computed HP number? Can you overlay two data sets - the G delta vs. time would be interesting.
Last edited by 74goldtarga; 02-11-2024 at 01:32 AM.
I'm also going to assume that, at best, the gain would be reduced by 5% for the 991.1 with the 3.8L. Maybe I should be excited for the end of my engine warranty, I'll get a tune to celebrate.
That's what I'd do lol... I voided my warranty by ways of over rev so there's that. The 3.8 responds very well to ECU tuning as well. Going by acceleration numbers collected by German tuners every GT3 and RS from the 991.1 onwards until now basically does the same times once tuned + exhaust.
It will be great to see you repeat it with the headers just to get a second set of data. I am not familiar with the device - does it also give you some computed HP number? Can you overlay two data sets - the G delta vs. time would be interesting.
I think the dragy computes the G load from GPS which is a little unstable unfortunately, but its times are known to be 99.9% accurate at drag strips (usually 1 or 2 hundredths slower than the track shows)
01-27-2024, 06:00 AM
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