Yes, what AFR makes the most horsepower in my opinion is based on what makes the most horsepower in reality. Running 12.2 AFR may be theoretically the right number, however put most Supercharged 3800s on a dyno, run then at different AFRs, and you'll find very few that make the most power at 12.2 due to spark knock.#1 - Referencing a 2003 Regal GS stock file as an example, at heavy throttle, the stock PCM will target an AFR of 12.13 at 3200rpm. By 5600rpm, the AFR command richens up to a more appropriate 11.4. Once the shift into 2nd gear completes, it goes back to between 12.13 and 11.9. In my experience, these AFRs are improper targets even on a stock 3800SC. By aiming for a richer flat AFR at WOT that doesn't change with rpm, torque is improved in the midrange around the peak torque rpm, KR is reduced which means the engine is safer and reduced KR improves horsepower and performance
-- This is all completely opinion. Also ive never found a stock GTP running this lean via a wideband ever. Also time plays a large factor in factory PE so your PE targets are completely dumb. Also 12.2 is IDEAL for maximum power on a stock car. You cant use "overall horsepower and performance" as a number to say its better by xxx%... it makes xx more power or xx more "performance". This all assumes your stock car is knocking, which would be a mechanical issue.
Not opinion, reality. I'm able to tune out a lot of real KR during throttle transitions, and that improve acceleration. "Very robust" is your opinion#2 - Even stock 3800s have chronic burst knock issues. Burst knock is when engine knock and subsequent KR spikes with sudden large throttle input. There are fuel commands set up like pump shots in a carb setup. Even with a stock pulley, these can be adjusted to reduce burst knock. This improves performance and improves engine safety
-- Opinion. I've never found it unless the car was broken. AE settings are very robust stock.
Again, not opinion, reality. Whatever records you have have nothing to do with this point.#3 - This is a "secret" of mine, I won't elaborate the fix, I'll simply describe the symptom. When you accelerate at around 1/3 throttle, timing advance will drop as engine load increases, which is normal, but as you increase throttle further something will happen and you'll see the timing advance come back up again, without any change in engine rpm and a minor increase in load. This sudden timing change causes burst KR, it also creates a soft spot in acceleration before you trigger this increase.
-- Opinion. If this exists it never bothered me, none of your cars you've tuned have even scratched any of my records.
Knock recovery rates has nothing to do with telling the PCM to ignore engine knock. KR is reduced when an engine knock event is no longer there or less severe. If the knock event is still occuring, the KR amount will hold.#4 - When you have a knock event and subsequent KR, then leave the knock event, the KR is reduced to bring timing back to full at the recovery rate. Stock programming allows for roughly 1/2 degree of timing advance to be added every second while the engine is under load. By allowing a faster recovery rate, performance is restored more quickly. Given the slow recovery rates and the stock PCMs tendancy to have burst KR, this is a problem area for performance. This doesn't impact engine safety as long as an appropriate recovery rate is chosen.
--Disabling safety. Ok you got me, you are making the car ignore knock faster.... Smart? no. More power? Yes. (reference tuning guide I WROTE)
The VE table is used and is mapped out based on engine vacuum which requires MAP sensor readings. Airmass calculations are blended from both the VE table and the MAF table at part throttle. Beyond I believe it's 3500rpm, it references MAF only readings.#5 - Anyone who's tuned multiple years and platforms with similar mods will have noticed the consistent changes that need to be made to the fuel trims. This is partly VE and partly MAF calibration. These changes are made proactively in my tuning, because chances are they'll be needed
-- LOL VE tables are not used, at all, ever, go directly to jail. Maf sensor calibrations can be up to 32% completely wrong and the car will run IDENTICAL to one that is 32% the other direction... because there is a cool thing called closed loop managing your fueling many times a second via the o2 sensor anyway. Might want to read my guide for some information on that. (reference tuning guide I WROTE)
Also, if you skew the MAF table 32%, it will only run the same as the non-skewed MAF in closed loop if the fuel trims have room to make adjustment. The LT fuel trims and ST fuel trims only have a certain % to adjust the fuel calculations if the O2 sensor shows improper stoich. Beyond that range of adjustment, the vehicle will indeed run rich or lean.
If you see a LT fuel trim at idle of 12% for example, you're saying it's "in spec" and technically you're correct that that % falls within the maximum adjustment range of the trims, but a good tuner will not accept that as ideal, it's far too easy and proper to make it closer to 0%. Closer to 0% means the computer doesn't need to make continual adjustments to create a proper stoich part throttle.
Correct, because if you require traction control to intervene to that extent in order to maintain control of your vehicle, then perhaps you shouldn't drive a vehicle with so much horsepower. I never said that I disable traction control, I simply change its implimentation behaviour. Abuse modes typically engage during big burnouts, this would be a very deliberate act by the driver, they should know the risks. Other abuse modes activate once you make too much horsepower, they're power limiters, they need to be recalibrated.$6 - I've seen people blow their engines when hitting abuse or traction control modes under hard acceleration which cut fuel injectors and aim for very lean AFRs. We can debate about how no fuel should equal no combustion and no heat but even still, this is what is. The jolting of the injector cut is also hard on the bearings in the motor. It simply makes sense to reprogram these controls to avoid such hard extreme actions taken by the PCM just to control wheel spin or max power outputs.
-- Yep, lets take off the factory failsafes. Who needs those? (reference tuning guide I WROTE)
Now you're just being silly. These vehicles can't even complete a 1/4 mile run without their boost dropping to 3psi due to the boost bypass valve opening. Whatever the reasoning for this, it makes absolute 100% sense to correct this when you want to improve performance.#7 - This is more of a Bonneville/Regal item but everyone who's hit 3rd gear knows what happens to the boost.
-- Yep, lets take off the factory failsafes. Who needs those?(reference tuning guide I WROTE)
Yes, I know how to use my equipment to achieve correct results, good for me!As for the wideband, again I've done testing, I know what the difference in the readings are and I know what to aim for when using a wideband in the tailpipe.
--LOL good for you "you know what to look for"
You chose to attack my credibility in this thread, that's why I replied.--I honestly never thought you would be stupid enough to call out a guy that has more experience, more credentials and fast cars to show for it all to just inflate your ego at the cost of scamming more people out of their money. The fact that you said you are tuning VE tables is really a stark testament to how clueless you really are on this. I really used to have no issue with you before but you went well out of your way to embarrass yourself with this one.
It was also a great platform to explain why indeed I can offer a tune that improves performance on even a stock GTP.
Originally Posted by GTPJIM
