After the Powerchip GB in the DC area

[BPMSport]

Originally Posted by ThorPR

Dyno's are so unpredictable. There are so many variables that determine the amount of HP and TQ you will see. Temperature, elevation, and humidity will play a role. The one thing I agree on is that you have to be able to see the AFR associated with those numbers. This is crucial in order to protect your engine.

I used to run a very aggressive tune for my GT500. The tune would give me the highest numbers but would require me to run 100 octane. It was imperative to know the AFR. When you are running at the limit you only need one bad batch of gas and your engine is gone.

Is this with forced induction?

You are running quite rich at the beginning which leads me to believe that fuel is being added to cool the cylinder charge due to either a very aggressive tune in terms of timing, or due to boost.

But then on top it leans out, which leads me to believe that this car is not FI? Nice numbers any way you cut it!


Unrelated to your post:
I also want to mention that dyno runs are very subjective, unless the car is dynoed before and after at the same session (meaning never unstrapped or removed from the dyno). The dyno charts I posted earlier are of cars that were never unstrapped from the dyno.

Meaning: If you dyno one day on dyno X, and then dyno another day on dyno X, it's possible that the comparison between the two is not accurate. This has been discussed quite a bit in Pencilgeeks dyno cheating thread: strap down, correction factor, input variables (wheel size, etc), temperature, humidity, not to mention a whole slew of other factors directly influence these results. Octane is also a huge factor.

Keep in mind that these cars have low and high octane mapping. Meaning that if knock is detected it will switch to a lower octane map and the car will produce less power.

[TLud]

Originally Posted by dhoggm3

OK, DonDon, how'd the dyno run go? These dudes think we're makin' it up...

I definitely don't think you're making it up. I've got a custom PC tune, so I know firsthand what kind of difference it makes and how much I've enjoyed mine. I'd just encourage anyone who modifies their software to get before and after dynos for the reasons I stated earlier.

[DoNDoN]

Originally Posted by dhoggm3

OK, DonDon, how'd the dyno run go? These dudes think we're makin' it up...

I wasnt the one that had the baseline dyno done. That was Mike. I will let him post what he got.

[ThorPR]

Originally Posted by Mike@Powerchip

Is this with forced induction?

You are running quite rich at the beginning which leads me to believe that fuel is being added to cool the cylinder charge due to either a very aggressive tune in terms of timing, or due to boost.

But then on top it leans out, which leads me to believe that this car is not FI? Nice numbers any way you cut it!


Unrelated to your post:
I also want to mention that dyno runs are very subjective, unless the car is dynoed before and after at the same session (meaning never unstrapped or removed from the dyno). The dyno charts I posted earlier are of cars that were never unstrapped from the dyno.

Meaning: If you dyno one day on dyno X, and then dyno another day on dyno X, it's possible that the comparison between the two is not accurate. This has been discussed quite a bit in Pencilgeeks dyno cheating thread: strap down, correction factor, input variables (wheel size, etc), temperature, humidity, not to mention a whole slew of other factors directly influence these results. Octane is also a huge factor.

Keep in mind that these cars have low and high octane mapping. Meaning that if knock is detected it will switch to a lower octane map and the car will produce less power.

Mike,

This is indeed Forced Induction. I'm was using a Kenne Bell Twin Screw SC. The V8 had forged internals which made it possible. The bad part was that the engine did not have any Knock protection so excellent gas and keeping your ears open was of outmost importance.

I totally agree with you that Dyno runs are notoriously subjective and the numbers will more than likely change from day to day depending on environmental conditions. You could hypothetically Dyno a car when it is 95F outside at a elevation of 2000f+ and then head down to sea level with 65F and do it again for a substantial increase in power.

The numbers are usually not what you have on tap all the time under all conditions, but rather, the potential under optimal conditions. Throw in some heat soak in the mix and numbers will start to fall after a couple of minutes of driving.

The key thing is to use the same Dyno for both the before and after runs, and also try to do so under the same environmental conditions. Any deviation from that will more than likely alter the numbers.

[dhoggm3]

OK, I agree. I'm lucky I had time to drive down to DC to get it done. No Dynos here, but I'm satisfied. Can't wait for the MS filter...

[bogdan]

I just drove my car for the first time tonight after the PowerChip and the RE Pulley upgrade.

Thanks Mike..... now first gear is useless at WOT and second gear is a joke at WOT below 40mph.

I have pre-PowerChip dyno's at two different locations (dynojet and dyno dynamics), and will try to get the car on the dyno again soon, and post up a separate thread after compiling the data.

So far though, no complaints... well... except from the rear tires!