With all the complicated ways we can evaluate performance and how it is increased or decreased with modifications to our cars, the first one I used and still use is also the simplest. I use the accessport logging function and calculate how long a full throttle pull takes.
Just log a pull in one gear and show the data in a spreadsheet. Pick an rpm range that you reliably have 100% throttle, I use 2500-6500 rpm. I.e. I always make sure I am at full throttle before 2500 rpm, and don't let off till past 6500 rpm. Interpolation between times is required, they never record exactly on 2500 or on 6500.
Take your 6500 rpm time, subtract the 2500 rpm time, and voila. The time tells the truth.
For example, when I was stock and had added a Mountune air box and 2 J downpipe, I logged and found no difference in delta t. What? I had improved breathing, but the data did not measure it.
Duh. Our cars will not respond to breathing improvements without revised ECU programming to take advantage of them. Hence loading a suitable Cobb tune was required to drop the time interval between 2500 to 6500 rpm.
My stock delta t was 8.6 seconds. Once I got lighter tires and wheels, rear seat delete and hard parts required for running Cobb S3 tune, I got down to 7.6 sec. Could not improve over that with 3" exhaust vs stock exhaust, so put the 3" aside.
I tried to improve by using Panda pro-tuning, which after two revisions failed to show any improvement in this simple measure of performance. Still fighting with them over the money I paid. I had the impression they promised improvement over Cobb S3, but the data just did not show any improvements, even with their E30 tune. I guess Panda does not believe in simple math.
Subsequent to that fiasco, I went back to Cobb S3. I also remounted my old 3" exhaust and fooled with it enough to make it barely streetable for me. Meaning 3" straight through Vibrant resonator and Vibrant muffler, and found a way to dampen resonation.
My latest Cobb S3 V220 logs consistently show 7.15 sec for 2500-6500 full throttle pulls. I honestly do not know how much of the improvement is due to 3" straight through exhaust vs Cobb's revised tune, but its a good combo for my car.
As one of my first posts on this forum says, F=MA. If M is unchanged between pulls, and A does not improve (delta t), then you did not get more F.
Obviously there is a whole lot of utility to real dyno's and VD comparison of curves for tuning, this technique is more like running a timed 1/4. You either make the car quicker, or you don't. For example SS's car is obviously quicker than mine in a 1/4 mile.
I calculated the SS 253 whp log time just for fun, 2500-6500 is about 7.0 seconds. This tells me is this particular simple measure of performance does not transfer very well car to car.
But for your own car, its a simple and useful method of determining whether you added F by mods.
Just log a pull in one gear and show the data in a spreadsheet. Pick an rpm range that you reliably have 100% throttle, I use 2500-6500 rpm. I.e. I always make sure I am at full throttle before 2500 rpm, and don't let off till past 6500 rpm. Interpolation between times is required, they never record exactly on 2500 or on 6500.
Take your 6500 rpm time, subtract the 2500 rpm time, and voila. The time tells the truth.
For example, when I was stock and had added a Mountune air box and 2 J downpipe, I logged and found no difference in delta t. What? I had improved breathing, but the data did not measure it.
Duh. Our cars will not respond to breathing improvements without revised ECU programming to take advantage of them. Hence loading a suitable Cobb tune was required to drop the time interval between 2500 to 6500 rpm.
My stock delta t was 8.6 seconds. Once I got lighter tires and wheels, rear seat delete and hard parts required for running Cobb S3 tune, I got down to 7.6 sec. Could not improve over that with 3" exhaust vs stock exhaust, so put the 3" aside.
I tried to improve by using Panda pro-tuning, which after two revisions failed to show any improvement in this simple measure of performance. Still fighting with them over the money I paid. I had the impression they promised improvement over Cobb S3, but the data just did not show any improvements, even with their E30 tune. I guess Panda does not believe in simple math.
Subsequent to that fiasco, I went back to Cobb S3. I also remounted my old 3" exhaust and fooled with it enough to make it barely streetable for me. Meaning 3" straight through Vibrant resonator and Vibrant muffler, and found a way to dampen resonation.
My latest Cobb S3 V220 logs consistently show 7.15 sec for 2500-6500 full throttle pulls. I honestly do not know how much of the improvement is due to 3" straight through exhaust vs Cobb's revised tune, but its a good combo for my car.
As one of my first posts on this forum says, F=MA. If M is unchanged between pulls, and A does not improve (delta t), then you did not get more F.
Obviously there is a whole lot of utility to real dyno's and VD comparison of curves for tuning, this technique is more like running a timed 1/4. You either make the car quicker, or you don't. For example SS's car is obviously quicker than mine in a 1/4 mile.
I calculated the SS 253 whp log time just for fun, 2500-6500 is about 7.0 seconds. This tells me is this particular simple measure of performance does not transfer very well car to car.
But for your own car, its a simple and useful method of determining whether you added F by mods.