I did a run on a curved stretch once and got an unusually high set of numbers. See the plots below and compare to the plots earlier.

The GTECH RR must do some sort of vector summation; ie the amount of latteral g's in the curve contribute to the forward g's to give a high reading. I did not repeat the experiment. Of coarse this is in drag strip mode were it assumes straight ahead motion.

I want to go to the track in the next week or two and compare it direct against the track.

I'd like to see Tony's also. Tony when you get some data could send a file or two to my email??

 

yeah i will.
Ive managed to go get 2 runs last night on the way back from costco... I need to find a better spot to do all this screwing around though. I dont have the room to safely do a 1/4 mile run.
Ive also got to figure out how to get the best lauch. Right now my times are going up in tire smoke for the 1st 60ft.

the time you have above is better than i have on my RR from last night. I did a 5.1 on the old gtech but you cant store it. Its amazing the difference between a 5.1 and a 5.4..5.5 You can really feel it when the car hooks up.

Stock, the best i could get out of my car was 6.38. Your car is fast! Is that an auto?

Ill get a screen shot in a few and then email you the file

here it is...

I need at PM so i can send the file attatchment.

 

The G-Techs can be pretty useful. There's quite a bit of information you can get out of the runs that you can download and analyze with the software. It's best to do a few runs to make sure you don't have a quirky one for some reason that you end up using for before and after type testing of stuff.

Here are a few runs from my '88 928S4 A/T:

 

Z
What have you done to your car.....5.0 0-60 is damm fast for an 88S4 auto (I figure a mid 13 1/4)...I also have an 88 S4 auto...I've only tried one 0-60 run and got 5.98.....I only have a K&N + RMB on mine....I figure I could drop at best a couple 10th's off my first run...so I'm hoping for a 5.7 at best...I'll have to take it out again and try!

 

Brian,
Look closely at Z's chart. Time is measured from 5 mph not 0 mph. So it's actually 5-60mph.

Andy K

 

i assume you weigh 180lbs?

 

yeah, it is, like mine, and actually like 99% of the automotive mags do. Some will actually disclose the fact in by calling it a street start or label it "5-60mph"
Many times they will say 0-60 when in reality it was a street start/5-60mph run.
If you have the software and ZOOM in, you can see that many times it is not 5mph but actually a lot less. In the exmaples above, you really dont have to zoom as it can be seen that they are a tad less than 5mph. I think the lighter the car/the quicker you accelerate and thus the higher your rollout speed is.

The first 5mph/12inches is part of the "rollout". even if he didnt accout for that, his car is still VERY fast!


see at the bottom of that first window, where it says "rollout"? add that time to his "published to get a true 0-60. I beleive that is one way to do it. In teh PASS software you can select whether you want to account for it or
not.



Andy, if you used a GTECH RR for that run and disregarded your rollout, you probably would be at 4.0 or eve 3.9ish!! I believe the $39.95 (older GTECHs) dont have the ability to ignore rollout. I believe that is correct...anyone?

If you ont have the RR with the PASS software, i would highly recomend it. 300 bucks but a fun toy and well worth it.

Ill dig up some 911 TT data and post it over mine in a few

 

Comparing mine...911TT...Esprit V8..Audi RS6




This screen is "time to distance" same cars




Same cars but i zoomed in on the "rollout" data. You can see that the AUDI being the heavier car wasnt going as fast as it crossed teh 12" line.
When i view the "G's" chart the 911TT pulls nearly 1g when accelrating




Pretty cool to compare actual hard data of other cars over a range of time or distance. Over time, when i improve my launch and do some fine tuning, i will be able to compare my runs against one another. Its pretty consistant in its results!

Mr Falkenberg, Im guessing your 4 door audi is PDQ! pretty damn quick!

 

This is fun...
Like i said, great tool!
This is the G screen shot for the '03 911tt
.95g's!!!

 

Tony thanks for sharing. Man now we're in the big league .... looks like there's always someone bigger better faster. But more beautiful ... not sure on that one

 

A free flowing exhaust and some fuel and ignition tuning were a good part of it. Besides that there was some tweaking of some other things. I've never had the heads off or the engine apart, stock S4 cams, stock transmission and 2.20 gearing, etc. I did change the cam timing a little bit to reduce the bottom end power in exchange for some at the top end. That helped reduce some of the wheelspin I was getting. That greater power was only available at the bottom of first gear anyway, so excess wheelspin was all that I really gave up. The RPMs never get low enough in any of the other gears for that low end power to be used anyway. In exchange for that loss in unusable power at the bottom of first, I gained power at the top of first, and all through the full throttle portions of second, third, and fourth gear.

As Tony mentioned, it uses the same "standard" rollout measurement that his and the vast majority of performance figures and and measurements do. That's one thing that's nice about using he G-Tech to compare runs like that. The software allows you to choose whether to use the rollout or not, and then it uses that same setting for all of the runs being compared and displayed. There's no using the rollout for one car and comparing it to another car without the rollout, or having it differ without knowing it like can occur with dragstrip times. The rollout is actually a measured distance (12") and not some speed like 5mph. The speed when the rollout is completed and measuring starts can be a lot higher than 5mph with faster cars because they've accelerated more in that first 12".

Below is a comparison of two of my runs to one from a '01 Cobra and one from a '00 Firebird Formula. The Formula has a 3200rpm stall torque converter, aftermarket airbox, exhaust dump, underdrive pulleys. It's very close between me and the Formula, with the Cobra falling behind, especially after it shifts to second.

 

Tony, I have been looking at your G-Tech file, the RPM graph sure shows that you were spending most of first gear smoking the tires, it is real obvious that you had to back way off the throttle at the 2 second point. When first I looked at just your G graph it looks as though the 2s point is where you shifted, but really you shifted at 4s according to the RPM graph, the 2s loss of G's was just trying to get a grip on the road.

When you get more traction the numbers are going to get REALLY good, not that they aren't already great.

The G-tech is way cool

 

here ya go....
not exactly straight line to 6000 is it!

 

Z
You are right about that wheel spinning torque on the bottom of 1st gear....even with our super tall 2.20 rear end I still had excessive wheelspin problems..I thought it was maybe a less than ideal road surface, but its probably the car....not the fastest way to acclerate, but damm its fun! Imagine what a GTS with its greater torque and 2.73 rear end is like in 1st gear...if it wasn't for the PSD it would really roast the tires!

 

Broke the 5.0sec barrier!
I tried a few differnt things and finally got pretty consistant. The biggest thing i did was use the kickdown switch which caused me to hold 1st gear until redline..vs 5k ish.
The fact that it was daylight and the road was warmer made a differnce as well!