I took my car out today for a few runs. Let me know what you think.

Conditions:

Mod - An AEM CAI that I cut to be a SRI
77 was the temp/typical New Orleans humidity
VSA & A/C off
Torque braked @ 1800 RPM in D5
The only thing that varied was me trying to feather the trottle and control wheelspin.


I did 6 0-60 runs:
6.35
6.28
6.31
6.50 - mad wheel spin, I still have the stocks
6.39
6.36
Average: 6.365

As you can see, all times seemed to be consistent.

I did 3 1/4 miles which where pretty close

14.83 @ 100.4
14.69 @ 100.8
14.90 @ 99.7
Average: 14.806 @ 100.3
I know the speeds are pretty high.

What do you think? All comments accepted.

juice

 

Good slap the OBX headers and repeat... make sure to run on the same road and in similar weather conditions and let us know.

 

Looks about right with the GTech. As Nashua mentioned, try the runs at about the same conditions at the same location for comparison.

 

get some toyo t1's to help with the wheelspin.

 

yeah, but what did you set your weight too? because setting the weight is the ONLY way to get a truly accurate reading on that thing.

 

Good runs! Did you make runs in both directions?

Dragoon, you don't need to set the weight for 0-60 runs.

 

but you do for 1/4 mile times

 

it seems to be consistant and i would guess pretty accurate too, except for the trap speed which should be low to mid 90's.

it will be cool to see the after headers run.

 

weight is only needed to estimate WHP!

 

 

What he said.

I did runs both ways. I will do my after runs on the same road. I will start a new post then. I am working a lot now and should be off a few days this weekend, if not next weekend.

juice

 

i never really messed with my Gtech after i bought it because i wasn't sure of the exact weight of my car plus me in it.

i just found a new respect for the thing

 

That thing is pretty accurate!!!

 

I sold mine after comparing it to actual trap times at the track. Not only were the ETs and speeds consistently wrong, there was no consistency to how wrong they were.

Here's the thread: http://www.acura-cl.com/forums/showt...threadid=65254

 

take it to the track and lets see what you do it will be 1/3 of a secound slower let us no

 

The trap times are off, because they arent trap times (which average your speed over the last 60' of the run), GTech gives you the speed you are running when you cross the 1/4 mile line.

 

whenever we have used the Gtech the 1/4 mile times were always within .05 and the mph was usually higher by 2mph.
Its all in the correct alignment of the unit, has to be pointed straight ahead and level. Set it up, get out of the car, go to fron tof car and check to see if its pointing forward, better if you have 2 people.
it works better with automatics because the manual cars have alot of up and down motion which can skew the readings.
make 1 run one way, then make another in the opposite direction. then average the 2 runs.

 

Actually, the average (trap speed) vs. end-of-run difference (GTECH) only accounts for 2-3 MPH. The additional 2-3 MPH (in addition to the error from not averaging) is due to the "pitch" of the car at the end of the run. (It can get even higher depending on the amount of pitch, relative front-to-rear lift due to a car’s velocity, and front-to-rear spring rate and static weight distribution.)

The "lift" on a surface is related to the car's velocity squared (V^2). The lift on the front is greater that the lift on the back of the car. The accelerometer on the GTech Pro does not correct for "pitch" (TILT) and as such, the force of gravity (1G) gets summed in to create a large and consistent MPH error (for a given car).

The 2-3 MPH difference is relatively constant and will occur for "most" cars.

The overly high reading (beyond the 2-3 MPH as explained on the GTECH site) depends on the individual car's aerodynamics...

 

those are good consistent runs
i do the same thing, go 2 ways and compare/average
always the exact same spot too

when i did runs when temp was in low 40's i got 2 way average of 6.0 and 14.6 quarter with and without stock tires and only k/n dropin
remember, not the track but great way to practice technique