CLpower

the GTECH was .5-.6 off? At pomona i saw it was only abot .1-.2 off. you also have to take into account the track and the last time they had there clock recalibrated. I know most tracks don't do it often unless they run NHRA etc events at the track.

Xephyr2K

Well Atco does do a lot of NHRA events there so I would imagine that the clocks are pretty accurate. I think it has more to do with the amount of squat the car expieriences under hard acceleration that throws the readings off. In regard to the Suzuki-Coors at the top I think its just the sponsers of each lane ... suzuki left ... coors right... Not sure though on that ...


Chris


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2001 Nighthawk Black CLS Type S - Xephyr Performance CAI, PIAA 19173(Yellow) Road Lamp Upgrades, Full Wood Trim, Spoiler, 1/4 Mile in 14.424@97.23 MPH Atco Raceway Best GTECH Sprint 6.05 Xephyr Performance Intakes

TakeFlight

I would trust the track before I trusted the gtech.

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2001 Acura 3.2 CL Type-S - San Marino Red / Parchment
non-nav - wheel locks - splash guards - PIAA 19169s
#26519

TakeFlight

Something else I'd like to point out when comparing gtech times to track times...

REACTION TIME

When using the gtech, it starts counting the moment it senses movement. So, in essence there is a ZERO reaction time, unlike the track where reaction time is present. If your reaction time is 5/10ths at the track then that will show 5/10ths slower on the 1/4 mile time when compared to what the gtech says. So, basically, that is why the gtech seems to always produce a faster result.

Personally, I'd like to see a gtech that gives you a beep or flash that prompts you to step on the gas. That way a reaction time could be recorded and make it more like the track.

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2001 Acura 3.2 CL Type-S - San Marino Red / Parchment
non-nav - wheel locks - splash guards - PIAA 19169s
#26519

EricL

Let me point you to the following link:

http://www.prestage.com/articles/RT.asp

It has info on RTs, ETs, and the effect of RTs on ETs. We had this discussion a couple of months ago. RT will affect the ET with caveats...

A track slip should show ET and RT, so somebody with a terrible RT is going to loose.

The GTECH only "starts" when the car moves -- true. However, I would assume that Chris reported his ET and not his ET + RT. The ET is influenced by RT, but don't make the mistake of adding RT to ET to get the total time.

The RT affects how fast the car is moving past the "start" beam. Here is an excerpt from the link provided above:

"When you shallow stage (ie:just barely light the stage light) your ET will improve because you get more of a rolling start before you break the starting beam. Conversely, when you deep stage your ET will slow down because you are closer to the starting line and get less of a rolling start before breaking the starting beam. I’ll discuss this a little bit more later on..."

So, I'll presume Xepher(Chris) just used the ET (not combined RT/ET). (If not, I'm in a state of shock!)

I think that the sine/cosine relationship of(gravity/forward acceleration) with the GTECH's single sensor getting screwed up is probably one of the biggest sources of error.

You are indirectly correct about RT affecting ET (as described in the link and excerpt).

(My best guess, this was a big discussion before...)



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2001 Satin Silver Cl-S w/ NAVI

• Mud Guards
• Wheel locks
• Toyo 235/45ZR17-97W* T1S Proxies on 17x8" SSR Competition rims (~48lbs lighter)
• (pre-SSR wheels time) --Gtech 1/8th tank 40F ~=6.1
• Zaino magic
• Sways, headers, CAI comming soon

TakeFlight

Thanks for the clarification. I thought I was on to something. Apparently I was, but not exactly what I thought. However, the fact is that it's like comparing apples to oranges when comparing track times to gtech times.

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2001 Acura 3.2 CL Type-S - San Marino Red / Parchment
non-nav - wheel locks - splash guards - PIAA 19169s
#26519

EricL

I think the consensus is: The GTECH is great at checking out upgrades on a single car. So, if you add headers, and want to see what happens, then run a GTECH. Want to see how outside air temps can lower your 0..60s: run a baseline GTECH on a hot day, then run one on a cool day.

All of the above, presumes that runs are taken in two directions for a single average, and the unit is calibrated before the run to 0.0.

Note: If someone measured the wheelbase, and could film the "squat/tilt" of a stock car, it would be possible to find out how much error was produced during acceleration (in our cars). This test would need to be repeated for a car with lowered/stiffer springs.

I'd pay the extra $60 for a unit from them with 2 accelerometers (to correct the "tilt").

------------------
2001 Satin Silver Cl-S w/ NAVI

• Mud Guards
• Wheel locks
• Toyo 235/45ZR17-97W* T1S Proxies on 17x8" SSR Competition rims (~48lbs lighter)
• (pre-SSR wheels time) --Gtech 1/8th tank 40F ~=6.1
• Zaino magic
• Sways, headers, CAI comming soon

[This message has been edited by EricL (edited 03-20-2001).]