Are these very accurate and reliable? Are they worth the money or more of a novelty thing? Thanks

 

They're worth the money if nothing else as a tuning tool. Most seem to be within .25 seconds and a couple mph of track times. Some are off more. However, they are consistant,, whether they match the track time or not. I could not imagine tuning in a car (especially a carbed one) without one.

 

Where is the best place to get one and about how much would it cost. I was thinking about getting one before I start any mods to determine how much each one helped, so I guess consistancy would be better then it's accuracy. Thanks

 

They've got 'em in Jeg's and Summit. They run $149.99.

-Mark W.
'88 SC Camaro w/ 305 TBI

 

G-techs are awsome. They have never been more than .10 off from my actuall 1/4 mile times. The MPH has been off up to 5 MPH, but I feel that the 1/4 time is more important anyway. I am borrowing a friends, and I will eventually buy my own. I was shocked, but its very accurrate.

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'87 Trans Am
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'97 Bonneville SSE

 

You think the e.t. is more important than the mph! E.T. is more everyhting going right but mph is pretty much independant especially when dealing with tuning issues as mph is a function of horsepower. For example my car g-teched at 14.62 at 102.4. It is not unreasonable to say that 102.4 is
13.99-14.00 territory. Why didn't I run .6 seconds quicker? Most likely driver skill and tires.(probably more driver than tires) That (E.T.) brings a lot of variance if you use it for tuning purposes. ------------------
82 z28 350cid, vortec heads, comp 262h cam, Holley 600cfm carb, 2in twice pipes, MSD ignition, turbo 350 trans, 3.73 posi, manly b&m megashifter

[This message has been edited by 82z (edited November 10, 2000).]

 

I got a good question about Gtechs, How Do they work ? do the Get MPH from the speedo or what? I understand That acceleration can be measured as a factor of Gforces, and Weight of car + time elepased and all that Can lead You to Hp, ET, 0-60 and So on, But what I dont understand is how It can calculate trap speed, Or Does it Simply link into the speedo ?

My speedo Like many of yours is really screwed due to tire size and gears, I havent botherd to re gear it yet Because I havent decided on a tire size and rear end ratio, PLus, When im Racing Vrs driving, I will be using differnt sized rear tires, same as when AutoXing,

Anyone able to Clue me In on this before i drop 150 bucks on this thing ?


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85 Z28 - Daily Driver
60 Ranchero - Project ( Money Hole )

 

It bases trap speed on the acceleration forces that it detects, it in no way interfaces with the speedo on your car. Accurate times require accurate weight measurements and a flat road to run the test on. Give it these two things and it'll give you a good estimate...

-Mark W.
'88 SC Camaro w/ 305 TBI

 

The reason the MPH is high on Gtech is because it measures (calculates) MPH at the finishline of the quarter mile where as tracks average the mph in the last few feet (100 feet?) you typically want to subtract around 3-4 mph from the mph on a gtech to get what a track would give you

but the important part is that they are consistent, the last time I used one was on a friends 95 mustang cobra with him riding shotgun, the first run i hit a 14.4 at like 104 mph
the second run was EXACTLY the same in terms of launch and shift rpm and road, the only difference was that i heard the tires chirp second gear, the gtech showed a 14.41 at 103.5 on that run

i like gtechs

 

I agree with Pablo on the consistency of the G-Techs. That's what makes them a useful tuning device. Sure the mph may be reading high, but it is consistenly high, therefore you can gauge the effect of your modification/tuning.

 

I wasn't really looking for it to give me an accurate ET and trap speed. I just wanted good consistancy for tuning and trying different mods. From what I've heard they all seem a little high on trap speed but that's OK as long as the consistancy is there.