Ok, right now my LO3 engine is stock, but i have other mods listed in my sig. Im getting ready to switch to carb and new cam intake and heads, so before i do that work i wanted to see what my car could do. Now these times were taken with a G Tech and i know that they are not 100 percent accurate but i figured i could get a good idea. So the first few passes i made i got horribe traction and could only run a 15.9 at about 93mph. Now i know that at 93 mph i should be doing better than a 15.9 right? So then i went out and found the most flat looking stretch of road i could find, and tested it out, i was able to get really good traction this time, and just a test run i ran a 15.7 at about 91. Im gonna go back again tommorrow and make several more passes and i will post the resutlts.

I own a gtech, they seem high on MPH. But I know of two different people in different cars, testing there gtech at the track, and during multiple runs, the gtech was always within 0.1s, just like advertised.

Beware in posting gtech times though, some people here will blast you for not having true track times. (especially if your times are faster than theres)

I've also heard and read the G-tech is accurate within .2 seconds, usually .1-2 lower than actual ET.

If I had to guess I'd say the reason is because of the "transfer" of weight when you nail the throttle. For instance, when you're at the dragstrip and you nail the throttle, the weight transfers to the rear, then there's a "rollout" of 6"-8" before the timer is started.

With the G-tech, as soon as it feels movement it starts to time the car. If you subtract the time it takes to transfer weight and to "rollout" at a dragstrip the sum could easily equal the difference between the G-tech and a "real" dragstrip ET.

From what G-tech says, the reason for the difference in MPH is because at the end of a dragstrip there are actually two beams at the finish line that calculate your MPH. One is right at the finish line and the other is 60' before it. It measures your MPH by using the time it took you to cross between both beams. I.E. it's an average, at least as close of an average as you can get while still accelerating through the beams. :shrug:

The G-tech does an instant reading at the time you "cross" the imaginary finish line.

Then there are other things to consider also. For instance margin of error. No two dragstrips are the same. Some may not be quite as level as others, nor as smooth, etc. Just like no two dynos are the same.

Yea, i have heard that at the drag strip it clocks you at the last 60 feet and g tech is exact 1/4 mile. The best i can seem to do is 93 mph, but thats with a lot of spin and 15.7 times. I havent been able to use it much because i have a bad driving record, and i get paradoid as crap on the street. We tried it on my buddies car last night, It went 13.88 @ 106. The MPH there seems high too.

Single accelerometer performance meters are also effected by vehicle lift and road imperfections. I don't trust them because I have tried g-tech, tazzo, g-tech pro and none of them have been close enough for me to say anything positive about em. All I can say is that the more accelerometers it has the more accurate it becomes. For that reason alone the Tazzo is a great tool/toy and the g-tech pro is that much better having 3 axis. I've gotten both the g-tech and the tazzo to show me times ranging 5-tenths either way and +/-3mph from my actual 1/4 mile time. What does that tell you, well it tells you you're in this range.
As for me, the 1/4 mile seems like the best place to measure a cars horsepower since it's always accurate.
If you aren't near a track than by all means use whatever's the next best thing! I just tend to frown on the single axis accelerometers... tazzo at the very least.

Well i found a better stretch of road tonight, and i was able to pull a 15.2 @ 95. I think i could have worked on it some more and played around with different shift points and knocked maybe another tenth off, but that was only from one run. Yea i also question the accuracy of the g tech, the biggest thing i think is the there is no stretch of road that is going to be as level as the drag strip.The track opens in may and when i go, i am going to take the G tech with me and compare the numbers to see how accurate it is.

hmmm, those times seam REALLY optimistic for an lo3.

That's what I was thinking. If my car could hit those numbers I'd be a grinnin' fool.

i ran 15.4 in the 1/4,
with open elament, 8mm wires, bored tb, fpr, headers, 3" y-pipe back, and no tuneing

Well, to be honest, with my mods that is about the times that i expected

my car was set up pretty much the same as yours, except for rear end (i had 2.73 open). My best run was a high 15.9. I really doubt you ran a 15.2. I'd guess the absolute best you'd run would be 15.4, and i think thats really optimistic. I had a victor 2000 in my car just yesterday, and was very surprised how much different roads, that all appeared flat, produced times that varied as much as 4 tenths of a second. Anywho. If even your times varied by as much as seven tenths. Just saying. If you can manage a stretch of perfectly flat land, then i'd trust it, but less you're in florida, or the desert. doubt it.

-chillen

What did I already say about guys flaming ya, if you post g-tech times.

There are people on here that have cars like mine with stock LO3 engines that are in the 14's. So i think that it is possible

It doesnt bother me, like i said in my begginning post, i know that the G tech is not gonna be the most accurate thing in the world.

I think the Gtech kind of gets a bad rap, in that it can be a valuable tuning device. Whether or not its off by .1-.2 is irrelevant just as long as it produces repeatable results. Thats where its value lies, to see if what you are doing to your car helps or hurts its performance, and not as a gauge of its quarter mile time.

Its not unheard of for TBI 305's to get into the high to mid 14's, my car has a shift kit, 3.73s, header back exhaust, open element and the normal ignition mods, controal arms and springs and shocks and it went 14.7 at New England Dragway on a prepped track. It definitetly can be done. Dont trust a G-tech tho, its cool for kicks, but its not a true performance test.

no, 14's are not out of the question.

I went 15.1 @ 93mph (with a miserable 2.2 60') with nothing more than headers/catback (with a cat still in place), an open element and some chip work, and 3.42's/posi. Had I had traction and busted out a 2.0, that would have been in the 14.7 range.

Also, a member on here, i believe it is 90rs305, ran a 15.3 with only a flowmaster muffler,L03,t-5..this is what is said in his sig and he is a moderator so i dont think hes pulling any legs..just thought id chime in..

Yea, well like i said i know that the g tech isnt 100 percent accurate, but it sure is fun to use