G-Tech and th elikes are bound to monumental errors if not properly calibrated. Your best bet is still the video cam, even with speedo error, youget close enough. I have professional datalogging in my car and don't use it.

 

which is very impressive for a 600whp car. (how much are you making)? A 1.61 is awesome, my best on radials is a 1.66...I am hoping for some low 1.5's when I put the et streets on.

This morning I pulled my blower off and pulled my valve covers off...I am dropping in some stage 3 crower camshafts...I am also doing a 6puck centerforce clutch and lightweight aluminum flywheel and long tube headers. I am expecting a 70rhwp gain and when I track her I am expecting to be right around where you ran on those runs....then the n20 is going on (probably only a 75 shot or so)...

 

He is more like 700 rwhp or more.

 

I am glad to see you enjoying your Porsche buddyg. It sounds like an awesome ride.

 

They come calibrated. Some guys might not like what they tell them, especially those guys having cars where the manufacturer's claims are a bit on the lofty side.

I was skeptical about the G-Tech. I, however, take it out to the strip and it is usually dead on or within a .1 or so 9 times out of 10. You do get a whacky anamoly every once and while, but those are obvious. European Car did a test of G-Tech and two other units and they were surprisingly accurate.

I know I wanted to think that my G-Tech was inaccurate as hell on some of my cars when I did not like what it was telling me. Anyway, they are cheap and close enough to give you some indication of what you are running so why not give them a try.

Who says video camera tape speed cannot be off, playback speed could be increased, and how many people have a perfectly calibrated speedo. See so much photo editing and video editing stuff on the web. I would think G-Tech could be just as accurate and wonder why these guys with $ 50k in mods don't give them a shot since they are so cheap and easy to use.

 

G-Tech results mirror dyno results from my experience. Whether they are correct or not, they both show the same. Timing and speed is percise.

 

Thanks Mana I can only imagine what that Viper feels like!

So which is your favorite to drive? tt, Viper or Lambo?

 

That's like asking about a favorite child. I love all of them, but they all have very different personalities. I guess it all depends on your mood. The Viper comes out when I am in a "ROCK N' ROLL" mood. The Lambo is by far the slowest but it definitely gets the attention and the Egear delivers a whole new driving experience. The Porsche has a good balance of both, it's really fast but is still exotic.

I have not seen my Porsche in about two months. It is still sitting at EVO waiting for HRE to get their **** together ....

 

Doug, 1999porsche911

My statement is based on the learnings from other people who posted on Rennlist and other. The GPS based Racetek AX22 for instance has shown variances of more than 4 seconds in a 60-130mph run, just because it was not properly calibrated for squat etc... Same for the DL...I have seen large differences on my own G-Tech pro just by changing some parameters and stopped using it.
I have no doubt that once calibrated perfectly, they will be as accurate or more than a speedometer, but you have no way of verifying calibration over the internet. As far as cheating on a video, I believe this is not the objective of anyone, because if it is, then any system is not reliable. Speedometers at those speeds are typically 5% off, still ok when comparing performance across states or countries with different temperatures etc.. RPM and speedometer can give you a very accurate reading when put together. Then again this is each one's opinion.
Thanks

 

Hi Jean, a lot of the drag racers do NOT rate the G-Tech (old and new) unit at all. I had one and let's just say a lot of the parameters were off. The main thing that's usually off on those is the MPH at the end of the 1/4mile. I've seen it be wrong by as high as 10mph, which in my mind means it's not accurate either

 

Alex,

You have to read the instructions on the G Tech and of course you have to level or calibrate it at the start. The G Tech reads the speed at the end of the quarter mile. The strip, I believe averages your speed of the last "X" amount of feet.

 

I did calibrate it correctly at the start (I have the newer unit) but it shows I trap 146mph which I don't believe is accurate

 

Alex,

Find out from the strip, when they give mph, exactly how they arrive at this number. It will make a big difference if they average the last so many feet.

And since you have one, calibrate it and tell me what you 0-60 mph time is.

 

Hehe that's easy I tried it already a couple of weeks back on the street and it said 2.4 but I don't know if that's accurate either?

 

Maybe not accurate ................. but it can be compared to the number we obtained on the day KA bent all six rods.

I don't attribute the difference so much to power as I do to the fact the tip makes a shift before it attains 60 mph.