Hello:

Be aware that the most common usage of "net horsepower" is typically "SAE net horsepower" or "DIN net horsepower", which is crank horsepower according to the relative specifications. This is in contrast to the pre-1971 "gross" horsepower of the musclecar era.

So, if the forum folks are arguing about net horsepower, just make sure you disciminate. SAE net horsepower is what the manufacturers quote their engines, so I like the idea of using a phrase like "road HP".





All I'm saying is the g-tech horsepower numbers will be low and not match a dyno, So don't be disappointed that the horsepower readings are lower then you would think. You can get a lot closer to the rearwheel if you do the numbers.

 

I had the cheap g tech and now have a tazzo vpc and played with buddies new g tech top of line.
In a nutshell.Gtech is accurate for et around a tenth .Tazzo is also accurate for et read about a tenth faster than track last time I checked.Gtech mph is higher than my tazzo and was about 4 or 5mph high .tazzo as it came was 2.3 to 2.5 mph higher than track.60ft on tazzo was right on.Cheap g tech is pain to level,doesn't have 60ft or 1/8 mile.And tazzo can do windowed hp tests and back to back 60ft runs.Display is good and easy to read.Also tazzo can be calibrated to be same as track for et mph and 60ft to nearest 100th.And hp measurements should be more accurate being windowed tests to eliminate wheelspin problems screwing up the gtech readings.Tazzo blows the old gtech away and for 99 bucks is a steal of the century.I paid 139 I think when I got mine.

New gtech was hard to read in some lighting conditions.It didn't even read the run about two times out of 5 not sure why.It does give a bit more data than tazzo kind of wish the tazzo would give some info like 660 and all that stuff..Also gtech can't be calibrated to match track times.I just didn't feel like the gtech was worth the money.I will wait until they come up with the next version or see if tazzo makes an even better unit.So far the tazzo wins hands down.

 

I agree with you 100%.

I never knew that cars had a horsepower rating for windy days vs. calm days!

 

Yes this is all true, but it gives us guys who dont have a dyno laying around, or close enough to run to every other week some kind of idea. Also something to do in a small town. And when you get guys saying my car runs 10 sec. You can say lets find out and they shut up! Just another toy us car people like to play with to see how close you can get to the real thing.

 

In my experience, the Tazzo has been VERY accurate. at the track, it was only 1 tenth and 1 mph slow straight out of the box and was just about dead on when calibrated.

the best 0-60 it ever gave me was 4.11 seconds which is pretty badass but the calculator i've used tells me i should be at around 3.5-3.7 with a full power launch (hooking of course) and a 7.68 @ 88.87 mph 1/8th mile.

since i've only used the 0-60 on the street though, i suppose i could have made some sub-4 second 0-60 blasts at the track.

 

That is a very good time. I think its a kewl feature you can program the tazzo. I wish you could do the same to the g-tech. But they are good to have around if anything else keeping track if you add any mods. I know you need a flat, smooth road to get a accurate reading but I have to say i have been pretty consistent with the g-tech.