Well eventhough I only have 2000 miles on my new engine and I wanted to have 3000 on it before I got on it hard I ran my G-Tech Pro on it tonight. I made 2 runs for Max HP and got 2 very different numbers.
The first run my max reading came up as 394, which would be absolutely great.
The second run came up as only 215, which would make me kill myself.
Both runs I came to a complete stop, hit the button on the G-Tech and went. I don't think the ground was particularly level either time though......can't really find a good spot around here. I know for sure the second time that the road actually goes down a bit.
What could have caused these highly varied readings?? Is it possible that my 383 only has 215 hp?? (I'm really gonna cry if so)

 

Did you enter the weight of the vehicle the same both times?

 

G-tech and accelerometers have to be run on a level surface to get a remotely close result. I use two levels at 90* angles on my Vericom to insure the unit is level,, then subsequently the road.

HP reading can be "tricked" by the shift point and angle of the road. You can be rolling and apply the brakes slightly while the unit is calibrating,, and get a huge HP number. You can calibrate at one angle and run the car at another and get funky readings as well. So,, you have to be completely level and totally at rest while it is calibrating. Also it's imperative to run in the same spot and calibrate the unit in the same spot each time.

How hard the transmission shifts can effect HP numbers. The Vericom can be set to run from one mph to another mph. I use 40 - 90mph and hold the car in second gear so there is no shift point variation - Can't remember if the G-tech can be set like that.

Still,,, it's all smoke and mirrors for HP estimates. You're not going to really know what kind of power the car has until you put it on the track. They're excellent for tuning tools, run level and in the same spot, and to give you a ball park of where you're running,,,, but that's about it.

You're actually better off running the G-tech for a quarter mile, getting the time and estimating the HP based on the ET and the weight of the car than using it's built in HP estimate - IMHO

 

I never turned the unit off so I shouldn't have to reset the weight right??
Also my transmission hits very hard. It's an automatic but will chirp the tires in second and sometimes third gear. Should I just run the car in 1 or 2 instead?? Also am I better off hitting it hard off the line to get the RPM's up as high as possible in lower gears or getting on it more at a higher speed?

 

That sounds about right... the 40-90 MPH part.

That's what I did with my G-Tech Pro. I have a shift kit in my car and kept getting different readings. What I did was put my shifter in 2nd, slowly accelerated past 35MPH so it wouldn't kick down into 1st gear again, then floored it. I did this three times and all three readings I got averaged out to 145HP. And IIRC that's RWHP. That seems about right with my car and the few mods I have.

I also had trouble finding level roads that I would be less likely to get caught on, so this also makes that easier.

To date, the best 1/4 mile I've ran with the thing is ~16.7 and using the calculator at www.smokemup.com gives me about the same RWHP #s.

The G-Techs are pretty cool, but you gotta baby the things in order to get somewhat accurate readings outta them.

Good luck,
AJ

 

I agree the HP calc on the Gtech is a joke, go to the scales and get the weight of your car with u in it, then use the gtech time. and just use an online calculator. Sounds like u should just hit the DYNO, and so should I.