happyricefob

iTrader: (7)

after reading the owner manually carefully... i stayed up till 2 am and hit the nearby empty roads in livermore and made 10 WOT runs on 1st gear. i input 3,150lbs for the car's weight including myself (i only weight 142lbs), the car has full interior with no spare, jack, trash, and whatsoever. (i keep it clean as a daily driver). since the road isn't long enough for me to make 3rd gear pull all the way to redline, i can only do it on first. anyway here are my 10 results from the g-tech pro meter...

1. 170WHP
2. 168WHP
3. 170WHP
4. 171WHP
5. 172WHP
6. 169WHP
7. 171WHP
8. 174WHP
9. 170WHP
10. 171WHP

notice that run # 2 and 8 are both kinda outlier of the data due to various reasons. it seems to me that g-tech pro is fairly accurate. it also consider real life factors such as drag loss, road condition, temperature, etc.

since i only made 139WHP on the dyno w/ ghost 0304 CEL... i don't know if these numbers are trustworthy. right now i have my new KS relocated to nismo14's relocation spot #1 + custom 2.25" b-pipe, and i'm getting a nice +30WHP including drag loss from g-tech pro....i don't know guys....help me out here.

BlueC

iTrader: (5)

I thought dyno runs are usually in 3rd gear? Or is 1st gear what you use with G-tech pro?

TheMax95

yea dyno graphs are usually the most accurate in 3rd or 4rth gear. 1st gear can be off a little cause you reach redline too quickly. Try the pull in 2nd gear and see what you get. The top of 2nd is roughly 65mph so it should give you enough room.
-Paul

DAVE Sz

iTrader: (2)

That and our 3rd is almost a 1:1 gear where 1st is a what 4:1? Also, using NISMO's KS relocation thing is SO stupid, especially when you do 10 WOT runs in a row. Put it back where it can actually do it's job. Why did you spend the $100 on it when you don't even need it with the location you chose for it?

Nealoc187

iTrader: (23)

Nay. GTech Pro is good for nothing, especially dynoing your car.

Stephen Max

iTrader: (59)

Well, it's based on sound scientific principles. But you have to know all the variables involved. For instance, the G-tech does not factor in wind resistance. For that reason it is good to do 1st gear runs to keep vehicle speed down. But then you have increased losses due to accelerating the internal rotating parts, especially the flywheel. Losses due to rotary inertia are lessened significantly when doing dyno runs in 3rd gear, and even more in 4th gear. But a 3rd gear pull with the G-tech will involve large aerodynamic power loss. So, the G-tech will always give lower power estimates than a dyno run.

Also, you may be off several per cent with your weight estimate, and that directly affects the power calculation.

hakk97se

Yeah the sensitivity of those accelerometers is very questionable. The GTech Pro is pretty cheap, and as any good computer/electrical engineer will tell you, good accelerometers are NOT. Check these out, they are designed for "portable acceleration and velocity data collection" and you'll notice, the sensor alone costs a lot more than the GTech.

http://www.spectraquest.com/cart/accelerometers2.html

Also, GTech's algorithm for coming up with the final result is unknown. There are a lot of factors that go into this. Even if you use satellite mesaurements to really get a "3rd party" to verify your acceleration, it is difficult. It's well known that GPS acceleration measurements are completely unreliable due to the speed at which you can update measurements from as many as 12+ satellites (3ft accuracy) and problems with dopplar shift when coming up with the calculated measurements.

Check out what professionals are using as a "best approximation" replacement (the VBOX) and you'll see why.

http://www.racelogic.co.uk/vbox/aboutvbox.htm

(Sorry you wasted money Kevin )

happyricefob

iTrader: (7)

thx for all the comments guys... i never expect this thing is a good-buy in the first place. never hurt to try out new stuff u know?

SR20DEN

iTrader: (7)

The Ghetto Tech pro works well for doing baselines and comparing between mods. So long as you input the correct data and level it properly it will yield fairly good results.

JSutter

iTrader: (46)

what did you estimate for your weight? When I weighed my 96 SE Auto it was 3110lbs. 1/4 of a tank in gas. Thats very close to your car Im sure.

DAVE Sz

iTrader: (2)

^ Were you in the car? I doubt it.

Midknight MAXX

iTrader: (1)

Just curious, why are dynoing your car? Seems like a waste of time if you can't get a good run in third gear. Why not just go to a drag strip and see how fast it is. Dyno numbers are good for judging mod gains and bragging rights. Oh yeah in no way is the G-Tech Pro new, I think the second generation one has been out over a year.

JSutter

iTrader: (46)

No with me in it, it was 3270 pounds. Used the scale at New England Dragway.

Broaner

iTrader: (10)

You'd be suprised how much more your car weighs than you think. I was thinking I'd be right at 3050 because of a fair amount of weight reduction but I was at 3120 with 1/2 tank of gas. So, with no gas and the 5Spd in I might break 3K. Sweet. Also. 4th gear is cheating. 4th in a 5Spd is a 1:1. Therefore two sets of teeth are eliminated, thus reducting friction. G-tech might be kinda cool but there is too much possibility for error to judge gain from mods. He!l, look at the numbers you pulled. There is a six HP difference from your best to worst run. Thats the difference of most bolt on mods. So, you could easily fool yourself into thinking that a mod has helped 7HP when infact it barely made 1. Also, why is there no TQ. I would think that we all know that TQ is more important than HP by now.

DAVE Sz

iTrader: (2)

^It's just like going to a normal dyno. There is ALWAYS a difference between runs. You can go to a dyno and do 10 runs with time between runs for the engine to cool and you'll always have that margin for error.

looslip

iTrader: (3)

I wouldn't use the G-tech to measure the power that you have rather than use it as a baseline tool and figure out approximate gains as you mod. Plus, didn't you dyno that one day in Fremont?
I took my Gtech to the 1/4mi one day and it read .3-.4 seconds too fast everytime... Now I hardly even take the thing out.

mad-max98

iTrader: (2)

i've had the g tech pro for a year now and as far as i can see it's pretty accurate but in order for you to get good readings you have to be accurate too in setting that thing up y,x.z dimensions, car weight with you in it , rpm ,and the closer you run to 1/4 mile the more accurate your readings will be cuze it links your average acceleration to your weight and rpm so go and be ready to set it up right once and for all and do it over and over tell you think it's the most accurate specially the weight well and the rpm +xyz lines,,, mine was 6-7 hp lower than the dyno cuze g-tech actually measures the real power that's pushing the car after drag ,wind,elevationand temp but on the dyno you don't have all this,,, and it was .1-.2 faster on the track ib think because it doesn't realize the car started moving immediately but that's .1 second i hope that helped so peace

deezo

iTrader: (3)

I don't trust those things. I did a dyno run with one when I was stock and it said I was dynoing at 142whp.

happyricefob

iTrader: (7)

thx for all the inputs. i knew this thing isn't the best product to get my WHP and 1/4 result. perhaps i was simply looking for a refernece point that's all. anyway i will make couple runs every week at the same spot/time with g-tech and record my results responsibly, and if the margin of error between each runs is minimal, i take that as a good reference data for my car.

Broaner

iTrader: (10)

I disagree Big D. Dyno's are much more consitant. The largest difference I've seen on my car is 4HP and 2TQ on a dyno. Boosted cars are a different story.