G-tech & dyno power figures

[Steampunk]

Hey all. This forum is not used a great deal but here goes ....
I bought a G-Tech Pro Competition (same as current version except different colours). Long story short .... got power figures between 92-99 HP@wheels.

Now ... Gtech claims that these are \"truer\" figures cause rolling road resistance is greater than rollers on dyno, plus wind-drag is a factor, therefore the figures should read lower than what you will get on a chassis dyno, and truer cause it takes out all possible drivetrain losses.

My car is a 94 NA. Mods: Ram-pod, straighter/larger steel induction pipe, Apexi 4-1 extractors, straight-through muffler.
No changes to internals or timing or fuel.

Does 90+hp/70+kW @ wheels sound too high, too low, just right?

Cheers


Andrew

[Steampunk]

oh .. forgot to mention.... did the runs at night, approx 22 celcius, negligible wind speed, plus I had to sit there and wait for traffic to die down, so some heat-soak happening on intake side of things.

[Steampunk]

UPDATE:
Just did a couple of runs at Redcliffe Dyno & Performance: 64.3kW@wheels.

I'm satisfied with that.

There are issues after 5,000RPM that I will need to research and address.

Inlet temp was 41 deg celcius. Not happy with that.

I'll post a photo of the graph on Monday and you can see that the top of the power curve is pretty crappy.

[Okibi]

90+hp/70+kW @ wheels

..64.3kW@wheels...Inlet temp was 41 deg celcius.....

64.3 kilowatts = 86.2277204 HP

http://www.musclecarclub.com/library/tech/intake.shtml

A common rule of thumb is that decreasing the air intake temperature by 10 degrees F will increase horsepower and torque by 1%

19"c is 66.2"f

So increase in power by 6.6%

6.6% of 86.2Hp = 5.6892Hp

so about 92HP

90+hp/70+kW @ wheels

Sounds pretty close then

[Steampunk]

Thanks Dave
I love my G-tech
How can such a little device bring so much joy?! .... girls ... don't answer that

I'll try and post a photo of the dyno graph now so you can see why I said I was \"satisfied\" with the result.

Check out the top of the power-curve. Yuck.
Air Fuel Ratio (scale on right) is also rather underisable for first half.



So boffins ... what do you reckon can be the cause of such a crappy power curve peak and crappy first-half air-fuel ratio?

My car is: NA8 133,000km, larger intake piping & air-pod, 4-1 extractors, spark plugs and leads replaced 4years/25,000km ago, Caltex Vortex 98, standard timing, everything else stock, runs fine.

[JBT]

I'd say it's down to the intake and exhaust mods. They don't always create improvement if they are out of harmony with the engine and/or each other.

Pity you couldn't go back to standard and try again just to see if there was a difference. I think you should have achieved about 70Kw ATW.

[blackster]

As mentioned above if you have lost power and upset the AFR then the cheap fix is to return the car back to stock.

On the other hand breathing mods may need to be utilised via some sought of aftermarket ECU intervention ie piggyback or standalone. The ECU intervention should fix the power and AFR curve. I wouldnt expect to much of power gain though with the ECU if the car is to remain naturally aspirated with no other mods.

[Steampunk]

You don't reckon the ignition isn't up to the task anymore at high revs? ie. I need new coil pack?

[Russellb]

Not the best from a 1.8
You can see on my graph the green line is with similer mods and it made it to 79 KW at tha stage it had 180000 Kms on the clock
the red line is with the turbo
Your AFR are about right for a STD computer.

[Okibi]

Pete's NA8 clubman at our dyno day.

[Steampunk]

Thanks for posting Pete's graph Okibi. I don't think I'm even close as his is nice and smooth throughout the entire rev range.
79kW is pretty damn good Russ, is that with ignition timing advanced?
Novice1 got 85kW with alot more things done to his, including cams, but I think his is a 1.6 ... ?

Thanks for the advice JBT & blackster.

I think, from all your advice, I know what the problems are, and fortunately, they are relatively minor and easily fixed.

By the way, nice power from your turbo too Russ. There was an SP there and it made 128kW@wheels which is pretty good anyways.

[Steampunk]

Hmmm ... just checked timing, correct @ 10deg BTC, spark plugs show normal wear, but spark plug holes has quite a bit of oil in it which means new cam-cover gasket.