G-Tech Pro RR newbie

[S2central.net]

Alright then - I stand corrected... So I'm seeing 210nhp on the G-Tech Pro RR whilst Andy is on a whopping 255 with the same darn software... Plus a fresh head gasket, 3B fw, opened airbox & exhaust mods plus RS2 IC.

Your dyno numbers of 57bhp losses are quite good. I think I'm mixing up some numbers in my head now...

Your dyno shows drivetrain losses to be approx 25% of what was delivered to wheels but my memory is that I saw 25% drivetrain loss compared to the power quoted at flywheel.

On your method, my 210nhp is approx 263bhp which is maybe about right for shyte fuel I'm using here... Its 95 with a dollup of octane booster in there. So close on 10% drop from known 280bhp reference on 98RON. Bumflaps

[Rusty]

I'm happy enough with the old clunker, it was afterall cheaper than a RR session and a lot less than a newer one.

[Rusty]

My last RR session dropped 55bhp so I used this as a rough guide (240bhp ATW = 297bhp ATF). 255 is too much but it's not far off so shows that things are working properly. I've yet to get to my test track and do some proper runs. The old clunky G-tech is a bit archaic but it's not too far out.

It would appear to integrate the acceleration to calculate speed and must integrate again to calculate distance for braking.

P=F.v is used to measure power, I'm guessing that F=m.a is uesd, hence the requirement to input mass.

[EspenW]

The original G-Tech can be tricked by boost spikes, etc. The new one is in a completely different league, as you can plot graphs. Going from a bleed valve to a ball and spring valve boost controller on my car didn't change peak hp much, but the thing hit peak boost much sooner.. Peak G's in 2nd went from high 0.5's to high 0.6's. This would not show on the original G-Tech.
The old G-tech does not take drivetrain losses into account. Shows net hp at the wheels, just like the newer versions.

[S2central.net]

255 (two five five) - no way - hp at the wheels ?

Thats 340bhp on the engine using 25% rule of thumb for rolling losses... Or does that old G-Tech you have do things differently. I have a memory it uses the g-readings, vehicle weight and a 15% drivetrain factor to produce its bhp claim... Which for you would be that 255*0.85 for 217 at the wheels divid by 0.75 for 290bhp at the crank.

1705kg is 3760lbs by my maths - that will give you higher figures of course.

The model I have just quotes nett power - it doesn't try to adjust for aero or drivetrain losses... Whats at the wheels is whats important.

All the runs I have done get about 205-215 nhp in 2nd or 3rd... Which matches dyno numbers pretty well.

Paul

[Rusty]

Using a weight of 3650lbs 1705Kg I achieved 255 WHP in 2nd and a 0-60 of 5.2

[EspenW]

LOL at you with your fancy smancy RS2 and E85 fuel... I have a mere K24 turbo with 280bhp on tap when I can get decent fuel in the tank. Thats not full boost in 2nd - need a higher gear for that, but then the G force drops

Yep, 0.5G is more than my Golf, though, seeing approx .43G as max in 2nd in that one. The RS2 pulls close to 0.7G in second, but the E50 turbo is far from properly spooled in that gear Not liking the hot summer weather, car feels like a turd these days. 10% power loss vs a cool day.

[S2central.net]

LOL at you with your fancy smancy RS2 and E85 fuel... I have a mere K24 turbo with 280bhp on tap when I can get decent fuel in the tank. Thats not full boost in 2nd - need a higher gear for that, but then the G force drops

[EspenW]

Now I'm pulling about 0.5g in 2nd gear .

Hmmm.. 0.5G in 2nd...half throttle run?...

[EspenW]

The manual clearly states that you should not launch to soft The most accurat is a firm, but not to hard launch.

Yep, you need to trigger the accelerometer, but that does not take much effort, a normal start is plenty good.

[Rusty]

The effect will be less in 3rd for exaple than 1st so perhaps it'll cancel out if you set it for second gear.

[magarv]

For hp measurements the launch can be a soft as you want. Just get started in 1st or 2nd, then shift into the gear you want to use for mesurement and put tha pedal to tha metal

The manual clearly states that you should not launch to soft The most accurat is a firm, but not to hard launch.

[Rusty]

I don't fancy finding 6500rpm in 4th 2nd or 3rd it'll have to be. It's a bit like doing a boost run in 3rd, road-gauge-road-gauge...

[S2central.net]

Yeah Andy reminds of the other ting - PITCH correction... The default setting is 2 degrees per G on my machine. Now I'm pulling about 0.5g in 2nd gear runs but everyone knows the S2 really lifts its nose when you nail it from low speeds. Surely 2 degrees is too conservative, but I don't yet know how much of deal it makes. Maybe best left alone.

[EspenW]

For hp measurements the launch can be a soft as you want. Just get started in 1st or 2nd, then shift into the gear you want to use for mesurement and put tha pedal to tha metal