G-Tech Pro RR newbie

[EspenW]

Start from the same exact point each time, that way the data won't be skewed by dips and bumps. I find second gear best for such comparison runs, as you can get rolling in second, and not having to shift into the next higher gear provides the most consistent results.
I measure less power on downhill runs... the unit gets tilted and measures less acceleration.

[S2central.net]

Yeriknow, but in fairness - not all the runs are *that* strong - I really need to get some more and average out the results.

Its amazing the difference if you do a cheeky run on a slight downhill - the GTech gets fooled into thinking you have ~300bhp at the wheels so the runs need to be on the flat for any kind of consistency.


Cheers,

Paul

[S-Express]

Amazing results for just an airbox! Just shows how poor the standard one is then.............

[S2central.net]

I got a few power runs with the lower portion of RS2 airbox fitted. You can actually feel the difference in the butt dyno. Attached is G-Tech comparison of best run with ABY airbox and best from that small test on the RS2 airbox. See how the graphs converge at peak revs... The gains are more noticeable in the mid range.

Using same fuel (95RON plus splash of Nitrox)
Same MAF attached to upper portion of ABY airbox
Same paper air filter
Same ECU and software
Same stretch of road
Similar weather about 12 degrees ambient
The air guide behind the headlight is NOT fitted though

I got some Shell 97 in the tank yesterday and the car is flying

Gonna get the RS2 air guide and MAF fitted next, but I should really get some runs on stock ECU with and without the RS2 airbox for comparitive purposes.


Cheers,

Paul

[EspenW]

Watching this thread with interest now as I also have a G-tech RR , but unable to use it as yet due to a recent operation. I wondered if anyone had strapped it to a bike as yet...I was thinking of hooking up a cig lighter adaptor on my bike to try it (when I can)?

Testing a bike sounds like an interesting proposal

[Ducky]

Watching this thread with interest now as I also have a G-tech RR , but unable to use it as yet due to a recent operation. I wondered if anyone had strapped it to a bike as yet...I was thinking of hooking up a cig lighter adaptor on my bike to try it (when I can)?

[EspenW]

Did some testing last night. Got to test in 3rd gear for the first time, and as expected, numbers (especially torque) were way up, since the turbo has time to boost, and less power is used to overcome rotational inertia. Test weight: 3560lbs
10 degs C, 55% humidity, 300ft elevation, 1011mb barometric pressue gave a SAE correction factor of approx. 0.96.
360hp and 320ft/lbs at the wheels. Uncorrected numbers (as would show on a G-tech) were approx 370hp. Note that unlike the G-Tech, this computer compensates for aerodynamic drag (approx 25hp at peak power in 3rd.)
Approx 0.5G's peak acceleration in 3rd.
Numbers in 2nd gear were 335hp and 287ft/lbs. Torque suffers the most in the lower gears, since the turbo does not have enough time to spool.
Last time I tested, ambient was -2 C, and it is easy to tell from the graph and feel that the turbo spools slower in the warmer weather. Changes since last time included new spark plugs, and I have gotten AF dialed in, so it sits at 11.8-12.6 under boost. Used to be at 13:1+ with former owners setup.. Had to bump fuel pressure to close to 6bar, though. Not too concerned about that, since I know for a fact that MTM used to run RS2 injectors at 7bar. Car feels fast, but missing that brutal kick in the back at 4K that one gets at freezing temps

[Rusty]

Yeah, holding it flat in 3rd and 4th isn't a great plan on the road.

[EspenW]

A very interesting drag racers equation is the following:
Multiply 1/8 time by 1.54 to get the estimated time in the 1/4
The 1.54 factor is amazingly accurate.
This way, you can measure 1/4 time by running the 1/8th mile. Less risk of hefty fines and whatnot.

[Rusty]

Yeah

I'm just interested as my runs were at 3750lbs and based on your calcs above my car weighs 1530Kg (Ozs = Avus) and has no AC but I make up for that difference. So rather than 1700Kg my car might weigh 1620Kg or 3572lbs, might have to go and do a few tests as it would seem that I've over-estimated the weight somewhat. I suppose it's all a relative measurement so I shouldn't worry so much. Consistency is the key and knowing a basic setup to test against.

[S2central.net]

Gonna see if I get some runs with a short shift to 2nd then direct into 4th and nail it so the G-Tech gets widest spread of rpm for decent graph with best chance for max boost... 6000rpm in 4th is plenty fast enough.

[S2central.net]

You saying I'm fat or something ?

LOL

I'm going with 1700kg that was measured at MOT with me and a hefty tester on board. Thats 3750lbs with Avus fitted. I weigh 80kg and he would have been about 90kg... Thats a car weight of 1530kg plus another 20kg for the bigger wheel difference (have measured that). So 1550 plus my 80 is 1630kg x 2.205 for 3594lbs.... Mmmm maybe I am understating the weight a tad.

[Rusty]

Weight seems a bit low Paul? Did you add your own body weight into the equation? 3550 sounds about right for the car but not with a person in it too.

[S2central.net]

Some more data from me then... Got a few decent power runs tonight and my 1st attempt at a decent 1/4 mile

Rollout = 12in
Weight 3550lbs
Ambient about 12 degrees C
Fuel about 1/4 tank of Esso 95 with a bottle of Nitrox added - so not great.
Software = Homefry 'N' stream => same as everyone else

Same old 139k mile K24 turbo, head gasket, fuel pump (and filter), engine internals, injectors and coil packs as ever. Standard airbox, MAF and everything else. Samco hoses the only hardware upgrade here...

Oh but I do have the 8x18 RS6 reps on ATM - they aren't helping.

EDIT - just for the record I have plastic (RS2) pressure pipe instead of metal one and I'm running ordinary paper filter.

If I can be bothered I'll post up the data files but here's the highlights of four good runs. 1st & 2nd achieved peak power in 2nd gear, but 3rd run had a short shift into 3rd gear where I was able to make more boost.

All numbers are nett hp calculated at the wheels.

1. This was a little downhill so can't really be counted at 267hp and 300lbft
2. This was slightly uphill with 186hp and 220lbft
3. Nice flat power run in 3rd gear with 221hp and 262lbft

On the 4th run I had a beautiful flat open empty quiet stretch with no natives to annoy with a noisy launch so I went for it. Never really tried one before... I used about 4000rpm and hooked up a smooth and strong launch. Looking at the G-Tech data my gearchange to 2nd was a bit slow and I suspect I was changing gear slightly too late (just over 6k rpm) in that I was arriving in the next gear too late in the rev band to ride the max torque (for max acceleration) on this lil old turbo.

Anyway I was quite pleased with the results of my 1st ever timed quarter --->

Max G in 1st of 0.74

60ft in 2.198s
330ft in 6.039s
1/8mi in 9.193s
1000ft in 11.876s

0-60 in 5.512s
1/4mi in 14.156s @ 99.4mph

Just denied the 100 marker by a natts chuff but I reckon I could do better if I was more aggressive on the launch and nailed the gearshifts... These are about 0.4s each when you look at the speedo data.

Lets see what times some other homefried cars can post this weekend at Inters.

More data to come from me and my G-Tech RR with various setups this summer !

Paul

[Rusty]

Sweet.

No cats and a decent exhaust is going to make a big difference over a standard system although I'm not convinced that a better DP is going to make much of a difference over the standard item on a k24, can't hurt to go 1/4" bigger though I suppose.

Milltek still splits but after the cat. Completely stupid design but I can see why they did it - to fit to theirs and any other cat back exhaust without modification. Going to speak to them about this as it costs more, is morre difficult to make and is detremental to power. Need to get up to the factory first though and that'll be a few months yet