GTI owners, do you have traction in 1st gear?

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Originally Posted by mikinoz

I don't think in gear wheel spin is a great performance indicator.

Have you ever put it on a dyno, you might find something out if you did - ie. AFR?

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I know its not the best indication of power, it at least give you some idea though, particularly as all the people who answered have almost identical setups including rubber.

So then can people say what MAF reading they get? That's definetely a better indicator.

But yes, i've put it on the dyno maybe 4-5 times, and i'm sick of it costing me $100 each time i do it. It's just showing me what i can already feel, hear and see.
And yes my A/F is very rich, about 10.5:1
It has been like this with two different tunes.



First tune with stock exhaust, and stock wheels. Went great for a week, and spun wheels like crazy in first.
Then after a week it lost power (and could not spin the crappy stock rubber in first now matter how hard you tried) and so i eventually got it dynoed, and as you can see it made pretty much identical peak power to a stock gti:

http://www.vwwatercooled.com.au/foru...KWAFRrpm-2.jpg


Then i got a different tune. This time I had the full 2.5" turbo back, as well as aristo rep wheels and KU31's. It would spin the wheels up in first.
Felt good for the first week and i got it put on the dyno out of interest. Most runs were about 110kw, somehow the 7th run got this figure of 117kw (you would have thought heatsoak would have reduced not increased power..)

http://www.vwwatercooled.com.au/foru...deN75AFR-1.jpg

http://www.vwwatercooled.com.au/foru...N75Boost-1.jpg

Then shortly afterwards, it seemed to loose power just like it did with the first tune, and it no longer would spin up in first.
Though it is certainly not as bad as it was with the first tune, though that is likely due to the exhaust.

Bit of a mystery to me and many others.

I know it might be obvious but have you tried a different diverter? And a boost leak check?

The tyres should be fine, as long as your pressure is in the right range. I would expect your wheels are making sheepskin more difficult due to increased unsprung weight.

I have similar engine and mods in the Polo, i don't tend to have wheelspin, but i don't let it rev through.

I'd be looking at your spring, shocks and maybe an updated front sway (or LSD). Has helped me.

Looking again, there are some other possibilities... Stock dogbone, other bushes, if your bushes are shot, it I'd not difficult for a wheel to slip. Most likely just 1 wheel, bushes on 1 side could be badly worn. This would let the wheel move around in the wheel arch. Try putting in neutral with handbrake on and moving the front wheels. If they move forward & back, could be control arm bushes.

Quote:

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Originally Posted by mikinoz

I know it might be obvious but have you tried a different diverter? And a boost leak check?

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yep first thing i did was change my stock DV to an R1.
I have not permormed a boost leak check as it seems to be boosting fine. peaking at around 19-20psi, and as you can see from the above graph, tapers off to about 10psi at 6000rpm. seems about right for a k03.

Quote:

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Originally Posted by noone

The tyres should be fine, as long as your pressure is in the right range. I would expect your wheels are making sheepskin more difficult due to increased unsprung weight.

I have similar engine and mods in the Polo, i don't tend to have wheelspin, but i don't let it rev through.

I'd be looking at your spring, shocks and maybe an updated front sway (or LSD). Has helped me.

Looking again, there are some other possibilities... Stock dogbone, other bushes, if your bushes are shot, it I'd not difficult for a wheel to slip. Most likely just 1 wheel, bushes on 1 side could be badly worn. This would let the wheel move around in the wheel arch. Try putting in neutral with handbrake on and moving the front wheels. If they move forward & back, could be control arm bushes.

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you could be on the money there, when i thought i noticed it lost power this second time, it was shortly after i had a the stage 2 suspension refresh kit installed as well as my shock and springs. and this was what i first put the stop in wheel spin down to, but the more i thought about it, the more i felt something was still up.

so yeah my car is probably OK, still running too rich IMO though, something funky seems to always happen at ~ 4000rpm.

Check your motor and trans mounts aswell as suspension, when they move too much it affects initial power transfer to wheels

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Originally Posted by meh

Check your motor and trans mounts aswell as suspension, when they move too much it affects initial power transfer to wheels

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interesting point, my motor does rock quite a lot when you start it, seems a bit exceessive. i've upgraded the dogbone/torque arm. and when i got suspension put in locally i got them to check the engine mounts too. apparently were ok

i'm not really trying to diagnose my supposed problem in this thread (though any suggestions are welcome), i'm just curious about how all the other gti's with simillar mods perform. dyno runs, maf readings, descriptions of traction in 1st etc... everyone should have an answer for at least one of those!
At least that will give me some sort of idea as to whether or not there are any "problems" at all, and to what extent, etc. cheers

ok i've since logged the car multiple times, peak MAF reading is a fairly consistant 150g/s.

my alter ego posted in this forum here: What peak MAF (g/s) readings do you get? - uk-mkivs

apparently it should be around 160-170g/s

So my advanced "wheel spin" diagnosis seems like it has worked well to indicate this missing powa!

Now for an indication of where those ponies are actually escaping!

I know it is running rich, about 10.5:1.

So i guess what makes a car run too rich???

Paul, the vast majority of UK GTIs have a K03s so as someone in the thread pointed out a K03 would flow a bit less.

I'd still be keen to see the AFR checked on the street.

When Beau and I went up the road last thing Friday, it was on fire.

Gavin

yeah i was about to edit my post after that same guy cleared that up
so apparently 150g/s is about right for our AGU's.

I know you've seen it happen where AFR improves on the road, but i get the feeling my car still runs rich on the road cos at night i've seen it blow smoke out the back like a diesel! I know, very technical.
And I can backfire on queue if i want to :) (used to be fun with the full BB exhaust, but not so fun now the stock back box is back on)
Yeah damn american, must have been the wrx keys he left in the boot :P