Hi all, well i had my vr4 powerd gti satria tuned at apc recently, i have a td05 16g small turbo on the engine that has been rebuilt and highflowed, so they tuned it to 150kw atw on 13psi which was dissapointing, i expected more, they said they cant boost it anymore because it experienced valve floating? how can i mod this for more boost? thanks guys
Valve Floating?
- Thread starter excelix
- Start date
Help Support 4GTuner:
you should be able to do it without taking the head off the car, however most people recommend taking the head off
check out www.importevolution.com or www.extremepsi.com and have a look for the valve springs, they're not too expensive
check out www.importevolution.com or www.extremepsi.com and have a look for the valve springs, they're not too expensive
CLuTZ
Diamonds are forever....
excelix said:
valve springs yes,
rob323
Don't drive it, RALLY it!
150 kw at the front wheels on only 13psi sounds about right to me. Unless the engine has done quite a few miles, I wouldn't have though that you shuold have this problem yet. You can run more boost, boost doesn't cause valve bounce, rpm does.
My car runs similar specs to yours, revs to 7500 no problem. What have you set your rev limit at?
Maybe get a second opinion from someone else.
My car runs similar specs to yours, revs to 7500 no problem. What have you set your rev limit at?
Maybe get a second opinion from someone else.
sounds a bit fishy to me, valves should only "float"/"reverberate" at high rpm or with miss matched cams and springs.
with a stock top end i wouldnt expect them to float till about/after 8000rpm.
but valve springs do sag/soften over time/abuse, but it really shouldnt, its not really something i have heard about with these engines.
most people bung a set of cams in, with stock springs and live happier lives.
also, boost WILL not affect valve float because its the oscillation due to opening and closing the valve at high rpm that is the cause of valve "float"
150kw at 13psi, does sound about right, what are your full mods?
with a stock top end i wouldnt expect them to float till about/after 8000rpm.
but valve springs do sag/soften over time/abuse, but it really shouldnt, its not really something i have heard about with these engines.
most people bung a set of cams in, with stock springs and live happier lives.
also, boost WILL not affect valve float because its the oscillation due to opening and closing the valve at high rpm that is the cause of valve "float"
150kw at 13psi, does sound about right, what are your full mods?
rob323
Don't drive it, RALLY it!
excelix said:
Still sounds fishy, I've never heard of anyone with stock cams experiencing this problem and the factory rev limit on a vr4 is 7500 rpm so you should still have another 500 rpm to play with, without problems.
And as I said before, rpm causes valve bounce, not boost, there is no reason not to run more boost if everything else is up to the task (fuel pump, injectors etc).
What computer are you using? AFM or Map sensed?
My full list of mods are as follows, microtec ltx-8, irridium plugs, top gun leads, 4bosch coil packs, 4litre throttle body, vr4 oil cooler, front mount i/c, td0516g turbo, veeport bov, 3"dump pipe, 3" front pipe, 2.5" magnaflow cat back exhaust, exedy heavy duty clutch, greddy profec b boost controller, thats it. the car was tuned for 16psi before i gave it to them
rob323
Don't drive it, RALLY it!
The stock vr4 injector (blue ones) and stock vr4 pump (you don't say which pump you are using) will be getting close to their limits at around 17 psi.
Are you still using the standard vr4 air flow meter or are you using a map sensor?
Are you still using the standard vr4 air flow meter or are you using a map sensor?
rob323
Don't drive it, RALLY it!
If you only have piping between the intake to the turbo and the air filter element, then you most probably will have a map sensor mounted somewhere with a vacuum hose going to it.
rob323
Don't drive it, RALLY it!
excelix said:
Using a map sensor instead of the factory air flow meter is a good thing.
excelix said:
Suprise, suprise :roll: I've been biting my tongue the whole thread.
yer, all the wanted to say was there was valve floating and they couldnt run any higher boost, even tho it was tuned for 16psi when i gave it to them ( i wanted more) they even charged me for fixing boost leaks when 2 weeks later i found my boost solinoid to be completely leaking causing huge boost cuts
rob323
Don't drive it, RALLY it!
Like I said earlier, maybe its time to get a second opinion.
