Another Dissapointing Results After New Turbo

[ztuned]

yes, another thread about poor results. i think it is the tuner? but ill see what you guys think

the mods are:

HKS GT-RS turbo

Power Fc

ACVR ebc

fmic

apexi pod

3.5inch cat back

3inch dump/front

xforce hiflow cat...also have bashed out stock cat, cant really feel a difference between the 2

BOSCH 040 fuel pump

Z32 AFM

Nismo 740cc injectors

with these mods i was expecting bout 350hp. but no

lol some of the stuff below may be a lil irrelevant, but i thought you guys might want to know the full story.

so i got my car tuned a few weeks back. got crap results at 300rwhp @ 1bar,

so the tuner reckons whenever put sets the car more than 1 bar the car starts knocking.

there is the ocasional misfiring too, but nothing major. so i thought it's ok for now

but the knock readings show on the pfc were hell high on normal driving, barely boosting and it reads 50+, and engine light comes on sometimes too,

so i took it back and he reckons he just needs to change the timing abit. and he does that.

all this time my boost gauge shows it's hitting 1.1-1.3bar, but i think it's because it's cold and has nothing to do with the ebc

ok so the car is still knocking. and fuel economy is shithouse. 260k's out of the first tank...my rear bumper is all black lol

so retune is done free of charge.

but the car still knocks and this time it's only making 290hp? @1bar again.

now fuel economy is now better but still not good. i got 320km's out of a tank..still a bit rich as i still get a black rear bumper after 2 days lol

and my boost gauge and ebc still reads the car is hitting 1.2bar, but again it may just be becasue of the cold weather

the knocking is still there, but only when the car is cold and for the first 5mins of driving, sometimes so high the engine light flashes. and im not boosting either

but when the car is warm and i give it shit it doesnt knock at all lol, stays under 30

tuner doesnt know what is causing the knocking. comp and leak down test has been done and it's fine.

What do you guys think it is?

im thinking of bashing out the xforce cat and put that in as it's 3inch and getting split dump and front....if thats gonna make a difference

and also splitfires for the misfiring problem

should i go back to the same tuner ? been there 3 times and he still cant find the problem..he says it's the car...but i think it may be him lol

here's the dyno sheet for the first tune. i dont think it has changed much.

do u guys reckon it's the tune? or do i need to change some part?

oh and my bov is very quiet for some reason, might quieter running at 1.2bar than at 0.8bar lol

also boost doesnt come on that early as some say about the gtrs, does that have anything to do with the tune?

cheers

Edited August 8, 2008 by ztuned

[Pal]

got a dyno with air fuel ratios on it

[PM-R33]

At 1bar peak boost pressure that seems about right for 300hp as thats around 230ish kw. However on 1.3-1.4bar you should be seeing around 330-360hp. Now wether its breaking down in spark at higher boost levels and not making more power could be the reason.

Does it missfire up high when it hits over 1 bar driving at night on full load?

[ztuned]

i've only had it missfire on my twice...and it goes away once i lift the throttle up. and both times were at full throttle around 5000rpm

i think the missfiring issues should be alright after new splitfires, spark plugs have been changed too.

im more concerned bout why it knocks atm

and sorry this is the only dyno graph i have, dont know what that bottom curve is lol

Edited August 8, 2008 by ztuned

[limpus]

First and foremost...i have been in the exact same situation...my rb20 with hks2535 started off making [email protected] was piss weak...everything seemed fine with the engine at that point...compression was good and everything else was healthy...

Turns out my Xforce cat was a restrictive POS and was the biggest restriction in the whole system...i bit the bullet and shelled out $300+ for a MetalCat and went in for a retune...instantly we were able to dial in more timing and ended up with 215rwkw@16psi...

I went a step further and installed a catch can...which might have helped to catch some oil vapour which can lead to detonation...and i also invested in a set of new coils...another tuning session later and power went up to [email protected] wanted to dial in 22psi but was told not to push my luck...lolz...

Now take what you will from this...i know alot of skeptics who said that a catch can and coils wouldn't give a gain...but its all in the tune...allowing more ignition timing to be dialled in will in turn make more power...

I will however guarantee that the xforce cat is playing a part in your dismal results...i was using an xforce cat too...bin that POS and see if you can address other restrictions in your system...good luck...

[paulr33]

i agree

yours peaks at 4600rpm (torque does) then it tapers off constantly until redline

youve got a restriction, the exhaust is the usual first spot

[R31Nismoid]

1. AFR graph, if you dont have it... makes everything impossible to tell

2. Not a disappointing result at all for 1bar, sounds about right. I think you've got higher hopes than you should have as that result for that boost is pretty much on the money

3. Before you bash the cat, just drop the exhaust from before the cat. Simple and easy to answer that

4. I think you might need to see someone else

[Al]

Just drop the exhaust off before the cat and do a run, then fit the cat do another run and compare the two result with this one.

Also sounds like your coils are breaking down, so make sure you get the Splitfires ASAP, and gap the plugs to 0.8mm

Here is my graph to compare to: The graph shows exactly what a shit cat can do to the overall power. Red line was using the original "hi flowing cat", blue line showing what happened with the "better" flowing cat

18psi

Tomei Poncams

Head porting

Std bottom end

3" turbo-back exhaust

[ztuned]

icic, knew the cat was shit, didnt know it could make that much difference like shown on Al's graph.

will invest in a new cat, is it worth it getting a 3.5inch split dump/front ?

new coils are definitely on the list, but is the catch can really necessary?

ne1 more ideas on the knocking? just a shit tune lol?

cheers

Edited August 8, 2008 by ztuned

[Green_s13]

change the coils and the cat then take it back for another tune, i think you will find the knocking will drop. with out the AFR's it is hard to tell, the other thing to change is your fuel filter is this hasn't been changed it a while it could be blocked

[BAMR33]

More boost! people run 14psi through they're standard turbo's. And given that you got restrictive standard manifolds that increase boost pressure but drop airflow you could run 20psi+ without worrying anything

Your bad fuel economy is due to your injectors, they're stupidly big for that amount of power. Its not going to change unless you change your injectors, 480cc s15 injectors would be much better for the application.

High knock levels at 1 bar is a bit weird, you haven't got an exhaust restriction to cause back pressure so it would have to be ignition timing. maybe your tuner needs to advance the ignition timing to safely increase boost levels.

[SafT]

More boost! people run 14psi through they're standard turbo's. And given that you got restrictive standard manifolds that increase boost pressure but drop airflow you could run 20psi+ without worrying anything

Your bad fuel economy is due to your injectors, they're stupidly big for that amount of power. Its not going to change unless you change your injectors, 480cc s15 injectors would be much better for the application.

High knock levels at 1 bar is a bit weird, you haven't got an exhaust restriction to cause back pressure so it would have to be ignition timing. maybe your tuner needs to advance the ignition timing to safely increase boost levels.

I disagree with almost everything you just posted.

You started out ok with your third point, but then went off track again.

[MR 33]

Bigger injectors don't always equate to using more fuel. They allow more head room. I'd suggest another tuner after all you've been through, if he keeps sending you away with your car knocking like that i'd be hitting him up for 7k for a rebuild pretty soon.

[bombtrack]

Your bad fuel economy is due to your injectors, they're stupidly big for that amount of power. Its not going to change unless you change your injectors, 480cc s15 injectors would be much better for the application.

My fuel economy is fine with 800cc injectors provided I don't constantly lean too hard on the throttle. Mr33 is 100% correct in saying bigger injectors just allow for more headroom.

[croat]

ztuned the power at 14psi seems pretty spot on, basically exactly what i made with it. with regard to the knocking get the mechanic to check your Crank Angle Sensor. inside it you should have these teeth which bight on with your cam. if these teeth are worn out you can expect to see your timing go all over the place. I had this problem and tuned it 2 times before one guy figured it out and all was good from then.

[evil_weevil]

Mine on 14psi is 233rwkw

When I even got my hi-flow turbo on ages ago, the cat was the most restrictive thing I had...simple fix and a couple hundred later all good.

And now with the gtrs its still good!

Id also suggest seeing another tuner/shop.

[J34]

Well worth getting another tuner to give it a quick run and check the tune out before changing anything major. If its running rich and knocking then the tune sounds pretty poor I just had mine looked at since I had similar issues and they got another 20kw out of it with a better A/F ratio and no knocking.

[ztuned]

i just measured my fmic piping, it's only 2inch. wondering if that could be a restriction too? or should it be sufficient

[R31Nismoid]

turbo outlet the same size yes?

therefore it wont matter

[STATUS]

turbo outlet the same size yes?

therefore it wont matter

exactly.