Help find my missing power.

[AdamOst]

So after a dyno day i seem to have an odd power/boost graph which doesnt look normal. Checked the error codes and nothing comes up so any idea what else might be going on. Or does it look normal.

Looks like it seems to run out of puss around 5k? Car is a completely stock v6 sti with just a greddy BOV. Might try grab a stock one to rule that out.

[Wiretap]

Your turbo shouldn't be running out of puff that low down, that's gen1 Legacy material. You may want to pull it off and inspect it for wear or damage. It's also running a bit rich when the boost drags back, but that's probably as a result of said drop in boost.

[AdamOst]

Was more to see if it was a possible common thing and some basic things I can look at to diagnose further before taking into a shop.

[Joker]

"power" is on the right

"torque" is on the left

my TT (boost spiking) graph does not look dissimilar

drops of 5500 rpms or soo

<< fixed spiking and lost 40 kw changing to 2nd hand turbo's

[AdamOst]

>_<

[Wiretap]

In any case, something is still off, there shouldn't be a big dip in the curve there.

[AdamOst]

Recommendations for places on the north shore of auckland i could take it to?

[WRXONP]

well to me - thats deffonatly not boost taper - the solenoid is clearly dropping the duty cycle to lower boost

and IMO it doesnt look like it should be doing that - as when the boost drops lower - the air fuel goes rich as if its fueling for the higher boost - one would think if the ecu is suppose to lower the boost - it would keep the air fuel in check

did they have a knock link or knock block on it during the run ? quite possibly getting knock and pulling boost

but realistically - its only at 10.7 or a small amount of time and your hanging around 11.1 -11.2 which is a tad rich but subys run around there standard anyway - my ver 3 would run around 11.0 at the richest and 11.5 at the leanest

i highly doubt the bov has anything to do with it - as the boost above the piston + the spring -vs the boost under the piston will hold the valve shut on boost

the power seems not that bad to me - if the cars fully stock - i mean whats on it a vf28 or 29??

[WRXONP]

the dip higher in the revs is rellevant to the the boost dropping - same RPM if you look at it

the lower dip in power is just after it hits full boost - alot of cars have a dip in power just after u hit full boost - even teznu's sheet shows a small dip in power after it hits ull boost - to me i think its because you make more power whilest the wastegate is shut - then when wastegate opens to hold boost power takes a dip

i may be wrong but thats how i see it

[AdamOst]

 WRXONP said:

well to me - thats deffonatly not boost taper - the solenoid is clearly dropping the duty cycle to lower boost

and IMO it doesnt look like it should be doing that - as when the boost drops lower - the air fuel goes rich as if its fueling for the higher boost - one would think if the ecu is suppose to lower the boost - it would keep the air fuel in check

did they have a knock link or knock block on it during the run ? quite possibly getting knock and pulling boost

but realistically - its only at 10.7 or a small amount of time and your hanging around 11.1 -11.2 which is a tad rich but subys run around there standard anyway - my ver 3 would run around 11.0 at the richest and 11.5 at the leanest

i highly doubt the bov has anything to do with it - as the boost above the piston + the spring -vs the boost under the piston will hold the valve shut on boost

the power seems not that bad to me - if the cars fully stock - i mean whats on it a vf28 or 29??

Stock turbo is a vf30 I think, although might be a vf28. The few people i showed the dyno to said it looked a little low, should be closer to 170kw and boost should be higher. I mean the car feels ok, but it just seemed a little low.

Didnt have a knock sensor hooked up unfortunately.

[AdamOst]

Makes same number of kw@wheels than the trueno does hp@motor

[AdamOst]

 hate-evoz said:

I reakon you'll have a vf28 strapped on there. Vf30 from a v7 sti etc

You are correct, for some reason i thought it was a vf30.

[AdamOst]

 hate-evoz said:

AdamOst you werent lieing when you said in your intro that your sti is just a little quciker then your old trueno ...hahah nah jks man...what does the car feel like inside when your boosting? is the pull hard or is there a slight pull but speed picks up?

Pulls pretty hard, pushes you back in the seat when taking off from 1st. It was still fast around hampton downs, i had no problems hitting the 180kph limiter over 50m before the pit entry. I had no idea it was possibly down on power until a few people looked at my dyno sheets and said it looked a bit off.

[WRXONP]

you would need a exhaust to get anywhere near 170 - WRC111 (think thats his user name) has a ver 6 sti - has a full 3 inch exhaust with siamese downpipe and a front mount and pulled 187 kw atw on stock boost solenoid which hit peak of 16.7 and held 15 psi the rest of the way to redline

his has the same dip in power ater hitting full boost also

[AdamOst]

It was more that power seems to peak quite early then flatline for ages which had me think it was running out of power.

[AdamOst]

Yeah im not worried at all, it was just when people said it looked a little down on power/boost and the dyno a bit odd I thought id ask. Looks like its time to remove the stock exhaust and get somethign a bit more substantial.

[AdamOst]

Sounds terrible and not what im going to do at all.

[WRXONP]

the power peaks so early because you have such a small turbo lol - with a 3 inch exhaust the power would peak even earlier - power is dropping off because the turbo is small also -plus the back pressure wont be helping the top end at all

[Scoobydoo]

Have a look on the steering column... lots of power goes missing there.

[AdamOst]

So im going to have to replace the turbo to get any sort of proper gains? dammit. What the max psi these can run?

[WRXONP]

no no no you dont have to change the turbo at all - the vf28 is good - but its not a top end turbo at all - it gives great mid range - it depends what your after as to turbo choice

going to a 3 inch downpipe and 3 inch exhaust will give you massive gains - not only in mid range but also top end - but the top end will still drop off as the turbo is running out of puff

as to how much boost u can give it - the turbo will love having 20 psi through it - BUT fuelling is whats important - you will need a walbro atleast before u raise the boost through the roof -

[AdamOst]

Ha cool. I have no immediate plans for the car but in the mid term of the next 6months id liike to aim for 180kw ish, so will start stockpiling a few bits if i see them.

So will look out for an exhaust, might have to find a dump pipe then pickup tez n u exhaust to get that side of things done. Mid range power is good to me, I will be doing trackdays in it but its more often a weekend car.

[WRXONP]

 hate-evoz']

[quote name='AdamOst said:

Sounds terrible and not what im going to do at all.

/quote]

Actually sounds quite good. The system I mentioned.

everyone has different likes and dislikes lol - the facto headers are fine with stock turbos fitted -

i for one would never own a subaru that doesnt rumble - whats the point ? for me -what sounds like SEkS is a 3 inch siamese down pipe and 3 inch pipe all the way back to a straight through 3 inch muffler - deep rumble - shakes the car - sets off car alarms everywhere u go - how i miss my old suby LOL

[AdamOst]

 hate-evoz']

[quote name='AdamOst said:

Sounds terrible and not what im going to do at all.

/quote]

Actually sounds quite good. The system I mentioned.

I meant the 5inch tip and tuned headers. Id prefer to keep it a little quieter for highway driving with still some boxer noise.

[WRXONP]

 AdamOst said:

Ha cool. I have no immediate plans for the car but in the mid term of the next 6months id liike to aim for 180kw ish, so will start stockpiling a few bits if i see them.

So will look out for an exhaust, might have to find a dump pipe then pickup tez n u exhaust to get that side of things done. Mid range power is good to me, I will be doing trackdays in it but its more often a weekend car.

then the vf28 is the turbo for you LOL -

like i said a mate has a ver 6 sti running vf28 - only has exhaust and front mount and ran 187 kw atw

with exhausts - the less back pressure post turbo is the best for power - and with that comes noise - so to keep one quiet it does rob power - just depends how quiet you want to go

2.5 inch is a substancial ammount quieter than 3 inch - flow is less tho so less power