just finished getting tuned..... again

[trrbo_tc]

so i just came back from getting tuned.. the ar is running really smoothly now, no more hiccups .. everything is running really nicely.

car's not throwing codes anymore ...

but my dyno run's revealed a problem ..

apparently,

in between 2K and 3800 Rpm's im boosting 7 psi but once i rev higher and go past 4K rpm - the boost starts going down .. eventually it goes down to 4 psi max at 5600 RPM

i cannot figure out for the life of me why that's happening ...

i basically have tons of torque and almost no horsepower.

my dyno readings were at

215 WHP / 282 Torque @ 5500 Rpm

wtf ?

anyone throw some suggestions ?

[2dot4]

small turbos create a lot of backpressure that kills boost at high rpms. Your turbo is smaller than a 16g, so it may just be that your turbo is too small for the car, so the backpressure it creates is preventing it from making top-end power.

Your car is fine - it's almost definitely your turbo.

282wtq is fuggin nuts for 7psi - sheesh! lol

[trrbo_tc]

my turbo is a 16g turbo ... :-/

it should be fine right ?

[2dot4]

hmm...you got stock exhaust? It sounds like a backpressure issue to me.

You're not using a manual boost controller are you? 7psi wG spring?

is 215 your peak hp? or is that the hp at redline?

[trrbo_tc]

no i have a modified exhaust,

7 psi Wastegate spring

no boost controller

215 is peak hp

[2dot4]

hmm...

engine management? injectors?

even untuned, you should be making atleast 230whp, regardless of torque.

[trrbo_tc]

engine management is Aem Fi/C

Injectors is deatschwerks 440cc Denso Injectors

[Krdshrk]

Custom exhaust how? What size? From where on back? What about the s-pipe? Cats?

[2dot4]

Check your timing - at low rpms, your car will run fine on stock timing, but as rpms go up, the timing should be slightly retarded. If the timing is off, it'll hurt high-end power.

[trrbo_tc]

shawn church's retarded the timing already on the high end ...

didn't make a difference, i think something on my car must be leaking .. dont worry ill figure it out.

[unvdistc]

Boost leak! Same thing happened to me.....ended up being a hole in one of the IC pipe connections. check all your lines and piping.

[trrbo_tc]

so then i probably have to replace all the damn silicone couplers..

what the EFFIN crap man ..

i checked all the hoses, tightened some of them up, they felt a little lose, but i didnt notice holes on any of the hoses .. maybe im just crazy ...

im still trying to figure it out ..

im also getting alot of blow by it seems with the turbo .. even though the compression test shows that i have good compression.

[JoshCrane1]

so then i probably have to replace all the damn silicone couplers..

what the EFFIN crap man ..

i checked all the hoses, tightened some of them up, they felt a little lose, but i didnt notice holes on any of the hoses .. maybe im just crazy ...

im still trying to figure it out ..

im also getting alot of blow by it seems with the turbo .. even though the compression test shows that i have good compression.
BLOW BY ISNT GOOD!!, and how do you know? u smell fuel in your oil? you blowin rear main seals?, doubt your rings are already fried.

[2dot4]

I had a lot of blowby with my turbo too - the oil in my catch smelled awful, and was like a clear brown...doesn't do it now though...so I have no clue what was wrong....unless the manifold pressure was blowing through the rear vacuum line into the valve cover, pushing oil through the PCV hose...I dunno.

as for the boost leak...I assumed you would have caught the fact that you're not reaching peak boost, or it's taking a while to get there....you have a boost gauge right?

[trrbo_tc]

yes, according to my boost gauge, i hit peak boost at 2600 rpm - 3000 rpm

but when on the dyno, the dyno says that my boost goes down as my rpm's go higher.

any ideas ?

for example, when we were on the dyno,

i would hit 7 psi at 3,000 rpm and by 5500 rpm boost would be down to 3 - 4 psi

[2dot4]

^^now that's your turbo

smaller turbos create backpressure that hurt boost at high-rpms. It's just the nature of your turbo.

[JoshCrane1]

wouldnt a new manifold help? or would he have to get a larger turbo?

[unvdistc]

I think you said you have the 16g...what exhaust do you have? I have the 16g and when we were tuning (when I had the built motor) i was running 18psi.... at 3500 rpm i was loosing boost and it was dropping down to like 12. After investigating I had a huge hole in my piping. I know you said you checked everything but this sound identical. once i fixed the problem I hit the boost level and it stayed there....

I'm currently running the car at 9psi and it keeps the boost the whole time. In my opinion you have a leak somewhere or your exhaust is not big enough.

also, in my last dyno i held boost through the entire pull. my HP and TQ were close so I would assume if you have 280 tq your HP should be close

[trrbo_tc]

ill check everything again .. but i cant seem to figure it out ..

the car is giving me alot of trouble now .. i might take the kit off now and sell it .. i dont want my motor to go ..

[Krdshrk]

And this is why we warned against these thrown together "kits" :p

[2dot4]

that's why I'll never go "Custom" again.

If I ever go back to boost, I'm buying a boxed kit, with a pre-programmed fuel management.

Custom's cheaper, but now I have $1800 on a credit card, and no turbo kit - never again.

[THansenite]

You need to make sure you do your research. I have kind of a custom/kit hybrid. In the week or two before my install, I kept going over everything over and over again to make sure I had everything I needed. I still had issues and unexpected things came up.

I am not saying you guys didn't, but for those out there considering going with a custom kit or doing things themselves, DO YOUR HOMEWORK. Buy books, spend hours reading, ask questions or research if you don't understand something.

I bought two books in preperation for a turbo, one regarding how everything works in a turbo system, and the other is about how to tune EMS's. These two books are my bibles and I have read a majority of both and still frequent them often for reference.

[2dot4]

^^agreed.

and don't cheap out on the turbo. it's the most important part lol

[trrbo_tc]

lesson learned right here.

[crex149]

I think you stated that you are not using an external boost controller? Most usually the stock wastegates do not hold true boost. I konw that on my brother's Eclipse, without the EVC IV, the turbo would taper off of boost at higher rpms. When we hooked up and programmed it, the boost held all the way to shift. We did this with three different turbo setups, stock, Hahn 16g and then the Hahn Super 20g. 32 lbs of boost from 3500 rpms all the way to redline will nail your butt to the seat and keep you there!

And like a couple of other people have already stated, don't skimp on the price when you boost a car. The cheaper route usually will wind up costing you more in the long run. Companies like Greddy, Turbonetics, even TRD, spend large amounts of money designing and testing kits so that you don't have to.