Replaced Turbo, Now Sluggish

[Sparky206]

Blew the exhaust wheel on my stock r33 gtst turbo a few weeks back, removed it myself and sent it away to hypergear for a highflow. Got it back and re installed it myself and now something just isnt right.

Car is really sluggish, like 5psi by 4000rpm sluggish, then really struggles to build beyond that, but will quickly after about 5500rpm .Boost wont hold at all and I've tried two new waste gate actuators, using the same air line I've always used plumbed straight into the actuator. Its getting up towards 15psi by 6000rpm, but defiantly doesn't feel like 15psi should, even accounting for R&R.

Other things I've noticed is the stock BOV seems to have gotten louder, and you can hear the turbo spooling whilst the car is still in vacuum according to the boost guage, which has read correct up until now.

I've checked for something obvious like a loose hose i didn't tighten properly, but to me it all seems the way it was before.

Mods are:

FMIC

3" exhaust

Any ideas on what my problem is, or where and how to go about starting fault finding?

Any help appreciated

[EeLeYe]

Is it ball bearing or plane bearing?? Plane bearing turbos usually need a bit of a run-in (about 100km). Mine used to take a while to before it began to build boost but now it feels fine.

You may also want to enlarge the oil feed to the turbo as plane bearings require more oil than stock and ball bearing turbos.

Regarding the louder sounding BOV - this would be due to the extra volume of air that the turbo is forcing through your intake. More air is being released when you throttle off, resulting in a louder sound.

EDIT - Try lowering the boost from 15psi. You may find this will feel better as the ECU doesn't compensate much above 12psi...

Edited March 4, 2010 by EeLeYe

[Jaysiin]

i would of thought being a high flow, not a stock turbo wouldnt it require a tune? or a basic safc or the like to run its best?

[hypergear]

With stock housinged high flow it doesn't really affect spooling time. Are you using OEM actuators ?

[Sparky206]

Im using the 7-9psi one atm, was using the 15psi proir to that. Im the guy you posted one to yesterday to swap.

The way its running, its more like something isnt connected properly or ive forgotten to connect something, loose piping or something. It doesn't feel as if the turbo itself is at fault, the car just seems generally rough, where prior it ran like new.

A mate did suggest the O2 sensor as it could have been damaged when the ceramic wheel blew itself off down the dump. Could this cause these symptoms?

The oil feed was enlarged, and supplied by hypergear. Im not trying to run 15psi, its spiking there. Most of rev range its spooling from about 2500rpm-4000rpm to about 5psi, then after that it really struggles and stutters to build more boost. Its pretty much taking 1500 rpm to build 5psi of boost.

As for a tune, i plan on getting one, but once it is behaving reasonable.

Edited March 4, 2010 by Sparky206

[hypergear]

mm.. interesting. Did you stick the BOV and breather plumbing back into the intake pipe? any leaks after the AFM? Also after fitting the new actuator you need to adjust the rod to make sure the wastegate is in a tight shut position.

[Crans]

blocked cat? your old exhaust wheel could be stuck in it

[Sparky206]

Cleaned out the cat while the turbo was out and removed all the fragments of my exhaust wheel, although i never did find the shaft that snapped off....

BOV plumping is all connected, checked it a few times and all seems fine, will check for leaks after AFM tomorrow, but im doubting it.

Wastegate was adjusted so it has some pre-load, adjusted it so that with both closed half the hole overlapped the pin, then pulled on the rod and slid it over the pin and cir-clipped it in place

[GTScotT]

by any chance, did you find the ceramic wheel in the cat?

if so, im sure u pulled it out, but did you consider it could have caused your cat to collapse? or if tis a metal one, might have mangled it.

look into it, or let us kno wat u hav done in regards to this.

[Sparky206]

Yes i found the wheel in the cat, in about 5000 pieces. I removed it all.

As far as i could tell, cat looked un-damaged, just looked like a spiral of radiator fins, none were mangled or showed any signs of an impact.

Looking down the dump you could clearly see where the wheel had impacted at the bottom of the dump, there was a large stain of ceramic dust followed by lots of little mounds of ceramic up the rest of the dump towards the cat. I would be fairly positive that the wheel was in many pieces by the time it arrived at the cat

[GTScotT]

how bout a cat full of ceramic dust?

drop the exhaust from the dump, just for test and see if it boosts round the block

[aerofocker]

did the engine ingest fragments of the turbo ex wheel? what happend when the turbo blew,did you back off the throttle or keep it nailed?

[GTScotT]

did the engine ingest fragments of the turbo ex wheel? what happend when the turbo blew,did you back off the throttle or keep it nailed?

it can't injest it from the exhaust side no.

its doubtful this would have any bearing on the issue in this case

[StealthX]

did you loose anything on the compressor side? i.e. from the bearings shitting themselves?

maybe a bit of compressor wheel has damaged a cylinder and youve lost some compression in affected cylinders?

+1 for taking off the exhaust from the cat, give that a boost around and see what that does.

other than that, maybe have a look at your MAF, it might be reading wrong cos its damaged (from said compressor fins), and its not reading your engine is under load which is causing only 5psi.

good luck! this ones a mystery!

[aerofocker]

it can't injest it from the exhaust side no.

its doubtful this would have any bearing on the issue in this case

oh yes it can bigman

[hypergear]

There is a small nipple on top of the BOV which is connected to vacuum source made to press the BOV piston down under load. Please check to make sure that is connected and the vacuum source is after the throttle body.

Or boost pressure will force open the valve after few psi and create a boost leak.

[**RB2530**]

There is a small nipple on top of the BOV which is connected to vacuum source made to press the BOV piston down under load. Please check to make sure that is connected and the vacuum source is after the throttle body.

Or boost pressure will force open the valve after few psi and create a boost leak.

+1 for me on this...

You have 4 things that suggest it is something to with a boost leak past BOV..

1. BOV sounds louder than what it previously did.

2. Turbo spooling can be heard even when inlet manifold pressure is in vacuum.

3. When boost starts to go +ve it is intially is very low and climbs..

4. The only way the standard ECU (I assume this is what you have) will allow the engine to run at 15psi @6000rpm and not hit airflow cut (which is different to R&R) is if some/most of the air that has gone past the afm is recirculating..ie passing through compressor, through BOV and back to the compressor, then to BOV etc etc...

Hope this makes sense...

[Sparky206]

Thanks for the reply's guys, they've been a great help in getting the mind ticking. To add another symptom, had someone tell me who saw me take off as i went for a test that the exhaust sounded like the engine had a miss in it, didn't sound smooth and healthy like usual.

As for when it happened, i had it floored and it was just coming off vacuum then nothing, probably held it there for half a second, realised something was wrong, got off it then back on it to see if it would happen again, then saw the massive cloud of oil smoke out the back and limped it the 300m home.

I too was very worried about ingesting ceramic dust, but after i took the dump off, you could follow the path of the wheel as it spiraled down the dump, then see the impact at the bottom of the dump, with many small mounds of ceramic dust pitted on the walls on the dump up until the cat. There were no signs of ceramic dust either in the dump before impact or in the exhaust housing. I must say though, the way the turbo snapped, it snapped the shaft flush off at the seals, and assuming the shaft was metal, i still haven't found it, and it certainly didn't get past the cat.

Compressor side of the turbo was undamaged. All fins were still in tact and shaft was still spinning like normal.

Just went and checked the BOV and the nipple you speak of is still connected, i didn't touch any of the hoses after the BOV. I do have the Standard ECU, and yes i have hit air cut once. Ill assume thats what happens when the car pulled all fuel and had to be restarted after it hit 15psi plus. Other times after that im backing off once i see its gone past what the wastegate is set at.

Next step over the weekend ill start checking for boost leaks around all the connections, whats the best DIY method for this without rigging up a gas bottle and pressurizing the system?

Once again thanks for the replys

Edited March 5, 2010 by Sparky206

[l_uk3y]

Hmmm. Maybe Its just me but the main thing that stands out to me is the ECU

The standard ECU with a modified turbo running 15psi is probably screaming out at you "What are you doing man?, I just shouldn't be breathing this hard".

I'd look at getting this new setup tuned with a power fc or equivalent. (you may even find a good tuner will be able to diagnose the problem during the tuning process). Then depending on your highflow you will probably be getting pretty close to pump and injectors as well (re tune after injectors as well).

Edited March 5, 2010 by l_uk3y

[Sparky206]

Re-read what ive been saying, Im not trying to run 15psi, if i could get it to hold even 5 psi id be happy, but i cant get it to hold any boost level, its spiking everywhere.

The car is a dog to drive atm long before it gets anywhere near 10psi