Jump to content
SAU Community

Recommended Posts

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 :D

Link to comment
https://www.sau.com.au/forums/topic/310638-replaced-turbo-now-sluggish/
Share on other sites

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 by EeLeYe

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 by Sparky206

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.

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

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.

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

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

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!

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.

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...

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 by Sparky206

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 by l_uk3y

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Back again. I returned to Japan in Jul/Aug to spend time with the car on my birthday and remind myself what all the sacrifice and compromise is for. It happened to line up with the monthly morning meet in Okutama, which I have been wanting to go to for a long time. It's a unique event at a unique spot with really rare, interesting, and quirky cars. It's where all the oldheads and OGs gather. The nighttime scene at DKF certainly has its place and should be experienced if you're into cars, but there's too much bad attention and negativity around it now. IMO the better time is Sunday morning at DKF or Okutama; it's more chill and relaxed. I'm glad I was finally able to go, but not sure it's worth the drive from all the way from Nagoya immediately the day before, unless I was already staying in Tokyo for the days right before the meet, because you have to wake up quite early to make it in time. Funnily enough though I didn't drive the car all that much this trip because it was just too damn hot. While there were zero issues and running temps were nominal and the A/C was strong, RBs already run crazy hot as it is. Sure, it took it all like a champ but something about driving these cars in the ridiculous heat/humidity bothers me and makes me feel like I'm asking too much of it. I'm just me being weird and treating the car like a living thing with feelings; I'm mechanically sympathetic to a fault. Instead I was mainly driving something else around - a KX4(silver) 2001 X-Trail GT, that I acquired in May. There's a few different flavors to choose from with Xs, but visually it's the Nissan version of the Honda CR-V. Mechanically it's a whole different story as this, being the top-trim GT, has an SR20VET mated to a four-speed auto and full-time AWD! It was a very affordable buy in exceptional condition inside and out, with very low mileage...only 48k kms. Most likely it was owned by an older person who kept it garaged and well-maintained, so I'm really happy with how it all worked out. It literally needs zero attention at the moment, albeit except for some minor visual touch-ups. I wanted something quirky, interesting, and practical and for sure it handily delivers on all three of those aspects. I was immediately able to utilize the cargo and passenger capacity to its full extent. It's a lot of fun to drive and is quite punchy through 1st and 2nd. It's very unassuming -in the twisty bits it's a lot more composed than one would think at a glance- and it'll be even better once I get better tires on it(yes, it's an SUV but still a little boat-y for my liking). So...now I have two golden-era Nissans in silver. One sports car and one that does everything else; the perfect two-car solution I think👍 The rest of the trip...I was able to turn my stressed brain off and enjoy it, although I didn't quite get to do as much as I thought. I did some interesting things, met some interesting people, and happened into some interesting situations however, that's all for another post though only if people really want to know. Project-wise, I went back to Mine's again to discuss more plans and am hoping to wrap that up real soon; keep watching this space if that interests you. Additionally, while working in the tormenting sweatbox that is the warehouse, I was able to organize most of the myriad of parts that my friend is storing for me along with the cars, and the 34 has a nice little spot carved out for it: And since it can get so stupid hot in there, that made it all the more easy -after I was standing there looking at the car and said 'f**k it'- to finally remove all the damn gauges that have mostly been an eyesore all this time. Huzzah. The heat basically makes the adhesive backing on the gauge mounts more pliable to work with, so it was far less stressful getting this done. I didn't fully clean it up or chase the wiring though; that will happen once I have the car in closer possession. Another major reason to remove all that stuff is to give people less reasons to get in my car and steal s**t while it's being exported/imported when/if the time comes, which leads us to my next point... ...and that is even though it's time in Japan is technically almost up since it's a November car and the X would be coming in March, I'm still not entirely sure where my life and career is headed; I don't really know what the future looks like and where I'm going to end up. I feel there's a great deal of uncertainty with me and as a result of that, it feels like I'm at a crossroads moreso now than any point in my life thus far and there are some choices I need to make. Yes, I've had some years to consider things and prepare myself, however too much has happened in that time to maintain confidence and everything feels so up in the air; tenuous one might say. Simply put, there's just too much nonsense going on right now from multiple vectors. Admittedly, I'm struggling to stay in the game and keep my eyes on the prize. So much so in fact, that very recently I came the closest I ever have before to calling it quits outright; selling everything and moving on and not looking back. The astute among you will pick up on key subtext within this paragraph. In the meantime I've still managed to slowly acquire some final bits for the car, but it feels nice knowing there's not much left to get and I'm almost across that finish line; I have almost everything I'll ever want for my interpretation and expression on what it is I think an R34 should be. 'til later.
    • Thanks for that, hadn’t used my brain enough to think about that. 
    • Also playing with fire if they start to flow more air down low than what the stock twins can. It's not even up top you need to worry, it can be at 3000rpm and part throttle and it's getting way more flow than it should.
    • Any G40/1000 or G40/1250 results out there?  
    • You still want a proper tune on the stock ECU though. Stock tune + stock ECU with GT-SS/-9s is probably playing with fire if you're running more than stock airflow/power.
×
×
  • Create New...