Hi flow turbo problems

[R32 GTSTT]

Ive got a standard rb20 turbo which has been hi-flowed, and its causing problems.

When u come onto boost and then back off, the air seems to be mainly coming out the pod filter in pulses, and you get a fluttering sound. Ive changed differnet bovs and its made no differance. Also when im cruising along the highway at 100km/h and you put your foot slighty and start making low boost, it starts making pulsing noises at the pod, as if its sucking air then stoping then sucking air etc. Ive got a 3'' solid intake system for it aswell, so i cant seem it restricting air for the turbo. Help me plz someone.

[Cameron_Datto]

Ive got a standard rb20 turbo which has been hi-flowed, and its causing problems.

When u come onto boost and then back off, the air seems to be mainly coming out the pod filter in pulses, and you get a fluttering sound. Ive changed differnet bovs and its made no differance. Also when im cruising along the highway at 100km/h and you put your foot slighty and start making low boost, it starts making pulsing noises at the pod, as if its sucking air then stoping then sucking air etc. Ive got a 3'' solid intake system for it aswell, so i cant seem it restricting air for the turbo. Help me plz someone.

i had the similar problem .. I was using a Aftermarket Blow off valve .. the spring Preload was to Hard on the blow off valve .. I was able to adjust the preload of the spring to a softer setting on the blow off valve to vent more air at lower pressures and fix the problem ...

[R31 POWER]

when im cruising along the highway at 100km/h and you put your foot slighty and start making low boost, it starts making pulsing noises at the pod, as if its sucking air then stoping then sucking air etc.

I don't know about you guys but that sounds like compresser surge.

[crack]

sounds like surge to me. engine can't use all the air that the turbo is providing.

[FATGTS-R]

hmmm.. if it was only happening when you backed off i would say its just your bov being too tight.

But if it happens when you are on the gas at 100km/h ( prolly tallgear = high load ) then as others have said I think you are experiencing compressor surge.

When it happens are you noticing your boost gauge thrashing about all over the place?

What was exactly done to your turbo to make it a " highflow"?

[R32 GTSTT]

Yer the needle thrashes all over the place. Its basically a stardard RB20 turbo, keeping the same compressor housing, but has been machined out a bit with a bigger wheel. The exhaust housing is slighting bigger with a bigger steel wheel.

The owner before me said it never surged. The reason i got this turbo was that my stock RB20 turbo failed. The shaft bent and the compressor wheel jammed up against the housing. I drove the car for another 25km thinking i wouldn't do any damage and basically i was driving a NA.

When the hi-flow turbo went on, and i started to have this problem i decided to disconnect the boost controller. It seemed strange that without a boost controller i was still making 12psi. I put the actuator from the RB20 turbo onto the hi-flow one.

Maybe driving the car for that extra 25km or so, has buggered the actuator spring and its not functioning properly, causing this problem. What to you guys think??

[predator]

Just doesn't sound like the new highflow turbo has been built intelligently?

Is it possible to highflow an rb20 turbo to good effect? I thought the compressor housing would be a little small?

[R32 GTSTT]

could it be the actuator

[R32 GTSTT]

ive had a talk to the guys at g-speed, they think it could be something to do with the throttle and the signals its recieving. Maybe the throttle is pulsing causing the pod to suck then stop then suck etc etc. What controls the throttle and want things should i be checking for?? Can someone plz help me

[GTS-t VSPEC]

Who built the turbo, cause I have to agree with the rest that it sounds like compressor surge, quite a common problem with hi-flows and hybrid turbos.

[R32 GTSTT]

the turbo never compresser surged on the previos owners car

it was of a guy called shaun, he owns a R32 gtst with a RB26 in it now GOT BOOST numbers plates, think he got it from performaz

[R32 GTSTT]

i dont understand how it can be the turbo when it is does it in vaccum

[Jay95R33]

Yepp, your getting compressor surge.

It's usually most noticable around zero to low boost. Like what you explained when your cruising and your boost needle is jumping up and down.

It's caused by a mis-match between the compressor and turbine wheels, and as stated before, your motor can't ingest all of the air.

Are you sure that the problem wasn't there with the previous owner? Or are they just saying that it didn't have a problem before?

You'll need to get the turbo off and get one or both of the wheels changed (talk to a expert about this).

J

[R32 GTSTT]

im just going on his word that it didn't compressor surge. Coz im runing a wolf with map sensors couldn't i take the pipe off before the throttle body and run it like that to see if it still does it. If it does still do it doesn't that mean its got nothing to do with the turbo??

[Jay95R33]

Umm, you could, but maybe the better thing to do is either take it in to a turbo expert for them to test it, or maybe figure out a way to disconnect the wastegate actuator and get it to hold itself wide open. But I think it still may generate a bit of boost this way (very late in the rev range, but still a bit).

If it was me I'd get some expert advice.

J

[amosite]

I have had many differnt high flows on various cars and at one stage I ran a T04B compressor on a stock turbine with a 5 deg back cut. This car was awsome! This was the biggest sleeper I had with a stock exhaust even (modified internals) Point being is that you would have to have a very big mismatch and I doubt any would cause light throttle surging.

The surging at light throttle doesnt seem right

I would get the cars AFR and timing checked.

But before that, what I would check is that the 02 sensor is connected and all wires are in tact. If not it will do this sort of thing as well as getting shit fuel consumtion.

I would also check that all the pipes from the AFM to the turbo are properly sealed and all hose clamps are tight. An induced air leak would cause the car to have inconsistent air flow voltage signals which would cause surging.

If you removed and fitted the turbo yourself, 90% of the time people have this type of problem because the forget to connect the 02 sensor- Heck, I forgot to do it 2 months ago when turning the gf's car to stock (was in a rush working and in the dark) and wondered why it got less mileage.

[R32 GTSTT]

why take it to a turbo expert, when theres alot of ppl saying that its not the turbo

[FATGTS-R]

In regards to the 02 sensor. I have no o2 sensor connected and never have, and I have never got any sign of compressor surge. And I have a TO4E on a RB20.

Did the previous owner have any modifications done to his head?

[Jay95R33]

But before that, what I would check is that the 02 sensor is connected and all wires are in tact.

I'm confused on how the O2 sensor would cause the boost to surge at light throttle when cruising ?

As the O2 sensor simply tells the ECU on what the A/F ratio should be when in closed loop. It has no control over boost levels.

R32 GTSTT - in the end it's up to you what you want to do. If you want to drive it around wondering what it is then that's cool. Me, I'd take it to a workshop.

The size of the turbo doesn't mean that you will get compressor surge. You could run a T76 on a RB20 and not get surge ! But if there's a big mismatch between the turbine and compressor wheels then you may see surge.

J

[RS500]

dude,

if it's compressor surge, can you can verify this by getting an exhaust place to tap into your exhaust housing and placing a brass fitting so that you can connect a boost/pressure gauge to it.

with this, you'll be able to see the difference in boost levels b/w the compressor and the exhaust side.

ideally you'd want to see as close to 1:1 (i.e., 10psi in inlet manifold = 10psi in exhaust manifold)but that probably wouldn't be possible with a standard engine.

if this isn't the case, and u fitted the hi-flow turbo yourself, make sure there are no rags or anything of that nature left in the intake pipe or cooler pipes ;-)

good luck.