Jump to content
SAU Community

Recommended Posts

This basically happens when the engines displacement is too small for the turbo application. What you need to do is think of it a little like this. An rb26 with twin turbos is essentially like having x2 1300cc displacement engines with single turbos on each (which in most cases is too large for the displacement. As you can imagine as you increase the turbo size (say gtrs's, -10's or even -5's) your tubro shuffle, compressor surge or axi-symmetrical compressor stall (what ever the hell you want to call it) will get worse. Hence why almost all gtr's fitted with gtr's or -10's will shuffle at some point in the rev range. Get an sr20 slap on one of the said turbo's to it and you wont see that type of shuffle (2000cc displacement engine running a turbo more efficient for its displacement).

Now on how to try cure it. You can increase tge turbine housing to try slow the compressor down, (or use smaller turbos), but here you will run into another dilema, LAG. You can increase the engine displacement (why you generally wont here shuffle on a rb30/26 engine with -10's etcetc). You can try have your tuner tune it out, baffled turbo pipes etcetc. But the most effective way ive found is to use a 3 dimensional boostcontroller. Its basically an electronic controlled solenoid (by the ECM) with an rpm input ( which alters the duty cycle of the boost control valve as the RPM changes), and a throttle position sensor input (tells the turbo how much power the drive is demanding and essentially tells the turbo how much air the engine is capable of swallowing to avoid such a surge). 9 times out of 10 this will work.

p.s ( i love brackets)

just finished re-reading HPI 126. was like de-ja vu reading this 20 mins later on. even same examples... except for the brackets

just finished re-reading HPI 126. was like de-ja vu reading this 20 mins later on. even same examples... except for the brackets

Thought the same thing. Maybe Martin Donnon has a second account hes using on here?

can u put more preload or tighten the bovs?

i think the bov's are opening on light throttle load - dont know why tho

The bov opening on low throttle (the stock ones do) will actually fix mild compressor surge.

Is now all but gone, Ignition timing appears to have shifter (car was feeling really slow) anything upto 15degrees retarded (yes really) barely does it now

Running too much retard will cause the turbos too boost much earlier and also cause it.

Edited by Rolls
  • 1 month later...

Time resurrect this.... because it is BACK!!!! Timing is now spot on 15deg, the turbo shuffle went, and with no changes made it has started to get turbo shuffle again.... But now.. It also has a couple of flat spots, and after a while of normal driving will really need a couple of decent runs to clear it out and get it going properly, it is not that long since I ran injector cleaner through it (not because it was playing up, just figured it could be worthwhile) but was still before it was running perfectly that the injector cleaner was in it. So all that has happened since it was running perfectly is that it has been driven to and from work, it has had a couple of little blats here and there but the thing gets babied 98% of the time.

I have not ruled out the possibilty of a cam being a tooth out, but is this likely to cause the probs I am getting?

Light throttle application, normally going uphill, the only way to stop it is to get off the throttle all together and start again, pretty much anytime you try to maintain a speed going uphill it does it. Has standard ECU, does not seem that accelerating will solve it

I've had GT-SS's, I now have -5s - no comp surge at all using factory piping and BOV's.

I've even used the stock ECU with GT-SS's on 15psi and it was fine.

Sounds like you need to visit a dyno and see what is going on. Timing/AFR etc.

Also you kinda do need a tune dude with larger turbos...

Yeah, have the PFC and am working to get approval for the tune... Just seems funny it went away for 2-3 months...

Weather is starting to change now that we are in a new season, probably effecting the way the turbo is making positive pressure. Air density, temp, precipitation changing etc will all have an effect...

I get the feeling people are crawling up hills using 1.68% throttle especially at higher speed.

Throttle body not open ?

That's ok here is a nice big high speed high load condition for you Mr Rb26.

WEEEEEEEEEEEEEEEEEEEEEEEEE.

WOO WOOOOOOOOOOO

"Come on Thomas, you have to help Percy up the hill" Said the Fat Controller.

Edited by Nee-san

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

    • What does it look like with highway driving? And yes, I had a similar thought as Duncan. It looks quite similar in my Stagea and I have made myself accept it as normal. Might have to look into it some day  
    • While I was waiting for the new parts to come in for the charge pipe and radiator I decided to do some turbo modification. The drive pressure (exhaust backpressure) was a lot higher that I thought it should be. For 32lbs of boost drive was 55lbs. The turbine housing is a 1.10AR and my turbo builder has suggested to go to a 1.25AR. To test if a larger AR would do anything to reduce drive pressure AND not spend any money I decided to hog out the divider in my current housing. I removed it from the inlet and the whole way through the housing.  After reassembly and testing it doesn't look like this modification did anything for reducing drive pressure or requiring more fuel (making more power). Oh well, it was worth a shot. We'll get some data at the track if it makes it past the 60ft. I also machined a $7 shift knob off Amazon to fit my Stillway shifter since I didn't like the Stillway shift knob. Next on the list was the radiator replacement and fabrication of a new intercooler tube that had no silicon coupler. No pictures of this - I was short on time each night after work to get this done and didn't stop to take pictures.  Next was to get the clutch disks out and replaced. Previously when installing the dogbox I had ordered a set of the same sintered iron disks I had been running because I switched to the 26-spline input shaft. I thought it was odd that they didn't have any markings or brand name on them like all my old disks had but installed them anyway. At the track I could not get the clutch to lock up using my normal strategies. After two track nights I reached out to the clutch manufacturer and ask their thoughts. They said they had to switch the material out because they were having trouble getting the original material and that this new material would not take to being slipped very well.  So out with the first set of 26-spline disks and in with the correct material 26-spline disks. While I had the trans out I added an inspection/service hole. I've wanted one of these for a while. Now I can have a look at things and change the front cover shimming when needed (clutch wear). I hustled and got the clutch change done in a few hours on a Saturday. Hopped in the car and drove home. On the way home I did a 1-3 pull. When shifting from 2nd to 3rd the core plug in the back of the cylinder head popped out and dumped all the coolant. Thankfully I was only 30 seconds from home and coasted it there. Datalog showed nothing unusual and 2.5psi of coolant pressure. That plug has been in there since 1992 but I guess it worked its way out. Pulled the trans AGAIN and replaced the plug, JB welded it in, and made a brace. Also deleted the head drain I had added in during the bearing issue fiasco.  I am currently changing my boost control plumbing to make it cleaner. After that is done I'll make another attempt at getting past the 60.
    • Are you 100% sure this isn't tune related?
    • 140-150 across the board. At this point hoping the grounding harness fixes it. My grounds are all tied to the chassis and none to the battery. For SR and KA that’s never been a problem for me but had a few other guys here and Reddit who told me RB really like a very solid ground setup tied to the battery so going to try that next, I’m stumped if that doesn’t do it. Never had a car have spark and fuel and not fire off before. Only thing I can think is the spark is intermittent/weak because of grounds nothing else really makes sense at this point 
    • I am having close to the same issue. Can you help me with what wire you grounded to get your pump to trigger?
×
×
  • Create New...