Jump to content
SAU Community

Recommended Posts

Hey all. my mates just had a VG30bb turbo installed on his RB20 and underboost it jerks around, the car really want's to go but it feels like a real strong head wind. yah can hear the BOV go off at 5000. the mechanic said it had somethin to do with the fuel cut. any ideas and solutions?

Cheers

Nathan.

Link to comment
https://www.sau.com.au/forums/topic/63107-rb20-with-vg30-problem/
Share on other sites

i dont think it would be fuel... sounds like it could be leaking air from somewhere, checked all the piping is connected up properly ?

not sure i won't see him till saturday. will check. the mechanics are highly recomended for turbo work so it doesn't seem likely. if it had a leak would it slightly splutter idleing? it runs smooth as. u put ur foot down. it'll spool up fine under small accleration.

that did cross my mind. i remember hearing that some bleed valves can spike or go haywire.

he has the turbosmart bleed that you just wind.

was workin find before thoe thats whats puzzling.

cheers.

my car has the same set up and and the same problem??? Have been told it is my cheap and nasty bleed value. Was told by two mechanics to invested in a electronic boost controller.     hope this helps.

when your's did this did your boost gauge jump around?

i was lookin at his and it would stay on 10 only dropping down 1-2 psi now and then but would drop to 5 when the BOV goes off @ ~5k but staight back to 10 after.

  • 2 weeks later...

ok he finally got around to removin his bleed valve. it ran @7pound but no change.

it was dynoed after they did the upgrade but it wasn't a full tune. he's gettin a after market comp soon but it is weird that other ppl are havin no problems with their exact setup just this 1.

the engine is in an aus r31 would it have anythin to do with using the RB30 AFM? or should that be fine?

If the "bov is opening at 5K" (the sound, anyway) without lifting off the accelerator, and you are getting fluctuating boost pressure, then it is compressor surge.  Simply a case of the turbo being too big for the motor.

yeah that seems right but why is this motor that is having that problem? no other rb20det running vg30 turbos are having this problem. it has a gtr cooler and the pipes are quite cool now, they were gettin real hot b4.

seems and if there not enuf fuel. still the std rb30 pump. doing his brakes tomorrow will do a pressure test underload and check fuel filter.

thanks for your comments.

How many other RB20's are running with BB turbos? The plain bearing turbo would be the common one, and the compressor and turbine are different.

I mean, you using a turbo meant for an engine with 50% more airflow. Julian Edgars "21'st Century Performance" book has some doco on fitting the same turbo to a CA18, which basically sh*t itself with surge.

A friend of mine runs a VG30DET with the BB turbo - only makes 14psi boost, and drops off the 9psi in the top end. Huge FMIC, EMS computer with boost controller - full boost at only 2k rpm, MASSIVE torque in the midrange.

Your friends turbo is stock isn't it? Hasn't had a super-60 wheel fitted or something like that?

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

    • I'm so far behind in the jobs I have to do at both work and home (including car) that I have become immortal. There's simply no way that I can die now.
    • Each to their own I guess  Me, I put just as much time into cleaning inside of the cars as I do on the outside As for getting wet, it is really no different than steam cleaning the carpets at home, apart from the cars carpet dries alot faster than the house, again, I only do it in the hotter months and leave the car opened up for a few hours As I only do it yearly, it is just before I do the diff and gearbox service, so I clean the carpets, then it's up on stands, wheels off, service, clean the undercarriage,  grease the bushings and do a nut and bolt check on everything  Disclaimer: I typically had all the time in the world to kill when I was working 馃ぃ, so spending a full day or 2 cleaning, serving and "looking at stuff" was,  easily achievable, and a fun mental therapy day As for time to kill, I retired last Wednesday, so apart from my physical training, my days are filled with lots of random jobs around the house and garden...."Idle hands are the Devils something something" I am also buying a new house sooner rather than later, I'm actually looking at a potential property tomorrow, I'm looking forward to getting a car hoist as I'm starting to get to old to crawl around under a car, I can only imagine all the undercarriage cleaning and looking at stuff when that gets set up
    • Yeah, I'm not interested in wetting the carpets, and I don't care about brown dirt/dust that lives deep in the pile or underneath. It's not like I crawl around on them in my birthday suit or eat dropped food off them (because there is never any open food in my car). The seats are alcantara (cheap Chinese imitation alcantara, to be sure!) with barely 1" of foam pad behind the surface. That's not getting wet either. Any car that I would be happy to get the interior wet, I would not care to put the effort into.
    • We have one that holds 2.8L of water. On floor carpet that hasn't been touched in 2 or 3 years, will take a minimum of 2 fills of the tank to do a bedroom, and that's going AROUND the bed.   In the cruiser, I used an ENTIRE 2.8L tank, just on the front passenger footwell. But it had some fungus growing, and had been full of mud from being used as a 4WD for many years. I can do that floor again, and it will still pull mud out. However, the water now only looks dirty, not pitch black and leaving full sludge in the bottom of the tank it sucks back into. Oh, and, this is about a $1500 unit.
    • This is mine, works a treat for the cars, suction is good, I use the Bissell clean and protect stuff I have found giving it a good spray and light scrub with the soft brush on the head of the nossle for carpet, and a rub with a microfibre for cloth seats and cloth door trims, prior to another quick spray before vacuuming it up works the best @GTSBoy You would surprised on what it gets out of carpet and seats that actually "look" clean, I recommend that you test drive yours when you have a little time to kill, then post pics of the muddy looking water that I believe you will find
  • Create New...