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just an update, put the vac line from the wastegate accuator to the intercooler piping just before the factory pipe that crosses over the motor, and it boosts in almost 500 rpm quicker, cheers for the help guys.

If you're on a budget just put an rb25 turbo in it. You'll have a lot more fun that way. I've been down the rb20 with gt2876 route and the terrible amount of lag got annoying really quick. I tried different wastegate vacuum locations and a smaller ex. housing with no big improvements. The best I got was full boost at 4000rpm with nothing but slug performance before that.

The cheapest way to fix your problem is as Dobz says above and go for a standard RB25 turbo. Though you'd be lucky to hit 200 rwkw.

If you want to stick with the current turbo, you could go for a Mx Performance Exhuast manifold (with 1" runners) and external gate. I have done this with my HKS GT-RS turbo and it has transformed the power delivery. I have also heard of good results with the RB20 (full boost on a GT3076 at 3600rpm) with this manifold setup. Though if you went down this route, you wouldn't get much change out of $2000 once you have it installed and a custom dump made to suit.

By limiting yourself to less than $1000, you don't really have much option other than the RB25 turbo.

Id say from the acuator to the front housing is the best or intercooler piping I guess. Shorter the line the better.

Getting boost signals (gauge or controller) from the manifold would be considered best because then all/any boost drops have been accounted for.

Where as off the housing where the turbo makes say 12psi, by the time it reaches the manifold it may have dropped to 10psi, due to inefficient intercooler design.

  • 2 weeks later...

havent really got much of a chance of buying much, job i have barely covers my bills, let alone 2g on turbo parts, also have to move interstate end of this year so saving is bit more important atm, was looking to find a cheaper way to fix what i have, but guess there aint much choice really :/ will just have to deal with it.

I wouldnt say the hks 2535 is the best for a rb20, i found it abot laggy but went good up top, 2530 is better but alot harder to find one. But both good good for 220kw+

Ifyou found a HKS 2535 laggy on a rb20 then there was something wrong with your setup or you need to find a new tuner.

You could maybe have your compressor wheel taken off and put a gtx67mm wheel on it in the future to make it less laggy. Be cheaper than buying a whole new turbo. I'm sure stao from hypergear will do this for you.

  • 3 weeks later...

living in out rural S.A at the moment but will be heading up to darwin in september to live, but i will keep that in mind once i get up there and find a decent person to work on the car, any one know a decent tuner in darwin for turbos and such?

It would have to be one of garretts biggest mis matched turbos in gt form. I guess there must be a market for them though. I can't imagine how lazy the gtx version would be on a rb20/25. Makes my stomach turn thinking about it haha.

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