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I know this question has been asked many times but here it goes again. I have built up an rb30/25 engine and it has come time to chose a turbo, the problem is i dont know a whole lot about turbos. After spending a long time on here searching and reading i am more confused than when i started.the turbos i am looking at are the

Garrett GT3071r 1.06ar with internal gate

GT3040 .86-1.06ar

GT3540 .86

I am hopeing for 450-500 flywheel hp my mods so far include

RB30 block rebuilt, bored 30thou weisco forged pistons 8:1 compression

RB25DE (r32) head with better valve springs std cams custom forward facing plenum

550cc injectors

Link plus engine management

Walbro fuel pump

FMIC

I would like a reasonable amount off driveability with minimal lag as this is a street car. Can anyone help me with some good advice on which off the above turbos would be most suited to my aplication also what size exhaust is required for this setup???

Thanks in advance.

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That would be a great idea for the fuel system, but you wont need to change the line size. Its a big job to do that, if your gonna change a few lines to 3/8 then you would need to change all the fuel lines to 3/8 all the way along the chassis rail. Thats alot of line.

I will give a full description on boost and rpm and everything else. There are a few others who have got that turbo on their rb30 hybrids who im sure can fill you in on those details.

My pick... The GT3540 with a .82

Will rank you in around 330-370rwkw depending on fuel/tune etc etc

It will have loads and loads of torque. Should be well on the show approx 3700rpm taking an semi-educated guess.

That suit you?

The walbro i found = useless.

Change it now rather than later as it'll only cause you grief. Keep it as a lift pump to a surge tank if your going that route, then use the bosch after that.

You wont require larger fuel lines. So scratch that off the list if you do the surge tank option

A set of cams probably wont go astray for this setup with whatever turbo you pick.

I have a RB30/25 in my VL commondore with a GT3040 & 0.82 rear. It's making 260rwkw @ 14psi and is very usable. Starts to spool by 1600rpm and 14psi by 2600ish rpm.

1st gear is useless if you nail it but 2nd gear hooks up fairly well if on a reasonably fresh surface. 235's and a 3.45 diff help there i guess. In an R32, you may find it turns the tyres a little easier.

For a 95% street driven car, IMO a GT3040 is spot on.

Thanks guys

The hicas has been 90% removed from the car but the 2 hydrulic lines still run along the chassis. thought about using these as fuel lines as they are quite large will need a good flush though.

I use them, works a charm. Not necessary for your power target though.

:P cheers :D

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