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High Flowing Standard Rb20 Turbo Worth It?

eightsixboy

By eightsixboy,
in Engines & Forced Induction

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eightsixboy Mentor

eightsixboy

Posted
Posted

After installing my vg30 last weekend I might have to put the standard turbo back on due to the vg30 being a little noisy after some dyno time, I was just thinking that maybe i could high flow the standard turbo but would it be worth it? Or should i just take the vg30 of and high flow that?

I'm not after huge power either, around the 170-180 rwkw mark so i could prob get that from a standard rb25 turbo at around 12psi?

The vg30 only made 147.5 at 12psi so yea I think its a little tired.

BenSm Enthusiast

BenSm

Posted
Posted
yeah if you only want 180rwkw the rb25 in std form should be good for that on RB20

agreed, dont bother with the rb20 one, yuck... lol. took mine off to change the exhaust gasket and i dont understand how it can push 10psi throw it. lol.

bubba Grand Master

bubba

Posted
Posted

As others have said if you're going to highflow, better off starting with something bigger (Neo has bigger exhaust housing than normal 25).

But if you only want ~180rwkw my RB20 made 183rwkw untuned through an RB25 turbo.

discopotato03 Grand Master

discopotato03

Posted
Posted

Your call but I think you'll find the VG30 turbos turbine housing a bit big for an RB20 , don't forget that a 3L is half as big again as a 2L and they make considerably more torque off boost as well .

I'm not sure if you are aware but the BB VG30 turbo actually uses a slightly smaller compressor wheel than the RB25 ones do - at least the R33 RB25 ones . If you try to fit the compressor housing off the VG turbo on an R33 RB25 turbo it won't go over the compressor wheel .

For a straight bolt on the R33 RB25 turbos are probably the go . They don't look it but the RB25's turbine housing passage is slightly larger than the RB20's one so I think a good try .

The OP6/VG30 turbine housing is a reasonable amount larger than the RB25's one , more than the difference between the 20 and 25 .

A .

jonesl Experienced

jonesl

Posted
Posted

I just installed a rb20 hi flow. so ill shed some light =)

First day i was very un impressed with power :whistling:

but after about a week i boosted it to 12psi and its pretty good.

Has no trouble frying 10" wheels on the back.

Response is amazing to!! By far the best thing about it :happy:

Iv driven rb25 turbo r32's. The hi-flow is defiantly better, But it cost 4x more so it would want to be better.

but at least you know its new and tuff. Not a 15 year old ceramic rape victim.

hyper gear (who rebuilt it, and is a legend by the way) have said it will make an easy 200kw.

Well its not the best turbo for the money. But its still going to be more fun than a vg30 hi flow.Yuck.

I recon choose between rb25 stocky. Or rb20 hi flow if you got the cash. F**k the vg30.

good luck =)

  • 3 weeks later...
DJRIFT Veteran

DJRIFT

Posted
Posted

dragging this up but anyway.

a race car i have worked on for the past few years started life with a r33 GCG hiflow. laggy as hell. made about 240rwkw on an rb20.

it failed and joined the list of failed ones i know of. GCG said it would cost just as much as it originaly did to get it rebuilt

in the mean time put a stock rb20 turbo back on and changed the car 100% the bloke was wrapped with having response again.

so we got a rb20 turbo hiflowed by precision turbos. it was also cheaper. put it on and its grate. highly recomended. spools fast and makes 220rwrw. comparison on dyno graph shows it drops off at the top but better every where elce.

also getting a turbo hiflowed by billet turbos in the next few weeks for another car. they wheel specks are the same as the HKS 2530 going in to a rb20 turbo.

as far as stock turbo bolt ons on my own car i have run a neo rb25 turbo and it was grate. they are noticable better than the r33 turbos. i run a r33 turbo on my street car and after doing a swap between a stock rb20 turbo and the r33 turbo i found it has a few hundread rpm more lag and far better top end.

Kinks Grand Master

Kinks

Posted
Posted
I'm not after huge power either, around the 170-180 rwkw mark so i could prob get that from a standard rb25 turbo at around 12psi?

yes, easily. no need for high flowing it. high flowing will hurt low end response. i had an Rb25 turbo (the later one with nylon compressor wheel) on my RB20 and it still boosted up nice and low, and was good to drive. Not quite the same response as the smaller RB20 turbo but there was more headroom.

Rolls Grand Master

Rolls

Posted
Posted

I have a gcg highflowed rb20 turbo, the specs are basically identical to their highflow rb25 turbo, just slightly smaller housing I think but they bore it out to around the same.

It is on an rb25 but it is on full boost by 3500rpm and has made about 6-7psi by the high 2000s.

Very responsive and makes over 200kw on just 10psi, expecting about 240 on 16+

On the rb20 I would do as the others have suggested and stick with a stock rb25 turbo, anything much bigger and you will be sacrificing response for top end, won't be much fun to drive.

  • 1 month later...
johnGTS-t Collaborator

johnGTS-t

Posted
Posted

im a bit confused by power quoted here. I have a R32 Gts-t with a highflowed turbo and I only get 220kw at 19psi running 104 oct race fuel. on pump it only has 200kws

has 444 inj, 040 pump, jjr coilpacks, apexi ecu, z32 afm. I was thinking of getting a R25 turbo highflowed so i could have more power and maybe less boost.

Rolls Grand Master

Rolls

Posted
Posted
Find a new tuner imo

if its an rb20 turbo with a sleeve bearing then its possible it just has steel wheels and is barely bored out. I've got a highflowed rb20 turbo on a 25 making only 240kw on 18psi, depends on the housing, the bearings and the trim wheel used.

not to mention how much dynos can vary.

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