Hi-flowing A R33 Turbo Vs R34 Turbo

[SS8_Gohan]

Hi guys,

just wanted to pick some brains here as i've only found out this rather crucial difference. The R34 rear housing on the stock turbo is larger than the R33 rear housing. Which got me thinking, would an R34 hi-flowed turbo be better than a R33 hi-flow or would the difference be negligible?

I recently got a hi-flow but at the time didn't think there was a difference between the 33 and 34, and the rear housing used was a R33. My R34 turbo is fine (after finding the leak in the FMIC piping) and wasn't used to make the hi-flow.

I see potential in the hi-flow i've got at the moment, and it's a new one that hasn't been tried before (with the bugs that go along with it, still being worked out) but wondering whether i should switch to a R34 rear housing? Obviously i won't bother if the difference isn't going to be worth the hassle. I'm not sure if it's easy/hard to just switch the rear housing around.

Keen on your thoughts

cheers,

daniel

[geraus]

what highflow did you get ? Yeh it does matter that rear housing makes a diffrence the more bigger more power. I just got my highflow done as well from hypergear!

[femno]

Big difference! Thats why 34 turbos are so popular...everyone hi-flows them for their 33s to make decent power.

Depends what you want...good midrange or good top end. Obviously the 33 housing will run out of puff sooner than the 34, but the 34 will be slightly laggier.

If your hi-flow turbo has a larger rear wheel you cant just swap housings, the 34 housing will probably need to be machined to suit.

[bubba]

I would think that the hiflow'd 33 turbo would have had the exhaust housing machined for a larger wheel so swapping on the stock neo exhaust housing isn't going to fit...

I have a hiflow'd neo turbo on my stag and it seems to be a bit bigger than all the other hiflows I've read about, it's making ~240awkw @ 12psi when the others I've seen make 240-260rwkw @ 16-18psi..

[R31Nismoid]

Its not a big difference - unless you call big "10-15rwkw" because thats about all it is between the two housings.

Considering your going from 190-200rwkw to around 250rwkw (R33) or 260/265rwkw (R34)... you really wouldnt notice a BIG difference.

You'd see it more on a dyno sheet than actual driving

[_Ryan_]

Its not a big difference - unless you call big "10-15rwkw" because thats about all it is between the two housings.

Considering your going from 190-200rwkw to around 250rwkw (R33) or 260/265rwkw (R34)... you really wouldnt notice a BIG difference.

You'd see it more on a dyno sheet than actual driving

fixed

street car you would be wanting the response?

[SS8_Gohan]

well, how big of a response difference are we talking about?

because the one i have in there at the moment is practically the stock response, the graphs on a hub dyno are very similar, so i could probably trade a bit off down low because the hi-flow i have at the moment is hardly noticable in terms of difference to response.

would i have to "run in" the turbo again if i changed the rear housings over?

[W0rp3D]

I have a high flow with a vg30 rear housing (im pretty sure its the same size as the r34 housing) i hit 16-17psi at about 4000rpm.

The main reason for a bigger rear housing is so it can flow more exhaust gas's, to take full advantage you probably need to make a high flow to suit, with the bigger rear housing you could run a bigger compressor with out it choking the exhaust housing and causing a restriction, atm im making about 210rwkw on a hub dyno (before it was tuned on a hub dyno i was making 223 on a normal dyno with standard ecu so im guessing hub dyno's read less) but i am also running the afm at 110% and have seen 100% duty cycle on the pfc hand controller.

[_Ryan_]

well, how big of a response difference are we talking about?

because the one i have in there at the moment is practically the stock response, the graphs on a hub dyno are very similar, so i could probably trade a bit off down low because the hi-flow i have at the moment is hardly noticable in terms of difference to response.

would i have to "run in" the turbo again if i changed the rear housings over?

bass junky had a 34GCG highflow with poncams, do a search for a graph? think ~260rwkw IIRC

[R31Nismoid]

fixed

street car you would be wanting the response?

whops

edited!

But the difference is minimal, its a few KW and a few RPM, both of which over 6000rpm you wont notice a lot

For the cost of pulling it off, putting on a R34 rear - totally not justified in my book

[Al]

I had an r33 hi-flow got it tuned and made 250ish rwkw. Got fed up of the compressor surge and upgrade to the larger VG30/R34 rear housing and made 274rwkw. Still had the compressor surge issue and sold the turbo to a friend (who loved the sound) and the turbo was fitted to his std rb25neo and made exactly the same power, on the same dyno, as my 33 did with poncams and porting.

The increase is more like 20rwkw.

[R31Nismoid]

Was that a GCG one or not?

Every hi-flow is different, and if yours was surging that's because of the wheel selection.

It depends as much on the wheels used as the turbo housing to start

[hypergear]

R33's rear is more like a .48, R34's is in .56, and VG30's in .63 which is the biggest one.

There will be power gain with bigger turbine housings. specially with .63 rear we can high flow it to 500HP. with .48 and .56 the main issues is back pressure. There are few ways to minimize it trade of with response. 250rwkws is about the max they can do.

[W0rp3D]

R33's rear is more like a .48, R34's is in .56, and VG30's in .63 which is the biggest one.

There will be power gain with bigger turbine housings. specially with .63 rear we can high flow it to 500HP. with .48 and .56 the main issues is back pressure. There are few ways to minimize it trade of with response. 250rwkws is about the max they can do.

isnt a standard 33 .6 and a vg30 .8?

[Al]

Was that a GCG one or not?

Every hi-flow is different, and if yours was surging that's because of the wheel selection.

It depends as much on the wheels used as the turbo housing to start

Mine was known as a sierra-sierra combination, apart from that i have no real idea what was done to it, before i purchased it second hand, as a r33 std hi-flow. I know GCG no longer made this combination, with the bearing centers, due to the compressor surge issue.

I agree with the regarding wheel size, the problem was that the compressor wheel was too big for the housing. By going a bigger exhaust housing i was trying to keep the factory looking turbo, but moving the flow a little higher in the rev range, where the engine may use the extra gasses.

[Al]

R33's rear is more like a .48, R34's is in .56, and VG30's in .63 which is the biggest one.

There will be power gain with bigger turbine housings. specially with .63 rear we can high flow it to 500HP. with .48 and .56 the main issues is back pressure. There are few ways to minimize it trade of with response. 250rwkws is about the max they can do.

The R34 GTT had two different exhaust housings, one was identical to the VG30.

I have seen this on my mate's (bassjunkie) 34, when he purchased a VG30 housing for his hi-flow, only to find the housings where identical, with the same casting numbers, etc.

isnt a standard 33 .6 and a vg30 .8?

[hypergear]

In some earlier high flows people were using T04E 71mm 16 fins 59 trim wheel with a To4E 74 Trim turbine wheel. That creates very high manifold pressure on the turbine side which forces the shaft towards the comp housing. Doesn’t take long to wear out the thrust washer so the comp wheels hit its housing then twist the shaft looks like some thing fail into the turbo.

Edited March 4, 2009 by hypergear

[SS8_Gohan]

ok guys, i have a dead R33 turbo here and i've got my R34 turbo from my car....

The r33 rear housing has "2IU" embossed on it, and my R34 rear housing has "OP6" embossed on it... does that give me any size indications at all?

[ZILR-34]

r33 highflow = 450hp

r34 highflow = 480hp

based on GCG readings

[R31Nismoid]

ok guys, i have a dead R33 turbo here and i've got my R34 turbo from my car....

The r33 rear housing has "2IU" embossed on it, and my R34 rear housing has "OP6" embossed on it... does that give me any size indications at all?

… we've already told you.

R34 - slightly bigger

That’s it.