Hi-flowing A R33 Turbo Vs R34 Turbo

[SS8_Gohan]

according to the turbo builder there is a .56 and .63 rear housing size. i'm trying to determine if i have the .63

if it's the .56 then i guess it's probably not worth the change over, as you've already pointed out. I will however seriously consider the change if i have the .63 or can get a .63

[MATT_R33]

hey guys. am i right in assuming that the R34 turbo will fit straight onto a Rb25 S2 manifold with all the same piping and everything with no mods?

[R31Nismoid]

according to the turbo builder there is a .56 and .63 rear housing size. i'm trying to determine if i have the .63

if it's the .56 then i guess it's probably not worth the change over, as you've already pointed out. I will however seriously consider the change if i have the .63 or can get a .63

R33 is smaller = .56 or whatever

R34 is larger = .63 or whatever

OP6 (via search) - has always been .63.

So you know where the base is to work out backwards in this instance that R33 would be smaller than .63... ie .56

[SS8_Gohan]

true, but i'm getting confused as previous posts indicate the R33 is .48 and the R34 can be EITHER .56 or .63 - Al previously mentioned that the 34 as TWO different rear housings.

[Al]

OP6 is the same size as the VG30 rear housing, so you have the bigger of the two housings, available for the R34.

[Al]

hey guys. am i right in assuming that the R34 turbo will fit straight onto a Rb25 S2 manifold with all the same piping and everything with no mods?

I am 95% sure in saying yes.

[paulr33]

mythbusters ahoy

GTR twin turbos are 0.48 a/r rear

so therefore a single GTS turbo would be larger, as its a big single, so 0.56 a/r rear for GTS turbo sounds about right

and 0.63 a/r for the OP6 sounds about right again - OP6 being for VG30 single turbo setup

[benl1981]

stick with your r33 cover. You have better boost response because of it. R34 will be laggier. I had an R34 cover and swapped it to an R33 on the BB highfow as I wanted better response

[discopotato03]

The turbine housing A/R number is just that - a number .

The important thing is the application of the largest of the three housings (OP6 one) - which was a four cam single turbo VG30DET .

I think the best way to look at them is 2L size , 2.5L size and 3L size .

I'd say if you fitted the OP6 housing to an otherwise std R33 GTS25T you would get a noticable lag penalty because the housings passage is larger and gas speed will be slower through the turbine blades .

If you did things to pull the bottom end torque up like increased CR or better cams or porting etc the loss of low end starts to disapear .

Nissan got around it in one case by using a larger 3L engine and another by having variable cam timing on the R34GTt .

The ability to vary cam timing makes a huge difference because you can alter the valve overlap period throughout the engines rev range . With less overlap at low engine speeds you can drag the dynamic or effective compression ratio up and not have the lack of low speed torque that say the R33 version would have with the larger OP6 turbine housing .

I noticed that people are quoting differences in power output ie the std vs OP6 housing on R33s .

There would be other influences such as more sophisticated engine mamagement and cam profiles etc but from memory an R33 made 184 Kw out of the box where an R34 did 206 Kw ?

I suppose the ~ 20Kw gives a rough idea of what the potential difference would be minus the electronics and cam profile differences .

Thoughts ?

Cheers A .

Edited March 6, 2009 by discopotato03

[MacGillaZ]

Pity you couldn't get a better curve with your turbo tune today Daniel

I have an OP6 VG30 rear housing just sitting here if you really want it, but I think you might be hunting down somebody else atm

Edited March 13, 2009 by MacGillaZ

[SS8_Gohan]

hey mate, nice to meet ya Andrew wasn't it? or have i got that completely wrong? sorry, i am shocking with names. Lots of people say that, but i really am stupidly bad with names.

i'll send ya a pm bout the OP6, keeping my options open at the moment.