Rb20 With T25 High Mount Mani

[Justa32]

got my high mount manifold and new turbo setup, the manif old is to suit an rb20 but has a t25 flange and the turbo is a gt3037s... apparently its suppose 2 bring on boost alot faster just wondering if any1 has a similar setup?

[Justa32]

helppp me

[dead32]

i fail to see a question in there?

any gt30 based turbo isnt gona be good on a rb20 for response, yet alone one with a t2 flange.

[Justa32]

im asking if any1 has any expierence with a t25 style flange on an rb20 and if its made a diference to the way the turbo spools comparied to a t3 1

[dead32]

im asking if any1 has any expierence with a t25 style flange on an rb20 and if its made a diference to the way the turbo spools comparied to a t3 1

fair enough, no it will be worse because the t2 flange is smaller, therefore choking it up more so then a t3 based flange.

[Justa32]

mmmmm so in no way it will b a plus side to having a t3? not even up the top?

[wolverine]

why don't you buy a T3 flanged manifold......like the one below.

Edited July 17, 2008 by wolverine

[Justa32]

becoz i already have the mani and the turbo to suit

[RBsileighty]

fair enough, no it will be worse because the t2 flange is smaller, therefore choking it up more so then a t3 based flange.

Not true... T25 might actually spool faster due to higher exh velocity due to the smaller cross section... There are plenty of T25 flanges on SR motors that are making very decent power levels with T25 based name brand kits so I would highly doubt it would be a restriction... especially on a RB20. I think there is more to be said for the design of the manifold being a restriction (lots of tight bends etc) than the potential of a T25 restricting flow vs a T3 flange at a GT3037's power level on a RB20.

[Justa32]

exactly what i was thinkin RBsileighty, was speaking to the guy who will b doing the install and tune he was saying that ill b coming onto boost alot faster than an ordernary t3.. i was just seeing if any1 here has actualy done this b4 and if ill lose any power up top? ill be running a hks gt3037s .73 through the t25 on an rb22.. suppose i like to b diferent ill post dyno results when its done

[RBsileighty]

Justa32... .73 is your AR? What's your complete setup? I don't think you'll run into a choke flow situation at the exhaust with the power levels you'll probably be hitting at any RPM... chances are you'll have a restriction earlier in your engine's air flow before the T25 flange becomes to small. Proper manifold design is key to maximize both your mass flow and your gas velocity so again I think the manifold itself or even the head would be a restriction before the cross section of the flange needs to be bigger (unless it's compensating for a really bad manifold design).

I'm no expert, but I hope this helps...

[discopotato03]

If the turbine housing on that HKS GT3037S is HKS as well it would almost certainly be A T2/T25/T28 (same) flanged GT30 housing because HKS had them made that way for SR20 and at times twin GTR applications . If you see twin non gated 2835's or 3037's they are generally like this .

Pics of the exhaust housing will tell us for sure .

When you think about it HKS had turbine housings up to the 1.12 A/R size made with the T2/25/28 flange , the only available HKS housing for their GT3240 (cropped turbine smaller comp trim GT3540R) is that flange in a 0.87 Ar housing .

Pics , A .

[Justa32]

yeh disco, its a hks housing non gated i got with it an external hks gate, its 0.73 ill get sum pics when i get home but im certain that its the flange ur talking about... so most ppl running single gt3037s on rb20/25's use garret housings then?