Wastegate Sizing

[turbotalon1g]

Ok folks, i have been busting my brain with searches and reading on this, what are your experiences/research show.

So far i have seen that if you are going to use a big turbo and run high boost you can use a small wastegate, but if you are using a low backpressure turbo with plenty of airflow you will want the biggest wastegate that you can fit on there.

Please help

Thanks
Aaron

[Speedfreak]

Well you should be telling us what your plans are for your car first, then we can answer what sizing will work for you. What turbo, what manifold, and what placement for the wastegate? Then what amount of boost do you plan to run? On what gas? What size motor?

The reasoning for being able to run a small wastegate on a larger turbo when running high boost is, it really doesn't have a big job to do. If you tried to run low boost for pump gas or something, it'll just boost creep.

Wastegate placement also has to do with how well it will work. On my car, my Tial 40 should be able to do the job with my 61. But because of my Turbonetics manifold with the wastegate placement on one runner, it just wants to creep its way up to 25lbs or so no matter what.

[JET]

For comparison I also have a Tial 40 on a 61, but I am mounted off the 02 housing. I can run 15 psi (1 bar spring) without an issue. Mine is an SCM61 though, both are 2.4's.

[Kracka]

I had a Tial 35mm and ran 15psi on my 20G with no problem.

[FattyBoomBatty]

I know of a conquest with a t3 1.15A/R exhaust and the tial 38 is mounted on one runner (it's more of a log style though) and he doesn't have any problems keeping it at 12-13 psi.

[At-Least-It's-An-Evo]

I had an Innovate Pro Gate 42mm on my T67 and crept from 14 psi(spring pressure) to 17-18 psi (mounted off the collector of the manifold). Anything over that was golden.

[turbotalon1g]

SOrry, plan is scm61, 2.4, off O2 housing, FP Race mani, E85, so the max boost that i can push on that.

[Pushit2.0]

With a little porting I would think a Tial 38 with a 1bar spring should be good for your set up Brown, unless you want to eat diamonds so your dookie twinkles you can get a Tial 44 or some HK$ monster.

~John

[gofastman]

Wastegate placement also has to do with how well it will work. On my car, my Tial 40 should be able to do the job with my 61. But because of my Turbonetics manifold with the wastegate placement on one runner, it just wants to creep its way up to 25lbs or so no matter what.
I would say placement is far more important than gate size, avoid the obvious stuff: no 90* angles, don't vent only one manifold runner, if possible vent the gate separately from the turbo exhaust. if not, merge them together farther down the downpipe (at least 18" from the turbo exit) at a gradual angle.

[JET]

My 40mm is plenty for that same setup, so the 38mm would probably be fine also.