Restrictions of various combos - TH / SV?

[Tim_K]

Of course, I know the best way to build a new turbo is to use a .63 turbine housing and a 3 inch swingvalve. However, those parts are very expensive, and given my current financial situation (dismal), I've got to cheapen it up a bit. I want my '89 2.5 Turbo Spirit running 13's at over 100 mph this year, then maybe this winter I can save up some more cash and build the turbo right (Super 60, .63, 3 inch, quick spool, etc).

So here are the various available combinations. I'm curious as to which part (TH or SV) will be the restriction in each combination. Also, maybe some of the more knowledgeable people here can place the 6 setups in best performance order, 1-6.

Here's the combinations we have to pick from:

1. .48 TH / 2.25" SV
2. .48 TH / 2.50" SV
3. .48 TH / 3.00" SV
4. .63 TH / 2.25" SV
5. .63 TH / 2.50" SV
6. .63 TH / 3.00" SV

I think the best performance list may be obvious, but then again maybe not. A .48 / 2.50" may be better than a .63 / 2.25", or something like that.

Can anyone take a guess at what the A/R of a Mitsu turbo is, RELATIVE to the .48 Garrett? I have one of each, and I'm guessing about a .34 - .36 or so.

Thinking of the Mitsu / Garrett THs reminds me of the old Hefty garbage bag commercials from the 80's. Remember those?

"HEFTY HEFTY HEFTY, wimpy wimpy wimpy"

[OmniGuy123]

I dont believe that mistubishi uses AR ratios on their hotsideds.

I would go for the .63 housing with a 2.5 if that was the only one you could afford. I think that you could hog out the SV a bit to gain a little more flow there.

I am willing to bet that a JY could produce a 2.5in. SV for pretty cheap. Heck, I would not give enough for the whole turbo from a JY to even be able to buy the SV from one of the vendors. They dont really go bad, so why not.

I would wait on the 3" SV until you are putting down some serious power.