Turbine clipping, would it be benefitial with my combo?

[86Shelby]

I'm building a 2.5L for my GLHS and am contemplating having the turbine clipped a bit when the turbo is rebuilt. I'll be using the stock garrett TII unit. I can't ante up the cash for a .63 turbine housing so I thought this might be a good alternative.

I plan on running in the neighborhood of 18 psi, 2.5" or 3" exhaust, stock '89 2.5 longblock, 2 piece intake, +20% injectors, ported exhaust manifold, MP GLHS electronics and an A555.

[crazy1eye]

Yes, it is a good alternative to the .63 housing, it will increase the flow at higher rpm. Do it.

[glhsken]

Nope.... Clipping does little to help... Ask 4sfed4. He has the dyno plots to prove it.

You can't beat the .63

[gdonovan]

Quote:

Originally posted by glhsken Nope.... Clipping does little to help... Ask 4sfed4. He has the dyno plots to prove it. You can't beat the .63

Dyno testing here has shown the same thing- If the mass of flow can't reach the wheel through the restrictive housing making the wheel more "free flow" will have little effect.

Bill Baker went from a .48 with a STAGE III wheel to a .63 and a STAGE II wheel and the car picked up 30+ hp.

A stage III wheel is far more free flowing then any stock wheel clipped.

Gary

[crazy1eye]

Ya, I forgot to mention the increased lag. I thought I read that it is a good cheap alternative to upgrading to the larger housing, although I probably read it concerning DSM's, oh well never mind.

[86Shelby]

What I'm gathering here is that if I really want a better flowing turbo I need the .63 housing and a better turbine wheel. What I'd like is a turbo that I can grow into as I continue to modify the car. Future plans are a ported head and that new turbo header I saw a pic of a few days ago; that looks pretty appealing!

Would the super 60 turbo be a more sound purchase with my inteneded mods? Or would simply the better turbine and .63 housing work well with the stock spec compressor and housing?

[Shelby VNT]

Yes, go with the Super 60. You won't be disappointed. It's a great turbo for a street driven car and it easily supports 300hp. It spools pretty quick, and at 3000 to 3500 RPM it's already at full boost on my dad's 2.2 liter. You might have it better with a 2.5 making the exhaust. Just make sure you get a true S60.

[glhsken]

For about the same $$$ a t3/4 hybrid stage II exhaust wheel is the ticket.

Spooling is nice.. But too much of a good hing will make the car worthless on the road as your HP (or torque for these cars) increases. Full boost in gears 1-4 in my car is worthless at 3500.. But worth a LOT to the tire companies.

I like the slower spool of the t3/4. Like you I have a 100% stock head and just a ported ex manifold. I dropped big et (.5) and increased 5 mph in the 1/4 on street tires (not just dot legal rather 100% street tires)