I'm running a Turbonetics TC76 F-1 0.96A/R on a 350 6-speed, mild heads/cam.

I'd like the car to spool faster. To me, the blower had more mid-range and came in harder than the current turbo setup. Is there a better choice for the turbine housing A/R?

Strictly a street car & also stock rods so limited to about 550-600 CSHP anyhow.

Thanks,
Scott.

 

Hey Scott, have you exhausted the tuning efforts yet? Tuning can really help with spool. If you have, try a .68 A/r or .81 A/r. Doesn't hurt to try.

 

Jon - I haven't even started tuning. Still got the FMU on it

I figure I'll try a 2-bar setup in the spring and might as well try something like a 0.81, especially with the modest goal of < 600 crank HP.

Nice score on the TIG - more options and capability is a definite plus.

-Scott.

 

ZDefinitely tune that puppy the right way MY BCM should be here tomorrow, so I may be able to get the shop car up and running

I can't wait to hook the tig up... I'll post pics this weekend.

 

That's a BIG turbo for that low of a power goal... Lower your A/R for sure should make it more inline with the power band of your motor.

 

Is this the same Turbo as mine, TC76 w/MPS Wheel? On a separate observation, I would never think a Turbo would hit as hard at lower RPM's as a Supercharge. I think they just are different approaches.

S/C = Lots of Torque down low, good power up high(consumes a fair amount of power to drive the device.

Turbo = Moderate Torque down low, GREAT power up High(consumes no power to drive)

Some guys are making low RPM Turbo boost gains with a Turbo valve(shuts off half the scroll at low RPM's, forcing ALL the exhaust into a smaller aperture, thus spinning the exhaust turbine much faster. I believe 33% faster is the figure I'm seeing)

 

That makes sense. Do you think the 0.81 would be best? They offer a 0.68 also.

Pretty much. The F1 incorporates the latest Turbonetics technology to maximize exhaust energy. It's has 10 blades, extended tips, and made of 713C Inconel.

Thanks,

 

A .68 is too small and will choke off a 446rwhp car, .81A/R housing is probably just perfect.

If you put the car in 2nd gear really low rpm and floor it, at what rpm does it hit full boost?

 

It takes forever. Feels like a stock 350 until well into the rev range. Maybe gets into boost at ~3800/5psi and then ramps quickly to 10psi at 5000. I shift at 5500 right now.

Pretty sure the header gaskets are done. I had a bunch of the bolts back out. But it still wasn't always right. Like RealQuick said, I got to get this thing tuned. The FMU takes the motor rich almost right away. I see 10:1 AFR (which is max rich on this gauge) right when boost comes up ~4K.

If I get it up a little bit like 3500 and side step the clutch in second - about 95% of the time it wont even break street tires. It will usually bog and take a two count to start 'feeling like a car'.

 

Ya give the .81 a try
For reference, on that same 2nd gear test, my rear mounted STS turbo was at full boost (7psi) @ 3000rpm. http://www.youtube.com/watch?v=rdjh3EY6shU