Thinking about a T-Trim instead of the S Trim

[Diabolic]

The intercooled S-Trim is in my 93 Lightning. I saw a max of 14#'s this last track outing during the DFW Fall Cruise. Truck weighs 4720# with me in it. I figure the flywheel hp to be around 550, but I still only have 18º of total timing in it and my AFR was rich at .76 Lambda. I project 575-600hp at the flywheel with the AFR leaned out to .78 and maybe 22º of total timing in it.

I'm really considering a swap to the T-Trim over the S-Trim. If I keep the impellar speed the same, what sort of boost increase should I see? Currently when the belt isn't slipping I can see 16#'s after the IC at 52,000 RPM< impellar speed. The T-Trim flows more than the S-Trim and I'm honestly looking to pick up another 25-40hp at the same impellar speed and shift RPM. Anyone here done the upgrade, and if so what improvement did you see?

[034V]

If it is more efficient pressure, it may be less..

Boost is irrelevant with the proper density and restriction limitations.

If anything I would expect to see less (or right at the same) boost with a cooler charge and a broader boost curve.

[034V]

S trim = 1000 cfm
T trim = 1200 cfm

1200 x .069 = 82.8 x 10.86 = 899.2 less power to run it = (shooting 25% loss) = roughly 624 rw supportability with efficient pressure.

[Diabolic]

My thought was that with similar impellar RPM and moving more air, the T Trim would make more boost sooner. I was hoping anyway.

[Diabolic]

I'd like to see it take me into the 7.40 range at full weight. Then I'll stroke it, Dart block it, and go for a daily driver that runs in the 6's or high 10's. that's the goal. Quiet, smooth idle, and cold AC.

[034V]

My thought was that with similar impellar RPM and moving more air, the T Trim would make more boost sooner. I was hoping anyway.

Not sure if it would build boost sooner but I know it would add power across the band.

[shumpertdavid]

The F1-a I had made more boost with a 4" pulley (21 psi @7200rpm) and started making boost @ 2200 rpm, than the D-1 I currently have with the same 4" pulley (16 psi @7200 rpm). The combo is exactly the same other than a smaller head unit. The step up ratio and impeller design difference in the F1-a accounted for the earlier and higher peak boost

[Broncojohnny]

I have done the swap. Your mileage will vary but on a 302 with decent heads the T-trim wouldn't build boost as fast. It made a few more psi up top but in the mid range it was slower to get there. It isn't a bad setup if you have traction problems.

[Diabolic]

I'm going to try this hub+Gen2 lower ring first. This way I can run a much larger blower pulley and eliminate the belt slip. This way I can go with a 3.25" blower pulley instead of a 2.85-2.95 and get the same impellar speed. The lower can be interchanged. I'll start with 9.1" from Metco. I'd like to see what happens with less belt slip. Maximize what I have then go from there. I'll be on the lookout for a T-Trim head unit. Anyone have one for sale?

[Cobraman]

I always wanted to do the wastegate setup in this article. May be the solution to your problem. Just run a small pulley and use the wastegate to control the boost. That will make the boost come in sooner.

http://www.musclemustangfastfords.com/tech/mmfp_0708_vortech_centrifugal_supercharger_wastegate_install/viewall.html

[dville_gt]

I always wanted to do the wastegate setup in this article. May be the solution to your problem. Just run a small pulley and use the wastegate to control the boost. That will make the boost come in sooner.

http://www.musclemustangfastfords.co...l/viewall.html

this doesn't deal with the shaft speed issues.

[shumpertdavid]

Nor does it cure belt slip, but the larger crank pulley allowing a larger blower pulley does. Belt wrap was always the main point I addressed, was always able to get good belt wrap on my mod motors

[Diabolic]

Man used T-Trims are as scarce as hen's teeth!

[Diabolic]

Well I picked up a Novi 2000 today so let the games begin.

[shumpertdavid]

that ought to do it