I have a 383 with a t trim 7" crank and a 2.95 SC pulley. It's making around 10-11#'s with this set up. With formula I got it, I figured that I had to shift around 6200 without overspinning the charger. I could have sworn that I seen someone getting about 18#'s out of a T Trim on a 383 smaller pullies. How is this possible. or am I figuring wrong and shifting early when I can shift later.


Any help would be great.
Thanks GS355

 

Ive heard a couple of people with your application running high boost on a t-trim. Im sure somebody with your setup will reply...ttt for ya bud

 

T-Trim....


Straight cut spur gear
Fits engines up to 825 horsepower
Maximum airflow: 1,200 CFM *
Maximum boost pressure: 26 PSI *
Maximum impeller speed: 55,000 RPM
Adiabatic efficiency: 73% **
Available with straight or curved discharge and clockwise or counterclockwise rotation



Chris

 

Hey George, I'm glad you posted this. It made me do some more checking. I had planned my T-trim around running it around 62000 rpm. This is what I had found on one web site as the max impellar speed. Now I have found that max is 55000 and called Vortech to confirm. This means that I will have to shift at 6500 instead of the 7000 that I had planned or change pullies. I hate to hear that you are only getting 10-11# boost. I was hoping for around 14 on my 396. Looks like you and CJ will both be coming back strong.

 

I'm about to go ouside and remeasure the pulley size and makesure I'm figuring everything correctly. I think I can go 2 sizes smaller but I don't want to overspin the sc. I'll get back with you guys.

Ronnie how long before the vette is running. Should be prettty tuff with a blower if thats the route you are going.


George

 

Hopefully I will have it running in the next week or so. I have the engine in and one head torqued so far. Yea, I'm going with the T-trim, solid roller 396, AFR 227 heads and so on. I got the 8 rib pulley set up with a 7.6 crank pulley and a 3.125" blower pulley. If the calculations are right, it should max out at just over 6500 rpm. I may have to get a larger pulley so I can take it to around 7000. I'll have to see what it pulls to off the blower first.

 

Ronnie, what formula are you using.

I'ld like to make sure I'm getting the correct one.

George

 

http://www.vortechsuperchargers.com/units/

Go to the above website and they have a place to go and put in your pulley sizes and rpm and that will calculate the impeller speed.

 

That helped alot Ronnie . The formula I had was off by 600 rpm. I figure that I can shift around 6600-6700 now or get smaller pullies. For now I'll try it like it sits. Now If I can get the BLM's straight, i'll be doing good.


George

 

If your cam and all are good to the higher RPM, I would do that instead of the smaller pulley. Less chance of slippage with the larger pulley. Let me know what max boost you end up with. Mine will be less than what you get. I would think so anyway.

 

Yeah the cam is good for the high RPM. I let you know what #'s I end up with. I figure I should be able to get a few more #'s getting the SC in the higher range.


George

 

You are never going to see high boost with a T-trim and a 396 with a good set of AFR 227cc heads. The blower is simply to small at 1200cfm. Not to say it wont make big hp, just don't expect to see big boos numbers. Your hp will be limited by the blowers max flow.

Rich Krause