Good idea bad??

advantages dissadvantages???

I was thinking on using the 7" crank and 2.75" pulley.. with some slippage I should be around 51krpm with the S-trim... The max impeller speed is 50krpm... will the supecharger granade??

will it star trashing and not compressing??? WHat do you guys think?

Is it worth to have the low end boost as opposed to the top boost???

Dont know specific just want oppinions on this...

YS-trim is too big for my goals..

I know LJ has run 9.99@139mph with that combo... I dont want to get there.. but its a good thing to know that to someone it worked more or less...

 

I used to run 7in crank 2.75blower pullies and shifted at 6,500.

I wouldn't be afraid to do it again.

 

I think you had an aftercooler as I do... Did you notice any boost increase? power increase?

What was your max boost??? if I was pumping 10 psi and ~600rwhp I dont know if the S-trim has more power in it... Let me know

What was your best run?

 

I always ran the 7/2.75 so I have nothing to compare it to.

Peak boost was 12psi at 6,100. Midrange boost was about 9.

On the dyno it made 634rwhp and 580rwtq.

Best run on radials was -

2.0 60ft 12.0 @ 126mph

On ET streets it was-

1.7 60ft 11.2 @128mph

That was at 3,800lb raceweight.

IMO, the aftercooler worked great on the dyno for 1 run, but needs a much bigger resivoir and pump to be efficient in the 1/4 mile.

 

I think the aftercooler worked great.. I was wondering what your cam is??

Actually... It wont work correctly on the dyno after 2 pulls... no incoming air.. I feel it worked great on my runs till 150, it all depends on many things.. I added another radiator and I will probably change the pump... So we'll see...

I was doing 10psi with a worn impeller... so I expect around 13 or so up top...

another thing if peak boost was at 6100 what happened in the other 400rpms?

Let me know

Thanks

 

Boost peaked at 12psi at 6100 and stayed there until I shifted at 6500.

The cam I'm running is a cam motion grind, 214/222 @.050 114lsa

 

What about IATs? did they spike after that??

 

I honestly don't remember what the IAT's were. I never had any good logs of them.

 

Why do you mention s trim and then ys trim? There is a t trim...


And i would not overspin a s trim to much. I know of a few people that have grenaded their s trims doing this.

 

T-trim...Thats another option... but I thought if I was going to step up, might as well step up to something big...

But the T-trim will have the same power caracteristics as the S-trim Ithink... I hope I can get one over ebay... I'll wait..

 

AggieZ28 has a t-trim head unit for sale about 6 posts down from this one. You Still have the kit and everything right? All you need is a head unit.
Scott

 

Yes but I dont have the $ he wants.

 

This is the combo I am running. I am actually running LJ's 2.75" pulley and his belt, but with a new ASP 7" crank pulley. After dyno tuning, I inputed the data into Jim's PCM with Edit that he sold me.

Advantages - it shifted the power curve to the left giving you a larger area under the curve. Secondly, you will see more power at the lower end. This is nice if you drive this on the street a lot. I actually got the max hp at 600rwhp at 5600rpm at about 11.4# of boost on a mustang type dyno with 91 octane gas (LJ's tuning ). After that the boost stays pretty steady.

Disadvantages - you are overspinning your S-trim so it will heat up the air. But we are ok with that since we have the aftercooler where we can throw ice in when we are trying to overspin it. Secondly, the SC may go boom, but I am not planning to overspin it too much and will shift at about 6200rpm.

Finally, LJ actually found that for his setup, the 2.75 gave no difference on the strip than with the 2.95" crank pulley.

 

He did tell me that it improved his ETs...

I want that lower boost.. I am not planning on overspinning it that much actually.. I want 12psi no more than that.. the last time I went with the 2.95 pulley and 6.66 crank pulley I did 555 on the mustang dyno... I was seeing 8psi...

I will do it then.. I want more power down low

How much $ did the crank pulley ran you???

 

The best is to get it use, but that seems to be impossible.

The next best is to get it at www.performancess.com and talk to Steve. He gets it from ASP (direct is $250). If you email Steve, and tell him Hugh or Quang send you as a friend, he may be able to get it to you below $220 shipped. Sorry, I can't tell you how much he sold it to me in the beginning . Unfortunately, you will have to wait almost six weeks in either case.

belt info - Goodyear Gatorback 4080415 8PK1055, 41.5" belt.

--Hugh