Just wanted to share my results from the 3.12" (9lb) pulley install. Thanks McDuck for the install tips!
I installed the pulley on Saturday and took a run with my base fuel map. Then I spent the next 4 hours tweaking different maps with the R4 software and below are my results comparing my first run after the pulley install and my last run after tuning.
I'm making 9.9 psi at 6500rpm! I'm not quite sure why but I'm gonna stay away from the redline if at all possible.
I'll probably get it dynoed again at the first of the year to see what the HP #'s look like.

3.12"Before R4 tune 3.12"After R4 tune
RPM Boost PSI A/F Ratio Boost PSI A/F Ratio
2500 1.9 11.1 2.0 13.3
3000 2.6 11.1 2.6 13.0
3500 3.3 10.4 3.3 12.7
4000 4.2 10.1 4.2 12.4
4500 5.4 10.1 5.3 11.7
5000 6.5 10.0 6.4 10.4
5500 7.6 9.8 7.6 10.9
6000 8.7 9.7 8.7 10.9
6500 9.9 9.7 9.9 10.3

Enjoy
Steve

 

Steve, do you have figures for what you were boosting before you did the pulley swap?

 

Yup,

Here you go!

3.33" AA tuned
RPM Boost PSI A/F Ratio
2000 1.6 9.6
2500 2.2 9.6
3000 2.6 10.6
3500 2.9 10.4
4000 3.6 10.0
4500 4.3 9.6
5000 5.2 9.9
5500 6.2 9.9
6000 7.0 9.9
6500 7.9 9.9
6800 8.5 9.9

 

Thanks, Steve!

Just doing some rough figures, that appears to amount to just a little more than a 20% gain in boost.

 

Good to see you got it on . What did you use to to datalog your runs on ? Or did you have it on a dyno to tune ?.....Bill

 

I used my Zeitronix datalogger- A/F and boost gauge. Pretty handy...

 

Cool...I just dropped off a Zeitronix at the shop to go in my car . I should be breaking in the new motor by the end of the week

 

Awesome Boog! Definitely let me know how your car runs once you get it broken in. I want to go the same route as you in the next 6 months or so with the AAM fuel system and built bottom end. By the way... what compression are you running on your new pistons?

 

9 to1 . Im putting on the 2.87 pulley after break in . Then I'll look into making a , or altering a smaller pulley on the blower

 

No need to Bill. Vortech makes a 2.62 pulley! Happy boosting.

 

could do the 2.62 AND a smaller pulley on the blower!

 

mcduck, I know what the math says about impeller speed etc. etc., but I may try the 2.62 pulley in the near future and see what happens. Who knows, the blower may be able to take it. No one has tried it yet, so no one really knows the answer.

My guess is that the Vortech would act more like a turbo (more of a kick than a linear boost pattern) with the 2.62, but you would have to pull so much timing that your top end power wouldn't be that good. Now on a low compression motor it is a different story.

 

I think that the 2.62 maybe to small to grab the belt good enough . Besides...my 2.87 pulley [ havent figures out why ] was to small and tore up the outter edges of the jackshaft assembly that sticks out of the bracket . No one else has had that problem , but going to even a smaller pulley , will cause the same problem for every one

 

Booger, what gain did u get from going from 3.33 to 2.87 pulley?

 

I havent put it on yet . When it tore up the jackshaft I had it milled but didnt put it on yet . LouZer has it on though

 

what are your numbers now anyways? (if u dont mind me asking?)

 

I had 351 whp on a Mustang dyno with the 3.12 pulley...and 10 to 12 % for dynojet numbers

 

Thanks, I'm curious about what the 3.12 will add and how the car will drive dufferently, if at all...is it even worth it?

 

yes it worth it . You'll need to retune to get the extra 10 to25 hp out of it though

 

Thanks boog....cause i already purchased it...i'll be sure to a before and after (tuned) dyno

Aaron