Paxton 3.5" pulley

[pumpgas]

Anyone with an SCT tuned Paxton car (and otherwise pretty much stock or few mods) running the paxton 3.5" blower pulley? I am guessing it makes 9-10lbs of boost instead of 7-8lbs on an otherwise stock car. Just trying to gauge people's experience with it.

Paxton says they have shipped a boat load of them over the years to (RSI, Doug Levin, A&C Performance etc. etc.) So I as thinking with the available tuning now via SCT (bigger pump, injectors, MAP sensor etc.) so that the A/F ratios are dead on with no lean conditions like sometimes with the old FMU setup, that some guys have upgraded the pulley too.

[NJDAVE]

Pumpgas,
I have a fully built motor & I am running the smallest pulley available for the Novi 2000 blower. It is a full inch smaller @ 2.5 and was for the Ford mustang kit. We modified the pulley because it was touching the alternator pulley the way it comes from Paxton. We had to machine it to fit & now it makes 15.5 PSI boost.

You will blow up your engine quickly if you try to add more boost to a stock Gen 3 motor. My stock engine with less than 15,000 miles & the stock Paxton kit damaged a piston & I was forced to either go back to stock & rebuild or spend the money on the forged internals & build it right for forced induction. I chose the latter. You need to upgrade the entire fuel system & scrap the piggy back pumps & split second box. The stock pulley on the Paxton makes 7 PSI no more.

[pumpgas]

Hi Dave, thanks for replying. Yes I have ditched the pumps and added injectors and a large in tank pump and had it tuned with SCT. Now that I can add enough fuel to ensure it does not go lean on the top end like it used to with the FMU, I wanted to add 1-2 more PSI.

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Oh yeah, how much power does the car make at 15psi?

[NJDAVE]

Pumpgas,
Right now it has an ultra conservative tune with the total timing advance at 19 degrees. I believe stock is 21 or 22 degrees of max advance? It makes 800 rwhp on a mustang dyno not a dyno jet. BTW I also have a methanol injection system that kicks on at 10 psi of boost.

Is your engine running stock pistons, rods, heads, cam ?

[pumpgas]

Yes motor is stock, no cats, twin 67mm throttle body, SCT tune and fuel. I do have methanol injection as well. Comes on at 5psi. A/F is 10.8 - 11.0 at 4,500rpm and above so it is a pretty conservative tune. 696 rwhp on a dynojet. I am looking to get it up near 750 rwhp.

[NJDAVE]

Pumpgas.
696 rwhp on a dynojet is about 650 to 670 rwhp on a mustang dyno. I would say that is about the most your going to get without adding more boost. The Paxton Novi 2000 will go up 1 psi of boost with every 10th smaller pulley. Paxton sells them in 10ths so you can go down from 3.5 to 3.4, 3.3, 3.2, and so on. Good luck.

[pumpgas]

Okay thanks Dave!