darsondriss

I recently had a deal come up to upgrade from my existing p1sc1 to a d1sc1 and figured I'd share my results on the p1 vs d1. No other parts were swapped out in this comparison, the only changes were the blower/pulleys and the mounting bracket as the newer bracket was included in the deal. Neither run was showing any noticeable signs of belt slip, so I don't think the bracket change plays a factor here.

My engine setup:
ls1 - stock bottom end 111k miles
Cam 224 232 114lsa
ported 317 heads
ls6 intake
LG pro longtubes
c5z Ti exhaust
other supporting mods to drivetrain and fuel system

My old setup was a P1 pretty much maxed out on a stock crank damper and 3.4" pulley. The new setup as first installed was the D1 with a 4.5" pulley. On the old car, it made about 10 psi and made a hair more on mine peaking at about 11 psi at redline.

P1 3.4"pulley 8.5psi to D1 4.5" pulley 11psi -1* timing



The highlighted red line is the p1 and the other 2 runs are best from the d1. Excuse having 2 runs in here but I didnt carry the top midrange run out to redline and wanted to give an accurate depiction across the entire rev range. They dyno I was using had some rpm pickup issues that is causing some wavy results but its enough to get the point across.

First observations are the peak hp is up by about 30hp at redline. But when you look at the whole graph its almost exclusively down on power vs the p1. Its losing 30-50 ft/lbs of tq until around 5500 rpm.

I was really not to happy with this upgrade at this point as losing that much low end for some 6400+ gains was really not worth it for a street car. Being it is a stock block with over 100k miles I was hesitant to push it, but in the end I decided I wanted to try to get that mid range back so I needed to switch to a smaller pulley. I figured I could drop some timing up top if I wanted to be a bit safer in the really high boost areas.

D1 4.0" pulley 2-3* timing removed after 5000rpm



now this is much closer to what I was expecting. Peak boost increased to about 14psi and it picked up some solid midrange and peak power. Ended up at a peak to peak hp gain of about 75hp and almost 100hp gained a bit before redline. Gains in the midrange were around 30 ftlbs.

Unfortunately, I dont have any logs of the boost levels from the p1 but here is a graph I made that compares the boost levels on the d1 from 4.5" and 4.0" pulley.




In the end, I was suprised how much work I had to put in to make the d1 out perform the p1. I was thinking I could just bolt it on with the 4.5" pulley and it would make more boost (which it did) and make a ton more power. For people that don't want to push your stock motor to the limits, it really seems like a P1 is a better fit than the D1. My engine is still alive on 14psi but obviously, 2 days does not longevity make.

ysb02

Good write-up! I'm in a worse boat than you with a ysi on a sbe.

Nosferatu333

P1 is a fantastic blower. I had mine for 8 years and it will roast my rear 335s. At 617 to the wheels it more than I will ever need for the street. However we Americans are fixated with ***** size and feel like we need the bigger blower. For pure street stockish motor the p1sc-1 is hard to beat.

That said I'll be purchasing a f1 shortly. Only be because I'm building a 427. Wanna hit 750. Do I need it no. Barely can control car now. But like I said I'm an American and want more.

Sorry you went through that headache. And thanks it was very interesting and informative.

ysb02

darsondriss

I dont want to come off like im unhappy with the results. I think in the end it is a nice upgrade but you have to really be willing to push the comfort zone to best a good p1 setup. I am going to work on either a stroker or a ls3 here soon though so the d1 gives me some headroom to grow.

It does make for an interesting dilemma though. I would say p1 is best for a stock motor but if you ever upgrade your going to want the d1 or f1. So it makes it a tough decision to go for optimizing your current goals vs what you might do in the future.

smokinstorm

Nothing at all wrong with a P1SC-1. 65,600 RPM impeller speed at 6400 RPM engine speed. 14 PSI.

neverstop

you can hook 750whp with drag radials on the street easy and make car very controllable. Nt05r were great on my car when it was in the 700s

I believe there is a guy on here with 700whp and D1SC on stock ls6 with e85, no crazy built motor necessary to make that power at all imo

d1 great blower though. i made 900whp and 860tq with mine on a 427

lilryan

My car is at the shop right now. P1sc with 3.7in pulley made 13psi and 678rwhp. I swapped to a D1sc, same pulley, with a little bigger headers. I will post my results when I get it back. Should be this week.

Ryan

Nosferatu333

Thanks for the input I appreciAte it.

Got 20s in the rear hears hoping they have drag radials in a 20. Would hate to rid myself of my hre's. Drag radials were t an option when I got my wheels I think. Ended up with zr1 tires. They are decent.

E85 is not readily available in California. Further I'm stuck with 91 octane. I'd like reliable 750 to the wheels with no worries of spitting a rod through the block. Easiest way (I think) is forged big displacement setup with a blower to match.

What tires did you run for the 427 @ 900?
Bravo btw.

fotoboy

Good numbers. I was 730 on my p1sc and stepped to a f1d with a waste gate to keep the heads from lifting.

p- 730/650 Impeller 80% of max
f- 818/778 Impeller 110% maxed

Nosferatu333

footboy whats your set up?
I'm looking at the f1-d. What you think of it. Does it sound every bit as vicious as the other f1 series blowers? Great numbers btw. HOws it drive?

neverstop

I run 17" ET Street R now on the car at just over 900whp. Sometimes if I'm very lucky with the right conditions it will hook up 3rd. i was surprised how much harder it was to hook 900whp vs. 760whp. At 900whp and 860tq if the tires aren't super hot the car will spin in 4th a bit on the freeway sometimes. 700s whp level is a great place to keep it.