355 LT1, should I get the P1SC or D1SC
 

Initially, I planned on purchasing the Stage II P1SC system (10-14#) with twin high-flow intercoolers. Now I’m debating whether or not to get a D1SC (12-20#) instead. What are your thoughts? Pros/Cons

I want the car to be streetable.

I have a motor from a 95 LT1 that I’m building on.
Here is a list of some of the parts I have so far:
LT4 heads (SV-4 exhaust valves) and intake [port/polished]
58mm TB
Eagle forged crank and H-beam rods
XE230-236 cam

I plan on getting a set of JE forged pistons so I can get in the 8.5-9:1 compression range.

I also have nitrous hooked up on the car which I don’t plan on getting rid of (unless I run high boost). I would like to use a 50 shot on race fuel when at the track.

Re: 355 LT1, should I get the P1SC or D1SC
 

Get the D1, it will give you alot of room to grow into it and you wouldnt have to worry about maxing it out as quick as the p1sc. Sounds like you have a good combinations of parts going in, just dont skimp out on a good blower cam.

Re: 355 LT1, should I get the P1SC or D1SC
 

A p1 is what they put on all of the stock motors for the kits. I would go with a d1, because you have the motor you might as well get the blower. A p1 is a good blower, but it is pretty small. I mean I just saw a new f150 the other day with a p1. Got to love it when procharger is in your home town.

Re: 355 LT1, should I get the P1SC or D1SC
 

I would get the D1 also... you'd be pushing the P1. Your cam might be a little large.. depending on your lope seperation. Might see what the overlap is going to be... you don't want any on a small blower car.

Re: 355 LT1, should I get the P1SC or D1SC
 

Actually, the P-1SC are D-1SC are extremely similar.

They are both built using the same casing--neither is larger or smaller in size. (I don't think you can even tell the two apart without looking at the serial tag.) The inlet and outlet are identical. The max RPM and internal step-up are the same. Really, the most significant differences are the impeller design and the bearings. The D-1SC has heavier duty bearings and uses a helical impeller (as opposed to the radial impeller in the P-1SC) . The helical impeller design produces a more aggressive boost curve with an ealier onset of boost. The design is also a bit more efficient, making the D-1SC difficult to spin slow enough to produce mild boost levels on a stock LT1.

If you're talking about a built LT1, the D-1SC will generally make more power more efficiently--but the P-1SC is by far no slouch. The maximum horsepower that the P-1SC is rated for is 825. The D-1SC is rated for 925. Not a big difference, but the bearings and impeller in the D-1SC are better suited for the task of higher horsepower and the track. If you want to make 800-900 horsepower, neither unit is really great for such duty--but the only other option is an F-1 and that's a bit of a custom job on an LT1.

Check out the write-up in the ProCharger FAQ on our website:

http://www.tenperf.com/products/atifaqinfo.htm#p1d1diff

And ATI's head unit specifications:

ATI's specs: http://www.procharger.com/models.shtml

The P-1SC is a great blower that's almost identical to the D-1SC. When the D-1SC is too aggressive for your application, it's a very close second that holds the potential to make some notable power on a modified motor.

In your situation John, I do think the D-1SC would be a good choice. You're going to have a capable motor and the only benefit to going with a P-1SC would be:

1) A possible longer warranty (at 10+ PSI I doubt you'll have the option for longer than a one year warranty with either unit).

2) A more gradual onset of boost, helping wheelspin on the street become less of a problem--which at the kind of horsepower level you're looking at is going to be a problem either way. :D

Dispelling the myth of what boost levels certain systems are capable of: you will be able to make anywhere from 4 PSI to way-more-PSI-than-you-want with either unit. It's just about the pulley combination. I would aim for no more than 12-14 PSI on the setup you're describing. Any more aggressive than that and you risk having more headaches than you will fun. And believe me, a very safe amount of boost on that motor will be plenty of fun. ;)

Dave

Re: 355 LT1, should I get the P1SC or D1SC
 

The LSA on the XE cam I have is 112.

Re: 355 LT1, should I get the P1SC or D1SC
 

Would one or the other be preferred with a M6, as in the onset of the boost curve?

Re: 355 LT1, should I get the P1SC or D1SC
 

I don't think the M6 really affects the decision much, but maybe someone else can jump in with some insight. At the power level you're talking about, just be glad you can't blow up a 4L60 anytime soon. :D

Dave <-- Waiting for his 4L60 to blow up.