Blackbird

I thought it may be interesting to debate this.

I see most running to the D1 blower because ohhhh it can flow 200cfm more it must be better..... when 95% of the people on these boards won't ever even max out a P1 let alone a D1. Seems to me the P1 is a better choice because if you have to spin it faster than the D1, that to me means the blower is building rpm quicker, thus I am getting more boost at lower rpm, which means more low end hp and tq. Perfect. Or I can lazily spin a D1 and not see significant boost until higher in the rpm band which means I have to wait for my power. The P1 looks to be perfectly capable of 600rwhp on the LS1 so why are most going D1? My theory is good marketing and or people just don't know any better.

I would really like to see some comparo's of the 2 blowers on the same car at lets say 10psi. Dyno with the p1 then swap in the d1 and dyno again. This could easily be done on the same day. Then overlay the graphs and see where each make there power. My prediction would be same peak power but more under the curve with the P1.

What are you thoughts???

Shinobi'sZ

There is a large difference between the P1 and D1. A 3.85" pully will make more boost with a D1 than a P1. Which means you can use a bigger pully to make more boost..which turn creates more surface contact area...now I am talking about the Y Body setup not the F Body setup as the crank pullies are different size as well as the configuration.

My friend just redyno'd his procharger with A&A's custom 8" Rib/Pully and new designed Bracket and a Single I/C with bigger plumbing. The only thing that is the same on this kit is the D1 blower vs the way the blower comes from ATI. He made 664/580 rwhp/rwtq on a 346cid....no dyno tricks. I was there and helped do some dyno runs..it is completely bad ***..none of that belt slipping crap that plagued me and many others both Y Body and F Body at the track...this sucka rocks.

Also the D1 has helical cut blades (more efficient compressor) and is at a 4:1 ratio...12-15lbs of boost is no sweat for a D1 Blower Unit. The P1 can't even come close..sorry...it is best left for stock applications as it was intended. The D1 has always been the "Tuner Kit".

Blackbird

Good info. I would classify your friends setup in the 5% though. If your going ***** to the wall then I agree D1 or F1, but most folks don't dare run more than 10psi. Would you still say D1 hands down if your only looking to make 500rwhp ??? I guess maybe my thinking is different because I want a maximum effort street car not a max effort strip car.

Draco

Compressor maps are also important. The D1 will be more efficient at moderate to high boost, which lowers IATs and allows increased timing and/or safer operation (less chance of detonation, which is very important on a stock motor).

CAT3

iTrader: (9)

Wouldnt the D1 pullied to 10psi make more power then the smaller P1 at its 10psi? You did say at 10psi, so the P1 will still not make as much power cuz it is not physically moving the air the D1 is. But I do understand your intrest in why so many w/ D1. I say itd for room to grow. Like me when i got my N2O kit, it was fine for 100shot, but glad it had the 200 pills as well!

Blackbird

well they should be moving the same amount of air. 10psi is 10psi on the same engine. now whether or not the air coming from the p1 is much hotter than the d1 forcing lower timing/higher octane and thus make less power is the question.

remember the point of the conversation is not which will make the most power, that answer is obvious. I'm debating those that are going to run 10psi or less paying the extra $$$ for the D1 which I see alot of people doing.

XLR8NSS

iTrader: (4)

Heath - I'm very interested to see if the SD tensioner stuff can max out a P1SC blower. It might actually make my supercharger kit worth something.

Blackbird

lol, well my pulley combo will come 10k rpm short of maxing it out.

XLR8NSS

iTrader: (4)

Are you trying to get around 9-10psi? I think that'll get you real close at 55,000rpm.

How close are you to testing things out?

Blackbird

yes, looking for around 10psi.
getting closer but still waiting on parts.
I need the inlet hat and sd still owes me a crank pulley. the one you see in my pics is the prototype that they loaned me so I could at least align things. it's a 2 piece though and he said he would not risk running it although it may work just fine. I am a whimp so I am not gonna run it except at idle to make sure everything is cool.
I also need to have my discharge tubing made. I am trying to scoot along but I can only work on it on weekends at my brothers (I don't have a garage) and it's my daily driver, so I can only get so far then have to put it back to a driveable state. I am really hoping to get it whining by mid Jan.

XLR8NSS

iTrader: (4)

Cool man!

The garage deal sucks...I know all about it.

I'm looking forward to your reports.

Shinobi'sZ

Once again...lets take the application with the example using a Y Body size crank...

For the sake of argument lets say a 3.85" pully on a D1 makes somewhere between 12-15lbs of boost (depending on mods).

With a P1 you would need a 3.60 pully or smaller to make the same amount of boost...the boost would be hotter as the compressor is different. But THE BIGGEST PROBLEM is going to be the belt slipping...the 3.60" pully being smaller is going to have far less surface area contact with the belt. I know I have been there many times...that is why I don't own an ATI anymore...however since Andy at A&A Corvette has completely and I mean completely redesigned THE WHOLE system..I would have no issue buying his setup and putting it on my car. The Y Bodies have more belt slippage at the track then the F Bodies...so imagine how bad it is when the FBodies have experienced trouble too with belt slippage. Andy's 8 Rib and new Design is the hot ticket for the Y Body.

Do yourself a favor and buy a D1..my same friend mentioned above that made all that killer power..ended up upgrading his P1 to a D1 ...which cost him close to $1K. Buy the D1 to start out with and you will not have to pay more in the future.
Good Luck.

frcefed98

iTrader: (16)

'cause it was only $250.00 more to upgrade it at the time of purchase
J

XLR8NSS

iTrader: (4)

I don't think anyone is denying(they can't because it's a fact) that a D1 will make the same boost with a bigger pulley. If the upgraded tensioner from SD concepts works though it'll be a nice addition to all those P1SC kits out there and cost less than a D1SC upgrade for people not wanting to spend all that money on upgrades.

One other thing. The ATI 6 and 8 rib setups on the Fbodys are very prone to slip no matter what blower is used. That's why I'd look to upgrade the tensioner/pulley setup first. If it works and gets you the power you want great. If not THEN maybe look to a bigger blower that can spin slower and still make the same boost. Heat is not too much of an issue with a good intercooler or water/alky injection at the levels most people want to run IMO.

BTW, I'm really only saying this for people that already have P1SC kits. Definately go right to the D1SC if you are planning on buying a Procharger in the future.

KHShapiro

iTrader: (10)

if you have a more efficent Motor you are going to need a more efficent impeller D1 and higher. D series impellar where the turning point for ATI as all impellers higher are based off that impeller. so if you have an Efficent motor that P1 is going to be pushing its limits to keep up with 10psi where as a D1 won't . If you research on who has a p1 you will find most are pushing them beyond there spec RPM range and risk exploding the impeller .this is due to there more Efficent set-ups hench the need for the D1

XLR8NSS

iTrader: (4)

The P1SC-1 that the LS1 kits uses actually has the upgraded D1SC "like" impeller I think. It's not the standard old P1SC AFAIK. Here are some pictures of the LS1 P1SC1

CAT3

iTrader: (9)

I may be wrong and please feel free to educate me, but...
I thought 10psi with a smaller head unit would net less air movement, due to it having a smaller unit, than a 10psi larger head unit. If I ram 10psi of air thru a drainage tile and 10psi of air thru a garden hose, I am certain to get more air out of the drainage tile!

KHShapiro

iTrader: (10)

best way to really find out would be to call ATI.

XLR8NSS

iTrader: (4)

True but, the motor setup(basically) is what determines boost level not the head unit. Assuming the motor doesn't change between the two head units test then 10psi would be the same CFM from both. Of course the D1SC might make a small amount more power from a slightly cooler charge but, basically things would be the same.

ATI said they used the helical impeller in the P1SC1 units because the standard P1SC impeller wasn't up to the task of huffing into a LS1. That's from way back when the kits first came out and I don't remember where I saw it.

Let me just say again definately upgrade to a D1SC if you're purchasing a new kit. If you have a P1SC1 kit I'd look into upgrading the tensioner/pulley setup first.

ChrisB

The other issue is @ the given sCFM level which compressor is more effecient - at the whatever mass/flow you are seeing at 10psi the P1 could be more effecient.

The other point is that a good intercooler or alchohol/water injection kit is going to make a much larger difference on the overall effeciency than a few percentage points on the compressor - so even if the p1 were slightly less effecient, if it made boost quicker and had a better area under the curve, and you had an overkill intercooler, it would probably be faster at the track.

But since ATI has decided that they will under *no* circumstances provide compressor maps to anyone it makes it impossible to properly spec out an ATI blower. So I would just get a Vortec