Anybody know what a realistic result would be of spinning the D1SC blower to 62,000 RPM impeller speed? I know ATI has a theoretical max of 32 psi listed in the tech info, but thats not on an engine. Anybody ever use a pulley combo that achieved max boost from one of these? Or do I have to be the guinea pig?

what engine rpm are u thinking of spinning the supercharger to 62000?
32 pounds is alot of boost ,thats like tripling your horsepower.you probably blow your headgaskets .u need race gas or alcohol to keep it from pinging.im guessing u might achieve more than 32 pounds but youll most defintely run into surging.have fun if u do try

I know it won't be more than 32 psi. 32 psi is what would occur if the blower was pushing air into a sealed chamber with zero flow. Thats the point where the blower would physically not be able to compress the air anymore. I'm guessing 20 - 21 psi with my motor. I was just checking to see if anybody else has maxed out a D1-SC. Isn't Willie doing that now with the cog pulley setup?

I have been wondering the same thing, I want to do it on my 352 destroked 400 motor, I know 32# is not possible but what is? and if the motor is built for it and reving to 7K rpm what would be practical? so basically what is practical and possible with around 350 cid?

Doing a little math, a stock TPI 350 should see 27 psi at 62,000 impeller speed. Judging from what I see in boost compared to what ATI rates the pulley at, I should see 20.5 psi boost at max RPM. I have the pulleys set for max blower speed at 5800 RPMs. I shift at 5600, so I should be getting pretty much the most out of the blower with the new pulley arrangement. We'll see. Its not on yet. This is all just theory right now.

The max boost is the maximum it can produce without dropping out of whatever the manufacturer considers it’s efficiency range (usually above 60% adiabatic efficiency). That has no relation to what it will do if you block off the outlet (compressor stall, most likely read much lower then that and break off the tips of the compressor wheel).

The amount of boost you will see at the compressor’s max rpm on any particular engine depends on the engine that it’s connected to, more specifically it’s displacement, the rpm and VE at that point. Ex, a 350 turning 6000rpm at a 100% VE will want to move roughly 608cfm or 42lb/min of air. If at that point the compressor is moving 1216cfm you will see 2x the current atmospheric air pressure (usually 14.7psia, so you’ll see 29.4psia pressure or 14.7psig boost).

Show me a compressor map for your D1SC blower and a torque curve for your engine (torque is proportionate to VE) and I’ll tell you reasonably accurately what your boost will be.

I have neither a copressor map or an actual torque curve for my motor. But if you give me a couple of hours, Ill be able to tell you exactly how much boost a D1-SC can deliver on my engine. The pulleys are on and got everything shimmed just right. Its going out for the maiden voyage in a few minutes. Keeping the fingers crossed...

And?? What happened? This is like reading an awesome book then the author is like "I'll have the ending done soon!" I'm dying to know!

I have @ss loads of boost. And amazingly only had to pul 5 deg timing out at wide open throttle. I'm seeing steady 16 psi boost from 4000 RPM up with peaks pegging my 20 psi boost gauge. The big problem now is getting rid orf the extra boost at part throttle. The ATI supplied surge valve can't get rid of enough air, so I was getting compressor surge. I have a Vortech Mondo BOV, going on this week. The car is down right now getting its new exhaust on to help expell the extra waste. 1 7/8" adjustable super comps. Talk about an install from hell. Should have everything set by the weekend and have some new times at the track next Tuesday. I figure deep into the 11's though. It ran consistent 12.20's with only 9.5 psi boost before.

Well considering you've nearly doubled your boost, I think you may be sub 11's with hook..At what point does the ATI surge valve start to crap out? I want to run about the same amount of boost you do...And if there is no point in getting the ATI valve, I'll delete it from the kit..Just like the ribbed pulleys Regardless, your car sounds sick..I can't wait to hear your times

If you're going to run big boost levels, just delete the ATI surge valve. Mine is surging cruising at light throttle and 2500 RPM. With the pulley ratio I have and the D1SC unit, it moves massive air already at 3000 RPM. Just delete the surge valve and spend the money getting a real one, like the GReddy type R race valve or the Vortech Mondo. Also, plan on a fuel pump upgrade. The ATI inline with a stock in tank won't be enough fuel for huge amounts of boost.

Yea that's what I've read about the ATI..I just forgot to add that in my reply..Do you know a general rule of thumb to go by for injector size? Xcfm with X#'s =Xlbs/hr..Something to that effect..

This site has some good basics for injector info.
http://streber.net/jflracecraft/main...tion_setup.htm