Blownramair

Hey y'all

I have a w2w blower motor (8:1 compress.) running C10 fuel. What is the MAXIMUM amount of boost you can run on a D1-SC WITHOUT hurting the blower? I'd love to run 15+ PSI but I heard 15psi was pushing the limits of the blower if I'm going to run at the track every weekend?. I have a COG setup so im not worried about belt slippage. Could I run, perhaps, more than 15+? I have no experience past 11psi and dont want to find out the hard way. This is a low 10sec car. Anyone experiment with this? Any and all help is appreciated.

Jay

andereck

You're not going to hurt the blower with high boost as long as the blower stays under its rated redline. The problem with very high boost is that the D1SC has a 4.10 internal stepup and is rated at 1400 cfm. The 4.10 gear makes it challenging to drive the blower all the way to its redline and the airflow will limit its ability to make much over 15 psi on a 346. I would recommend an F1 for your situation as it has a 5.40 internal stepup which makes it easier to drive it to redline and has another 100 cfm or so (2+ psi). The main feature is the internal stepup ratio. The F1 will go where a P1SC or D1SC fits.
When using cog pullies try to use a drive that allows for a large blower pulley. At rpm the heavier cog belt likes to "grow" over the top of a cog blower pulley and it can strip its teeth if it looses root contact with the pulley.

EPP

iTrader: (22)

I agree, the F1 isn't much larger, maybe .38" in diameter. I'd also go with the F1 also in your situation, although your 8/1 compression ratio is really low for a centrifical supercharger. Your engine would be more efficient with another point or a point and a half in compression. Your engine is ripe for a massive turbo! Bob

kp

iTrader: (34)

I'm making over 14psi spinning a D1 blower to only 54K or so but my compression was just under 10:1 and I have a small cam, if you have a fairly large cam and 8:1 compression its possible you can get close to 15psi at max impeller. One way to find out - figure out your pulley/max engie rpm combo and see what happens.

If you have the stock intercoolers and swap to a bigger front mount that will give you a little more boost along with taking the plastic air filter elbow off and making a screen for track use. I pick up nearly 2psi at peak by removing the intake elbow but the midrange boost doesnt really change a whole bunch - looks good on the dyno but doesnt make the car go a whole lot quicker so I leave it on..

Blownramair

This is my setup guys (See pics). I talked to the guys at the shop and they said that an F-1 would be too hard to maneuver around the A/C. I dont want to get rid of the A/C (dont ask). I am stumped and not sure what to do guys. I'd like to run high 9s and im sooo close to it. I just need a little more power or weight out. Also, with my A/C still on the car will the F-1 hit the A/C condensor or create a problem? Does anyone have pics of an F-1 with the A/C still on? If you have any more questions let me know. Any and all help is appreciated guys.

Jay

andereck

Think you can wait a day for some measurements? I'll do my best to compare volute sizes and get back to you. You have a cog, so I'd say let the D1SC eat and run it on up to redline. It's a good blower and makes some good air, and I'd hate for you to get blower envy. 1400 cfm should get it done.

Slowhawk

iTrader: (12)

If your running C10 I would raise the compression. 8-1 is way too low for a D1 setup.Just bringing the compression up to 9.5-1 would gain you 2-3 psi and a ton of HP.

kp

iTrader: (34)

If you are that close and all you want is the 9 I would pull the intake elbow off and just make a screen, may be enough to get you there. That accordian hose and stock filter is hurting.. If the blower is maxed out RPM-wise there is only two things you can do, up the compression or use a bigger blower to get more out of it. If I were to go through the trouble of upgrading blowers I would go right to an F1R, rough to get it in there though..

Nice looking setup by the way

andereck

The F1 volute is identical in size to the D1SC. The transmission case will move the blower approx .230" farther away from the bracket.

The F1R volute is .750" larger in diameter and the inlet will be moved .625" farther outwards over the F1. So the overall depth of the F1R would change approx .850" over the D1SC.

Hope that is useful.

Josh@KY-Turbo

iTrader: (120)

who has the brackets for the F1? How much are they?

andereck

P1SC-x D1SC and F1x share brackets.

kp

iTrader: (34)

Is there a disadvantage, besides size, of going up to larger blower? Say I wanted to put an F1/F1R on here and keep the impeller speed down just to get 3psi (relative number) more then the D1. What would I be losing in the process out of curiousity, lower end flow/boost, more parasitc loss from the higher step up?

Josh@KY-Turbo

iTrader: (120)

so i can use a F1 with the P1SC kits brakets.

Pro Stock John

iTrader: (34)

I'd look at increasing the timing first... assuming the car is not currently maxed out.

What does it run at the track, et and mph, what does it weigh?

Got Me SOM

iTrader: (2)

andereck you sure seem to know a lot about ATI blowers, do you work for them?

andereck

<---------- sworn to secrecy. Just trying to be helpful... : )

Got Me SOM

iTrader: (2)

I knew it..

andereck

Yes you may.

Pro Stock John

iTrader: (34)

How's the weather down there?

andereck

You generally want to keep the blower in its upper 1/3 of its rpm range. This is where its most thermally efficient. When talking large blowers a bigger volute will usually have a bit cooler outlet temperature.

Any increase in parasitic loss from a steeper stepup ratio is usually offset by greater belt wrap in a serp type drive resulting in higher boost from a given pulley combination and longer belt life when you're pushing it hard. Belt wrap is also important for a cog system, many don't realize that.

In your particular question you posed the F1 flows a bit over a 100 cfm more than a D1SC so the airflow increase would only result in 2-3 psi more. The F1 might be a touch softer on the low end, but not for long.