Drewstein

I did a search and didn't find exactly what I'm looking for on the D1 and over spinning it.

I have a 8.5" crank with a 4" blower pulley and I want to go to a 3.4" as the 4" only makes 12# in cold air. In the summer it barley passes 10#s. If I throw a 3.4" in there is my blower going to explode or what?

What's the math on my blower RPM to what it's rated?

kp

iTrader: (34)

62K is max on a D1SC. it most likely wont explode at 64K but the higher you turn it the better chance of something failing and its just going to get to the point where it will make more heat then boost.

its crank pulley diameter/blower pulley diameter * step up (4.1 for a D1SC) * engine rpm.

Drewstein

So my math comes up with 59,245rpm for what I'm at right now. It's rated to 61,000 right?

And if I slap the 3.4" on there I'll get 69,000rpm which is 7K to much. But if I go with the 3.8" I'll get 62,000rpm, a much better result!

I think I'll go 3.8 and call it a day. Right?

kp

iTrader: (34)

Its 62K max

I would go with the 3.8 and see where you are at, maybe a 3.7 if you want to try going 2K over

Jake@EPP

Like others said, it wont blow up, it will make more heat and your IAT will yank timing.

Drewstein

So what you're really saying is slap that 3.4" on there and go for it!

My above math was based on 6,800 where my limiter is set. Since I shift close to that I think I'll go 3.6" and a 110 octane tune. I'll post the results in a new thread in a week or so.

Thanks a ton for the formulas!

ls1290

iTrader: (20)

I do not think there is be much benefit for spinning it that high. The extra air flow will be offset by the much high IAT temps and timing removal.

Keith

Drewstein

I believe above the 62,000 limit is where the heat generated is compounded in a drastic increase. I've always understood the D1 to be pretty efficient up to it's limit and many over spin by 2K with good results.

I won't over spin by 7K, but I'll let everyone know how the extra 2K is being taken.

mdhmi

iTrader: (1)

Is there a certain turbo car you are afraid to lose to?

Drewstein

Actually the turbo cars around here I don't have a problem with (Except 2 turbo vipers that put down 1000rwhp on pump but there's no competing with that).

There is however a Ford GT here that's running a 3.2 whipple with meth that put down 750rwhp on a mustang dyno that I want to kill. Since his gearing is perfect for such a torque monster of a blower I'm going to put my rig on kill just because I can.

If he tries to up it any more I'll throw a 100 shot on.

NicD

iTrader: (7)

Drew, use nitrous in addition to the smaller pulley and race gas. No more problem.

As far as local turbo cars not having a problem with... bring it.

Drewstein

The 3.6" is on the way. I'm going to fill her up with 110 for you tomorrow, just tune it like you do Nic!