[Tom Vaught]

Passed this info one to a few people on the board. Thought it might make a good Sticky.

General Rule of Thumb:

The size of the supercharger is based from the rotor length. A 6-71 supercharger has a 15-inch long rotor, and an 8-71 has a ~16-inch one. This keeps going until the 16-71, which has a 20-inch long rotor.

This Listing will give you actual dimensions for the 6-71 "Small Bore" unit to the 14-71 units:

6x71__"Small Bore"__ Rotor Diameter=__5.505"
Rotor Length=__14.975"__Cu.In per Rev= 339 cubic inches

6x71__"Std Bore"__ Rotor Diameter=__5.778"
Rotor Length=__14.975"__Cu.In per Rev= 411 cubic inches

8x71__"Std Bore"__ Rotor Diameter=__5.778"
Rotor Length=__15.975"__Cu.In per Rev= 436 cubic inches

10x71__"Std Bore"__ Rotor Diameter=__5.778"
Rotor Length=__17.000"__Cu.In per Rev= 466 cubic inches

14x71__"Std Bore"__ Rotor Diameter=__5.778"
Rotor Length=__19.000"__Cu.In per Rev= 521 cubic inches

16x71__"Std Bore"__ Rotor Diameter=__5.778"
Rotor Length=__20.000"__Cu.In per Rev= ~551 cubic inches
(calculated)

Maybe this will help out the Roots Blower Guys with their s/c selection.

Tom Vaught

[GTOGEORGE]

Gee Tom thats already been posted about a ZILLION times. LOL


GTO George

[johnta1]

Here's a table of some specs on blowers:

Blower Specs

[Tom Vaught]

Originally Posted by GTOGEORGE

Gee Tom thats already been posted about a ZILLION times. LOL

GTO George

Don't read much George?

How is someone on this board that is new going to know where to look for these dimensions, Mine and John Wallace stuff if we don't have a sticky on the boost forum.

That was the point of this post.

Yes, I posted my info at least 6 years ago and John has it or similar data as well as new data. Why not put the data or a link to the data into a sticky. If I had not made my post who knows when john would have posted his link.

My data came from a Roots Engineer, do not know where John's data came from.
I really don't care where it came from if it is accurate and can help someone else.

Why don't you go back and play with your Nova.

Tom Vaught

[GTOGEORGE]

Yes Tom I will playing with my Nova (DUH) ...........especiially at Norwalk, I'll be racing not watching like you! LOL


GTO George

[Tom Vaught]

I may not even be there this year George as I have other things going on and I heard the number of fast cars was going to be lower. Course that was before the 6.11 car made its name known.

Still about a 10% chance this year so your NOVA will have to carry on without my traditional support (a hello wave) each year.

Tom Vaught

[GTOGEORGE]

A lot of quick cars will be there, this IS the All Star game for Pontiacs. Yea we all have other races during the year but this is where you put up or shut up! So just because YOU don't think a 10, 9, 8 & 7 sec. A$$ KICKING Pontiacs out there are quick, seriously who cares not the owners of the cars! A lot of the racers started out running 16's, 15's or even slower have worked their way down with their blood, sweat & tears (I'm one of them) so tell them to their faces their cars are slow (not a quick car as YOU called them) Lots of luck with that BUDDY. So yes Tom there will be a lot of QUICK Pontiacs at Norwalk and I can't wait to see them ALL!


GTO George

[twooldgoats]

Well put, George. Thanks.

Jim

[Tom Vaught]

I actually don't care much about any Pontiac Engine much these days, George, or Buick, Chevy, etc engines. You see I lost a bunch of my retirement money on this last deal with the GM boys, so I could really care very little about GM hardware.

In order to play with you boys I would have to run a Traditional Pontiac Engine at Norwalk. That isn't going to happen in my lifetime as I have a long memory for things like losing my ass on GM stock. Think 240K George. Bond Holders got paid, Execs got paid, Bob the Putz got paid, School Systems and Retirement Funds lost their life savings.

So don't throw out challenges that mean nothing to me.

I haven't looked at my 64 GTO ever since that BS. Bad memories.

So I try to help people on the board with their problems, (notice I said THEIR PROBLEMS), only reason why I am here, outside of pushing your button for old times sake. Suck it up, big boy. Run your 11 psi of boost at Norwalk, have fun, enjoy the people, don't tell me what to do with my money.

Tom Vaught

[GTOGEORGE]

Tom,
What challenge (gosh theres something wrong with you}!.........I told you about your Meds. LOL
So you guys heard it here FIRST, he doesn't care about Pontiac engines (he typed it)! Ford Guy?



GTO George

[Tom Vaught]

Yep George, Burned out with all of your excuses about being able to run in the 7s when a car I wrenched on in 1998 (15 years ago) FORD MUSTANG with a 347 cid engine was 7 tenths faster than you at the same weight. The only meds I take are coffee and a blood pressure pill when your bs gets old.

Tom Vaught

[GTOGEORGE]

LOL!


GTO George

[60man]

Good tech info...
I always only related blower model number to number of the old Detroit diesels..
They all had 71 C.I. per cylinder...
The blower for the 6 cly was a 6-71 unit..& a 8-71 for a 8 cyl....and so forth..
Just saying..has nothing to do with using blowers on gas motors, Just trivia..

[Jack Gifford]

Originally Posted by 60man

... Detroit diesels.. They all had 71 C.I. per cylinder...

Or 53 c.i./cyliinder. Yeah, it's just trivia. I just recently learned that there was even a 2-xx (can't remember if 71 or 53)? Ever since Mickey ran a 2-xx blower on the two-cylinder Pontiac landracing engine, I had wondered if he cut down a 3-xx or 4-xx, since I'd never heard of a two-cylinder Detroit deisel.

[Jack Gifford]

Supercharger question for you Tom V-
Looking at [pictures of] the Whipple screw blowers, I see that many of them have unequal-diameter rotors. I've searched their website and tried posting this question to a couple of users (like the Target-550 streamliner owners), but haven't found the answer yet. Simple question: why? What's the advantage?

[Tom Vaught]

The best guy to answer that question on Whipple Screw Blowers would be Art Whipple himself, or his Chief Engineer "Bennie". Dustin, (Art Whipple's son would be a 3rd choice. Deal is they are very selective about who they talk to. Ask Brand X about that deal, if I remember the correct PY member who bought the Whipple stuff from them.
The Whipple SC is an excellent screw blower. Ford uses them on the Cobra Jet SS Mustangs.

So back on your question. You might have better luck talking to Dustin on facebook:
https://www.facebook.com/whipplesuperchargers

It has to do with the basic Screw Supercharger design. From Whipple's site:

"A screw compressor is a positive displacement machine that uses a pair of intermeshing rotors to produce compression. The rotors comprise of helical lobes affixed to a front and rear shaft. One rotor is called the male rotor and it will typically have three bulbous lobes. The other rotor is the female rotor and this has valleys machined into it that match the curvature of the male lobes. Typically the female rotor will have five valleys. The rotors never touch, but are timed by a pair of gears operating in a lubricated chamber, which is separated from the rotor chamber. With the 3-5 rotor combination, the male rotor turns 1.66 times to every one time of the female rotor."

If the male rotor has 3 lobes and the female has 5 valleys, and the valleys match the 3 lobes shape, how can they be the same diameter?

The Advantage? Simply that it is a compression supercharger vs a Positive Displacement Supercharger. The 3 lobe-5 lobe deal actually makes pulsations which on a race car mean little but on a street car require extra NVH work.

Tom Vaught

[Jack Gifford]

Originally Posted by Tom Vaught

... Advantage? Simply that it is a compression supercharger vs a Positive Displacement Supercharger...

Yes. But that's the advantage of every screw blower over a Roots; even the equal-diameter-rotor screw blowers. Nowhere have I found a justification for unequal diameter rotors, nor can I "see" an advantage.
[No need to quote Whipple's website contents; as I said, I read it all]

[Tom Vaught]

Like I said Jack, Dustin might talk to you and you could ask him the question but Art and Bennie are the guys with the answers.

Speaking of answers How is your streamliner project going?

Time line when you hit the salt?

Tom Vaught

[Jack Gifford]

Not a "streamliner"; I have a lakester. Lakesters (traditional drop-tank style) aren't at all "slippery" like 'liners (Cd ~ 0.9, vs. ~0.15).

I just finished all design/mock-up/machining of the DOHC top end. A running car is not in the near future.