[flamedabone]

Count me in.

I drive mine every single day, plus a 3000 mile round trip to the drag strip to run 120 mph 1/4s.

I LOVE my blown Pontiac, -Abone.

[Jack Gifford]

Originally Posted by BruceWilkie

... an armasteel crank... Ohio crank has a forged 400 crank ...

You'd be MUCH better off driving a blower from the snout of a forging.

[BruceWilkie]

Thanks Jack, I guess I'll have to find an alternate use for the current armasteel. If the armasteel crank was stock I wouldnt question what to use. But someone back in the day spent alot of time with it. Found this motor in Fulton Ny a few years ago and almost passed it up as the outside was filthy dented stock sheetmetal etc.. BUT, the ports were heavily taped and it was free (in addition to the 59 Catalina with the original 420a trpower motor in it that the guy sold me.) Later inspection found JE domes(4.12 bore), SD rods, ported heads(60 vintage), Isky E2 cam, edge orrifice solids, aluminum flywheel, and nicely detailed crank. No signs of the engine ever being run. Bearings etc. not a mark, no carbon anywhere. Bearings dated 1964. Dont know who built it but the Decks are stamped JB on the front. The only builder I know from that era was in Rome (John Bravo) and he said he never put his initials on anything. Its a heck of a foundation to work with for sure. Obviously for a blower motor the pistons will have to go and I'm not about to test the early SD rods.

[7T2]

Originally Posted by Brian Baker

I went with the 14 because they're more plentiful to find used than an 8, and cheaper too by at least $500 on average. Plus, for my purposes, I can spin the 14 slower to make the same boost as the 8, which means less rotor strip maintenance. I won't be spinning it 40% over like some folks do or plan to.

spinning a -14 slower vs -8 for same boost gives better adiabatic efficiency too. maybe not as important with alky mix like it is with gas, though.

[BruceWilkie]

By the way Brian thanks for the Dyers reminder, I forgot about them.

[Colin]

Originally Posted by pontiac jack

Why would anybody in their right mind run a blower designed in the very early part of the 20th century??

I dunno.........apparently noone told the top fuel guys either.

[GTOGEORGE]

Dude,
I am still headed for the 7's, getting closer all the time. Just seems like I'm always adding weight to it! NHRA always seems to be changing the rules, seems like they get a kick back from the safty equipment manufactuers. I werighed it at Norwalk, came in at 2,990 with me in it ...........pretty heavey for a tube chassie car!

Anyways just came back from the 10 Grand Nationals at Norwalk, raced all 3 days, engine never missed a beat! Ran high 8.30's to very low 8.40's at 159 - 161 MPH. Now thats running the blower at only 3% over ................that's 7 lbs of boost on my Digital boost gauge. Pretty DARN impressive, leaving the line at only 3,500 rpms with a best of 1.17 60 foot at 82 plus degree temps with a head wind all weekend.

I now know that I have plenty of power with the KRE High Ports and the MR-1 block. I put double digit passes on it and the engine ran flawlessly and consistent. I learned a lot in the 3 days I raced it.

Thanks again to KRE for all of their help!

[tikiklubracing]

WHATS THE DIFFERENCE between 6-71 and 14-71, size of your winkie?

[Tom Vaught]

Tiki,

I posted this info once before for Pontiac Jack:

Each inch of rotor has a volume of 27.2"
Every blower has a different length.

A 6-71 has a 15" long rotor pack so times 27.2 = 408 cid
A 8-71 has a 16" long rotor pack so times 27.2 = 435 cid
A 10-71 has a 17" long rotor pack so times 27.2 = 462 cid
A 12-71 has a 18" long rotor pack so times 27.2 = 489 cid
A 14-71 has a 19" long rotor pack so times 27.2 = 516 cid

A 14-71 is about 25% larger vs a 6-71.

Tom V.

[mechanickeith]

Tom, Got any info on 3-71,4-71 & 4-53???

[GonicGM]

A high helix offers what, less pulsations, more consistent pressure?

[Brian Baker]

Originally Posted by GonicGM

A high helix offers what, less pulsations, more consistent pressure?

Hi-helix = 120 degree twist on rotors.

Standard-helix = 60 degree twist on rotors.

At the same driven rate, the hi-helix offers more boost potential. Spin it slower for like boost as a standard with less adiabatic pumping losses.

[Jack Gifford]

Originally Posted by Colin

I dunno.........apparently noone told the top fuel guys either.

Umm... how many years (decades?) since a top fuel car ran a Roots blower?
(If you didn't "see" the sarcasm in my post, check out some pictures of my Roots-blown Pontiacs)

[Jack Gifford]

Originally Posted by Brian Baker

Hi-helix = 120 degree twist on rotors...
At the same driven rate, the hi-helix offers more boost potential.

But, WHY, Brian? All kidding aside, I'd like to understand how the faster helix accomplishes what it does. I've witnessed the improved air flow, but can't explain it. The faster helix doesn't increase the displacement of the blower, so what's the deal? Does the faster helix cause the "blower" to behave a little bit like an axial "compressor", at least at one end of the rotors (the front)? A "common sense" view seems to get me nowhere- a high helix rotor would appear to allow more opportunity for air to "slip out" of the rotor cavities and back to the atmosphere.
Anybody really understand rotor helix in Roots blowers?

[Colin]

Originally Posted by pontiac jack

Umm... how many years (decades?) since a top fuel car ran a Roots blower?
(If you didn't "see" the sarcasm in my post, check out some pictures of my Roots-blown Pontiacs)

Sorry.........kinda hard to "see" sarcasm.
As far as I know they still run a roots type, just much larger than they used to be............maybe Im missing something.

[GonicGM]

Is a PSI still considered a roots? Who's running a roots, hi helix or a PSI, which classes?

[Brian Baker]

Originally Posted by pontiac jack

But, WHY, Brian? All kidding aside, I'd like to understand how the faster helix accomplishes what it does. I've witnessed the improved air flow, but can't explain it. The faster helix doesn't increase the displacement of the blower, so what's the deal? Does the faster helix cause the "blower" to behave a little bit like an axial "compressor", at least at one end of the rotors (the front)? A "common sense" view seems to get me nowhere- a high helix rotor would appear to allow more opportunity for air to "slip out" of the rotor cavities and back to the atmosphere.
Anybody really understand rotor helix in Roots blowers?

That would be my guess, since every one I've ever seen had a delta exit at the front (also called a retro opening).

They still run roots type blowers in Top Fuel...that's all the rules will allow. Whipple type blowers aren't legal, even though they're more efficient, largely because the blowers creator and company owner will not pay NHRA and SFI the exorbitant fees involved with having a part safety spec'd by SFI for use in competition.

[Jack Gifford]

Originally Posted by Brian Baker

... They still run roots type blowers in Top Fuel...that's all the rules will allow...

My apologies to Colin and others (Brian's right- I need to get out more!). With screw-type blowers "taking over" in most big-V8 motorsports, I was thinking fuel drag machines were also using them. I'm sorry.

[Jack Gifford]

Brian- If I remember right (questionable!), high-helix blowers showed up before the "retrofit" deal did. If so, then I'm just as puzzled as ever about how the higher helix improves flow. And doesn't Dyers or somebody still sell straight-rotor (zero helix) blowers? But, come to think of it, they were two-lobe, weren't they- which would increase the displacement, so that would just confuse any direct comparison.

[Colin]

Originally Posted by pontiac jack

My apologies to Colin and others (Brian's right- I need to get out more!). With screw-type blowers "taking over" in most big-V8 motorsports, I was thinking fuel drag machines were also using them. I'm sorry.

LOL......its cool. I thought maybe I was mistaken there for a while. You had me wondering if the huffers they use now were maybe different. Your trying to confuse me