[bad69bird]

Originally Posted by GTOGEORGE

bad69bird quote: "You guys can debate over that root style chit all you want...my street car is sooooooo efficient that it sucked up a couple of those helix 8-71 blowers at Norwalk to get a spot in the Q-16!

Yea right "Mister - I could only get in the Quick 16 when a car broke!"


GTO George

LMAO! Doesn't matter! On my 8.440 pass I sucked up one of those roots blower cars! I made it and that is all that matters! LOL Did you get into the 7's yet???!!!

[GTOGEORGE]

bad69bird quote: "Doesn't matter! On my 8.440 pass I sucked up one of those roots blower cars! I made it and that is all that matters! LOL Did you get into the 7's yet???!!!"


...............and I knocked one of those "Hair Dryer" blower cars out of the KRE Quick i6 when I qualified for the Quick 16 on Sunday.......................anyone we know? LMAO



GTO George

[bad69bird]

Originally Posted by GTOGEORGE

bad69bird quote: "Doesn't matter! On my 8.440 pass I sucked up one of those roots blower cars! I made it and that is all that matters! LOL Did you get into the 7's yet???!!!"


...............and I knocked one of those "Hair Dryer" blower cars out of the KRE Quick i6 when I qualified for the Quick 16 on Sunday.......................anyone we know? LMAO



GTO George

Who? I didn't race you.

[Tom Vaught]

Originally Posted by firechicken

The supercharger with lower efficiency is the one that can move the same cfm at the same boost pressure at the same engine rpm on the same engine but heats the air more and/or has more parasitic loss and in turn has less mass flow and/or less power at the flywheel. I'm done.

Some additional info for the board:

http://www.team-interceptor.dk/index.htm

The amount of boost produced by various superchargers is a topic of considerable debate. Few people understand the many variables that can alter a manifold pressure (boost) reading. The displacement of the engine, the efficiency of the engine, throttle opening, valve timing and overlap, load on the engine, atmospheric conditions, and the amount of fuel going through the supercharger are just a few of the many factors that can greatly alter a boost reading. While it is possible to obtain standardized airflow figures produced by a supercharger, only a few true supercharger dynometers exist. Consequently the testing facility required to obtain these numbers are outrageously expensive. For that reason the boost capabilities of each supercharger shown above are based on a mathematical formula and experience. Your particular engine combination may actually produce more or less boost than the figures shown.

Sizes Rotor Diameter Rotor Length Cu. In. per. Rev.
6x71 Small Bore 5.505" 14.975" 339 c.i.
6x71* Std. Bore 5.778" 14.975" 411 c.i.
8x71* Std. Bore 5.778" 15.905" 436 c.i.
10x71* Std. Bore 5.778" 17.000" 466 c.i.
14x71* Std. Bore 5.778" 19.000" 521 c.i.

The 8x71 supercharger is about 20% smaller in Cubic Inches per Revolution compared to the 14x71 supercharger. That means that the 14x71 supercharger can run 20% slower, (here is that compressor rpm deal again Chicken) and move the same cubic inches of airflow to the engine as the 8x71 supercharger.

How to calculate boost pressure vs Air Mass Flow (info from Garrett Turbos).

http://www.turbobygarrett.com/turbob...o_tech103.html

Read the whole article, calculations are in the middle. (You notice Chicken that all of the maps had compressor speed information on them.)

And finally good information from Gale Banks about CFM vs air mass vs CHARGE DENSITY

http://www.bankspower.com/techarticl...o-Making-Power

Tom Vaught

[Tom Vaught]

George, A question for you:

What is your max engine rpm, your supercharger/engine pulley ratio and have you ever put a temp gage into the intake manifold to see how well your methanol fuel is lowering the charge temp of the air?

Tom Vaught

[GTOGEORGE]

Tom Vault Quote: "George, A question for you:

What is your max engine rpm, your supercharger/engine pulley ratio and have you ever put a temp gage into the intake manifold to see how well your methanol fuel is lowering the charge temp of the air?"

Engine made max power around 7,100 rpm (on the Dyno), I shift anywhere from 6,200-6,600 rpm. I use a 58 tooth bottom pulley and I've run 3 top pulleys so far with this engine combo 56,54 & 51. The most boost I've run is 8 lbs. so far. When I DRIVE back from a pass my blower is cool to the touch, I have not installed a temp gauge in the intake. I am not an Engineer but my guess is the charge going into the intake is pretty cool!


GTO George

[Scott M]

Originally Posted by GTOGEORGE

I use a 58 tooth bottom pulley and I've run 3 top pulleys so far with this engine combo 56,54 & 51.

The most you've ever run is 14% over?

C'mon, George; be a man.

Step it up with a 45 top pulley, willya?

[Tom Vaught]

George, I ran through the air calculations (from this website):

http://www.turbobygarrett.com/turbob...o_tech103.html

The numbers are lining up really close to your performance at Norwalk and the 8 psi number vs the HP/ et on the passes.

Misus suggestion to go to a 24% step-up might get you another 120 hp and might get you in the 8.0s but you also raised the supercharger rpm by 10% so the air would be hotter and the density lower assuming the same cooling by the methanol.

Still for a 8-71 supercharger deal, the engine is running well. A 14x71 would get you another 250 hp over where you are now based on the same spreadsheet.

Lot of tear-up for your program though.

I ran across the spreadsheet and the other info and decided to use your set-up as a checking tool. Program seems pretty accurate for a calculation.

Tom Vaught

[Scott M]

Originally Posted by Tom Vaught

Lot of tear-up for your program though.

Negative; $50, tops, for a used 45-tooth blower pulley.

$50 for 120hp?

Not too shabby an investment.

[Tom Vaught]

Originally Posted by Scott M

Negative; $50, tops, for a used 45-tooth blower pulley.

$50 for 120hp?

Not too shabby an investment.

No real tear-up for the 120 HP pulley deal, Sonny. The tear-up would be removing the 8-71 that he has and going to the 14-71 unit.

Tom Vaught

[62fatcat]

Travis Q.,
thank you,
this the point i was trying to make when i started the thread.

[Torment]

I doubt 24% would hurt George's parts a bit - maybe a couple lbs from the 13% (58/51) tuneup. Must be an efficient 525ci to run only 8lbs at 13% - or a tired blower. I'd expect closer to 13lbs with that blower OD/engine ci. If it isn't the blower I'd estimate a couple tenths improvement with the bump. With carbs the fuel tuneup is almost a non-tuning issue as well and Dom's should be just enough to feed it.

Should be able to make near 3hp/ci with a 20%OD 14-71 methanol deal falling off a rock - so another 250hp from George's 1300hp signature line sounds about right.

[Scott M]

Originally Posted by Torment

Should be able to make near 3hp/ci with a 20%OD 14-71 methanol deal falling off a rock - so another 250hp from George's 1300hp signature line sounds about right.

Of course. Pops Vaught is a lot smarter than he looks in person.

[Brian Baker]

Tom, what does your chart say about a 14-71 @ 6% over, E-heads in the 325-cfm range, and 440 cubes?

[Scott M]

Originally Posted by Brian Baker

Tom, what does your chart say about a 14-71 @ 6% over, E-heads in the 325-cfm range, and 440 cubes?

"grenade"



Say, Pops; quit bogartin' that chart and post it up here, willya?

[Tom Vaught]

Originally Posted by Brian Baker

Tom, what does your chart say about a 14-71 @ 6% over, E-heads in the 325-cfm range, and 440 cubes?

Things I need:

Max rpm of engine

shift rpm

cfm of the throttle plate system (Bugcatcher) vs in George's case I knew he had dominators

expected HP

Tom Vaught

[GTOGEORGE]

Tom,
Numbers at Norwalk? Which ones I ran 8.50's, 8.40's and 8.30's! Temps at the track ranged from mid 70's to mid 90's.............your too silly. I figure that a top 47 tooth pulley should get me in the 7's at about 13 lbs. of boost on a average day.

Torment,
Blowers not worn out getting same boost number the last 3 years!



GTO George

[Brian Baker]

Originally Posted by Tom Vaught

Things I need:

Max rpm of engine

shift rpm

cfm of the throttle plate system (Bugcatcher) vs in George's case I knew he had dominators

expected HP

Tom Vaught

I don't see it pulling more than 7500 rpm through the traps...shifting at approximately 6500 but with no tach, who knows (only gauge is going to be oil pressure). Given the age of the Crower 8-port and the era in which it was designed/built, AND the fact it's a small port Crower, I'll hazzard a guess it flows comparable with a bug and not a bird, but what that cfm rating is I don't know. Can't be more than 1750-cfm? Projected HP in the 1000-1200 HP at 6% over blower speed.

[Tom Vaught]

Your numbers are pretty good really.

1150 to 1250 with the 1.06 overdrive ratio

I think you could make the 1100-1200 without that deal as the 14-71 blower rpm
will be 7950 in the traps (7500 engine rpm). Going through the traps at 7000 with
no overdrive would still make the power you want.

Shifting at 6500 with no overdrive you should still be making 1100 hp at the flywheel.

Tom Vaught

[Brian Baker]

Originally Posted by Tom Vaught

Your numbers are pretty good really.

1150 to 1250 with the 1.06 overdrive ratio

I think you could make the 1100-1200 without that deal as the 14-71 blower rpm
will be 7950 in the traps (7500 engine rpm). Going through the traps at 7000 with
no overdrive would still make the power you want.

Shifting at 6500 with no overdrive you should still be making 1100 hp at the flywheel.

Tom Vaught

Thanks, Tom...that's about where I want to be to have it run 7.50's (which is all the chassis will cert' for). On paper it looks like it could run a little better than that, as I don't see the race weight being more than 2300 lbs. but...that's on paper and real world is different (LOL).