Unlimited jd

Fastest currently or ever? I think the spider boat was fastest ever, old school was the fastest side by side when it had 1200's in it @ 112.

kvogt

The spider boat did 117mph.

Zero Patience

The screw compressor 8.3 whipple takes much less crankshaft hp to turn than a 8 or 10- 71, to make the same boost. That's why all big air compressors are Screw type. So if a 8-71 takes 300 crankshaft hp to turn 5000 rpm, and engine output is 900 hp, the engine is really making 1200 before the parasitic loss. The 8.3 uses less than 150 hp to turn the same boost out, thus the gains. That why turbos are so great, no parasitic loss. Ever wonder why blower belts are so big? It takes a lot of power to turn them. The new Chiefs are 588 ci, 9 psi boost, inter cooled , 1143 hp on Chief Dyno. And they idle very well.

frickstyle

So for argument, a whipple probably makes higher AVERAGE HP than a roots? IE: 1143hp roots vs. 1143hp whipple, the whipple should accelerate faster and probably top out at a higher top speed, everything else being equal.... ?

ICDEDPPL

^^ let`s not discount the Roots blower, does it "beat up' the air creating more heat ... sure. Does it take 150hp to turn it? No way. ( 50-100hp depending on boost) An 8000hp funny car with an 14-71 pushing 54 PSI takes 600 hp to turn the blower , thats 8%. That means a 900hp engine eats 72hp to turn the blower but we`re not pushing 54PSI either so I`d guess it`s around 50hp @ 7psi.

Check out the chart:
http://www.offshoreonly.com/forums/g...ml#post4412506

Is the Whipple a better supercharger... sure. Is it night and day, I have yet to see that proof but if you have no budget why not.

Stick a couple carbs on top of a roots and your highest intake air temp will be no more than 150* Add an intercooler on a hose (way less pressure and water flow then in boat) and that temps drops another 30* and adds about 25 hp)
So with an intercooled roots you`re at 120* intake , less in the boat. (70*day)

How much less heat can a Whipple make, I`m not sure nobody seems to ever put intake air temp gauges on them.

Unless I`m missing something heat and parasitic loss are the 2 main advantages to a Whipple, besides the bypass for a smooth idle.

On a 70* it`s not going to be ambient, I`d say 100*? so as additional 20hp over a Roots? Add in some parasitic loss gained (questionable under 10psi) and I`d guess a Whipple is worth 50, 60 hp.

Bang for buck that`s is some expensive HP.

Rick G

Jesus Dan I'm a CPA and I had read that twice just to check the math .
But why hasn't any one dealt with the effect of the franistan and whether how it is connected affects center of gravity .
RG.

mmb

There you go again defending that 80's technology lol. SCREW thats why it makes the power and no teflon strips.

I can point you to a 7,000 rpm drag car that picked up 10mph just by switching from the roots to the whipple. There is no comparison Basically went from 9 second et's to 8's

MILD THUNDER

I have some data from when they were testing a 6-71 GMC supercharger, back in the 60's.

To turn a 6-71 Blower, at 5000RPM, with a discharge pressure of 6psi, it required around 25 BHP. At 8psi=30hp, 10psi=35HP. 22PSI =70HP. As you can see, the power required to turn, goes up substantially as boost increases, as well as blower speed. Those guys running 60lbs of boost, spinning the chit out of a roots, heck yea they are taking some big power to drive. A 1:1 ratio, 6-8psi pump gas deal, its not as bad as everyone makes them out to be. Certainly a screw is more efficient in that area, without a doubt, and they really are in the big boost stuff as well, where PSI's main market is.

In a separate test, a mini 144 B&M was tested. At 5000 ENGINE rpm, (not blower rpm) on a small block chevy, HP losses to drive the supercharger, was 30hp, with a temperature rise of 90 degrees over ambient. So, on a 90 degree day, that combo was 180*degrees in the intake on that combo.

Icdedppl's 540, made 900HP with a 10-71 making 8psi of boost. If you were to take an engine, that made 500HP N/A, and gave it 14.7psi, it would make 1000HP sans any parasitic, or other efficiency losses. IF his 10-71 blower, was consuming 300HP to turn, that would mean he's actually making 1200HP at the crank, with no losses. To make 1200HP with 8lbs and no losses, that would mean his 540ci, is making around 800HP on engine alone. I think BDS, Blowershop, Hampton, Littlefield, and many others, would be out of business, if by bolting on one of their products, only gained 100HP over a N/A combo.

Now, if we assumed his 540 was making around 625HP on motor, adding 8psi, would net 965HP without any losses. That sounds alot more reasonable to me, and coincides with the testing done on the 6-71 Compressor back when they were becoming popular.

ICDEDPPL

Heresay like this is exactly why these bar talk misconception exist.

I had someone tell me a 100 hp increase, turns out they forgot to mention the CNC head change at the same time.

ICDEDPPL

YOu better sharpen your pencil with Joes post