Fevre

One of the IT guys I work with is a mustanger and races with a super charger. We got to talking about me putting one in my vette and I asked him if they make diff size pulleys like roots sc and he told me he took the clutch pulley off his a/c (which is took out) and put it on the his sc. He can switch it on and off when every he wants. First time I heard of that. Sounds like a great idea to me, seems it would make it last alot longer and save wear and tear on the rest of the engine.

norvalwilhelm

Sounds fishy to me. What are the chances of the output of the air conditioner and the output of the supercharger being the same so the pulleys are interchangable?
I would be very sceptical about this. If you did run a supercharger why would you want to turn it off anyway. They are ment to be driven constantly.

Fevre

I trust the guy, he know his stuff. Why have the super charger turning 3000 rpm's on the e-way if your just cruising some where? He says he was mostly racing it so he had it on must of the time but says he saw no ill effects when he switched it off. I will hold final judgement till I see it perform in person.

Metal Wulf

If you do it, make sure you post the write up on the install !! I've always dreamed of having a Mad Max style supercharger where you can turn it on and off with a switch!! :D

Fevre

I'm just hoping to get my 5-speed in without major problems, then tpi and if I am still alive and sane I will do the supr charger. I will see if he has any pics but I know his cars is apart for a rebuild right now.

TONYS68L36

I thought that the ac compessor (along with the ac switch in the car!!!) was what caused the pulley to kick in...not the pulley by itself. Am I making sense...


[Modified by TONYS68L36, 3:52 PM 1/13/2003]

Fevre

It may depend on the system, I will try to get more info. He told me that when energized it acts kinda like a clutch in that there are clutch like pads that kick out and engage against the inside of the pulley.

75 BBC Stingray

Sounds cool, but I wonder about the details. I've been talking w/ some friends about this since I saw Mad Max. Here would be the sticky points:
1.) For roots style supercharger - you turn it off... how does the air get into the engine?
2.) For centrifugal style - still a restriction, but perhaps you can plumb up a diverter valve to take air from another air filter.
3.) Does an AC unit take about the same torque to turn as a cetrifugal SC?
4.) How do you set up the engine so that its not a dog when the blower is off, and not having too high of compression when running.

Here would be my cool idea for a supercharger...
Run off of a variable speed electric motor, tied into a boost gage. Would vary speed to maintain a certain boost curve, w/ override **** near the driver... This way you could hook up a closed loop system to remain at a constant boost pressure if that was what you wanted...

:smash: Enough craziness out of me...

71vettman

He must be running a centrifugal blower.......right? If it were a roots type blower it hase to be running all the time if the engine is going to get any air.

As far as the ac pulley goes it is simply and electro magnet. When you turn the ac on you energise the magnet which locks the drive hub to the pulley.

rainman69

Mercedes runs a factory "electrical on/off" supercharger on some of their cars. It is a roots style blower that has a clutched pulley on the snout. Works just like an A/C clutch pulley.

Supposedly it is "power when you want it, tame when you don't."

:steering:

ddecart

Exactly the same things I was wondering.

norvalwilhelm

Here would be my cool idea for a supercharger...
Run off of a variable speed electric motor, tied into a boost gage. Would vary speed to maintain a certain boost curve, w/ override **** near the driver... This way you could hook up a closed loop system to remain at a constant boost pressure if that was what you wanted...

75BBC Stingray. This would produce a runaway motor. If you provided a constant boost level the motor would not respond to the throttles position.
Every time the valve opened a cyinder would be filled and you have no control over it. Your throttle controls the amount of air in the intake so you can slow the motor down.

To everyone else what is wrong with running and blower supercharger constantly. Are we that worried about wear on them? Blowers on trucks runs forever. The supercharged motor runs low compression be compensate for boost so the motor is candicaped with the boost.
For all those who have never gone blown try it and you will never go back.

norvalwilhelm

My wife's Bonneville runs a roots blower that puts out 7 pounds of boost. It is extremely smooth, gets fantastic mileage and there is no surge of power when getting on it. Just a smooth flow. It runs all the time.

Ganey

AGREE W/ NORVAL.

Fevre
It would not save wear and tear on the rest of the engine.

The only reason for a cutoff would be to save gas.

TONYS68L36
The a/c pulley spins freely when the a/c is off- engaged by electromagnetic clutch when on. (as 71vettman said)

Running it full time would help mix the air/fuel mixture even when not in boost in a draw through set up like Roots.


[Modified by Ganey, 8:31 AM 1/14/2003]

flood

If you had a shut off for the supercharger wouldn't you also want a computer to readjust your fuel air mixture? You would be running rich I would think. Also the computer could trigger the opening for another fresh air source.

I agree with above that there really isn't a need for that at all.


[Modified by flood, 8:27 AM 1/14/2003]

Fevre

So running 4 to 10 psi's will not cause anymore wear and tear on seals than running none? Increasing the pressure in the cyl will not cause any wear and tear on the rings? Increasing pressure won't cause any detonation problems? Increasing the pressure doesn't cause increased heat which can heat related problems? :confused:

I am not arguing that the benefits would be incredible but may be worth looking into.

ylose

personally.....I don't think I would be able to force myself to turn it off if I had one.....I like to drive with every pony possible at all times....

:steering:

Fevre

BTW Just found out he is running about 17 lbs of boost and about 600-700 hp out of a 5.0.

norvalwilhelm

My 8-71 blown motor or my wifes supercharged Bonneville runs no NO boost regardless of speed. We can both cruise along at 80 mph with ZERO boost, even a vacuum like normal engines but touch the throttle to pass and the boost instantly jumps up and you are running on boost, back off again and the boost is gone. Boost is controlled by throttle position not speed. If you want the power you want the boost. I can get full boost at 1500 or nothing at 4000. It is up to me how wide I open the throttle, not the blower.
So no my seals do not see boost all the time and the cylinder sees the same pressure as a normal aspirated engine except when I call upon it for boost.
As for mileage I also feel like Ganey that there is an advantage to mixing the fuel
With 2 850 double pumper carbs, a 460 motor, 4.11 gears I still get 12 mpg around town.

flood

why not just run a turbo? If your not on it (engine load) then you get no boost. Not only that but turbos are ALOT more efficent than a supercharger that robs HP.

Wouldnt' a supercharger always provide boost because the pulley is always turning? :confused: