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mad max car

SpartacusSpartacus Member Posts: 14,415
edited January 2012 in General Discussion
in the original mad mad (1979) the patrol car had a cable operated bolwer disconnect.
can that really be done?

thanks
tom

Comments

  • gesshotsgesshots Member Posts: 15,678 ✭✭✭✭
    edited November -1
    Have thought of this too. I would say no because a super charged engine needs a significantly lower compression ratio than a normaly aspirated engine. Just my reasoning, I welcome all opinions, since I have had this discussion many times since 1979. [;)]
    It's being willing. I found out early that most men, regardless of cause or need, aren't willing. They blink an eye or draw a breath before they pull the trigger. I won't. ~ J.B. Books
  • SpartacusSpartacus Member Posts: 14,415
    edited November -1
    well, if it's anything like turbos, the boost can be significantly higher than "recommended"
    so if the blower ran 8psi on a 10:1, you could still run some boost on a 13:1 performance engine, right?
    kinda like a shot of nitrous.
    but how would you mechanically do the disconnect on the blower?
  • gesshotsgesshots Member Posts: 15,678 ✭✭✭✭
    edited November -1
    quote:Originally posted by Spartacus
    well, if it's anything like turbos, the boost can be significantly higher than "recommended"
    so if the blower ran 8psi on a 10:1, you could still run some boost on a 13:1 performance engine, right?
    kinda like a shot of nitrous.
    but how would you mechanically do the disconnect on the blower?


    Since a blower is belt driven - an electric/ mechanical clutch is an option. If there is such a thing.... for a supercharger.
    It's being willing. I found out early that most men, regardless of cause or need, aren't willing. They blink an eye or draw a breath before they pull the trigger. I won't. ~ J.B. Books
  • yoshmysteryoshmyster Member Posts: 22,042 ✭✭✭✭
    edited November -1
    quote:Originally posted by gesshots
    quote:Originally posted by Spartacus
    well, if it's anything like turbos, the boost can be significantly higher than "recommended"
    so if the blower ran 8psi on a 10:1, you could still run some boost on a 13:1 performance engine, right?
    kinda like a shot of nitrous.
    but how would you mechanically do the disconnect on the blower?


    Since a blower is belt driven - an electric/ mechanical clutch is an option. If there is such a thing.


    Or maybe like a bicycle with the free wheel?
  • grumpygygrumpygy Member Posts: 48,464 ✭✭✭
    edited November -1
    madman-inter.jpg

    I seem to remember he would do something in the car and then the Blower drive belt would begin spining.
  • SWAT 50SWAT 50 Member Posts: 4,074 ✭✭✭
    edited November -1
    quote:Originally posted by gesshots
    quote:Originally posted by Spartacus
    well, if it's anything like turbos, the boost can be significantly higher than "recommended"
    so if the blower ran 8psi on a 10:1, you could still run some boost on a 13:1 performance engine, right?
    kinda like a shot of nitrous.
    but how would you mechanically do the disconnect on the blower?


    Since a blower is belt driven - an electric/ mechanical clutch is an option. If there is such a thing.


    You need look no further than your Riding lawn mower.
  • SWAT 50SWAT 50 Member Posts: 4,074 ✭✭✭
    edited November -1
    Besides it is a movie, don't look too close.
  • grumpygygrumpygy Member Posts: 48,464 ✭✭✭
    edited November -1
    And you all are not the Only ones thinking of this.


    quote:yes for years people have laughed at the clutch mounted in the blower of that awsome holden cop car and sait it's imposible, blowers use so much power a clutch will not handle it and so on, but... the other day I changed the drive chain in my explorer's transfer case and found an electromagnetic clutch that connects the front axle, man this thing handles all the engine torque transmited to the wheels and is quiet a lot, Toyota has an electric clutch driven roots supercharger in the 4AG engine fitted to the MR2 sport car, so what is the problem? maybe 8-71 blowers are too big but they are not driven on the streets daily, what about the small 144/177 range street blowers? it would be great having the pull switch on the stick shift to activate the blower, the motor runs pretty well without power to the blower, I have driven my own sbc 350 motor wich has a B&M 144 blower for long time without the drive belt when it broke once and I had trouble finding a new one, the motor behave just like it had no blower, even the big cam was tamed, it surely makes me think it's possible.
    Would it be possible to use a muti disk modified A/C clutch? compressors use lots of power, I'd say a 3 lined disk setup with the electromagnet pressure plate, go kart motors have clutches that handle more than 45 hp.
    Has someone ever made a device such as this hollywood gadget?
  • fishkiller41fishkiller41 Member Posts: 50,608
    edited November -1
    If the blower vanes stop turning it instantly chokes off air to the engine.
    Mad Max was JUST A MOVIE!
  • yoshmysteryoshmyster Member Posts: 22,042 ✭✭✭✭
    edited November -1
    madman-inter.jpg

    I forgot that ride had two spoliers. I wonder why them fart can cars only have one big one like the "Super Bird"? I say go with three. One on the hood right up front to keep the nose down.
  • remingtonoaksremingtonoaks Member Posts: 26,245 ✭✭✭
    edited November -1
    quote:Originally posted by yoshmyster
    madman-inter.jpg

    I forgot that ride had two spoliers. I wonder why them fart can cars only have one big one like the "Super Bird"? I say go with three. One on the hood right up front to keep the nose down.

    That's what the air dam under the front bumper is designed for
  • yoshmysteryoshmyster Member Posts: 22,042 ✭✭✭✭
    edited November -1
    quote:Originally posted by remingtonoaks
    quote:Originally posted by yoshmyster
    madman-inter.jpg

    I forgot that ride had two spoliers. I wonder why them fart can cars only have one big one like the "Super Bird"? I say go with three. One on the hood right up front to keep the nose down.

    That's what the air dam under the front bumper is designed for


    I meant on ricers.
  • SpartacusSpartacus Member Posts: 14,415
    edited November -1
    quote:f the blower vanes stop turning it instantly chokes off air to the engine.
    Mad Max was JUST A MOVIE!

    correct, that's the whole idea of the question. run a high performance engine ambient pressure, with the ability to activate boost
    the electronics to boost fuel pressure/delivery are basic.
    the mechanical link is what's not been done, near i can see.
    I have a 1987 grand national buick with worked 3.8L turbo. It has an electric header cutout mounted in the turbo exhaust feed. I can launch the car on the engine and headers, then switch to turbo and straight pipes.
    that's what i'm looking for with a blower, but mechanical engage.

    tom
  • SoreShoulderSoreShoulder Member Posts: 3,148 ✭✭✭
    edited November -1
    Ford sold a 3.8 V6 with an Eaton blower that had a bypass duct which returned the compressed air to the top of the blower. It went into some late '80s Tbird IIRC. When you wanted full power a butterfly valve would close off the duct.

    The goal is to keep from having the blower fighting the throttle when you are driving slow because generating extra vacuum causes extra throttling losses.

    Someone mentioned compression but the thing is, if you're cruising at 35mph then the throttle is preventing the blower from pressurizing the manifold anyway, or else you'd be accelerating. In other words, by closing off the inlet to the blower, it's making the blower compress a high vacuum to make a lower vacuum, so the cylinders only get partially full and you don't develop the full horsepower the engine is capable of, when you don't want it.

    So, it has been done. It helps save gas. You still get the reduced economy of a low compression engine, but at least you're not forcing the blower to create a super high vacuum under the carb, just so the manifold pressure stayed low enough to keep the car cruising steadily rather than accelerating.

    You couldn't just stop the drive belt unless you gave the mixture another way of getting into the manifold, as another poster has mentioned.

    One of the reasons some of our early WW2 fighters were criticized was the fact that you couldn't turn up the blower at high altitude. The state of the art setup was a two speed, two stage blower. That was so you could have high boost at high altitude to make up for the thin air, but that high boost wouldn't blow up the engine at low level, and there'd be less parasitic drag at low level because you wouldn't be controlling the boost by throttling back and making the blower fight the throttle. Instead, you'd run the blower at a lower speed.
  • TexasVetTexasVet Member Posts: 2,847 ✭✭✭✭✭
    edited November -1
    Mercedes has had an electric clutch on some of their superchargers for for the "kompressor" cars for several years.

    It's not a real big supercharger like the 671 on the Mad Max car.
  • SoreShoulderSoreShoulder Member Posts: 3,148 ✭✭✭
    edited November -1
    I don't think a bypass would work with a conventional carbureted blower setup because there'd be no telling what the fuel would do when the bypass opened or closed.

    A port fuel injected engine puts the fuel in downstream of the blower.
  • redneckandyredneckandy Member Posts: 9,715 ✭✭✭✭
    edited November -1
    quote:Originally posted by TexasVet
    Mercedes has had an electric clutch on some of their superchargers for for the "kompressor" cars for several years.

    It's not a real big supercharger like the 671 on the Mad Max car.

    Yep. Basicly it uses an oversized A/C clutch.
  • Horse Plains DrifterHorse Plains Drifter Forums Admins, Member, Moderator Posts: 40,220 ***** Forums Admin
    edited November -1
    quote:Originally posted by fishkiller41
    If the blower vanes stop turning it instantly chokes off air to the engine.
    Mad Max was JUST A MOVIE!
    Yep, break the quill shaft in a Detroit, and see how fast it comes to a halt.
  • SoreShoulderSoreShoulder Member Posts: 3,148 ✭✭✭
    edited November -1
    One extra sealable duct going around the blower and the engine will run fine with the blower stopped.
  • legearlegear Member Posts: 6,716
    edited November -1
    quote:Originally posted by Spartacus
    quote:f the blower vanes stop turning it instantly chokes off air to the engine.
    Mad Max was JUST A MOVIE!

    correct, that's the whole idea of the question. run a high performance engine ambient pressure, with the ability to activate boost
    the electronics to boost fuel pressure/delivery are basic.
    the mechanical link is what's not been done, near i can see.
    I have a 1987 grand national buick with worked 3.8L turbo. It has an electric header cutout mounted in the turbo exhaust feed. I can launch the car on the engine and headers, then switch to turbo and straight pipes.
    that's what i'm looking for with a blower, but mechanical engage.

    tom


    We need pics of this said GN or else it aint true....[:D]
  • TempestTempest Member Posts: 1,273 ✭✭✭✭✭
    edited November -1
    This topic is just the reason nitrous came into being.
  • SoreShoulderSoreShoulder Member Posts: 3,148 ✭✭✭
    edited November -1
    quote:Originally posted by dennisnielsen
    Cars built to run with boost pressures run like crap without.
    Thing is, you're not going to have boost pressure when you throttle back to cruise anyway, if you don't have a bypass.
  • SoreShoulderSoreShoulder Member Posts: 3,148 ✭✭✭
    edited November -1
    quote:Originally posted by dennisnielsenAre you saying there is no additional intake pressure from the blower with the rotors/impellers turning?
    No, not when you're cruising at part throttle. What the blower amounts to is this: you have to hold the throttle more closed.

    You're only making enough horsepower to cruise at a steady speed, so why should the lower manifold have more pressure in it than a normally aspirated engine of the same size also cruising at the same steady speed, in a car of the same air resistance and rolling resistance?

    You have much higher vacuum behind the throttle plates in a blower engine at part throttle cruise, which then gets compressed up into a lower vacuum below the blower, which is about the same as the manifold pressure in the same car with the same size non-blower engine cruising at part throttle at the same speed.

    Of course it's not exactly the same because your camshaft timing is going to be different so you need a slightly different manifold PSI in order to make the same part-throttle power. Also, the blower car has to generate a little more HP in order to overcome the extra drag.

    If there was more pressure in the manifold, then you'd be making more power and accelerating-or cruising faster than the car with less manifold pressure, if it's the same car with the same size engine.
  • SoreShoulderSoreShoulder Member Posts: 3,148 ✭✭✭
    edited November -1
    That's why blower cars are less efficient. At part throttle, you're powering the blower to pull roughly the same amount of air past a much more closed throttle than you would if there was no blower.

    You'd have a lot less mileage even if you had some sort of perfectly frictionless blower and drive system.
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