Landracing Forum
Tech Information => Technical Discussion => Topic started by: smitty2 on February 13, 2009, 04:27:01 PM
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DrofRockology mentioned front mount blowers in another post... I was wondering who it is that is producing it? Is it just for Chevy/Ford/Mopar, or is there a "Universal" mount available?
Am I asking too many questions?
Smitty :cheers:
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These guys http://www.thesuperchargerstore.com/ make a set up to run a Procharger off the front. If you wanted to run a conversational style blower on the front it wouldn't be that hard to fab up something. I built one for my GMC 6 and couldn't fit everything in my roadster the way I wanted, so I went with a reverse rotation Procharger instead.
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Thanks Mag.. those are some sweet set ups.
I have a 4-71 that I have rebuilt, and was hoping to mount it in front of a Chevy 153 inch Banger. Since I'm on a starvation budget at this time I believe I'll end up machining something up in the garage. I'm open for suggestions :-D
Thanks... Smitty
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"Potvin" front blower drive ... havent been manufactured for quite awhile ... check ebay or surf the web for old racing equipment ... JD
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Smitty, You could run a bellt drive or a Lovejoy connector http://www.lovejoy-inc.com/ and then fab up a housing around it. Also Steve at uncommon engineering http://www.uncommonengineering.com/index.html (about half way down their is a picture of a 471 on the front of a flat head Ford) has a coupler he made for a 471 to flat head Ford. Try giving him a call and see if he has coupler for your application.
Tony
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Tom Cobbs also made some front mount supercharger stuff. I own one of his units for a small block chevy.
Tom G.
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Potvin! that's the name I was trying to recall. The Mooneyes rail has a Potvin front mount. I was looking at Marlo's Streamliner awhile back, and it seemed to me that his was a belt drive arrangement... pretty slick setup. I will look at EBAY and see if someone has a setup that will work for this... If not I'm kind of looking forward to a fabrication project :-D
Thanks.... Smitty
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Moon Equipment may be able to assist with Potvin drive equipment.
Joe
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Come on guys! You have a shaft that needs to be turned ,the blower, and one that is turning, the engine, any of us with any level of fab ability can make that happen. I would probably go with standard blower pulleys and toothed "rope" to drive it. Lay the blower on its side, I'm talking 4-71, 6-71 etc GMC style roots blower here, with the inlet on one side and the out let on the other and I think that the biggest fab challenge is making a good plenum between the blower and the engine. Important to get the air slowed down and going in the direction of the inlet ports so I would do some sort of turning vanes internal to the plenum and I would make it BIG with lots of volume to get max pressure, evenly distributed to all cylinders.
Rex
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There is a NOS Potvin setup on Ebay currently.
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ru=http%3A%2F%2Fsearch.ebay.com%3A80%2Fsearch%2Fsearch.dll%3Ffrom%3DR40%26_trksid%3Dm37.l1313%26satitle%3D%2B220390168224%2B%26category0%3D%26fvi%3D1&item=220390168224&viewitem=
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Come on guys! You have a shaft that needs to be turned ,the blower, and one that is turning, the engine, any of us with any level of fab ability can make that happen. I would probably go with standard blower pulleys and toothed "rope" to drive it. Lay the blower on its side, I'm talking 4-71, 6-71 etc GMC style roots blower here, with the inlet on one side and the out let on the other and I think that the biggest fab challenge is making a good plenum between the blower and the engine. Important to get the air slowed down and going in the direction of the inlet ports so I would do some sort of turning vanes internal to the plenum and I would make it BIG with lots of volume to get max pressure, evenly distributed to all cylinders.
Rex
I've seen fotos but never seen how, if you just placed the front of the blower to the front of the crank it would be turning backwards so they do something to drive off the rear of the blower??
Ken Walkey had a 671 style front drive on his chev streamliner, try talking to him. I always thought a front drive on a roots blower would be a good idea and if running gas you could plumb in an intercooler.
But i would never run a roots blower on gas.
JL222
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I've seen fotos but never seen how, if you just placed the front of the blower to the front of the crank it would be turning backwards so they do something to drive off the rear of the blower??
.
JL222
John,
If you look at the front of a GMC blower all belt drives come off the right hand rotor. When you use it as a front mount you use the left rotor to drive the blower. Since GMC blowers just use two gears to turn the blower rotors one gear turns clockwise the other turns counter clockwise. Hope that helps.
Tom G.
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Tom, that Hot Rod pic is just TOO EFFING NEAT!
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That's beautiful but no aftercooler! Does the car have a radiator?
Harv
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The picture came off the internet so I really don't know if it has cooling or not.
I have a front mount for one of my Desoto's. I really want to put it into a track style 27 Ford T Roadster. I always thought it would be cool to have a long nose with the hood hinged in the front. Just for looks put a 14-71 Hi Helix on the front with electronic FI, and a set of Howard's Aluminum Desoto Heads.
Tom G.
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I shot these fotos at Bakersfield just for this site.
I was told that Fred Larsen built this application when he worked for Moon. It's like he had on his streamliner.
It is the Potvin application.
FREUD
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Re: "biggest fab challenge is making a good plenum between the blower and the engine"
I agree - the air speed in those tubes is far too high to turn into the manifold runners. The manifold itself appears to have been designed to minimize height (which was the original purpose), but I can't see the manifold as-is working very well even if the air speed is down by the entry point.
IMHO a better manifold choice with smallest aero penalty is probably a TR with short runners and the entry through the face like some modern EFI.
In addition to larger diameter transfer tubes, they both originate in a box (very crude), and centered on the exhaust side. If the blower drive is reversed the exhaust volume will be from the front 35% or so in the usual triangle, and that should be the minimum area for the tube(s). If you want to use commercial tubing, 2 or 3 each 6" diameter.
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When early front mount blowers were made, most everyone at the time ran all the fuel through the blower. Even with the popoff valve located on the discharge side of the blower, you still had a bomb just waiting to go off. That was probably a good reason to keep the manifold on the small side.
Which brings up a good question. Under pressure do you really need to have good flowing bends in manifolds etc. At first I thought yes, but now I don't know if it is all that important.
A PSI Screw blower is a perfect example. The early Blowers they made compressed air and forced the air out of a delta opening in the back bottom portion of the blower. The compressed air then was trapped (between a plate you had to install on the manifold) and forced to follow built in ribs on the bottom of the blower before being released into the manifold. Yet these blowers took less HP to operate, and delivered cooler air than similar sized 6-71 GMC blowers that discharged directly into the manifold.
Tom G.
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The system may be trash but it sure worked on the Larson and Cummings car
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The system may be trash but it sure worked on the Larson and Cummings car
Rich,
You can't knock success, and they set a lot of records with that car. One of my all time favorite cars.
Tom G.
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The system may be trash but it sure worked
That statement was also offered in defense of the Ford V8 rather than that weird new Chrysler motor in 1951. Took a few years to be disproved - read Garlits.
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The only problem with front mounted blowers is that they can't be overdriven. Years ago some guy was selling a coupler to overcome this problem but by then racers found the top mounted blower to be more efficient so he only made a few.
Here's another bitchin' front mount setup. :-D
(http://)
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The system may be trash but it sure worked
That statement was also offered in defense of the Ford V8 rather than that weird new Chrysler motor in 1951. Took a few years to be disproved - read Garlits.
I worked on a few motors with front mount blowers that seemed to work well at the time. Pratts and Wrights mostly. 2800s and 3350s. I like that Chrysler picture.
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That picture with a centrifugal supercharger reminds me of a time I was at Pomona for the drag races. In the pits I run across Doug Herbert who at the time was running in the Top Alcohol Dragster class. He had a huge centrifugal supercharger mounted in front of the motor. Needless to say NHRA outlawed his setup, but it was cool.
Tom G.
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Cagle ran one in the 50s, It was a cabin pressure centrifugal type that was furnished by Don Alderson (Milidon) It was off a DC-7 I believe.
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they can't be overdriven
...well, not easily.
If you really need the centerlines concentric, a planetary works.
If you can stand some offset (and if moved sideways the blower is still narrower than the engine), a chain drive can be pretty small and cheap. A pair of #50×2 sprockets need only be 2" thick and 8" diameter, moving the blower CL in a 4" circle (4" L or R, up or down, or 2.8" in both directions etc.), locus at the crank . A 20 + 21 set is 1.05 or .952, 21 + 19 is 1.105 or .905, etc.
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I have one that was over-driven. 10% as I recall, been too many years since I looked at it. I bought it off Doug Hartlet (sp) in San Diego. Looked like quick-change gears to me. If it wasn't so buried I would pull it out and take pictures for you to see.
Tom G.
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Which brings up a good question. Under pressure do you really need to have good flowing bends in manifolds etc. At first I thought yes, but now I don't know if it is all that important.
Tom G.
Tom, I've thought about that, too.
Part of the question brings up the term "under pressure". Air at sea level is "under pressure" - what you've done by supercharging is changed the relative pressure between the opening, unfilled cylinder and the manifold pressure. Obstructions in the conduit of flow remain obstructions, regardless of the differential between the open cylinder and the manifold pressure. Given the short period of time that a valve stays open at, let's say 7500 RPM, any restriction can cost you horsepower.
How much? There is likely a point of diminishing returns, and I suspect sufficient artificial manifold pressure could overcome a questionable (albeit beautiful) manifold design.
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Old timers will recall the Burkhart, Burns, Erdman, sometimes Brammer '29 Lakes/ Drag Roadster having a front mount 671 that had gearing capability -maybe with quickchange gears, but don't quote me on that aspect. Things were in a housing as I recall.
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That picture with a centrifugal supercharger reminds me of a time I was at Pomona for the drag races. In the pits I run across Doug Herbert who at the time was running in the Top Alcohol Dragster class. He had a huge centrifugal supercharger mounted in front of the motor. Needless to say NHRA outlawed his setup, but it was cool.
Tom G.
I remember that, the early 90s I think, and was it Walt Austin who built a front drive for a Whipple supercharger on a funny car?
Thats a setup for somebody [that had room] running a Whipple on gas. Because you could run a large intercooler.
Bet he still has it :wink:
JL222
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In the middle fifties, maybe 56 or 57, someone ran a roadster (?) with blower mounted on the front 90 degrees vertically. GMC 6-71?
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Joe Panak of RotoFaze has a front mount 6-71 with a over drive he designed and built in his machine shop. It's on the front of a V-12 Cadillac in a 34 Ford coupe.
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The story I heard was that the dragsters went to top-mounted blowers not for the ability to overdrive them, but for quicker throttle response. I'm sure someone who knows the inlet speed could prove or disprove this. Nailing a front-mount from the two to the five wouldn't count here.
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Anyone have any better images of the Drive coupler or details?? Was Tom Cobbs set up the same ?
Thanks
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It's a rather simple 1:1 chain drive as seen in the e-bay ad
Pete
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If you have room machine a small gearbox you might machine one that will accept quick-change gear pairs. They easily handle the rpm and torque and can be swapped for ratio changes as you tune up.
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I like that idea ,,but trying to "recreate" so want to copy how it was done 'then' which seems simple and straight forward,,just wanna make sure to get all the details and fine points :)
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google potvin blower drives, there are pictures of what you want. The crank and blower drives are a sprocket with a double row chain to couple them.
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next question ,,I don't see a harmonic balancer in any of the pictures,,what is done to maintain the balance ?
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Those engines aren't externally balanced.
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Those things are more properly called Harmonic dampeners. And are used to dampen whipping of the crankshaft. Most race engines do not use them for balance, that I know.
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We use one. :-D
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Me to. Just not for balance.
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Those things are more properly called Harmonic dampeners. And are used to dampen whipping of the crankshaft. Most race engines do not use them for balance, that I know.
Thanks I was not aware of that ,,thought it was one of those "must have " things
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Thanks I was not aware of that ,,thought it was one of those "must have " things
If you use a motor that is externally balanced, by the use of a harmonic balancer and flywheel, you must use those two pieces. Only way around it is to have the whole assembly internally balanced which could be very expensive using Mallory metal.
I would recommend using a motor that is internally balanced to keep costs down. Good luck.
Tom G.
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Those things are more properly called Harmonic dampeners. And are used to dampen whipping of the crankshaft. Most race engines do not use them for balance, that I know.
Thanks I was not aware of that ,,thought it was one of those "must have " things
They are sure good things to have, it's just that the purpose of most of them is not for balance. They are for damping the harmonics that can end up breaking a crank. But again, most, not all, are zero balance. I don't know why people have always called them balancers. Most of the early V8s that I have had any chance to fool with were balanced internally. The flywheel and dampener were zero balance.
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Some harmonic balancers have a offset weight that help balance the crank. My 400 small block chevy has one. The flex plate (flywheel) has a small offset weight also. I believe some Fords also use them. It would be wise to check on this before assembly. Like Rich says most don't have offset weights
Harv
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Very cool ,,thanks all this info helps greatly,,( needed to figure out the few cloudy issues ) Think this is gonna work out just fine.
BTW - motor I'm using is a 287 Pontiac
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As mentioned, the dual chain coupler on the Potvin drive did not have a harmonic dampener. Also, mentioned, a dampener is a good thing. However, the lack of a formal dampener may not be as bad as it sounds. The chain coupling and the blower drive with its impellers, all serve to dampen some frequencies. I'm not sure of the resonant frequencies involved but it is probably better than no dampener at all.
On current blower drives using a timing belt, the belt does as good a job as a dampener and it is not needed.
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That picture with a centrifugal supercharger reminds me of a time I was at Pomona for the drag races. In the pits I run across Doug Herbert who at the time was running in the Top Alcohol Dragster class. He had a huge centrifugal supercharger mounted in front of the motor. Needless to say NHRA outlawed his setup, but it was cool.
Tom G.
Why was it Outlawed ?
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Probably cuz nobody else had one.
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Stan is partly correct. In NHRA when you come up with a better mousetrap that no one else has and you start running good or better than everyone else, your mousetrap gets outlawed, or they add weight to your car. When I used to follow NHRA, I saw it happen too many times.
Tom G.
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NHRA "Ingenuity in Action" . . . :cry: not!
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If I were trying to couple the two together I would use a Lovejoy connector. They can take the abuse and the RPM and they come in many sizes and what they don't have they can build for you. Tony
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OK,another Coupler question.
Looked at the Lovejoys and have also found the old Chain style. In regards to RPM's , am I basing that on the RPM of the motor itself ? I ask this cause was thinking on the whole "load" issue and that the crank driving the blower seems a rather simple task ( as appose to the coupler driving a transmission or such ) and that the actual load on the coupler would seem minimal.
So trying to figure in all these things,,are they relevant ? or is it just the coupler uint coming unglued cause the motor is turning 6-7000 RPM's ?
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NHRA "Ingenuity in Action" . . . :cry: not!
:-D
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OK,another Coupler question.
Looked at the Lovejoys and have also found the old Chain style. In regards to RPM's , am I basing that on the RPM of the motor itself ? I ask this cause was thinking on the whole "load" issue and that the crank driving the blower seems a rather simple task ( as appose to the coupler driving a transmission or such ) and that the actual load on the coupler would seem minimal.
So trying to figure in all these things,,are they relevant ? or is it just the coupler uint coming unglued cause the motor is turning 6-7000 RPM's ?
aanyone ?? :?
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The load on the coupling is not insignificant! The blower can consume anywhere from a 100HP to 400-500HP depending on the application. You not only have load applied by compression of the air but you have acceleration of the total rotational mass as RPM increases. 400HP at 5252RPM is a torque force of 400lbs/ft. Based on flywheel studies done by David Vizard a 300 RPM/sec increase can cost 85HP alone and is an additional factor. Even though there are no relative RPM differences between the two shafts, there is centrifugal force. The force may be small due to the small diameter but RPM may be important. Be nice to your coupler! Spec the correct size and then add safety factor. :-)
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Thank you :)
few more questions :)
1 : people speak of boost,,I know there are gauges to measure the boost pressure on a system like this where would you mount such a gauge ?
2: using a fuel system that is pressurized ( think its 14 lbs ) do I need to consider that pressure plus the blower for my final ##'s
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(1) After the intercooler if so equipped. If no intercooler it doesn't make any difference where it is. But why a gauge? Why not use a sensor and log the data?
(2) Not sure what you mean. But your fuel pump may need to be referenced to the boost pressure depending on pressure and application (Carb? EFI, MFI?). If boost is low (<5psi) maybe no fuel pressure augmentation is needed. If >5psi maybe it is needed depending on the fuel delivery method.
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EFI cars use a boost referenced fuel pressure regulator, that adds fuel pressure in direct proportion to the boost pressure so the pressure across the fuel injector is always constant.
I my car the base fuel pressure is 43 psi, at 20 psi boost, the fuel rail pressure would be 63 psi gage, but the actual differential pressure across the fuel injector is still 43 psi.
Fuel flow varies at the square root of the pressure drop across the injector so even small boost pressure can lean you out without a boost referenced fuel pressure regulator.
If you are running a carburetor, many setups enclose the carb in a pressurized box so its air circuits see the same boost pressure as the manifold, or they use a draw through setup where the carb is upstream from the blower so both the fuel and air go through the blower. The fuel in that case helps cool and seal the blower on roots type blowers. On centrifugal blowers there is less advantage to the fuel cooling, but the heat of compression does ensure the fuel is completely atomized.
Larry
Larry
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OK,another Coupler question.
Looked at the Lovejoys and have also found the old Chain style. In regards to RPM's , am I basing that on the RPM of the motor itself ? I ask this cause was thinking on the whole "load" issue and that the crank driving the blower seems a rather simple task ( as appose to the coupler driving a transmission or such ) and that the actual load on the coupler would seem minimal.
So trying to figure in all these things,,are they relevant ? or is it just the coupler uint coming unglued cause the motor is turning 6-7000 RPM's ?
If it were me I would go with what is proven. Which is the chain coupler. My Brother had a Lovejoy coupling on a hydraulic pump on his D-2 Caterpillar, it worked OK but chewed up the star shaped dampeners for some reason. If you want to experiment go with the Lovejoy, if you just want to put it together and forget it go with the chain coupler. JMO.
Tom G.
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OK,another Coupler question.
Looked at the Lovejoys and have also found the old Chain style. In regards to RPM's , am I basing that on the RPM of the motor itself ? I ask this cause was thinking on the whole "load" issue and that the crank driving the blower seems a rather simple task ( as appose to the coupler driving a transmission or such ) and that the actual load on the coupler would seem minimal.
So trying to figure in all these things,,are they relevant ? or is it just the coupler uint coming unglued cause the motor is turning 6-7000 RPM's ?
If it were me I would go with what is proven. Which is the chain coupler. My Brother had a Lovejoy coupling on a hydraulic pump on his D-2 Caterpillar, it worked OK but chewed up the star shaped dampeners for some reason. If you want to experiment go with the Lovejoy, if you just want to put it together and forget it go with the chain coupler. JMO.
Tom G.
Tom, Sounds like your brother might have had a bad coupler. We used a Lovejoy to connect the alternator to the back of the water pump on an Indy Car engine and spun the engine to 13,000 rpm hitting the rev limiter on and off for 4 hours and had no problems. But you are correct the chain is the proven path. You might even want to look into a belt set up. What ever you choose do some research and have fun with it.
I run mechanical fuel injection with my Procharger on the GMC and use a Hilborn boost compensator valve that richens and leans the engine under boost. It was originally developed for the Indy cars on turbos with mechanical injection. Tony
Picture form Hilborn Site:
(http://i273.photobucket.com/albums/jj236/maguromic/fuelsensor.jpg)
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...a little aside, I was watching this music clip on youtube, and it has a great bunch of footage of back in the day drags....
when I was reading the comments I saw this
"Oh man, I just love the Potvin front mounted blower setup on the dragmaster. I had one for years, but never knew what it was for, so I sold it for scrap....been kicking myself in the arse ever since ."..
ha ha , here's the clip
Southern Culture on the Skids/ Deja Varoom! : http://www.youtube.com/watch?v=Gd4Aj4tbf50&feature=fvw
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Neat clip, interesting variety of cars/power, thanks for posting.
Looks like could be the Detroit Nationals, '59 or '60 maybe?
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http://www.archive.org/details/Ingenuit1958_2 (http://www.archive.org/details/Ingenuit1958_2)
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Wonder if back in the day anyone went with a Rag Joint ,,like the old Grahams ?? or maybe those turned with less resistance
(http://members.shaw.ca/rjsill/sams6.jpg)
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Wonder if back in the day anyone went with a Rag Joint ,,like the old Grahams ?? or maybe those turned with less resistance
You need to think in terms of mass weight. Have you ever turned a 6-71 over by hand? Just a standard blower with out strips has a lot of mass weight to accelerate, and that is not including the power it takes to pump the air. All the blower snouts I have seen are at about 1 inch in diameter. That should give you a good indication of what it takes to turn a Roots blower successfully.
Tom G.