Stutz Supercharger & Clutch activated Blowers

Earlier this year there was a really cool thread about a potvin style scot blower that Clark found in a suitcase stashed in a body shop attic. That thread is here: http://www.jalopyjournal.com/forum/showthread.php?t=168801&highlight=potvin+blower

I agonized over that thing, but in the end it I left my kids college funds intact and p***ed. When this came along last month I could not resist it. In 1930 you could buy a Stutz with a supercharger. The estimate is that about 25 cars were made. There are 3 known cars still in existence including one of the original Le mans racers pictured below. Along with the 3 cars, there is this blower as well as one other that is not as complete.

For whatever reason, I've always been infatuated with superchargers. Probably something I got from my dad, I just always found them to be really cool. As far as blowers go, this setup is right near the top in coolness as far as I'm concerned. It's a potvin style blower mounted forward of the engine beneath the radiator. There is a clutch (clearly visible in the pictures below) which is activated by a rod which extends to the dash. The blower is engaged by the driver when he needs/wants it and delivers a 4psi boost which is good for 40% HP boost. There was a gauge on the dash indicating boost. The boost blows through the Carb as opposed to ****ing like most centrifugal and roots blowers. The entire setup is similar to the SS/540K Mercedes (which was good for 60% HP boost with 7psi) with the difference being you can leave it engaged. The Mercedes engages off the gas pedal and you get 30-40 seconds before you blow the engine. There is more info on the mechanics of this on my website: http://home.townisp.com/~alsancle/StutzSuperCharger.html

This blower was removed from a car in a wrecking yard outside Chicago by William Johnson in 1937. Mr Johnson was an engineer and as a side job worked for local racers. He wrote a letter to Stutz in 1937 inquiring about parts and the availability of more blowers, as well as the performance characteristics of the SV16 and DV32 engines while supercharged. The response from Stutz came back within 2 weeks and informed him that all the engineers were gone and that the company was more or less gone with just a service shell remaining. He also made detailed engineering drawings of the blower with the idea of adapting it to racing. After WWII he moved to southern CA and around 1951 his dad packed up all his "junk" including this supercharger (in the crate pictured below) as well as other racing parts including a Duesenberg Grand Prix engine and Model A Duesenberg blower and shipped everything to him. He seems to have "retired" from the racing hobby with his move to California so everything stayed locked in his garage until his death a few years ago. Most of the contents of the garage were purchased by a well known restorer and his even more well known celebrity client. Fortunately they were not in to Stutz so I got this.

My question for the Hamb is this: Do you know of any other clutch activated blower applications ala Mad Max? What is the advantage of having the blower on standby other than it's cool to be able to kick it in when needed? Less wear on the engine? Better gas mileage?

 

Bumping to the top. That thing's cool.

 

Thats odd, looks like the blowers on the vac trucks where I work only smaller. Cool find and hope you get to use it on something.

 

Color me impressed (and jealous).

 

Isn't it funny how you just gotta have cool ****! Its a sickness I tell ya, a sickness! Cool story.

 

I have always wanted to setup a clutch driven blower setup. I remember as a kid watching Lone Wolf McQuade (wasn't everyone a chuck norris fan when they were 8?). There's a scene in the movie where he is in his bronco or blazer covered in rubble and he hits this switch which engage the blower and he drives out and kicks ***.

Anyways that has always seemed cool to me.

I have often thought about maybe using a AC clutch or something similiar to engage/disengage the blower.

Anyone else thought about this?

 

Thats Fn COOL!! The newish smaller Mercedes Kompressor cars have an A/C style clutch on them but they are pretty small as they are for 4 cyl engines.

 

Research "Blower Bentley"

 

I guess the air intake is out in the fron there and the compressed air is piped throught the carb.

The only advantage of dissengaging the blower I can see is you would not lose horsepower at lower rpms driving the blower when it really isn't making enough boost to matter. But when you are in Chuck Norris mode - you have it all tweaked out and you engage it because you NEED THE SPEED MAN.

That is a beautifull piece man. All those fins - oooohhhh

It would be a wicked set up hanging between the rails up front like in that photo.

 

The 4.5L "Blower Bentley" was similar in that it was a front mounted roots blower. It was different in that it was always engaged and the ****ed through the carbs. I"m not sure of the PSI, I know that W.O. did not approve and the cars had dependability issues.

http://en.wikipedia.org/wiki/Image:1929_Bentley_front_34_right.jpg

 

mercedes had a clutch driven set up I think. But you need a byp***. The K3 Magnette had developed something similar for useage at low speeds too keep from fouling plugs.

 

If memory serves, one of the early Bugattis had a front blower, direct coupled, and the drive was later modified with a clutch. It's been years since I've seen the article & I'd have to dig it up to see which model it was.

Might have that backwards, though....seems like most of the early clutch setups were problematic & were discarded.

 

The Mercedes K, S, SS, SSK, 380, 500K (pictured below), 540K and 770K employed a very similar setup to this. Like the Stutz blower here, the Mercedes setup was a roots blower that was engaged via a clutch and then blew through the carb. It was good for 7 psi and a 60% HP boost. It is engaged by pushing the gas pedal past a "catch" which throws a rod (clearly visible in the left picture below) and causes the clutch to engage. Simultaneously, a valve closes the air cleaner off and opens the blower to the carb. There are two additional fuel jets in the carb that open

Both these systems are complicated. Along with the clutch, you have the added problem of dealing with the impact of the blower boost on the fuel system. Stutz dealt with it by kicking in a mechanical fuel pump when the blower was engaged. The Mercedes setup is mind bogglingly complex and involves the blower pressurizing the fuel tank.

Were there any hot rod applications where the blower blew through the carb? I'm not very up to speed on Bugatti, although they used a roots blower I always thought it ****ed from the carb?

 

I know a guy who has/had a flathead with clutch operated blower on top, I have not seen it.
But I always wondered how you would set up the extra fuel delivery, and if the carbs are on top, how does the fuel get past when the blower is not spinning? I think thats why the blowers you guys are talking about push through, rather that ****.

I may be wrong, but I am told Lexus had/have a clutch operated blower as well.

This is something I have always wanted to do, but just have not put enough thought into it.

Cool history on your blower by the way......good luck.

 

I've never seen that set up before. Very nice.

Doc.

 

Clutch driven Superchargers are common on a lot of Japanese cars,Toyota have had them for years .The clutch is the same as you find on a Aircon compressor.

 

I'd love to know how that works. You make a good point about why the clutch blowers probably push rather than ****.

Here is a picture of how the Mercedes fuel system works with the blower. Line 12 is pressurized when the blower is engaged. It pressurizes the fuel tank as well as opening another valve in the fuel pump. The complex result is more gas in the bowl. The second picture shows the Stutz system which is much less complex. Basically there is a mechanical pump up on the Cam cover that kicks in when the blower is engaged.

Both systems have a mechanism for switching from the air-cleaner to the blower. The Mercedes is attached to the rod that engages the clutch. The Stutz has a spring loaded valve that closes when the blower puts positive pressure on it. I know the Mercedes carb is designed for the blower especially with the extra jets. I think the Stutz uses a stock carb but I'm not sure. I wonder if this system would work with your basic 4 barrel or Stromberg carbs or if the pressure coming in would screw stuff up.

 

Did any of you guys see this flathead blower for sale? The seller says it has history in the late 30s early 40s. It is not a Mercedes blower as the seller is thinking. Anybody have any idea what it might be? Pulley driven roots setup that looks to have been adapted to the flathead from another application. Very cool but very expensive.

http://cgi.ebay.com/ebaymotors/SCTA...012QQitemZ220176857594QQrdZ1QQsspagenameZWDVW

 

The Mercedes M62 is available cheap with an electric clutch, but it's only suitable for engines up to about 150". I don't know if the clutch can be retro-fitted to the largest cheap Eaton, the M112 suitable for 5.4 liter engines.

A front-mounted blower must either be fairly large, or have a step-up gear built into the nose drive since speed-up by pulleys is impossible.

George C. Scott's 1956 BMW 503 has a blower drive selectible by dash switch in the movie "The Last Run".

More on blower drives: http://victorylibrary.com/mopar/blower-drive4.htm

 

I think most blown late models with Eaton blowers use a clutch
on the drive,with a byp*** circuit for the air when not on boost.

 

The Mercedes is the only one I've seen, all the others have a vacuum operated ****erfly byp*** valve.

 

I spent a number of years working on Mercedes 500 and 540 k Cabriolets as well as some Gullwings and those Blower setups were always a pain. I was the Sheetmetal/fab guy for most of the projects but did some final ***embly work on those same cars where we fudged the whole thing.....most of the cars we did ended up as Garage Art anyway...

 

Getting the blower and the fuel system to work on those cars is almost "rocket science". When they do work correctly they are a hoot however. Here is a picture of a Mercedes blower & carb off the car. It would look pretty good sitting on top of a flathead I think.

 

Wow - what year models did those come on???

I'd love to hear more about the hoot!!

 

Didn't the VS-57 blowers pressurize through the carb(s) used on '50s Fords and Studes?

See:

http://www.vs57.com/indexvr57.htm

 

The blow-through carb thing is a point of contention, as is the clutch drive on a 'part-time' supercharger.

Let's talk about carbs. A carburetor is basically a vacuum leak, controlled by a flapper valve and fed by a toilet.

Don't get me wrong- I love carbs...but they are hardly rocket science in their most-basic form. When drawn upon by negative pressure (vacuum), they respond in kind. They are consistent, and can be tuned for that reason. The hardest thing a carb does is idle, and the easiest thing it does is run wide-open.

So, let's throw a blow-through setup into the mix.

Once you push more air through the carb than vacuum has ever called for, what happens to your 'tune'? It gets all messed up!

What about other carb systems, like float levels? Once the carb is pressurized, this could be dramatically affected unless the carb is vented to atmosphere and the fuel system is adequate to feed the needs of the now-100-plus percent efficient engine. Going lean under boost is common, and was even more common back in the early days when stuff like this was still being figured out.

So, let's say you modify your carb to deal with life 'under pressure' and it works perfectly at WOT under full boost.

Now, you take your foot off the gas pedal, and it has to work under the draw of vacuum again. Guess what? Different needs once again...

This is why we see two things relative to supercharging today- Draw-through carbs on top of superchargers, and EFI being responsible for the modern revolution in supercharging (with modern centrifugals and twin-turbos seeing more popularity than ever before).

Now- Let's look at a part-time, clutch-operated supercharger.

First, the engine has to be fed while the supercharger is not engaged. So, some type of capable fuel delivery system has to be installed 'downstream' from the blower, and have access to incoming air. Then, once the supercharger is engaged, this incoming air stream must be sealed off to prevent leaks and the fuel delivery system must seamlessly integrate to life under boost.

If that's not tricky enough, the clutch apparatus must be strong enough to deal with the on/off command with the engine at speed! That's quite a request. Consider the A/C clutch idea- and then look at how much the A/C compressor must compress when compared to the supercharger.

To make serious pressure (7-plus psi, like a typical Roots or centrifugal), the clutch would be approaching 7-8 inches in diameter, I'd guess. Anything less would not hold up for too long. Remember- serious superchargers require cog belts because typical V-belts or multi-rib serpentine belts simply won't hold up...and those superchargers have the benefit of ramping up (rpm and boost-wise) with the engine, as opposed to being 'activated' at the engine's full song (and peak torque)!

So, the concept of a part-time, Mad Max-like supercharger is fatally flawed. I know clutch-operated superchargers exist, but they must do so at low boost levels to be reliable.

I know blow-through carb setups exist, but every single one I've ever dealt with (and there's been quite a few) was somehow flawed due to compromise. They either ran great under full boost or they ran great on the street, but never both.

EFI was the perfect solution- a programmable fuel delivery system mounted downstream of the blower, with cylinder-to-cylinder control capabilities to account for manifolding differences. It can be boost-referenced to alter the tune (both fuel and air) to perform regardless of rpm or boost levels. The high pressure fuel delivery system (electric pumps with 45-65psi or more of steady pressure) means lean-out is a thing of the past.

So, if I were wanting to run one of these part-time blowers, it'd be a low-pressure deal (4 psi keeps being mentioned, and it sounds like a reasonable level) and I'd stash an EFI setup underneath it all...even if there was a 'carb' body acting as a throttle body.

It could be done, and it could be done very coolly with some effort.

We always have to remember that supercharging in this manner (via compressors) adds a lot of heat to the incoming air/fuel charge, and that the increased power production in the cylinders is also going to add heat. The engine must be prepared to deal with the additional power boost and the heat that comes with it!

The most successful, affordable, and effective part-time supercharger is still nitrous oxide. It's adjustable, simple, and actually cools the incoming charge when it's activated. But...

....it ain't traditional (yet!)

~Scotch~

 

Huge apology: left out an entire math function in power predictions in earlier post (now deleted).
See better, more conservative math: http://victorylibrary.com/mopar/blower-c.htm#power

 

Those pictures show the blower off this car which is a 36 500k Cabriolet "C". They are a "hoot" cause they make a sound like a air raid siren and do provide a noticeable power surge. That blower was being rebuilt because it wouldn't disengage after the engine warmed. If you hear one of these start up, the blower whines for about a minute then stops - this is because the oil has warmed enough for the clutch disks to separate. When it won't stop whining it means the fingers in the clutch need to be re-calibrated which can be done with a pair of pliers that have been ground for the task.

Btw, Scotch - nice write up on why the "push" systems are so complicated and scarce. I know that the Mercedes setup works but is intended for only full throttle. I saw the Stutz blower on the dyno and it was good for 40% at 80% throttle but I have no idea how it would work if you were going down the road at 1200 rpm going up and down on the gas.

 

Man i want need must have a simple Clutch drivn blower for my AD truck.


What does a Blower do to your fuel milage??? Say for cruising down the hiway at 65mph Around 26oo rpm vs non blowing engine???

Thanks Jaime

 

I just got this and thought it was a cool article. Note that 1500 bucks bought a pretty decent car all on it's own back in 1929.