Advice please - Drouin Superchargers

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May 24, 2003
Hi folks,

For me the Drouin supercharger is more myth than reality, near impossible to find any information on them or see one in the flesh.

Did they work?
Did they require other internal changes to part specifications similar to when you fit a turbo you may have to upgrade the rods, studs etc..?
Any idea how many were produced - I saw just one photo of a bike equipped with one many years ago.
If you had the chance to buy one are they are they worth it or was it just a white elephant?
What would you pay for one, very secondhand?

Thanks any advice you can give and regards to all after a long time!

I owned one that was brand new. Had it many years and had replaced the grease packed bearings because the grease had hardened off.
I had bought a low compression head and had made metal base gaskets to do the needed discompression of the engine.
The early models ran a pair of 1/4 V belts to drive the blower. I was looking for replacments and started looking at the drive system, the small pulley had a one inch pitch and the large one had a five inch pitch. When you read the instructions it said to never exceed 6500 rpm if you do the math at 6500 rpm the two little bearings that carry the blower shaft are doing 40,000 rpm. The bearing supplyer said that the max rpm was 20,000 in clean oil. The use of grease as the super charger was set up for took the bearings down to 15000 rpm. So you would be needing to take this apart a lot to replace bearings. This more than any other thing got me to sell it on Evil Bay a long time ago.
There is a man in the eastern US who will sell you the latest up dated model for 1500 US dollars last I checked. Older models should not be run. The unit needs a timming belt drive and a blade slide type carb to run at all. There are issues getting it to shut off after it has got to full speed.
Claim that it could give 100 hp at full 8lbs boost there was no waste gate very scary and at 100 hp the end of the crank shaft breaks of as proven by others who race Norton's
Dont pay much for a used one I would say no mare than .50 per pound the current price for scrap alum. Your miledge may vary. norbsa
Norbsa thanks your swift response and great info, couldnt have asked for more. Would be interested to make contact with the guy in the east to see what he has to say so grateful if you could post his details or email me privately off line.

Once again many thanks
His name is Denis John Cavalier, Nyack, NY. 10960 phone# is 845-358-1957 He also sells other parts for Norton's
Denis sold his entire Norton inventory at Jerry Woods' auction in Daytona this year. He's bought a motor home and is planning on managing some kind of musical group for a while?! Haven't heard from him since Daytona, but I don't think he's dealing in any parts at this time.
I just called to find he has one Drouin left less a fan. And some boxes of stuff to go though. Thanks for the heads up Ron.
I have an old magazine article on this item with test results and such...if interested, let me know and I will do up a PDF and send it to you......
I was wondering if you could PDF me that file on the Drouin Supercharger also. I just bought 2 Norton Comandos '69 (in many parts) one of which has a drouin supercharger on it and wouldn't mind reading up on it.
Give this a try... ... harger.pdf

I added a couple of nice old ads...will take a few minutes to load, but is interesting article. I was an inthusiastic owner back then , and saved all sorts of articles and ads.....maybe it was the pretty babes.....lord knows.
Have still a nice JPN review, a "Hop up" article for, I think the 750...lots of stuff....dragracer story too...orginal Gus Kuhn Catolog w/pricelist...Dunstall Cat too...

Someone start a thread just for downloads...we must all have something we could pdf and put up for others to see......even I might be convinced to contribute....and not turn it into a Blog......

Where is the thread for bragging about where we all live and what there is there to see???
Well firstly, thankyou for the was interesting to read.
Now for the sake of it why is my Drouin different?
The case is one piece instead of 2. Also the guy (he told me he bought it back in '75 and went to Detroit to pick it up) that sold me the nortons said he blew the first Drouin due to a 1/4 turn throttle (sounds like the first edition of these superchargers)and revved up til it blew up on startup and then was sent a new one with a titanium impeller after much discussing with the co.. What he also told me is there was another version with some sort of electro-magnetic engagement of the supercharger.
Anyone heard of this model
CBR1000 Hurricane
CBR1100XX Blkbird
2X '69 Norton Comando
there is an old saying that goes you always get a screwin with a drouin....the last design-toothed belt and flat belt-works really really well when you get it sorted out and learn the starting dance-and it is a dance-the controlled dribble fuel injector requires very careful set up and beware of swelling of the slide when it sucks up gas-it will stick at the most embarrassing times so be prepared to machine it to size so it slides has been suggested that replacing it with a carb is the best way to go....when setup properly you have all the go of a hyabusa and all of the handling of a stock sure that your chassis is absolutely right and you have good brakes...stock rods are ok for moderate use as long as they are perfect--mirror polish,resize ,dead nuts staight,new nuts and bolts, as well as pistons...venolia will make pistons specifically for blower motors-thicker domes,lower comp. ratio...if you are really a good wrench and can get it all together you will understand that there really is a God and She has got a sense of humour...whenever i ride mine i am either laughing or crying with joyous emotion...however you are taking the engine far beyond what it is designed to handle and even if you throw a pile of money at it do not expect it to last long[i am looking to pickup any drouin stuff available so when you get tired of destroying engines please let me know....] you can also forget about riding in hot weather because things run so hot that the gas boils in the injector after about 5 miles...let me know how you make out and good luck barry
oh boy...there goes the rent money again.....these are both second design drouin units that were reputed to be hard on bearings acccording to herb i think it was at flint indian sales....which bearings he did not specify but when these were out norton was having a lot of main bearing problems and this would have accellerated [ha ha ha]a lot of that...acordig to a response else where on this site the impellor bearings are mentioned as being inadequate...i have seen one of these apart and i tried to get these bearings and for some reason they were made of unobtainium...they looked like extra wide 6201 or 6202[itsbeen 12 years]and i suppose that with some machining something could be done but i think there was a steel insert in the casting or something that retained them that made the setup for modification difficult....nothing is imposible of course but beware this is not something that the local garage is going to solve...this is the style of unit that i would hope to be able to duplicate by cutting up a modern turbo...some of the toyota supra twin turbo units[toyota ct 12] look about right for desecration...or a garrett from a chrysler daytona if anybody has one looking for a good home...rpm is the answer to blower efficiency as in really lots of and the single stage belt of the second design drouins was pushing bearing and belt tech too far...the 3rd design with 2 belts was the best way but then they had to go and put that ...and i use the term loosely...fuel injection on it and opened a whole new can of worms....if any body has any blower stuff around they have given up on or destoyed even if it is junk i am looking for it for patterns and ideas...there used to be a lot of marshall-godfrey rootes type units around surplus that were used by early 60's racers...they came off of gryphon powered spitfires and were used to pressurise the cabin for extreme high altitude photo recon work so if you see any at a swapmeet....these are the rolls royce of blowers and although heavy they can be made to work... think somebody had a record setting vincent single with one if anybody has a reference on this please let me know....well ive babled long enough on this regards barry
any reason on planning on going with a turbo versus a supercharger?
i would think the scharger would be better due to the almost lack of lag. Possible candidates are a supercharger from a VW Corrado G60.. those superchargers are pretty reliable as long as you take care of them. I cant think of any other cars that had schargers on them
in this case i would be using only the compressor section of a turbo to make a supercharger....there is a far greater variety of turbo units available to experiment with and im a lot better at pully and belt stuff than exhaust pipe stuff...bearings are the stickler in this as a lot of turbos use plain instead of ball bearings and oiling in either case is critical...some aircraft used a turbo with lifetime[ha ha ha] lubed ball bearings but these are fairly large units....if i could get a really small turbo like some of the jap 650 cc units from the early 80s then that would be a good possibility....i will have to check out this vw setup...what years were they offered? its a matter of falling into a unit at this point and just playing what if? the main thrust of all this is to get my drouin back together on an engine that will take the abuse...riding it was a pinnacle experience in my motorcycle escapades and i know i will get a lot of 'when you find another one let me know....' so i wanna be able to say 'well heres what cha gotta do if you think you are so sharp...' cuz just going out and getting one for mere money and bolting it on in an afternoon seems to be a pretty shallow endevour...maybe im being a little old fashioned about this but i gotta keep the creative juices flowing....this is not to say that i would not consider a turbo unit from whatever cuz there are enuf of them around that would be adaptable somehow and maybe i better get some pipe bending experience....[when ive got nothing else to do] so im open to all suggestions and thanks for the tip on the vw unit....anybody else got any ideas?
Well I thought I'd post a couple of pics of the brand spanking new Drouin that came with the 2 '69 Norton 750 Commandos I just picked up.
Also BTW as I was reading up on the board both these engines came with the Dunstall 810 kits on. I'm actually pretty excited with these Nortons (first time I've ever owned one,let alone 2 :twisted: ) Now the big question is whether to install this Drouin or not
OK I need a little help how do I insert pics here :( [/img]
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