Drouin superchargers

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Aug 29, 2005
well...made ya look.... :roll: does anybody have a second design drouin blower apart that could send me the dimensions and numbers on the impeller bearings and the width of the impeller shaft and the housing it mounts in? i am trying to come up with improvements on this.. thanks barry
Oh gosh darn Barry,

I was just going to lurk awhile but probablely have
the data you seek and an expert to point you too soon.
There are better bearings and better way to support
and space them. The impellers are mis cast and
need balancing once evened up. While I'm sourcing
up my own notes for you, could you describe your
induction device and any thoughts on detonation
on pump gas? Don't leave garage on the supplied
Lake injector.

Steve hobot Shiver
hi hobot...welcome aboard....this bearing exercise is something i am trying to get info together for a friend and i dont have the unit in front of me...he got it in pieces and wanted advice on what to do...i think it has the tillotson carb setup which is from what i hear a better way to go than the injector as far as ease of use goes but i think a mikuni would probably be better these days...no panic on this...he has had it for years and not gone anywhere on it but i guess he's bored so i thought i would see what i can come up with....a couple of things to keep in mind if you are setting one up....when you get gas try to get it from a pump that only dispenses hi test-the several grade pumps will give you a hoseful of whatever the last customer got and that may be most of a tankful....check out some supercharger websites like b and m or whoever the hot automotive suppliers are and see if you can get any reccomendations about compression ratios and follow them....i had venolia make pistons but i dont remember what the cr was specifically but if you go the new piston route tell them it is for a blower cuz they will make them with thicker domes....it would pay to put an exhaust temp guage on to dial in the jetting...its surprising how fast it climbs...water injection would be another way to go to help with the pump gas especially if you were not building a blower only motor....i sure did like the injector as bad as it was...nobody else could ride the bike and you really had to be sharp to get it to work or even start but when it worked right it was really right but in these modern times i think a mikuni which i know a lot more about than i did then or an electronic fuel injection would be the way to go when i reinstall this beast....this really is a big pain in the ass all around but once you ride one.........best regards barry
Oh my Barry,

SO You've experienced a Drouin blower on a Commando!
To a man each one has expressed how world class awsome
beyond anything else experienced, not GP bikes Not
Hayburna's not Nos injected liter CBR's, NOT NOTHING!
Yet to a man each has ceased to use or posscess
the Dorouin beasts d/t deaths, divovrce, or just
plain too much a hand full for stock Commdos.

Until I dig up your data, here's some ramble on my boosting.
Last few years of my life has revolved around getting a
Combat spiffed up to take HI power and put it to use.
I feel I've got that part sovled in spades with the
Watt's iso rod controls. Next was to get strong bottom
so got some Maney race cases, then steel Flywheel
etc. But on a shoe string so it will have ~10:1 C.R. with
the 2S cam as that whats here and also because a
'70's useer told me he'd run 11+ C.R. and even hotter
cam in youthful exerberance for long period an did fine.
Awaiting Totalseal ring set, tech dept said a sealed
sencond compression ring would do me good.

I'm going to draw thru a 38 mm QuickSilver flat side
dual cable cam action carb, designed from the Lake
injector and the Lectron carbs. Should be good for
at least 230 cfm which iimpllies over 150 hp iright now
if your listening. Its set up to monitor data but am
still hung up on a programable ign system and its
triggering. I''m designed a boost power'd water injection
to kick it at say 6# and maybe spike with H2O2/methanol.
Deer knocked me out saddle in March which knocked
another bike and this special one back 3 seasons.

hey hobot...sounds like a lotta fun yer puttin together...hope you can expand on few things for me...what are watts iso rod controls? ..what experiences have you had with nortons[specially injected ones]? you are right that a blown norton is unlike anything-i think the only way the english language would currently let me express it would be magikal-when you grab that first handful and watch the manifold pressure jump from vacuum to boost and your world consists of only you,bike,road you will understand that there really is a god and she has a sense of humour and forever after you will recall that moment with startling clarity and your whole existance will have been changed....you will discover this for yourself and i bet i will hear confirmation of this....there is a i-told-you-so in here ...prepare yourself well for that moment...you may have actually found the perfect use for a boyer,,you could trigger your electonics with the magnet assembly either with the coils on the plate or with a hall effect setup....maybe check out a pertronics unit or a mallory unilite optical thingy...lotsa possibilities there...i hope you are going through the chassis to match this...checkout the ontario norton owners website for the article i wrote on setting up the primary chain cuz you are gonna wanna be sure that you can get the power back there....derek wilson knows how to setup the clutch so it works properly...he can be contacted through this forum...nortons are famous for overheating under race conditions and a big problem i had was on really hot days the gas would boil in the ijector cuz there was just so much heat down there...baffling would help the gas boiling problem but there is still a lotta heat to dissapate so alloy barrels would be worth looking into if you are going that far...if you are running a blower a mechanical compression ratio of 6 to 8 :1 gives you a cr of maybe 11 or 13 :1 when corrected for volumetric efficiency- 10:1 [mech] might give 15:1 [effective] so do some research on that...you can run a lot higher lift/shorter duration cam if there is not as much piston in the way....and i wish you a full recovery from you deer episode,watch out for those things eh? i have not lost my drouin but am slowly working towards its revival...it is the last design and i broke the flat belt so that was the excuse to set it aside until i could properly setup the rest of the bike...still awhile yet but the boys are now 16 and 19 so it is drawing that time when they should also experience a blown and injected norton....until then we are working out our frustrations and learning the trade on lesser brands of motorcycles-i would not want them to miss the jap experience but if i started them on a norton what would the point be? or something like that....anyway,gotta pay for some jap junk on ebay so over to you to tell your story....best regards barry
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