80smetalfan

Hey everybody,

I know this idea has surely been thought of before, but I haven't been able to dig up much by searching. For one thing, if you search and click "Search in title" it doesn't bring you results with the terms in the title anymore, but I suppose this belongs on another board. Anyways....

Would it be practical to use an M90 on a draw-through roots setup? I wouldn't think the fab work would be too bad. I've got a couple square to spreadbore adapters (that work both ways) sitting around, and thought I could even use those in the fab work of mounting it to my intake where it would sit just like a 142 or 6-71 style blower between my intake and my Q-jet. I had the M90s from supercoupes in mind, as from what I've been able to gather from pictures, they look like the opening on the bottom is at least close to the right size. I don't know enough about the rest of that particular unit (or really, any Eaton blowers) to know if I could just make an opening in the top of the case for the carb and seal any other openings on it and be good.

Also, I read on another site that using Eatons for a draw through setup would cause the internals of the blower to fail because they weren't designed to be draw through blowers and come into contact with gasoline, and I figured some of you guys on here would know more about that.

I'm not exactly hellbent on doing this with an M90 as you can always get a Weiand setup that's ready to go, but the idea kinda popped into my head today as a cheap alternative for a draw-through carb setup.

Thoughts?

Guss_B

I think the problem with a setup like that is that the rear rotor bearings in the eaton aren't sealed and the gas passing through the blower will dissolve the grease in no time. Having said that, magnuson offers a setup utilising a carb, and their superchargers are basically eatons. I'd be interested to know how they differ.

http://www.magnacharger.com/images/l...GN11C_0547.gif

Also, most m90s have relatively short drive snouts, and I don't think they'd reach over the waterpump to be driven from the crank

Damon

Yeah, Magnuson uses Eaton blowers in their kits and they're built for a carb setup. It looks similar to a little Holley/Weiand 142 setup from the outside but has significant differences/improvements over that older design.

I think you'd spend as much getting an EFI M90 converted over to work with a carb on a SBC as you would just buying the kit. But really the biggest obstacle would be the PITA of it all. Mounting flanges, intake manifolds, pulley kits, etc. In this case I think buying a kit would be money and time well spent.

83 Crossfire TA

iTrader: (2)

Well, WRT to the bearings… yea, they will wash out with gasoline run through the blower, but there obviously are bearings that will survive (magnuson and stillen both run gas through them, the question is figuring out what bearings to use/modifications need to be made).

Snout assemblies are interchangeable and you can get all sorts of different lengths from Magnusson.

faj

Here's a couple of pictures of my 1990 vette with a M112 eaton blower. It's a draw-throu setup with a Holley carb.

Intake manifold = Weiand 6-71 intake with a home-made adapter plate.

I used scrap sheet metal pieces to make an adapter for the carb to supercharger mounting.

I usually dont come around here so please feel free to mail me for more pics or questions! johan (at) junkshop.se

83 Crossfire TA

iTrader: (2)

Johan, I’m sure that everyone here would like to see more pics/details, and at the very least know what bearings you used in the case

faj

I bought the supercharger from some kid in Florida. After one day of testing i noticed oil was leaking out from the pulley/snout. (I guess you get what you pay for...)

I replaced the front seal and everything has been running pretty good since then. All the bearings etc are from the original supercharger. I guess time will tell if anything breaks because of the gasoline... I get about 5 psi of boost with the original supercharger pulley and the original corvette 1990 TPI crank pulley. Will replace the supercharger pulley for a smaller one this winter...

I will post more pictures tonight when I get home from work!

faj

Starting out with a standard Weiand 6-71 blower intake manifold..


Making sure the Eaton footprint will "fit" inside the bolt pattern of the intake


Paid around $40 dollars for a "scrap" aluminium sheet, 10mm thick. A lot of cutting, drilling and measuring and the Eaton and intake manifold could be bolted together


The kid from Florida was kind enough to not include the vacuum thing that opens the internal bypass valve when the engine is under vacuum.

Soooo.....


A piece of old exhaust pipe was pressed flat, cut, drilled and welded...



...Into this. Now the vacuum bypass valve is complely shut. I think this mod will only have a bad impact on gas mileage, not affecting engine power.



Making a flange for the Holley carb...


Making walls for the carb adapter...


Another wall...


Voila!

faj

Carb adapter fitted to the supercharger. Good fit!


Engine bay... Very messy, i know


Intake manifold installed...


Supercharger with carb adapter in place...


The Eaton looks kind of small under that air cleaner, doesnt it?


Here's a shot of how the belt has been routed. I hade to add an extra pulley to create some belt wrap. Pulley has been taken from some old Audi A4 car that was scrapped during a cog-belt service.. (I work in an Audi workshop in Stockholm)


Made a pipe to replace a coolant hose. It didnt clear the alternator so it had to be re-routed


Is the engine to high or is the hood of the car to low? I'm not really happy about the height of the engine. When driving around in town I have to "look around" the engine. Not good, but it does looks interesting

faj

Final shot.

I get around 5 psi of boost and it actually made a big diffrence! I will get a smaller supercharger pulley and see what happens...

This winter I will probably remove the carb setup and make an EFI installation to reduce the height of the engine. (It's nice to actally see where youre driving )

When the EFI is working I will probably make a turbo setup that blows into the supercharger. YES turbo + roots blower... Havent seen ANYONE doing this in a car yet so it'll be an interesting project.

Guss_B

Its nice to see a custom set up like that up and running. People seem to think that there's so much work involved that it's easier to just drop a few grand on a kit.
If the rear bearings do last (at least for a fair while) I'd be tempted to do something like that with my m112. Its from a jag so has the intake on the rear, I thought it'd be cool to run 2 large su carbs directly on the back, so it wouldn't be too tall, and would look unique. It also has a smaller exit than the lightning blower, so it could be persuaded to bolt to a regular 4bbl intake using two plates sandwiched between the manifold and the blower. I mocked it up on top of a tunnel ram and the result was an instant trouser tent!

faj

I actually enjoy planning, thinking and fabricating stuff more than I enjoy driving the damn car Been looking at "china turbochargers" from ebay and I'll probably get a pair pretty soon and get started on welding the headers.

Still not sure what engine management system to get... Megasquirt looks pretty decent for the money.