The V8 Owners Forum -

Hi,

I bought a eaton M90 blower to fitt my offenhauser on my 3.5 Land-Rover off-roader with auto gearbox.

Apparently it came from a Buick park avenue 3.8 V6 build in 2000

I don't have the crankshaft pulley. And don't know its size.

Since i have a off-roader and not a racer, how many rpm will i have to spin the eaton to get the best performance for my car ( i am thinking low end en mid range torqe ?)

Will be running the car only on lpg, sucking it through the blower.


Thanks

Steven,

M90 is 90cubic inches in size.

Quick calculations show drive ratio 2 will bring about 6 psi boost with an Eaton M90.
So it will spin 12000rpm when you hit 6000rpm on the engine.

At drive ratio 2.2 it will bring slightly more than 8psi
By memory they become inefficiënt above 14000rpm.

Are the Eaton seals resistant to LPG?
What drive belt are you planning on using?
I supercharged my previous 3.5 (centrifugal supercharger) and couldn't get the V belt to transmit enough power - kept getting belt slippage only making 2 or 3 PSI (but still quite an noticeable improvement!)
I would recommend using the serp 7 groove pulley from the later engines but then you need a different water pump and auxiliary system - when trying to upgrade to a serp pulley I ended up buying a 4.6 which comes with a serp pulley for free

Tom.

At least I know the rotor seals of an Eaton doesn't like fuel. Not sure about propane.

Have you considered LPG injection. It works great with MegaSquirt.

As I recall, Spag ( Mini V8 ) did some testing with the flow pattern of the M series Eaton blowers using smoke equipment. Complete foto deatils where here on this forum, but guess the old forum.
M series did not have an ideal flow path meaning back cilinders get it all, fornt cilinders get less.

I've done LPG with an Eaton M112, the seals dont live long with LPG.

You'll need to go the injection route.

You could plumb it up blowing through the carb - although don't know how well your carb works/if at all in blow through mode?
That would also negate the potential problem of poor distribution to the front cylinders. Would need to fabricate a mount to mount the blower.

Tom.

Rossco wrote:I've done LPG with an Eaton M112, the seals dont live long with LPG.

You'll need to go the injection route.

How long did they last ?

SuperV8 wrote:You could plumb it up blowing through the carb - although don't know how well your carb works/if at all in blow through mode?
That would also negate the potential problem of poor distribution to the front cylinders. Would need to fabricate a mount to mount the blower.

Tom.

I have al holley street avenger and should not be able to accept boost.

Another problem is that my charger is from a 3.8 V6 and the snout would have to be a bitt longer, however i don't find diffent length options.

grtss
S

JP. wrote:M90 is 90cubic inches in size.

Quick calculations show drive ratio 2 will bring about 6 psi boost with an Eaton M90.
So it will spin 12000rpm when you hit 6000rpm on the engine.

At drive ratio 2.2 it will bring slightly more than 8psi
By memory they become inefficiënt above 14000rpm.

I found on the internet that :

14.7 + boost x engine cappacity / 2 / eaton volume = pulley ratio.

this uses a theoritical of 100 % of the blower, in real life this would be 80 %

This is about wat you say 2/ ratio.

grtss

Steven

Steven 90 wrote:

Rossco wrote:I've done LPG with an Eaton M112, the seals dont live long with LPG.

You'll need to go the injection route.

How long did they last ?

About 2 days

Rossco wrote:

Steven 90 wrote:

Rossco wrote:I've done LPG with an Eaton M112, the seals dont live long with LPG.

You'll need to go the injection route.

How long did they last ?

About 2 days

And was it a new one ?

So blowing the lpg would be better

Steven 90 wrote: So blowing the lpg would be better

What about that carb then ??
Eatons can't handle fuel also for the same reason.

One way or the other if you want to run an Eaton blower it would be fuel injection or LPG injection below the blower. As Eatons blowers only can handle air.

Or swap that Eaton for a 4-71 or Weiand 144.
By the way Holleys can be easy converted to go blow trough.

I only run on lpg.

I was planning to fit the eaton on the side and then blow through a injection inlet manifold.
So I can go the injection way if I want.

How can you convert a holley ???

Steven 90 wrote:
How can you convert a holley ???

http://www.hangar18fabrication.com/blowthru.html

Thanks !

I am thinking about dropping the holley offenhauser and fitting a injection manifold.

Found som pics ans seems resonable to make it all work.... I hope