M45 eaton supercharger and 327 conversion on a 325i cab!

[mincedbeef]

Hi all,
I recently got hold of a eaton m45 charger for very cheap that i hope to fit to my 325i cab during the winter. I'm going to get the engine out over the next few weeks to start the re build and maybe a 327 conversion while its out, it would be rude not too!

Does anyone have any info or diagrams on this or 327 conversion that could be of any help to me!

Cheers dudes!

[Turbo-Brown]

Sorry mate, the M45 is WAY too small for the 2.5 engine!

Need an M90 or bigger for one of those

[CraigG]

if the M45 is too small for a 1.6 4cyl, it aint got a hope in hell of feeding a 2.5 6cyl

[mincedbeef]

I've done lots of reserch into this model eaton charger and its aparently good for upto a 3.0 engine, runs at over 1 bar of boost and i found a place you can get bigger or smaller pullys for them. I was just looking to find out if anyone had put a charger on a 2.5 and how you would go about fitting it and what parts to use.

[Steve]

spec of M45 http://www.automotive.eaton.com/product ... rs/M45.asp

The Eaton Supercharger Model 45 is designed for 2.0L to 3.0L passenger car and light truck engines, but may also be suitable for other engine sizes, depending on total system performance requirements.

/you might have more luck in the FI forum, shout if you want the post moved

[Turbo-Brown]

Right so,

6200rpm at 85% VE on the 2.5 engine gives us a consumption of:

((6200/2)*2.5)*0.85=6587.5 L/min (of air)

The M45 can deliver 0.75 L/rev so must spin at 6587.5/0.75=8783.3rpm just to keep up with the N/A demands of the 2.5 litre engine.

Now we wanna supply it with air at 1bar so we've got a pressure ratio of:

(14.7+14.7)/14.7=2 (or 100% more air)

So we've got to suppy twice the volume of air to the engine to get our desired 1bar of boost which means spinning the M45 at 17566.6rpm and we can clearly see from the graphs that it can't go fast enough and it will be massively inefficient!

It's not big enough mate.