Eaton M112 Data / spares / parts??

The Original Tom · Post by **The Original Tom** » Tue May 29, 2007 11:28 pm

Any ideas where I can find a data-sheet and spares for an Eaton M112 supercharger?

Cheers
Tom.

The Original Tom · Post by **The Original Tom** » Wed May 30, 2007 11:34 am

Oh yeah, and what sort of static compression is good for a charged engine? Is 8.4:1 or 8.8:1 ok for a small boost? (say 5-8psi?)
I've currently got a 9.35:1 engine, which when I put composite gaskets on, will be about 8.8:1.

Eliot · Post by **Eliot** » Wed May 30, 2007 2:22 pm

I'm running 7psi into a stock small block chevy running 9.25 with cast pistons. So I wouldn't worry too much about lowering your compression just yet.

Phil Ringwood put about 9psi into his 9.75:1 rover IIRC

The Original Tom · Post by **The Original Tom** » Wed May 30, 2007 3:34 pm

Bloody hell! You must be using premium fuel at that high compression!

What power difference did you notice boosting it with that compression to 7psi?
i.e. is it worth my effort to get pulleys made, and to make a mounting bracket and piepwork etc. or am I not going to notice that much?

Tom.

Eliot · Post by **Eliot** » Wed May 30, 2007 3:46 pm

I have two ignition maps - it will run std unleaded but have to pull out about 10-12' at full boost. With vpower i can return a few degrees.

General concept is for long runs down a motorway (or just plain skint) I just fill it with std, then for local blatting around i use vpower etc.

Difference in power? - Massive - It will keep up with a supercharged V8 Jag XJR both from a standing start and a roll-on. (and i was running my retarded std unleaded map at the time!)

kiwicar · Post by **kiwicar** » Wed May 30, 2007 3:56 pm

Hi Tom
If you are thinking of going this route I would recommend reading around the subject a bit as there are alot of variables. I read the book by Alan Alard on turbocharging and supercharging, bit out of date these days but it would give you a good grounding in the subject and enable you to chose CR and pressure ratios (boost) with some confidance.
7.5 PSI and 9.25 CR with ally heads is not that extream, Eliot has heads with a fast burn chamber, designed for the american market and high CR, their "premium" gas is 92 octane, their super is 94 to 95, their standard is 88 octane Our standard tescos rubbish is 95 octane and super dooper stuff is 97 to 98 also modern fuel contains a fair bit of ethanol which tends to cool the charge a bit which is usefull with supercharging.
The americans regulaly run 10.5 to 1 cr with 92 octane fuel and fairly conservative cam timing (remember they like brake servos on their week end drag cars!

) with these heads. Then you can always water inject

.
Mike

kiwicar · Post by **kiwicar** » Wed May 30, 2007 4:04 pm

Tom
If you haven't already, have a look around Eliot's site, he has done one hell of alot of realy good work on that car and put in alot of time and skill. He also is prepared to experiment and is maticulas about recording and learning from the results. His set up and aproach though could be applied to virtually any engine chassis combo.
(by the way out dragging an XKR is no mean feet take one for a test drive!

)
Mike

The Original Tom · Post by **The Original Tom** » Wed May 30, 2007 4:13 pm

Well mine's by ne means a strip-car! so I don't exactly need shovels of power, but a 0-60 of under 15 secs would be nice

I may end up having to incerase the CR further (dependong on what;s causing my water leak) so it would be nice to know I can run a reasonable amount fo boost even with relatively high CR.

I've looked at eaton superchargers and they claim that 50% is a realistic minimum power increase with 60% more than likely, putting my motor up by 50% gives me about 225bhp (currently 150ish) - which I think is too much (for now

).
If I low-gear the charger so I just get 4-5psi, (appx 190-200bhp?) I shouldn't have any problem running standard unleaded or LPG (110 octane?) or worry about stressing the engine too much hopefully...

I intend to read as much as possible before taking the plunge - the bracket will take me ages to make, I'm no fabricator!

Also I've decided that if I do charge, that 200hp is my limit without more expenditure, as my LPG vaporiser is only rated at 200hp, and I'll make it gas-only so that I don't have to worry about fitting my carbs to it either.

The Original Tom · Post by **The Original Tom** » Wed May 30, 2007 4:24 pm

One more thing...

If I do get into this charging thing properly, with the spare 8.13:1 pistons in the garage, and composite gasket, I can get CR into the mid-high 7:1's, would that allow me to run anywhere NEAR full boost on my engine? (1.6 bar or 23psi on a 3.5l with a M112!!!) or will I need ported heads etc to deal with that?

kiwicar · Post by **kiwicar** » Wed May 30, 2007 4:33 pm

Hi Tom
There is so much more to it than "lower the CR and wind up the boost" 7 to 1 and 12psi boost could pink like hell if you get it wrong but it could take 3 bar+ there is no real way to tell.
Mike

JP. · Post by **JP.** » Wed May 30, 2007 5:19 pm

There's no need to lower the CR on an Alloy engine and run about 7 Psi.
Alloy has a differend heat release range than cast iron blocks. And more inportand, alloy has a differend expansionrate than cast iron that means if you'r driving the blower with a fixed tensionair youl need atleast 2"of slack in the belt.

I am running 7psi on a 9.35cr block. Heads where been milled that much that the RS Composite gaskeds reduced Cr to about 9.35???? ( was running somewhere around 10:1)

I Must I am running a Boost timing master on our ignitionsystem.
On the dyno I had a Blower curve in our distributor.

O yes I am running it on euro 95 with an in tank Fuelcat...........

Sheets can be found at http://www.magnusonproducts.com/mp112.htm

The Original Tom · Post by **The Original Tom** » Wed May 30, 2007 11:17 pm

I was hoping to keep the fuel system as standard as possible, or completely remove the petrol system so that I don't have to buy new carbs (pricey) or fabricate a way of mounting them - I can see the LPG being much easier to fit to this, and promotes cooler burning.

There is a station near my home (like half a mile) that does that 85% ethanol. I can fill a petrol can with this and dilute it into my tank to about 15% (max safe on an un-modified engine I believe?), to help cooling.

Unless I can dig up some info on blow-through systems? But then I guess I'll need a powerful fuel pump that can be fettled to deliver a constant fuel supply at a pressure above manifold pressure (so say if I'm running 7psi boost, I'll need 10psi at the carbs or something? Any way... I'm off to read!

Why is nothing with these motors cut-and-dry!? hehehe

The Original Tom · Post by **The Original Tom** » Thu May 31, 2007 2:04 am

OK. Using a mixture of info found on JP's link, eliots website and this map:
http://www.eatonperformance.com/superch ... e-map.html
... I've mapped my engine onto the MP112 datasheet.
It woud seem that at 7psi, it will be a little low for maximum efficiency.
Can someone tell me how to post pictures on here it's hard to explain stuff without!
Basically I've put max torque at 2500rpm (on feel of driving it alone), redline at 5500rpm, and my initial desired boost at 1500rpm.
At this point, I'm assuming that the way to plot info on a supercharger map, is tha same as planning it on a turbo curve.

@ 7psi (PR 1.48 ), and 1500rpm (pulley ratio 1:1.41),the charger will shift 233.5 cubic m/hr, which isn't on the map, but will fall into the '58' area on the map.
@ 2500rpm, it comes out at 389.2 cubic m/hr, and that sits within the '60' area. Near, but not within the desired 'center' of the map (at '62'). The '62' portion of the map won't come in until about 3000-4000rpm - hardly ideal for a heavy vehicle.
@ 5500rpm, the air volume/hr is 856.2 cubic m/hr, which falls within the ''58' area.

So it would appear that upping the boost to about 10psi would prove most efficient?

I'll probably work that out exactly tomorrow, I'm tired of number-crunching now!
That is, unless someone tells me I'm doing the calculations wrong.

Cheers all
Tom.

Eliot · Post by **Eliot** » Thu May 31, 2007 7:31 am

Based on your figures, here's what I assume you are saying:

which is straight down the middle of the map at max efficiency, with headroom to crank the boost up if you want.

I dont have time right now to verify your maths, plus i cant see what spec your engine is (size) and desired use. (4x4 or road) - so if you post that up, and perhaps we can kick the figures around a little.

The Original Tom · Post by **The Original Tom** » Thu May 31, 2007 12:34 pm

Cheers Eliot - that's pretty much the plot I came up with, except that I plotted mine across from PR1.38

.
That does look a pretty good match now.
The engine is a 3.5l, and is mainly used on-road but I don't want to sacrifice any bottom end as I rarely exceed 70 on road any way. It will also be used for towing / recovery etc, and like to change gear at 3k, so I want most the power low-down really.
It's in a defender 90, currently weighs about 1750kgs at a guess.

Thanks again
Tom.