Eaton Supercharger ID and Injector Q's

[scott.venables]

I have been inspired (like many others) by Greg Gordon to supercharge my 2.5 75. I think I've found a unit, but I'm not exactly sure it's an M62. I sent a diagram of a 3rd Gen. M62 to the seller without any dimensions on it and asked him to fill out 4 important measurements. (A,B,C,D)

The First pic is what he came back to me with. The Diagram is representative only, there are some details in which the unit I'm looking at differs. Namely, It has 4 lugs/ears sticking out around the unit (for supports?), the top 2 threaded holes on the inlet port protrude above the body, the inlet port is not as radiused in the corners and the outlet port "F" dimension is smaller than the "E" dimension where the diagram shows square. There are some other small differences in the castings. Excluding the snout though, the dimensions(A,B,C,D) line up exactly with what I found at http://www.capa.com.au/eaton_m62data.htm

The other 3 pictures are taken from the Ebay auction.

Is it possible they could be so similar yet different?

My other question is about Injectors. Injectors out of a Nissan RB30 6cyl are very similar to the L-jet V6 ones. Physically the same, impedance the same, but flow is different. They are rated at 200cc/min @43psi, while the Alfa ones are 180cc/min at 36.5 psi. Running the Nissan injectors at Alfa pressure is only a difference of 4.25cc/min, or about 2.5% more. My question is, will running the Nissan injectors at Alfa pressure muck up the spray pattern? I understand some variance is OK as it allows the same injectors to be used in different motors, but we're talking about 6.5psi.

The formula I used for injector flow is :
(Sq. root(New pressure/Old pressure)) X Old flow rate = New flow rate
and
Pounds/hour X 10.2 = cc/min

Any contribution is much appreciated
Thanks, Scott

[turbolarespider]

What is the blower from? Normally, they are cast with very specific intake and outlets for a particular model. The only one that I know of that isn't like that is from the Ford Super Coupe- which is an M90.

You can find a lot more information about the blower at Eaton, BTW- a few years ago, I downloaded the flow characteristics from their website. Which is helpful in deciding the pully ratios.

As for the injectors- I doubt the spray pattern is all that different between the inejctors- the 80's era injectors didn't have much to speak of in terms of spray pattern. And from the videos I've seen, the only time it really matters is during the first min of operation. After the engine fully warms up, the injectors basically are injecting vapor, and the spray pattern is barely seen.

You probably could go a lot bigger on the injectors, if you like- how are you planning on controlling it?

Eric

[scott.venables]

Thanks Eric. I had a look at the Eaton site but it didn't seem to help me much. The one I'm looking at would be a few years old and the website only seems to have 5th generation specs. I guess it would be good for estimating. I'm almost understanding the performance map.

I have no idea what the blower's off originally. Not many cars were fitted with 62's here. Only Mercedes I think. The most common unit here is the 90 which was used on some Commodores (one of the top 2 sellers). It was on Ebay as "Eaton Supercharger", no model numbers and no hint as to what it's off. It didn't get a bid so I'll negotiate with the seller if I'm sure it's a 62.

Initially, I'll run the L-jet. Later on though I'd like to change to Autronic/Gotech or something similar. These injectors are attractive because they're readily available, dirt cheap and virtually identical to the Alfa ones. Funny you mention larger injectors, they built a turbo RB30 here that used 260cc/min @43psi injectors. At Alfa pressure that's about 234cc/min, compared to 180cc/min stock.

Thanks for the help,
Scott

[alfettish]

well done Scott, I hope you can realise this project.

[turbolarespider]

Quote:

Originally Posted by scott.venables Thanks Eric. I had a look at the Eaton site but it didn't seem to help me much. The one I'm looking at would be a few years old and the website only seems to have 5th generation specs. I guess it would be good for estimating. I'm almost understanding the performance map. I have no idea what the blower's off originally. Not many cars were fitted with 62's here. Only Mercedes I think. The most common unit here is the 90 which was used on some Commodores (one of the top 2 sellers). It was on Ebay as "Eaton Supercharger", no model numbers and no hint as to what it's off. It didn't get a bid so I'll negotiate with the seller if I'm sure it's a 62. Initially, I'll run the L-jet. Later on though I'd like to change to Autronic/Gotech or something similar. These injectors are attractive because they're readily available, dirt cheap and virtually identical to the Alfa ones. Funny you mention larger injectors, they built a turbo RB30 here that used 260cc/min @43psi injectors. At Alfa pressure that's about 234cc/min, compared to 180cc/min stock. Thanks for the help, Scott

[Greg Gordon]

Those injectors should work, I have found you can go about 1/3 bigger before you run into real serious problems.

That supercharger is probably a M62 and if it's a M90 that's OK. The M90 will work although it's not quite as effective on a 2.5. The way to tell is the width of the rotor case. The M90/112 rotors are wider than the M45/62 rotors. In other words that dimension "E" is what you need to be looking at.

Greg Gordon,
www.hiperformancestore.com

[Trav]

I have a couple of M-62's from C230 benzes I will measure tonight. The one you show looks like one of mine, I'm not sure what year but is was advertized as off a C230.

I have had difficulty finding alternate sized drive pulleys for the Benz unit as it( at least mine) has a splined shaft

Greg, not to doubt your expertise but doesn't the displacement change with the length of the rotors?

Does anyone recall the output of stock 2.0 injectors (1986) ?

Trav

[Greg Gordon]

Hi Trav:
Hey, you can doubt my expertise all you want. I am still learning to!

The displacement does change with the length of the rotors. A larger rotor cross section (width) also changes displacement. The Eaton family uses two different cross sections. The first is on the M45 and M62. The 62's rotors are longer, that's where the extra displacement comes from. The M90 and M112 share a larger cross section. The M90 rotors are about the same length as the M62's but they are wider. The M112's rotors have the same cross section as the M90 but they are longer. I hope all this makes sense.

Be carefull when buying a supercharger off a Mercedes. The same model car, even within the same model year can have a M45 or a M62. The Mercedes Eatons are also the odd ducks of the group usually lacking an internal bypass valve and using that very non standard pulley system.

As a side note it's more efficient to increase displacement via rotor length. Increasing the rotor's width is usually done due to packaging and strength concerns, not supercharger efficiency.

[scott.venables]

Thanks for all your help guys. I think I just need to go and confirm the measurements so I can tell if it's a 62 or not. Im not too worried about the pulleys, something can be firued out. And for a bypass I was planning on using an cheap turbo wastegate, maybe with a manual boost controller as well.

Trav, thanks for that, if you can post the measurements from yours that would be a great help.

Still not sure about the injectors. The larger Nissan turbo ones are exactly 1/3bigger, and the non turbo ones are near identical to stock. Suck it and see?

Thanks again for all the help guys.
Scott V

[Barbalatte]

Hi guys, I have read all your posts and it's all been very interesting. I have a racing GTV6 and need more power, the easiest way. I think I have found it! Anyone is Sydney installing Superchargers?

I have just a few questions if you don't mind.

1. Besides the Super Charger its self, what else is required? Eg. Pullies, Pipes etc.

2. Is there any electrical involved?

3. Is there anyone is Sydney installing Superchargers?

Thanks guys
Daniel

[scott.venables]

Hi Daniel.

Greg Gordon sells a complete kit that can be seen at http://www.hiperformancestore.com

The only reason I'm putting my own together is because as a fitting and turning apprentice I feel I can fabricate most of the parts myself. It would also be great a experience which I'm looking forward to. Also, I would like to modify the system a litle bit compared to the kit.

If you're looking for some extra reading material, have a look at http://www.hiperformancestore.com/superredverde.htm (also one of Gregs kits)

Forum member alfettish is also installing the kit which can be seen at Supercharged GTV6 - Christeen

Scott

[Barbalatte]

Thanks for the help. But isn't this guy in the States?

[alfettish]

Yes, I don't know if he ships them out.

[Trav]

Scott, sorry for the delay posting this, I had to work.

I turns out Greg was right about M-B using different models on C230s. Looks like I have a M-62 and a smaller on I'm guessing is a 45???

Anyhow the M-62 is closest to the diagram you posted so the dimensions are from it. Dimensions are in CM, which I assume is appropriate as you are in Oz, and are as best I could do in a hurry.

B = 20
C = 13
d = 18 +/-
e = 9
f = 9
g= 6 top and 10 bottom

As best I can measure with out dissassembly the rotors are 16 to 17 CM long in the M-62 and 11 cm in the other.

Greg, I remember you previously mentioned the 45 might be a good choice because it will be operating at a more effecient RPM ( higher) than the 62.

I'm shooting for a stock 1986 2.0 with about 8 PSI. Probably use water injection and may add a water air intercooler if boost temps are high. Does this sound reasonable?

[Greg Gordon]

You can use either a M45 or a M62 to get 8 pounds of boost on a 2 liter. The effects of using different sized superchargers are actually pretty complex. In this case the M62 will be slightly more efficient due to its longer rotors. This discussion could get complex but think of it this way, with everything else equal longer rotors will increase supercharger efficiency.

Now with that said, that doesn't mean the M62 car will outrun the M45 car. If they are both set up for the same amount of boost at redline ( 8psi in this case) the M45 car will have more boost at low and mid range rpm and probably outperform the M62 car except at very high rpm.

Think of it like this:
On a 2.0 liter Alfa with 8 pounds of boost and a normal engine redline, a M62 will have these advantages over a M45.

1. slightly lower drive power requirements
2. slightly lower discharge temps
3. make less noise (is this an advantage?)
4. use a bigger pulley which will simplify belt tensioning issues

The M45 will have these advatages:
1. More agressive sound, ie more noise
2. more boost at all rpm below redline
3. more power and torque under the curve (meaning the average amount of power throughout the rpm range)

Either will work and which to use can depend largely on personal preferences.
In short the idea of a 8psi M45 on a 2 liter Alfa is entirely reasonable.

I will have a large pamphlet out soon (more of a book really at about 100 pages) with a ton of data on this stuff.
Greg Gordon,
www.hiperformancestore.com