M62 interchanging housings

EDIT: A post of mine has gone missing from this thread so it may not make sense to those that read it from the beginning. I am hoping that GRM has a copy of it or if anyone copied it PLEASE email it to me or re post it in this thread.

It was a brake down of the three basic stages of boost and the modifications that accompany them. You will see references to stage 1, 2 or stage 3 boost setups. In this thread and that post has gone missing.

Thanks!!!!

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I have had a M62 on the shelf that I got form a GRM member about 4-5? years ago. The problem was it is from a 230 and had the big 3.5" magnetic clutch type pulley. So I had a custom pulley made using two alternator pulleys and although it works the fab job was less then stellar. Another issue is that the pulley is now a bit smaller than I like boost would end up being around 11-12 PSI. I want around 7.

The good side is that the back rotor housing for the M62 that is used on the C230 is a very nice piece. Compact, very nice machining and the mounting holes are located such that making a mounting adaptor is a snap.

Then I get thinking. The early 90's Buick's have M62's on them and they use a short snout unit with a 2.5" Pulley but the housing is meant to be mounted to the top of the motor making it not the greatest for standalone installations. I was actually thinking or making up a 1" thick box out of steel to mount the unit to. This box then be easily mounted / adapted to with flanges so that it would allow for mounting it in the engine compartment.

Then I get thinking again. (see a trend here) Why not take the shout and front housing and rotors from the Buick M62 and install them into the back housing of the C230 M62. Exterior inspection of the units and measurements show that they appear to be identical and have the exact same bolt patterns. Even the casting divots and whatnot are identical between the two units. The only one visual external problem I can see is that the drain / fill hole for the snout oil will be facing down on the Buick snout if I maintain the alignment of the housings. Since these units can be mounted in any direction I was thinking I would just flip the snout 180 degrees. OR just live with the fact that I have to remove the supercharger to change the oil. I would then only have to make up a mounting bracket for the fount of the unit. A simple piece of 1/8" x1.5" angle iron would be all that is required a little drilling and some cutting and the mount would be complete.

The unknown I have is the bearing size at the back housing. I have not looked up part numbers to see if they use the same bearing. Since I have both on the bench at the moment I guess it may just be simpler to take both apart and measure things.

So the question is has anyone ever swapped housings between M62 compressors?

In case anyone is wondering This is for my 924ssc project. Yes I am going to have stickers made up in the Porsche font when it is done just to mess with the Porsche purists :-).

While on the subject of M62s...

Since you seem to have one apart, could you measure the length of the rotors? I have what I could swear is an M62, but I've seen the same unit listed for sale as an M90.

Regarding snouts... I am not sure what you mean by flipping the snout 180 degrees. Doesn't only one rotor have drive dogs on it? The bolt pattern/dowel pin arrangement is also asymmetrical, but that can be dealt with.

Per Eaton, the blowers can be run in any orientation as long as the fluid level is correct. The fill plug location is just determined by what orientation it was built for - they all take the same amount of fluid.

I actually have 2 m62's and an M90 all lined up on the shelf at the moment. Do you have any #'s off your unit?

M90s are cheep as they are really only good for bigger 6 cylinder motors and very small v8's . The M62's are very good for 4 cylinder cars. I think the perfect match would be C230 Kompressor M62 mated to a Toyota 4AGE. Keep the stock magnetic clutch and add a manstrom(sp) valve and you would have a really cool (and fast) setup.

An easy way to tell am M62 from an M90 is the distance between the two side bolts on the front of the unit that hold the snout to the back impeller housing With the unit sitting on the bench measure Center line to center line between the two bolts on one side of the unit. You will be measuring vertically. The M62's are spaced 2" apart and the M90 is spaced 2 3/4" apart

Here is a photo I just took of the Buick M62 (right) and a Supercoupe M90 (left) With the measurements.

You are rite about the bolt pattern. There is an 1/8" difference between the spacing of the bolts on the top and bottom of the snout housings. So flipping the snout relative to the housing is a no go I guess.

Here are PIX of the M62's

The two M62's side by side. What I want to do it take the snout and rotors as an assembly out of the bottom unit and install them in to the back housing of the top unit.

Looking at the snouts of the M62's noting the difference in the bolt spacing at the top and bottom of the snout.

I bought it used, from someone who swapped out from his (X) year Grant Prix. It had the usual drive donut rattle, at the time there was no cheap fix for it so he bought a junkyard unit. HE said it was an M62, but other people say that GM went to the M90 before that model year. I've long forgotten what model year the blower was actually from, as it was supposed to go on a Volkswagen PG engine for my Golf. The Golf that I got rid of years ago...

Odd you should say that the M90 is cheaper. It used to be that I could find M62s for $100 and M90s for $200 but now everything is way more than that.

I'd much prefer to have an M90. An M62 looks like its max airflow potential is 250hp, which I can almost do naturally aspirated.

dean1484 wrote: M90s are cheep as they are really only good for bigger 6 cylinder motors and very small v8's . The M62's are very good for 4 cylinder cars. I think the perfect match would be C230 Kompressor M62 mated to a Toyota 4AGE. Keep the stock magnetic clutch and add a manstrom(sp) valve and you would have a really cool (and fast) setup.

Interesting. I was thinking of a turbo option for my 4age 20v, but the c230 M62 seems like a very nice compact unit. Do you have dimensions you could post? I would like to build a wood block mockup to see if it would fit my somewhat cramped engine bay. Also, how much air does it flow (I'm looking to find a ballpark horsepower/torque estimate). Edit: Looks like the C230 was advertised at 190hp. That would make my Midget scream!

If anyone's looking at getting rid of one of these in operating condition, I'm very interested.

The C230 M62 dimensions are

7 1/2 wide

9 long. The pulley sticks out another 2.5" for the stock magnetic pulley.

5 1/2" deep

If you are seriously looking at these there is an early and a late version of these. They area easily distinguishable by the pulley size as well as the later ones being more design specific for the application. The one I have is an early one.

Here is a on line spread sheet I made that will let you play with boost and air flow on various superchargers. It does not give HP as this is subject to so many variables. but you can estimate based on the boost level you get and then look at what others are getting with similar boost on your motor.

http://www.ehadesign.com/~dsmith/ENGINE_AIRFLOW.htm You may need to install an add on for your IE to use it.

I got on a tangent a while back wondering about intake pipe diameters versus boost and air speed. There is a whole section in the chart that deals with this. The Eaton site will tell you max RPMs of the particular supercharged you are using / interested in. I don't remember exactly what the M62 is at the moment but I think it is 14000 RPM. I will be getting up to around 12K so things should be ok.

I'm sorry, I got confused about the bit about wanting LESS boost.

I just realised thet I just created Dean's Quantom Boost theory. Kind of like Alton Browns "Dip Theory" LOL

Hehe, good explanation.

I plan on building my Miata next winter to Dean Stg 3 tune! But I'm planning for rods/pistons, ARP studs all around, etc.

I planed this long ago it started by sourcing a 83 944 motor. It has lower stock compression and a complete forged bottom end stock from the factory. It is the only NA 944 that they did this through the whole run. There are rumors and hearsay that later 944's got forged lower ends and there has been a long standing debate on what 951's got forged internals. The post 85.5 944's and 88 up 924s's got higher compression motors than the early ones. The 83 in my book is the sweet spot. It has the forged internals and lower compression than the other NA cars making it the perfect candidate for adding boost. I will probably be adding a 951 head gasket if I step over in to #3 category. At this point it really will be cheaper to just get a 951. But what is the fun in that. Another rout would be to put 951 pistons in the 83 motor or just swap a 951 short block in.

was confused at first, thinking you were talking about the m62 bimmer engine. now I got it. just thought I'd share my post-work confusion=]

z31maniac wrote: Dean Stg.. . . .

I think I know what my screen name should be changed to. I don't think there is any higher complement one can get.

Remember to keep up the oil level to prevent #2 rod bearing failure.

Naaaa Rod bearings in 944's are regularly scheduled service item. To be changed every 2 timing belts. I have had P cars for so long I am actually starting to believe that this is "normal" . LOL

Back in the mid 90's I was spending a lot of time on track with 944's and after the 2nd or third motor failure I learned that stock 944 motors and sweeping left hand turns don't mix. I then installed an accusump and that has prevented that from being an issue in my cars from then on.

I'd like start with the Dean Stage 2, with possibility for Dean Stage 3 in the future once I throw some pistons. I wonder if a 4age 20v could live with a C230 M62, an intercooler, and an RRFPR.

Edit: which c230 M62 is the better one to look for? I don't know much about Mercedes's's's.

Quick sidebar, please: can somebody decode RRFPR for me? (I assume FPR is Fuel Pressure Regulator...?) Thanks.

Stealthtercel wrote: Quick sidebar, please: can somebody decode RRFPR for me? (I assume FPR is Fuel Pressure Regulator...?) Thanks.

Rising Rate Fuel Pressure Regulator. They are boost-referenced (they have a line from the intake plenum) and raise fuel pressure in proportion to boost levels: they could go from 1:1 up to something like 3-4:1 if I recall correctly in order to proportionally increase fuel pressure to the injectors and enrich the Air Fuel Ratio to deal with higher pressure levels from a super-turbo charged engine.

What is the crank pulley diameter on those motors? I ran the calculator with a 5" crank pulley and a 3.5" pulley for the magnetic clutch (I just measured the one I have) I came up with 8.28 PSI. What is so cool about that is that you get the benefit of the magnetic clutch that allows you to effectively disconnect the supercharger. Combine this with a quality bypass valve and you get the best of both worlds.

This puts you squarely in #2 category. Here is anther problem I have run in to. People just want to add on spark control and a RRFPR and that is good BUT if you are using quality pieces (not the cheep ebay knockoff stuff) you are probably less than $100 away from going to a complete standalone MS2 V3.0. The problem here is that you have to do a complete tune versus augmenting the factories. I can see the logic in this. In base ball terms it would be like hitting a double and starting at second base. The down side is you will be limited to where you can take this.

Once you have a MS based (or any other standalone programmable system) up and running it allows you all kind of options. It also gives you much better and complete control over things. I ran into this and actually sold off all my "adders" and just went MS once I figured this out. The only way I would go with the factory ECU is if the car I was working on has an easily re programmable ecu. Honda's are a good example of this. I messed with MR2's for quite a while and one of the real PITA's was that the ECU was not all that friendly.

Things may have changed now. I think MS has a plug and play version not for Toyota as well. However these are another $300+ above piggyback add ons but well worth it.

Getting back to one of your original questions about an intercooler. The answer is YES. It is my opinion that you will want / need one at 8PSI. It will go a long way to prevent detonation. I also recommend them more with piggyback systems as they have less control and the intercooler gives you a little more margin for error.

Lastly a WBO2 is a must. I forgot to mention this in my long post above. Even in the most simple systems it is really the only real time feedback you can get that tels you what is going on.

Teh E36 M3 wrote: Rising Rate Fuel Pressure Regulator. They are boost-referenced (they have a line from the intake plenum) and raise fuel pressure in proportion to boost levels: they could go from 1:1 up to something like 3-4:1 if I recall correctly in order to proportionally increase fuel pressure to the injectors and enrich the Air Fuel Ratio to deal with higher pressure levels from a super-turbo charged engine.

1:1 is not a rising rate regulator. All EFI cars (well, except for returnless systems) have 1:1 referenced regulators. The idea is that fuel pressure is constant relative to manifold pressure - this standard pressure differential is the base pressure. If there is 15 inches of vacuum, the fuel pressure needs to be dropped ~7psi, if there is 5 pounds of boost, the fuel pressure needs to be raised 5psi.

Rising rate regulators increase the pressure out of proportion to boost levels, so that the base pressure changes as manifold pressure goes up. Rising rate.

They're a band-aid fix, since they increase fuel flow by the square root of the pressure increase, over and above what the airflow sensor is providing. Typically there will be one range where it runs properly, but it'll go pig rich or insufficiently rich elsewhere. And then there's the problem where it's easy to get fuel pressures that the fuel pump can't even generate, even before figuring that fuel pump flow goes down as pressure goes up.

Back to RRFPR There really is only one out there that I have found that really does the complete job. A RRFPR is simple in theory BUT it actually needs to be tunable. This is especially true if you are to the point where you need bigger injectors

One of the problems many people have is they want to also add bigger injectors thinking it will give them the fuel they need. the problem is that when you do this your car will run like crap out of boost due to the bigger injectors putting to much fuel in. You need a unit that allows you to dial the fuel pressure back when out of boos. My scenario went like this. I wanted to replace the #19 injectors with #35's. The problem is that off boost I would still have 30 something PSI of fuel pressure and it would run really rich out of boost with idle being a huge problem. To solve this you have to actually be able to lower your out of boost fuel pressure to say somewhere around 18-20 psi so the larger injectors squirt less fuel (The same as the small injectors would at the OE something fuel pressure at idle)

Another "Issue" with RRFPR especially when they are used a a piggyback and are the only / primary way you are increasing fuel in boost is the transition from NA to boost. You have to be able to tune this to start the rise in fuel pressure before you actually go in to boost. Think of it kind of like how an accelerator pump dumps a bit more fuel when you press the gas peddle. Or in modern EFI car it is called "accel enrichment"

So you need a RRFPR that can drop fuel pressure to around 20 PSI or less when you need it and you need to be able to "tune" how and when the fuel presser rises. Especially around the transition in to boost. See if you can find a cheep eBay knockoff that does this.

The only manufacturer of RRFPR that I found that can do this BEGi. They make a unit that is by far the best one I have seen for this application. See here>>> http://www.bellengineering.net/product_info.php?cPath=7_77&products_id=7 The only draw back is it is large. Like over 6" tall!!!! and at well over $300 it is not cheep but again since this unit will be keeping your motor safe I think it is a very wise investment. But now start looking at the price of piggy back ignition systems and or the cost of an ECU tune and you are getting in to stand alone engine management territory.

The biggest problem with this whole adding boost thing is that there is no easy or rite answer. It is kind of like a Rubik cube. Move one thing to get something rite and you change something else. It is a juggling act.

Thanks, guys. Following this discussion with great interest!

The E36 M3 wrote: Edit: which c230 M62 is the better one to look for? I don't know much about Mercedes.

I like the early ones (like mine) They are more compact and the 4 bosses in the casting make them easy to mount in other engine bays.

AND THE ANSWER IS.. .. . . .. YES!!!!!! THEY INTERCHANGE!!!!!. I AM SO EXCITED THAT THIS WORKED!!!!!!!!!

The back housings on the two units are interchangeable!!!!!! This makes for the perfect small M62 with a short snout and a small pulley. This would be perfect for a 4AGE or a Miata or?????

Photo of the two units swapped next to each other.

From This To this!!!!!

This opens up a whole bunch of possibilities

Something is really screwy here. My post with my "boost theory" has gone missing. Did anyone copy it? Is it just my computer acting weird? Is was rite after "z31maniac " post at June 23, 2012 12:53 p.m. What is going on here. I don't have a copy of it and I don't want to try to recreate that.