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frenchyd
frenchyd PowerDork
9/2/20 7:39 p.m.

Kicking around a thought.  Looking for a couple of cheap used blowers. 

Mr_Asa
Mr_Asa Dork
9/2/20 7:56 p.m.

Size you're looking for?  I passed a couple attached to some pontiacs in a JY today

I bought 2 Eaton M90s off of early 2000s GM 3800s on a whim. I paid like $35 each at the U Pull It. I have no idea what I'm going to do with them but I can say I own 2 superchargers laugh

 

frenchyd
frenchyd PowerDork
9/3/20 9:04 a.m.

In reply to Mr_Asa :

Something like a m90. I need a pair.  A friend wanted me to put my supercharger on my XJS by cutting a big hole in the hood   yuk!! 
But a pair, one on each side  would achieve the same thing and I can even use a pair of SU carbs  to keep it simple. 

frenchyd
frenchyd PowerDork
9/3/20 9:09 a.m.
stanger_mussle (Forum Supporter) said:

I bought 2 Eaton M90s off of early 2000s GM 3800s on a whim. I paid like $35 each at the U Pull It. I have no idea what I'm going to do with them but I can say I own 2 superchargers laugh

 

That's exactly what I'm looking for a pair of M 90's 

 

can you please give me some sizes.length back to front of the pulley, width, thickness. 
 

what years would have those ? Only Buick? 
any idea of how much boost they produce?  
 

If you ever want to sell them let me know

Patrick (Forum Supporter)
Patrick (Forum Supporter) GRM+ Memberand MegaDork
9/3/20 9:57 a.m.

I think your hot ticket will be thunderbird super coupe ones.  Or a single m112 or m122 from a ford product.  Lightning, cobra, etc.  the gm m90's are designed to bolt to the lower intake and are all wonky and some have the throttle body cast in.  The thunderbird ones are simple.  

nocones
nocones GRM+ Memberand UltraDork
9/3/20 9:58 a.m.

An M90 displaces 90 cu-in of air per rotation.  They are positive displacement meaning they will put 90 cubic inches of air into the engine if you have enough HP to pump it.  Boost is not related to any inherent feature of the Supercharger but the ratio of supercharger volume to engine displacement.  You control the ratio of engine to SC displacement by supercharger RPM through pulley sizing (With some variability due to flow characteristics of the supercharger resulting in more or less effiicency at different superchager flow rates). 

Google says the stock crank pulley is 7" and SC pulley is 3.8" on the Buick 3800 (Available on Buick, Pontiac, and Chevrolete with the 3800SII supercharged engine).   Looks like that results in stock boost of 8 psi.  

frenchyd
frenchyd PowerDork
9/3/20 10:58 a.m.

In reply to nocones :

That's great info. I'm going to use a pair of them  on a 5300 cc engine ( 326 cu in)  so I might under drive them a little. 
My Roots  type pumps out 250 cu in. Per revolution  looks like a GMC 6-71 but a little smaller diameter. 

STM317
STM317 UberDork
9/3/20 11:03 a.m.

Some Nissan Frontiers and Xterras also had an M62s.

frenchyd
frenchyd PowerDork
9/3/20 11:06 a.m.
Patrick (Forum Supporter) said:

I think your hot ticket will be thunderbird super coupe ones.  Or a single m112 or m122 from a ford product.  Lightning, cobra, etc.  the gm m90's are designed to bolt to the lower intake and are all wonky and some have the throttle body cast in.  The thunderbird ones are simple.  

I'm trying to use a pair of them  along side the engine.   Anything on top of the engine might work for drag racing but would leave you pretty blind looking across the hood and in front Not something you want doing wheel to wheel 

I know they use m45's on MGTD's but the biggest engines I see those on are about 2 liters or so. 
so a pair would not be enough for 5300cc (326 cu in 

do they make 75's. Where would they be used? 

frenchyd
frenchyd PowerDork
9/3/20 11:08 a.m.
STM317 said:

Some Nissan Frontiers and Xterras also had an M62s.

How common in junkyards?  How big are the engines?  

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
9/3/20 11:11 a.m.

Frenchy, I think you need to do some fundamental reading on superchargers and sizing and efficiency. It'll help you get where you want to go.

frenchyd
frenchyd PowerDork
9/3/20 11:42 a.m.

In reply to Keith 

Since I'm doing something other than production there has to be an element of guess work.  My first priority is finding something sized right. physical size. 
I'm starting  out with 7.8-1
  compression and  in an engine  similar in size to an 5.3 Chevy.  But I can't stick one on top and call it good. A 60 degree V is taller than a 90degree V   The alternative is two smaller blowers along side the engine. That work's since the Engine is only 22 inches wide  and the stock manifolds don't exit in front but on either side.  So ducting is workable.  
I know the superchargers will work with carbs. While I'd like to use a pair of SU's on each blower, a pair of 2 barrel Holley's might wind up being the easy button. 
Size wise I'm limited to physical dimensions. I suppose I can google  those.   I'm not worried about pulley sizes. I figure I'm going to have to  turn my own. But maybe they are enough varieties  I can go off the shelf. 
 The alternator and power steering might force me to get clever But I have the space up in the V if needed. 
While I'll be using E85 to keep the charge temps down.  Fabricating mounts and ducting is just straight forward work. 
I'd like to use the biggest pair That will fit.  Just because it gives me more options. Since it's a race car only, not anything that will be used on the street. Even if I lose if efficiency  the engine has been tested up to 8300 RPM without issues by the factory. So Spinning it faster is a cam change away. Luckily my performance trends computer will help with that.  
Or. The  basic design was built to go out to 8 liters. And 7.3 litters is just a regrind of the crank and  bigger pistons away. 
In other words I've got a lot of options 

californiamilleghia
californiamilleghia SuperDork
9/3/20 11:48 a.m.

which ones work like an old GMC 671 blower with the intake on top and the "out" on the bottom ?

I know some have the intake on the end......

frenchyd
frenchyd PowerDork
9/3/20 1:10 p.m.

In reply to californiamilleghia :

Sorry it's so dark. This is a roots type like a GMC 6-71 if it was sitting on top of the engine the 3 ( SU) carbs would be on the top. And the opposite side would be the bottom. 

It's set up for an in line Six cylinder do it's sideways. 
most Eatons I've seen draw air in at the front and blow it out the back. I don't know if they are all that way  but I'm learning. 

MadScientistMatt
MadScientistMatt PowerDork
9/3/20 1:17 p.m.

There used to be a site out there around 2001 called toohighpsi.com - it looks like that one lapsed and someone else bought it, but you can view some of the pictures via the Wayback Machine. It has a number of junkyard forced induction builds, including putting two Buick 3800 superchargers on one 351W and stuffing that into a Thunderbird.

A few years ago, I met the guy behind that site - he's now the president of Magnuson Superchargers.

frenchyd
frenchyd PowerDork
9/3/20 1:24 p.m.

In reply to Keith Tanner :

Keith , 

I've got  8&1/2 inches on the sides of the engine before I have to start moving metal around.  There is 15 inches from the back of the pulley to the front of the intake.  And 9 inches deep from the hood to the frame. 
Just eyeballing a 45 looks to be about 15 inches long.   So  The next size might be pushing my space.            

Will
Will UltraDork
9/3/20 3:03 p.m.

Around here, supercharged Grand Prixs seem to be more common in junkyards than Supercoupes. That said, there are two flavors of Supercoupe M90: 89-93 and 94-95. The later blower was good for an extra 20 hp and 15 lb-ft in factory trim. However, the 89-93 has a smaller pulley than the 94-95, and adding the early pulley to the later blower is a cheap power upgrade.

californiamilleghia
californiamilleghia SuperDork
9/3/20 3:32 p.m.

are there smaller junkyard superchargers  for a 1500cc-2000cc motor ?

I know there are the tiny ones on Ebay etc of Japanese Kcars but they are pretty expensive compared to pick a part prices !

dean1484
dean1484 GRM+ Memberand MegaDork
9/3/20 3:41 p.m.

I have a couple Eatons on my shelves.  I think I have two M62s and an M90.  If you take the snout from an early Buick (1992 I think) and then put it on the back housing of a Merc 230 Compressor (again the early version with the HUGE pulley) you get a really compact little M62 with s slightly longer snout than the original M62 that was on the Merc. 

So hypothetically speaking Frenchy you could get two of the Buick and two of the Merc units and piece together two very compact M62 units.  AND the M62 front snout from teh Buick has a pulley diameter of 2 3/8". I assume this is how they got it to work in the 3.8l.   This in theory would give you 6-8lbs of boost on a 7.6l motor BUT that does not take in to account efficiency losses as nothing works to 100 percent so for 5.3l I think two of these little units would be more than enough to do what you want to do and give you really good fitment.

Now some photos to prove that I actually did this and this is not just internet myth and legend.  Yes I have actually done it

The top unit in the photo below is the M62 from the C230.  I tried putting a alternator pulley on it (from a porsche 944) to get rid of the really large clutched pulley.  While it worked it was ugly and it put the unit really far forward on the motor.  This made packaging a bit of an issue.  So I got the M62 that you see below it from an early Buick and . . ..   

 

Vola swap the front snouts and associated impellers and you get the unit on the left.  Perfect for what I am doing with it  LOL

 

As a complete side note I think this is how the unit that is used on some twin supercharged Aston Martins is  actually made but if you try to purchase one of those M62 units you have to pay Aston Martin pricing. I have never inquired with Eaton if they would actually sell this configuration.   

For comparison here is an M62 from an Aston Martin DB7

 

Yes there are some differences like the number of ribs on the pulley but the basic M62 unit and snout look to be basically the same.

dean1484
dean1484 GRM+ Memberand MegaDork
9/3/20 4:06 p.m.

Frenchy

I plugged in the information I have in to my trusty excell sheet I made for calculating things like this (It also calculates air speed in the pipes at a given pipe diameter that you may want to know for other reasons)

Anyway 6500 RPM with a 5.4" pulley at the crank and a 2.37 pulley on Two Eaton M62's should net you about 11.62lbs of boost on a 5.3l motor at 100 percent VE.  Realistically you could expect 8-9lbs I think and that may be a lille optimistic. 

The issue you have with this setup is you really can not go any further up the RPM range as you will be spinning the unit at 14,810 RPM in this configuration.  They tend to go boom at or over 15,000.

 

 

frenchyd
frenchyd PowerDork
9/3/20 4:35 p.m.
dean1484 said:

I have a couple Eatons on my shelves.  I think I have two M62s and an M90.  If you take the snout from an early Buick (1992 I think) and then put it on the back housing of a Merc 230 Compressor (again the early version with the HUGE pulley) you get a really compact little M62 with s slightly longer snout than the original M62 that was on the Merc. 

So hypothetically speaking Frenchy you could get two of the Buick and two of the Merc units and piece together two very compact M62 units.  AND the M62 front snout from teh Buick has a pulley diameter of 2 3/8". I assume this is how they got it to work in the 3.8l.   This in theory would give you 6-8lbs of boost on a 7.6l motor BUT that does not take in to account efficiency losses as nothing works to 100 percent so for 5.3l I think two of these little units would be more than enough to do what you want to do and give you really good fitment.

Now some photos to prove that I actually did this and this is not just internet myth and legend.  Yes I have actually done it

The top unit in the photo below is the M62 from the C230.  I tried putting a alternator pulley on it (from a porsche 944) to get rid of the really large clutched pulley.  While it worked it was ugly and it put the unit really far forward on the motor.  This made packaging a bit of an issue.  So I got the M62 that you see below it from an early Buick and . . ..   

 

Vola swap the front snouts and associated impellers and you get the unit on the left.  Perfect for what I am doing with it  LOL

 

As a complete side note I think this is how the unit that is used on some twin supercharged Aston Martins is  actually made but if you try to purchase one of those M62 units you have to pay Aston Martin pricing. I have never inquired with Eaton if they would actually sell this configuration.   

For comparison here is an M62 from an Aston Martin DB7

 

Yes there are some differences like the number of ribs on the pulley but the basic M62 unit and snout look to be basically the same.

Wow that seems to be exactly the combination/ package I'm looking for. I might go a little more conservative on the pulley size. It just seems I'd be a few missed shifts away from a bang.  
could you give me some sizes please?  I know I'm working with about 15-16 inches from the back of the crank pulley to the front of the intake .  I also have 8&1/2 inches from the engine to the inner engine compartment panel.  Plus about 10 from the frame rail to the hood. 

yupididit
yupididit PowerDork
9/3/20 4:47 p.m.

I have a eaton m112 sitting on my workbench from my Jaguar XJR, if you need measurements. 

So you're twin-supercharging and 5.3 jag v12 huh? Why didn't you just say that instead of spouting off engine specs? We all know those specs and dimensions from reading them all over this forum. "The engine i plan to use" so vague lol. Anyway this would be an interesting setup. 

californiamilleghia
californiamilleghia SuperDork
9/3/20 5:09 p.m.

which combination of parts makes the shortest supercharger with intake on top and exit on bottom ,  not on the ends ?

And how long would that be ?

Thanks

dean1484
dean1484 GRM+ Memberand MegaDork
9/3/20 6:30 p.m.

Sizes on the hybrid m62???  Sure I can do that. I will most likely get them tomorrow as it is bolted to a motor that I need to uncover. 

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