Anyone make a Billet elbow or Blank flanges for the M90?

EAC

Registered User
Hi, new here.

I picked up a M90 supercharge for my 1996 NSX. A company called, Gruppe M made a supercharger kit for the NSX that used the M90. Since that company stopped making the kit, I’m going to fab up one myself.

What I’m trying to find are things to make the process a little easier.

Does anyone make billet elbows for the top or blank flanges for the top or back of it?

Here is what the kit looks like and what I’m trying to achieve.

8.jpg
 
Hi, new here.

I picked up a M90 supercharge for my 1996 NSX. A company called, Gruppe M made a supercharger kit for the NSX that used the M90. Since that company stopped making the kit, I’m going to fab up one myself.

What I’m trying to find are things to make the process a little easier.

Does anyone make billet elbows for the top or blank flanges for the top or back of it?

Here is what the kit looks like and what I’m trying to achieve.

8.jpg

Nice looking setup. Do you have pictures of the rear of the blower?


Ken
 
Should I just start out with the stock M90 pulley? I only want 6-7 psi to start with.

3.0 liter engine
8,000 max RPM's
6 inch crank pulley
 
You are going thru all that trouble to put a stock M90 blower on it. They are not all that efficient. You should invest in at least a ported late 94-95 M90 from a SC or fab a kit that will utilize a twinscrew supercharger.

Is this going to be intercooled?

You can check out this website for some M90 related parts.

http://www.magnumpowers.com/
 
You are going thru all that trouble to put a stock M90 blower on it. They are not all that efficient. You should invest in at least a ported late 94-95 M90 from a SC or fab a kit that will utilize a twinscrew supercharger.

Is this going to be intercooled?

You can check out this website for some M90 related parts.

http://www.magnumpowers.com/

I do have a 94 M90, and am having a local guy "steigmeier" port it. It won't be intercooled initially, but I'll probably add one later.

Here is a graph from one guy with a M90 on his NSX, stock motor with 9.5 psi.

The M90 has been proven to outperform all the whipple kits, on the NSX atleast.

5k1ufp.jpg
 
The 94-95 blower and pulley produced 11-12 psi of boost on the Supercoupes. But these engines, although larger, do not breathe well at high RPMs. The stock redline is below 6,000 RPM. So the NSX's smaller engine will probably demand more air than a SC 3.8 when all is said and done. But still, the exact blower drive setup is critical to the question.

Here is something to get you started. Download the .ZIP of the second spreadsheet. On the first tab are some tables that you can manipulate to estimate the blower RPM at the speeds you want. You will need to add some rows and swap in the right pulley diameters. If you aren't going to use a jackshaft, set the two columns for the jackshaft to have the same pulley diameter, so it won't change the calc.

http://www.sccoa.com/forums/showthread.php?t=54113&highlight=spreadsheet

Once you have the blower speed, you can:
A) See if it is within the safe operating range of the blower.
B) At each RPM, take the blower's volumetric efficiency and your engine's volumetric efficiency, multiply them by their displacements, and compare the ratio, to get an approximate pressure ratio for the system at that RPM.
C) Then take the pressure ratio, multiply by ambient (14.7), subtract ambient (14.7), and that should be your boost at each RPM.

Edit:

Here is a performance map for a 5th-generation M90. That is the next one after what you have. The blue contours are % volumetric efficiency. Pressure ratio is on the left. Inlet flow is on the bottom. And the blower RPM is the green vertical lines. A little confusing, but it's got some good info.
http://www.eaton.com/ecm/groups/public/@pub/@eaton/@per/documents/content/ct_128485.gif
 
Last edited:
Wow, thanks for the link and information. I'll play with this tonight and see what I come up with. Thank a ton!

The 94-95 blower and pulley produced 11-12 psi of boost on the Supercoupes. But these engines, although larger, do not breathe well at high RPMs. The stock redline is below 6,000 RPM. So the NSX's smaller engine will probably demand more air than a SC 3.8 when all is said and done. But still, the exact blower drive setup is critical to the question.

Here is something to get you started. Download the .ZIP of the second spreadsheet. On the first tab are some tables that you can manipulate to estimate the blower RPM at the speeds you want. You will need to add some rows and swap in the right pulley diameters. If you aren't going to use a jackshaft, set the two columns for the jackshaft to have the same pulley diameter, so it won't change the calc.

http://www.sccoa.com/forums/showthread.php?t=54113&highlight=spreadsheet

Once you have the blower speed, you can:
A) See if it is within the safe operating range of the blower.
B) At each RPM, take the blower's volumetric efficiency and your engine's volumetric efficiency, multiply them by their displacements, and compare the ratio, to get an approximate pressure ratio for the system at that RPM.
C) Then take the pressure ratio, multiply by ambient (14.7), subtract ambient (14.7), and that should be your boost at each RPM.
 
The M90 has been proven to outperform all the whipple kits, on the NSX atleast.

That is the fault of the kit, more so than anything to do with the particular blower. A screw style compressor is always going to perform better than a roots style compressor for a given compressor displacement. Better in less energy to turn it and less heat generated when operating.

That said, if a M90 is enough, then it's enough. Certainly they can be significantly less expensive to acquire, though I'm not sure how the value proposition works out once you start porting the M90.

Running without an intercooler is probably fine for street driving, or for putting down a number on a dyno. But if you do any autocross or road course driving you will definitely want an intercooler. Since you have to fab everything up now, it only makes sense to include that option in your fabrication. I don't know of any blown application where someone wished they "didn't" have an intercooler.
 
That is the fault of the kit, more so than anything to do with the particular blower. A screw style compressor is always going to perform better than a roots style compressor for a given compressor displacement. Better in less energy to turn it and less heat generated when operating.

That said, if a M90 is enough, then it's enough. Certainly they can be significantly less expensive to acquire, though I'm not sure how the value proposition works out once you start porting the M90.

Running without an intercooler is probably fine for street driving, or for putting down a number on a dyno. But if you do any autocross or road course driving you will definitely want an intercooler. Since you have to fab everything up now, it only makes sense to include that option in your fabrication. I don't know of any blown application where someone wished they "didn't" have an intercooler.

Although the car is setup to hit a course, I won't be doing it anymore. Our local track (Gateway) closed down. Once I get into fabbing it, I'll most likely throw the intercooler on. Right now, I'm just planning on getting it mounted up and turning.

Right now, the only kit available is the Science of Speed 2.1L Whipple kit, which runs $10,500. $12,000 with the laminova intercooler kit. Even then, the M90 outshines. Sure, the charger (Whipple) itself is better flowing but the configuration isn't.

That being said, anyone sell flanges? :)
 
I don't believe anyone has any ready made flanges. If you e-mail XR7 Dave he may be able to point you to someone that can make some. Also you could contact kenewagner and see if he would be up for it.

Alternatively, find a local machine shop and see if they want to do some side projects with you. It wouldn't be particularly difficult to fab up a plenum and flange for the rear of the blower, nor for the outlet. Any machine shop that does fabrication should be able to handle it.
 
Thanks guys, I don't mind flabbing and cutting some aluminum flanges. I just hate making the mess int he garage :)

I'll reach out, thanks guys!
 
Although the car is setup to hit a course, I won't be doing it anymore. Our local track (Gateway) closed down. Once I get into fabbing it, I'll most likely throw the intercooler on. Right now, I'm just planning on getting it mounted up and turning.

Right now, the only kit available is the Science of Speed 2.1L Whipple kit, which runs $10,500. $12,000 with the laminova intercooler kit. Even then, the M90 outshines. Sure, the charger (Whipple) itself is better flowing but the configuration isn't.

That being said, anyone sell flanges? :)

That supercharger kit is a 2.1l kenne bell blower. And most likely they cost that much because they probably have to buy a complete kit from them. Since kenne bell refuses to sell just the supercharger. A kit should not be that expensive.
 
Although the car is setup to hit a course, I won't be doing it anymore. Our local track (Gateway) closed down. Once I get into fabbing it, I'll most likely throw the intercooler on. Right now, I'm just planning on getting it mounted up and turning.

Right now, the only kit available is the Science of Speed 2.1L Whipple kit, which runs $10,500. $12,000 with the laminova intercooler kit. Even then, the M90 outshines. Sure, the charger (Whipple) itself is better flowing but the configuration isn't.

That being said, anyone sell flanges? :)

That supercharger kit is a 2.1l kenne bell blower. And most likely they cost that much because they probably have to buy a complete kit, from another application, from them. Since kenne bell refuses to sell just the supercharger. A kit should not be that expensive. Its not a whipple though.
 
No the 2.1L are Kenne Bell. Kenne bell used to used Autorotor for their kits. But when it became hard for them to meet demand they made their own version of it made in the US not Sweeden like the AR were.
Autorotors came in a popular 1.7l 2.0l 2.2l and 2.4l size there were other sizes but they were are different series of blowers. They are using a kenne bell for the 2.1l and kenne bell does not like to sell just blowers they sell kits and can only be had straight from them only. Trust me. ;)

So I think not only do they overprice NSx kit because its an nSX, but also because they either are buying a complete kit from them or someone at the company is sleeping with someone at kenne bell and paying lots of money to kenne bell to get just the supercharger and snout.
 
Gotcha, thanks. I did not know that.

Talked to the guys at magnum power, they don’t have flanges. :(
 
Gotcha, thanks. I did not know that.

Talked to the guys at magnum power, they don’t have flanges. :(

It may not be such a problem. Try asking Steigemeier if he can fabricate a flange for you. If not, well, some aluminum plate, a drill, and a bandsaw or jigsaw will take care of it.
 
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