Allen Supercharger Information and Questions

[Stanley]

I'm trying to find information on the Allen Engine Development superchargers, but as the company disappeared circa 2008 it's hard to come by.

QUESTION
How can you tell if a seller has a 6-psi or 9-psi kit? Either by picture, or by giving him instructions to check X or Y if he doesn't know. What are the signs?


GENERAL INFO
I'm just going to collect some of what I found below for my own future reference / in case other people might find it useful, so skip this if you don't care. There's some PDFs at the bottom you might find interesting, however.

First of all, there's AED's old website. You can view the final version via this May 2008 Internet Archive link:

Allen Intercooled Superchargers

They had an older website with some different content circa 2006, found here:

Welcome to Allen Superchargers

Their kit was intended for 96-97 Birds only, but they offered support for 94 and 95 as well, though you had to buy additional parts, listed here:

Extra Parts for Thunderbird Installation

VARIATIONS
This is the hard part. It seems there were all sorts of variations on this kit over the few years it was around, and it's making it really hard to tell what someone might have or even what I actually want should I find it.

For the MN12, the design was built around a slightly modified, M90 Gen III blower. They offered two main versions of this: 6 psi and 9 psi (plus a crazy Race version that was the most powerful option, using a Lysholm 2.3 Twin screw blower instead of the M90, but I'm not interested in that).

According to this post:
"Allen sells a kit without an FMU [fuel management unit] as well."
This post implies that was just for the 6-psi version.

This post and this post talk about an older variation:

COP = Coil on Plug ignitions. The '98 and up Crown Vic and '99 and up Mustang GT uses COP ignitions (no spark plug wire), so AED need a place to mount the 8 individual coil packs. If your AED kit was bought in '99 to present, then you have the COP provisions. If you have an older kit without the COP provisions, then you cannot port the NON-PI runners to PI style since their isn't enough material to safely do this.

Next to each fuel injector boss there are COP provisions (coil-on-plug). If you have these, your runners are able to port to PI style. If you DO NOT have these COP provisions, you won't be able to remove enough material to match a PI port. It's rare to have the NON-COP REV-I runners. They're are out there though.

If you bought a used kit or have a really old kit, you may have these runners.

Why are they there if we do not have COP ignitions? ... they were there for the '98 Crown Vic and '99 and up 4.6L engines and trucks that use the COP ignitions. Eventually, ALLEN SUPERCHARGERS went to the REV-II kit which all have the COP design in the castings.

Overall, AED had Rev I and Rev II versions of the superchargers. However, for the MN12 specifically they only ever sold a Rev I version:

According to this 2006 post from the same guy:
"The M90 used on the AED REV-I kits was a GEN-III M90 with an S-Port, hence M90S.
The new REV-II kits ... use the GEN-V M90."

This post explains what an "S-Port" is:
"S-Porting is an “efficiency” port job that’s performed to all of the M90's supplied with the AED kits. The S-port is performed at the discharge end of the blower.... The S-port is the transitional undercut of the inside of the port performed to aid in a smoother, less turbulent path for the air to travel as it exits the blower."

Further clarified by this post:
"All AED REV-I kits have S-Ports. Most REV-II kits as well. The newer REV-II blowers that are GEN-V Eaton M90 superchargers DO NOT have the S-Port since they DO NOT need it."

This post on a Mustang forum says that the Rev II was named after the new manifold design, but also mentions the later-gen blower:
"Your kit is actually called a REV II (named after the manifold design). ... The difference between your blower and a standard 4th Gen MP90 are that the lobes with the 5th Gen units are Teflon coated to improve efficiency and the 4th Gen MP90's are not."

This post says:

The REV-II manifold was designed for the '99 and up Mustang GT, the Crown Vic, etc. The REV-I kit was designed for the '96-'98 Mustang GT, then adapted to the '96-'97 T-Bird/Cougar and finally...the '94-'95 T-Bird and Cougar.

Getting the REV-II kit to work on the MN12 would require hood space and few odds and ends. This is similar to how Mike Siska custom fit his AED Race Blower onto his engine in the '95 T-Bird. Other than that, there really is no physical limitations.

I've seen a couple of mentions on TCCOA of people wanting the Rev I kit over the Rev II kit. If I understood correctly, I assume that's because of the above: the Rev II doesn't seem to fit under the stock hood, like the Rev I does, due to the new manifold design. In addition to that, this post says using a Rev II on a Bird would take some further work:

you would want to use the 96-97 fuel rails. You would have to custom fab up the egr tube. You might need a raised cowl hood to clear the throttle body. I don't know if the rev 2 kit has fittings for 2 coolant temp sensors. You would definitely want to use the rev1 96-97 belt routing and you might have to modify the alternator bracket to accomplish this. The reason why is it gives the supercharger pulley a much better wrap with the belt and reduces slippage.

A 2002 listing of Allen products does not list a Rev II as available for the MN 12 at all. That seems to be categorically backed up by this post:
"All of the standard ’96-97 Thunderbird, ’96-’98 Mustang and “Race Kit” units are REV I castings. The ’99-up Mustang, Explorer, Crown Victoria, etc manifolds are REV II design."

A natural question then is whether or not you can at least take a later Gen V M90 and backport it to a Rev I kit (swapping out the Gen III and thus getting better flow). I haven't been able to find a 100% certain claim either way.

This 2004 post seems to imply that it was available:
"If you order a REV-I or REV-II AED kit for a Mustang GT, T-Bird, Cougar, Crown Vic, or truck...you WILL get an Eaton M90 Gen-IV or if you request, at an updated cost, an Eaton M90 Gen-V blower."

But it's implied to be unlikely in this post:
"I don't believe [that the Gen V blower is] a direct replacement and I can't recall exactly why. If my memory is accurate, I thought it was due to the built in by-pass valve making the unit longer than the GEN-III M90."

How to tell if you have a MN12 version rather than a Mustang version:

Why are there differet plenum lids used with the AED REV...

www.tccoa.com

There were 2 different types of REV-I plenum kits. The Mustang GT used a cover that was uniform and higher. The MN12 cars used a plenum cover that was cast with the lower-dimpled section to clear the sloppy hoodline of the T-Bird and Cougars.

However, there were variations of these covers. I have a few here and each one is a different height. ALLEN experimented with a few different depths and plenum volumes before settling on the final design.

Some covers had the raised letters and some had the letters flush with the cover. The MN12 covers always had the letters cast below the surface of the cover.

I doubt the Mustang cover would offer much improvement over the traditional MN12 cover, and it would never clear the stock MN12 hood.

This is a shot of an Allen for a Bird. Note the slope in the bottom third or so of the cover, where "Allen" is written:



This is one for a Mustang. Note the completely uniform flat top cover:



I'll keep updating as I find more info.

Attached are some relevant PDFs. First is the 96-97 install manual for the MN12, taken from their website. I found a very rough set of scans on TCCOA, but this is the original and easier to read. Also included are the 94-95 modification instructions they produced, and a set of brochures.