Eaton M90 questions + other

[heviarti]

So I've been wanting to supercharge my 300. I've come up with a plan to use a drawthrough setup with the supercharger on an electric clutch via a special valve I've designed to transition from aspiration to boost.

I see a great deal of discussion about mounting the M90 to a 300. has anyone actually done this? I've determined the M90 as supplied in the Thunderbird supercoupe is perfect. It's the early M90 with the 'noisy' ouput port, and both the inlet and outlet are where I need them to mount the blower on the left side of the engine. Fuel will be supplied via my Weber two barrel.

I'll be doing this after I rebuild my bottom end. I already did the top end and ignition. I figure I'll need a forged crank, heavy rods, performance pistons in a suitably low compression range,blueprint, balance, cam, glyptol coat, high volume oil pump and an aftermarket balancer. I also want the piston fuel pump they supply at racepumps.com, but I don't know how much trouble adapting it from the 302 type to the 300 will be. It's inline, not lever operated, so stroke and pushrod depth are the only concerns. 302 has approximately .40 of lift on the eccentric lobe. I can get the electric clutch for the blower from Ogura.

Anyway, words of wisdom as to the M90 and 300 would be appreciated.

Edit for spelling due to smartphone chiclet keyboard.

 

[StrangeRanger]

Have you sized your supercharger with this map:
http://www.eaton.com/ecm/groups/public/ ... 128485.gif

Depending on where you're trying to build boost and what you're doing with the engine, the M90 may be a skosh small for the 300. The M112 might be a better fit
http://www.eaton.com/ecm/groups/public/ ... 128487.gif

Basically the M90 has to run at something like 2.5 times crank speed to get you a pressure ratio in the range of of 1.4-1.5, so at 4000 RPM you're spinning the blower at 10K, which is starting to drop out of its maximum efficiency range. The peak efficiency of the M90 occurs at 6000 RPM which translates to only 2400 engine RPM so for a low revving tow pig, the M90 might be the way to go.

The M112 only has to run at twice the crank speed to achieve the same boost so at 4000 engine RPM, it's only turning 8000 RPM which is still pretty high on the efficiency curve. Because of the lower drive ratio, the efficiency peak is at 3000 engine RPM which is likely to be more in keeping with a street/strip application

Play around with Eaton's calculator a little:
http://autoapps.eaton.com/Simulator/Landing.aspx

 

[heviarti]

I guess the bug question is is there a 112 with tail inlet, top outlet.

I guess I could research my other idea.... I was wondering about a backwards CVT to alter the blower rpm to have a bottom and top both in the efficiency range.

any which way it has to fit in the engine compartment and have the ports where I need 'em.

bottom end checklist look good?

 

[StrangeRanger]

What kind of pressures are you planning on running? The forged crank, aftermarket rods and forged pistons are overkill at moderate pressures. As you crank pressures up, they become progressively more necessary but the M90 becomes progressively less applicable.

So define two things: the max boost you intend to run and the max engine RPM you ever intend to reach. Those two things determine what blower you need and what engine mods are required to support it

 

[heviarti]

I'm figuring On better than six, but no greater than ten pounds of boost, and as far as I'm concerned the more overkill the better. It'll be driven naturally aspirated most of the time, so the better I build it the more life my engine will have.

I only figure to use it in third and fourth gear, Third from about 2000 to 3500, and fourth from about 1200 or 1500 to 3500. I can count on one hand the amount of times I've exceeded 3500 in a year, and on one finger the times I've been at 4500 or greater.

I basically need a little extra punch at the top to convince folks not to try to pass me if they want to try it at above the limit out here. People with the 1P plates are too impatient. Speed limit reads '55' not '75'. Acceleration is constant but not rapid as is. Fuel mileage is good, even with the Weber, which is why I want the electric clutch setup. I'm really curious if I could rig kind of a backwards CVT to lessen my ratio at high rpm, and increase it at low rpm to stay in the blower's efficiency window... If there's not a 112 supplied with the ports where I need 'em I'm kinda toast.

Many people here talk about the M90, but I have yet to see one mounted to a 300. I had initially intended to use an M62, but it's too small, and nobody could tell me if it was capable of running inverted.

 

[StrangeRanger]

6 PSI and 10 PSI are two very different situations

At 6 PSI I wouldn't waste the money on forged pistons; a good set of hypereutectics will do nicely. At 10 PSI you probably need forged. Aftermarket rods are a waste in either of those scenarios, go with a prepped and peened set of stock rods. They're more than good enough. As for the crank, a prepped stocker is way better than you need at 6 PSI and should be fine at 10 as well. Get up to 14 PSI and a forged crank makes sense.

The more boost you run, the higher your pulley ratio has to be and the faster you have to spin the blower. At 4500 RPM and 10 PSI you're looking at a pulley ratio of around 2.9:1 and over 13,000 blower RPM with an M90. Aside from the thermal efficiency going to heII in a handbasket, you're getting into grenade territory. At 6 PSI and 3500 RPM you're only looking at a pulley ratio around 2.4 and less than 8500 blower RPM. Like I said, two very different situations.

 

[heviarti]

I Think I've hit four grand a few times but I seldom break 3500.

I've got an NP435 and 3.70s with 235/75R15s, but I may move to a 33 or 35, which would further lower my rpm requirements.

If I simply set up that reverse CVT, I could conceivably have a ratio of 3 or 3.5:1 at 1500 and 2:1 at 4500. It's just a matter of tuning the springs. The downside is that I'd have to mount the electric clutch at the balancer beneath the CVT.

That's a bit nuts, but I think it would work. Or, I could use the 112, but again I'd like to know about the ports. I've got to have a rear inlet so I can come from the left side beneath the carb, across the valve cover and down to the inlet... and a top outlet to come up across the valve cover with at least six inches of space between the ducts to 90° directly to the front of the carb. I can't go over ten PSI because it's drawthrough. I can't intercool, or I'd have a bomb under my hood. I figure I'll get something from going straight up with the boost, and I could fin the output duct or affix a peltier... but none of that complication is worth the other four pound of boost.

I've designed a valve with a single moving part to transition from aspiration to boost. I've got no idea how much to expect from the 300 under boost, I just know it will increase my fuel usage, and I don't need it 100% of the time. I doubt I'll need it 20% of the time.
I'd look more seriously at Eaton's site, but many of their apps are difficult if not impossible to use in a smartphone environment (my sole access to the net.) I've wanted to try intermittent boost for a very long time, but it's been til last month that it was possible (the simplified valve opened a lot of doors)

I do know the M90 does top out at somewhere between 12600 and 13200 RPM, I've done some research, but a great deal of this idea treads on uncharted ground.

 

[Broncitis]

I think you are making this incredibly difficult with little benefit to all the gadgetting and what kind of fuel control do you have for all that switching, make it easy and mount a carburater flanged mp112 with an adapter plate directly to the intake and run about 5 to 6 psi and you can practically stay with most stock parts except the pistons, 10 psi is a totally different animal, at 5 to 6 on the mp112 your not getting into to much heat and you won't have to intercool it, realisticly you will gain about 60 to 70 horses from a basically stock 300, seat of the pants will feel like more.

 

[Broncitis]

I went back and read that you are going to use a weber two barrel, if you are running the correct AFR say at 3000 rpm N/A and kick in the blower, you will run lean and hurt your motor and its probably not maybe, the first expense I would buy is an afr monitoring system and run at least 13.5 and 11 to 12 under hard accelleration at least as starters to see how the plugs like it.

 

[heviarti]

I actually think it's a bit rich at the top... I know when I accelerate quickly it almost chokes on the fuel the carb will deliver. I've got an idea to deliver more volume. The Eldred Norman book states that the more air you pull through the carb, the more fuel it will deliver per intake stroke. Saying that a carb can't operate that way is like saying a carb at half throttle can't run at full throttle according to Norman.

Also, the flanged 112 in a regular configuration wouldn't come near to fitting under my hood. If the 112 is available with the ports in the right places I won't need the CVT. Trust that the valve I designed is extremely simple. If I can find the right blower (which everyone thought was the M90) It'll be no problem making it do what I need as to engage/disengage.

My 300 is already more powerful than stock, but I have no idea how much. Nobody has a dyno. My great uncle has a fresh stock engine in his '77 pickup with the same transmission, unknown gears and taller tires.

I have the Weber, an MSD, a Mallory Pro Master coil, a set of Harland Sharp roller rockers, a flex fan, and a Delcotron alternator... My great uncle Drove it while we were trying to diagnose a power train vibration and commented on the fact it acted like it had more power than his. I'm still not satisfied with it's response, though. That and the fact that I've always wanted a supercharger on an electric clutch lead me to decide to do it to this one.

 

[StrangeRanger]

a 300 with a blower on it running at about about 6 PSI is going to look almost exactly like a normally aspirated 428 to a draw through carb. You need an appropriately sized one. Personally, I'd want something in the 750-780 CFM range with vacuum secondaries.

 

[heviarti]

Yeah, I guess I could expect almost 150% efficiency, but I doubt I'll get it. If I can get 100% I'll be doing good. I think the head on a 300 only manages something like 60% naturally aspirated (that's 180 of 300 cubic inches it draws for six intake cycles)

Couple that with the efficiency of the blower (the percentage of air that passes through it it compresses) I seriously doubt I'd manage as much as 428 artificial cubic inches. If I manage 350-375 I think that'd be all right.

I have yet to determine what this carb's theoretical maximum is. I have yet to determine for sure what model it is.... markings are chundered and the box is faded beyond reading. and I'm suddenly very very tired, more later

 

[StrangeRanger]

I picked the 428 intentionally as a comparison. It has the same stroke as the 300, lives at low revs and unless it is fitted with a set of high performance heads it is also very "challenged" when it comes to volumetric efficiency. A 427 or a 429 would need even more carb but would not be a valid comparison to a boosted 300.

Doing any performance modifications on a 300 without first prepping the head is a waste of time and money

 

[SoCar72]

The Eaton superchargers really don't care what their orientation is. As long as it spins in the right direction it will work. I've seen them upside down, on the side, even turned around backwards. The post-generation 3 SC's utilize internal vacuum actuated bypass valves, which will work either as a draw through or blow through. When the bypass is open, as in low throttle demand situations like idle and cruising, the SC consumes an very little HP, so it will be almost like the SC is never there. The CVT sounds really cool and would be a great idea on non-bypass SC's, but would be absolutely redundant with a bypass valved SC.

Overall, the M112 is more efficient than the M90 and wouldn't need to spin as fast to achieve the desired output. Either would work, but I'd lean toward the M112.

Magnuson makes (did make) an MP112 - a carb version of the M112 with an internal bypass valve. Build an adapter plate or custom intake manifold and you're in business with far less effort. I saw these listed on eBay sometime back for $575 each brand new.

With your 300 at 4500 rpm (assuming this is your max rpm) and about 7psi, your asking the carb to flow about 590cfm. With that boost level, think about that 300 as having 450cid. I wouldn't carb any less than a 600cfm vac sec. If you push to 10psi, go for at least 700cfm.

Once you add boost to the intake cycle, you start taking intake vacuum (volumetric efficiency) out of the equation. Sure, a great VE intake tract will respond stronger (more cfm at same psi) than a poor one, but even a poor one wakes up considerably. Even with an all stock intake tract, you're 300 will start behaving like a BB V8.

 

[heviarti]

The CVT has nothing to do with engage disengage, rather it would alter the pulley size to change the drive ratio in relation to engine speed. Same thing as on a snowmobile or a combine. Increased rpms change the size of the pulley, thus altering the drive ratio. The electric clutch would handle engage disengage.

I had asked several people if the eaton supercharger could be inverted and nobody answered. I really appreciate the info. That makes life a little easier. I prefer the earlier model eatons with the 'noisy' port. If I have a blower, and it's running I want it to howl a little.

My valve is designed to totally isolate the blower from the system. I *really* don't need it all the time. Part of the reason I'm doing this is to see if my idea works as well as it should. Everyone who has seen the model (and has a technical background) agrees it is sound in principle. Plus pulling a two speed diff switch to engage a supercharger would be cool.

I have had a head rebuild and stelite seats installed, as well as roller rockers. Wood's didn't offer a port and polish. I am considering a Clifford manifold, even before I supercharge. As it is my carb is on a two to one adapter fit to a stock manifold. I think I might see some improvement yet by getting a more open manifold. I'd post a pic, but I think this is the forum software I can't post to.

Still need to identify my carb, and I need to get rid of the &*$!@# electric fail-o-matic choke. I also need to find a better valve cover. The only aluminum one I've seen is way too tall, and way too expensive. I've got several checklists full of stuff I want to do to it. I need to find out what the lift of the eccentric is on a 300. if it's .40ish I'm in good to go for something else I want to do. There's a piston fuel pump I really want to try even if the guy who builds them is a cheese-nob. Darn fool has been building custom fuel systems since 1973, and doesn't understand the first rule of *good* jerry rigging.

 

[Broncitis]

Very good follow up posts to help this feller out, I bought one of those mp112's for 575 with shipping, tried to buy another and they are sold out, I think it would kick some butt on a 300 and stay plenty cool under 7 PSI, the m90 would just have to spin to fast and create to much heat at that boost level, one could creat a monster and never have to go past 4500 rpm with the right setup, getting ready to put mine on a 350 chevy with only 5 to 6 psi,I agree, Blaspheme!!!!

 

[heviarti]

is there an application I could look for the 112 in? Something I could ask the scrap yards if they had?

Is there a flat snout for the 112? a bunch of these have waaaay long input shafts. I don't need a draft line across my engine compartment. I need to stuff this thing in around where the power steering pump would go (if I had one...) so stubbier is better.

I really don't want to do the CVT, it's just a possibility I considered to work around the m90 efficiency map. Generally if something ostensibly won't work and I need it to, I figure out how to make it happen.

I have come up with several versions of the valve, the latest being the best. I've repeatedly discounted the idea of a second carb mounted to the blower, as it would be too much of a pain in the butt.

 

[SoCar72]

The SC'd F-150 Lightnings ran the M112's as well as 03-04 Cobra Mustangs. I'm sure there are other applications, but these are the Fords that I'm aware of. This website offers a lot of rebuilt / remaned SC's.

http://www.invasionautoproducts.com/supercharger-ford.html

A quick eBay Motors search yielded about a half dozen offerings.

I have a '79 F-250 with the 300 and I was considering the Mustang M112 option, tilted sideways with the inlet pointing up and the outlet pointing at the lifter cover. I'd run a cool air duct to the inlet and duct up an over to the carb as a blow-through. Second thought was to use the F-150 model mounted to a custom intake and mount the carb on top of the inlet as a draw-through. Then I found the MP112 carb SC and bought it (Broncitis and I have the same idea). I'll likely build a custom intake.

What I'm driving at, and missing the point with tangents, is you have a lot of room along the driver's side of the block. I wouldn't lose any sleep over the input snout length, especially if you rotate the SC sideways. Sideways you'll only need about 6" of lateral room. Since the F-series trucks don't have the Mustang/Falcon shock towers, you can take a few more liberties. Keep in mind, these SC's were designed to mount top center on small to mid sized V8's. So the the input snouts are pretty close to the same length regardless of application. If you feel you must have the shortest possible, you'll have to order from Magnuson as they are the only dealer of non-factory spec'd Eaton SC's. M90's and M62's were designed to fit V6's, they tend to be the shortest. The M45's (too small for any or our applications) were found on L4's.

SC howl sounds cool. But the the reason why Eaton reshaped the inlet wasn't to make it quieter, but to make the SC inlet more efficient, hence higher output efficiency. Regardless of how quiet the SC is, when the bypass closes, you're still going to hear it pay off.

 

[heviarti]

I've got some things poking out on the left side of my block.... Most notably the fuel pump and distributor, and directly across from the distributor I have a high output coil. I've been considering a mallory unilite distributor to replace the factory unit. I won't gain any clearance from it, but it will be smaller than the one that's on there.

What year was this F-150 lightning supplied? I can scour the yards for it and the mustang.

Have you seen the M62 as supplied on the Mercedes? That's the snout I'm looking for. I do want the blower forward, because boost will enter the valve as much as eight inches in front of the carb.

 

[SoCar72]

I can't tell you the exact years, but the M112 was found on the mod motored lightning's, not the Windsor blocks. I believe the Mustang M112 was the same years.

If you're running Ford's DuraSpark ignition (I didn't notice what model truck or engine you're running), you will be well served sticking with it. You'll likely not notice an improvement with Unilite unless, considering the rpm band you detailed.

I do want the blower forward, because boost will enter the valve as much as eight inches in front of the carb.

Don't understand what you mean by this, but if your ducting from the SC to the carb as a blow-through, distance won't effect it's operation except under extreme conditions. Intercooled turbo units can have feet of duct between the compressor and the carb. Sure, you want it as short as possible, but a foot and 3 feet of ducting will be unnoticeable except to the most extreme tuner. Just look at any intercooled centrifugal SC'd V8 Mustang. But, if you feel you must have that short of a snout for the M112, you're only option will be purchasing a custom built one from Magnuson.