Supercharging - M90

[MaccyD]

Ok, so its been a while since ive been on here. I did have a number of running issues which i was helped through by Bushwhacker and also from Gloverman (of The Cartune Company). After getting my car on the road i discovered HUGE rot in the sills amongst other places so went for a reshell. This is what im left with at the moment:

http://img.photobucket.com/albums/v..._543727055676568_1617638581_o_zpsa64010e5.jpg

Now ive been toying with thoughts of where to go from here. Im not seeking mega power as this is my daily and is already quite alot to run a 4.0 as a commuter in the UK with fuel prices knocking on the door of £1.40/litre.

For some reason i have in my head that someone somewhere mentioned that an Eaton M90, although not the most powerful option (remember im not number chasing) can be run on stock management?

To begin with i guess first id like to know if this is true. Ive seen i can get an M90 shipped from the states for around £200 and a recon kit of bearings and seals and oil for about £50 so lets say £300 for the lot. Plan is then get a donor inlet manifold, customise it and mate it up to a laser cut flange that the charger will sit on.

So yeah, ive used the search engine and tried to find some relevant information but stuggled to find anything that is at least less than 4 years old so was hoping to get some advice and spark up a little discussion. if i HAVE to run management, can it be done turbo style with an S-AFC2 or similar as a piggyback? Or does it have to be a full ECU like Link?

Anyway, im rambling, help and advice welcome. Looking for around 300-350bhp at the fly.

Cheers

Maccy

 

[stevechumo]

Your goal is easily achieved with 6 psi of boost. All you need is a big high pressure fuel pump such as a Walbro 255 lph-hp or a stock Supra TT Denso pump, and you'll also need a FMU 12:1 ratio. No need for aftermarket ecu and tuning.

 

[MaccyD]

Ok, so im already running a walbro in my conversion. Forgive my ignorance here, what is 12:1 FMU? Not familiar with the achronym, cheers

 

[MaccyD]

Ah, ok, an aftermarket fuel pressure regulator, or, in this case, a rising rate fuel pressure regulator. Will any do, or does it have to be that specific ratio? Also, are the stock injectors up to the job or do you need some bigger ones?

Thanks already for the quick response. Im getting over excited already haha

 

[stevechumo]

That ratio 12:1 is to increase the most fuel pressure to make sure the engine has enough fuel during boost. There're other lower ratios, but this is the safest ratio to use. This FMU is to use with stock injectors. Don't use bigger injectors, because you'll need an aftermarket ECU to control them.

 

[MaccyD]

Ok, and its perfectly safe to run with the stock ecu? Or is it wise to get something like an air fuel controller to manage the map?

 

[stevechumo]

Ok, and its perfectly safe to run with the stock ecu? Or is it wise to get something like an air fuel controller to manage the map?

Yep. Read my post above:
Your goal is easily achieved with 6 psi of boost. All you need is a big high pressure fuel pump such as a Walbro 255 lph-hp or a stock Supra TT Denso pump, and you'll also need a FMU 12:1 ratio. No need for aftermarket ecu and tuning

 

[MaccyD]

Sorry, i do get what youre saying, and i wouldnt want to go for a full ecu and map as its expensive. But for the cost of an Apexi SAFC2 and a setup on it, for safety, i was wondering if it would work.

This is a long term thing just wondering if its worth keeping my ear to the ground and picking up an M90 on ebay and rebuilding it whilst i wait to pull everything else together.

Does anyone run an M90? There seem to be a few different versions, im wondering which is the best to go for.

 

[stevechumo]

You'll only use the SAFC if you'll run bigger injectors. The SAFC is used to trim down the fuel from bigger injectors, but not to increase the fuel from stock injectors. It can increase it, but it'll damage the stock injectors due to the injectors' maxed out capacity. For safety below 8 psi of boost? It's not really safer.

I've seen quite a few M90 setups. They use the long superchargers, not the short ones.

 

[EyesofThunder]

Buick installed the M90 on the 3.8L Buick V6. With poor flowing heads it made 240 hp/260 lb-ft torque, and comes in very quickly. The Eaton M90 isn't the most efficient, it isn't even a positive displacement blower, but it is low cost and is simple and well supported with pulleys down to 2.8 inch. There was a version that was 260 hp/280 lb-ft torque on the Grand Prix Comp G I believe. Used a Gen 5 M90 instead of an Gen 3 M90.

The best are the newer TVS designs, (like on the Supercharged Audi's and Blue Devil Corvette/CTS-V), but much more expensive. An older Gen 3 M90 is a solid workhorse, but at higher boost with a 3.3 inch pulley will have a lot of heat (they don't call it a Heaton for nothing). So if you can design in an intercooler. With the Buick design, the blower exit is out the bottom like older Roots blowers. The Ford 3.8L V6 (Ford Supercoupe) is out the TOP and came with a factory intercooler. And it came with a 8 rim pulley and smaller pulley than the Buick version (6 rib pulley and 3.8 inch pulley stock).

Lurk around 3800pro.com for a LOT of tech on the 3800 M90 Supercharged engines. I am top poster there, but I don't get on as much as I used to. Feel free to ask questions. Lots of nutty M90 people there.

Depending on your displacement, A M112 might do better, I wish the 3800's came with M112's, they heat the air less and are more flow.

Without computer management special for the M90 do consider exhaust and intake upgrades, and every possible attempt to keep the intake charge cool. Pinging is quick death to a blown engine. And expect only high octane fuel too, the risk on low octane is high to cause piston damage.

 

[MaccyD]

Wow, i like it, lots of info there!

So i understand that 'heatons' have problems at high boost, but the thing is, im not chasing numbers. I think at the moment with the stock management, custom manifold back exhaust and free flowing intake im probably around the 260-270bhp mark. With the M90 im hoping to see myself comfortably in the low 300s, anywhere from 310-340, which id have thought could be achieved with 6psi boost, which shouldnt see overheating problems should it?

I want to do it on a budget, not by cutting corners, but by being smart. Ive just seen a ported and rebuilt M90 on ebay for around £350 landed in the UK. I can laser cut some steel and modify the standard inlet to accept the blower. As has been mentioned, you can run at low boost (6 psi counts?) with standard management, though i imagine i will run a piggy back fuel controller (Apexi SAFC for example) for safety and then potentially will only need bigger injectors if i want a bit more boost.

Long and short of it is, im expecting it to cost around £600 in total if i budget £300 for a blower. If i chase numbers and look at M112 chargers or twin screw then we are looking at at least double id say, if not more. I dont want to put that much money into the car really. If you think id be able to get over 300bhp (which i think is pretty certain) then im happy to go ahead with it.

Thanks for the heads up on the tech contacts. Ive been thinking more recently about how pressure release valves are incorporated into the eaton chargers. It looks like plumbing them in is fairly straight forward as they dont compress so you can just run them in a closed loop. But i need to understand where these fittings are on the M90 and how i go about accessing them.