So I have a spare m90 Supercharger.....

[merlot566jka]

It flows enough air for the 6.2l, can make up to about 14psi before charge temps soar, why not?

Thats why I come to you guys today.

Ive been discussing this with some guys over on the fiero.nl forum, and what it seems, that this could be feasible.
Now I know most folks here would say "turbo is free power..etc etc" but I don't have $3000 to shell out, I have a free supercharger, impressive fabrication skills, and an 86 sub. This could be run into the category of 'sh!ts n' giggles' You know, do it just to do it. This truck is my daily beater, and I think this would just be too much fun.

With that said, lets work out the technicalities.
1. mounting, well I have 2 manifold choices, the hummer intake I have on there now, or the stock egr manifold. Either i can hack up, or fabricate an adapter plate ontop. Or I could fabricate an entirely new manifold...

2. After cooler... Will sit beneath the supercharger, made from an old oil cooler from a Saab turbo. I will use a bilge pump to move the coolant from the after cooler to a small radiator located in front of the stock radiator.

3. Fuel... As of now I have the c-code IP, stock (new) injectors. Would the c-code IP move enough fuel? I want a new one anyways, which should I aim for? (again only looking for about 12-14psi boost)

4. Belts.... I am in search of the serp belt setup off a newer 6.5l, I think I have found one. Once installed and the supercharger fab'd up, I can determine the new length of belt and any additional tensioners/idlers that I may need.

5. Tuning... Now we don't get the luxury of an ecm or any sort of control over our injection. But I wonder what the California emmisions control ecm did exactly? If I could monitor things such as tps position, egt's, coolant temp, rpm, intake temp, and mass air flow, I could have some important data to attempt to make changes to the fuel.

6. Exhaust.... I have fabricated headers in the past, so it seems reasonable to me to make some for the burb. Maybe have a couple of header flanges punched out of some 3/8 mild steel, and adapt a set of big block long tube headers. (mainly because the big block headers are made for our trucks and that the exhaust port spacing on the 6.2l is pretty close to that of a big block). Run it out to dual 3 inch pipes all the way back to some sort of muflers.

7. Intake... Lastly, the superchargers inlet will face the firewall/cowl area. I could run a 3 inch j-pipe in an almost 180* 3inch radius out from behind the supercharger and lead to the stock fresh air supply. Or run it straight into the cowl area and find some way to get a filter in there.

Any thoughts?

I know some of you are scratching your head thinking 'WHY the hell..' But I am a creative person and I like to do things that haven't been done yet. Ive shoe horned several engines that don't belong into a fiero into one, adapted several different cars ecms into one workable system, and even made intake manifolds from fiberglass. I like to go out side of the box...WAY outside of the box. Sometimes it works, sometimes its a good hour of laughter. Either way, its my hobby and my fun.

Well thanks for any help guys!

[convert2diesel]

Interesting topic. The charts I have for the M90 show it will flow up to about 525 CFM at 10PSI. Our engines in their NA configuration need about 300 (@2,800) thus this should give us a theoritical airflow increase of 75% or the possibility of about 280HP less the 40HP needed to drive the blower. Doing up a well designed dual exhaust system should pick up about 15HP on these engines giving us a figure of about 255HP, well within the range of a big bore DB2 pump (4911).

Granted I have not done any calcs re efficiency loses etc. but this should give us some bench marks. I have also assumed that the loud pedal is welded to the floor.

One of the real advantages to using the Eaton blower is the variable blow-off valve. This would allow us to run 1 or 2 PSI at around town or at cruise to clean up any volumetric inefficiencies and thus get good mileage. At 2 PSI, the M90 is only chewing up about 1.5 HP, well below the restrictive losses associated with a turbo charger. When we need it the blow-off closes and we are off to the races.

Before I get too far into this let me state that while I have done lots of work with blowers and turbos, this is the first time I have ever tried to design a system from scratch. So if my thinking on this is out of wack, please jump in. This is all about learning.

I am currently thinking along the same lines as you but it is my intent to drive the blower with a hydraulic pump and motor. I just don't have the room in the car to locate a turbo, or for that matter a blower, thus my desire to relocate the blower to somewhere else.

Lets hope this thread generates some interest, especially with those more versed in forced induction.

Bill

[merlot566jka]

Interesting topic. The charts I have for the M90 show it will flow up to about 525 CFM at 10PSI. Our engines in their NA configuration need about 300 (@2,800) thus this should give us a theoritical airflow increase of 75% or the possibility of about 280HP less the 40HP needed to drive the blower. Doing up a well designed dual exhaust system should pick up about 15HP on these engines giving us a figure of about 255HP, well within the range of a big bore DB2 pump (4911).

Granted I have not done any calcs re efficiency loses etc. but this should give us some bench marks. I have also assumed that the loud pedal is welded to the floor.

One of the real advantages to using the Eaton blower is the variable blow-off valve. This would allow us to run 1 or 2 PSI at around town or at cruise to clean up any volumetric inefficiencies and thus get good mileage. At 2 PSI, the M90 is only chewing up about 1.5 HP, well below the restrictive losses associated with a turbo charger. When we need it the blow-off closes and we are off to the races.

Before I get too far into this let me state that while I have done lots of work with blowers and turbos, this is the first time I have ever tried to design a system from scratch. So if my thinking on this is out of wack, please jump in. This is all about learning.

I am currently thinking along the same lines as you but it is my intent to drive the blower with a hydraulic pump and motor. I just don't have the room in the car to locate a turbo, or for that matter a blower, thus my desire to relocate the blower to somewhere else.

Lets hope this thread generates some interest, especially with those more versed in forced induction.

Bill


You pinged on the very questions I had, thanks!

So you say DB2 (4911) pump, Whats the slang name for it...Thats the j-code from non-turbo apps?

And how does this variable blow off valve work exactly? I have the valve on the charger, but I dont know its control source. I belive it to be a vacuum line, but here-in lies the problem. No vacuum on a diesel.

I sure hope this generates some interest. I dont see much home-brew engineering on this forum compared to the other car forums I belong to. Could be the engine and fact that its a truck based site, and the others are more performance oreinted vehicles. Lets see who is out there.....

[convert2diesel]

You pinged on the very questions I had, thanks!

So you say DB2 (4911) pump, Whats the slang name for it...Thats the j-code from non-turbo apps?

And how does this variable blow off valve work exactly? I have the valve on the charger, but I dont know its control source. I belive it to be a vacuum line, but here-in lies the problem. No vacuum on a diesel.

I sure hope this generates some interest. I dont see much home-brew engineering on this forum compared to the other car forums I belong to. Could be the engine and fact that its a truck based site, and the others are more performance oreinted vehicles. Lets see who is out there.....

The 4911 is the one used in the early turbo applications before they let Bill Gates control the pumps. Larger high pressure plungers. The original DB2s would max out at about 25HP/cyl (200 HP) while the 4911 can give you 37.5 HP/cyl. (300 HP)

The variable blow-off re-routes upper deck air back into the intake, thereby unloading the compressor. At atmospheric pressures, the Eaton only chews up about 1/2 HP. The M90s used on the gassers are set up to vent everything during low load conditions (high manifold vacuum), effectively turning the engine into a NA untill you pushed the go pedal down. This was done to increase fuel mileage while still giving you some HP when you needed it.

I see no reason not to set it up so that under low load, to maintain at least 1PSI upper deck pressure. This would get rid of any volumetric inefficiencies in the engine (read 100% efficient).

Spend some more time on this board and you will find lots of guys and girls (one can't leave out Robyn) doing some real neat things with these engines and their trucks. Check into the diesel conversion threads and spend the bucks on the full membership and get some information literally not available anywhere else, including Jim Bigely's power projects. Worth every cent of the subscription cost.

As far as information on GM diesels, there is no better place to be then right here.

Bill

[merlot566jka]

Very good info, keep it coming.

What does the 6.5td ecm do exactly with the IP? How tied in is it to the engine as far as control of the engines behavior?

is the 6.5td IP capable of more than 300hp? (300hp sounds great right now, thats like 250% increase, just outa curiosity)

I know that the stock vacuum pump on the 6.2l will provide plenty of vacuum to open the charger's bypass, but how would i controll the vacuum so I could make boost?

having 100%ve at cruising rpms sounds phenominal. With my 3.08 rear gears I bet my mpg would skyrocket!!

[arveetek]

Cool idea! Sounds like you have a lot of the basics covered.

One problem that I see and that you are aware of concerns the blow-off valve: there are no throttle plates or intake vacuum on a diesel. On a gasser, when you mash the go pedal, the throttle plates open up and the intake vacuum disappears as the engine starts to ingest as much as air as possible. When you suddenly let off the go pedal at high rpm, the throttle plates close, but the supercharger is still producing boost, but it has no place to go, so it goes out the blow-off valve (relief valve).

On a diesel, there are no throttle plates, so the engine is ingesting as much air as possible at all times. When you mash the go pedal on a diesel, all you are doing is adding fuel and advancing the timing a bit. When you let off the go pedal suddenly, the supercharger is still producing boost, but that's not a problem, as it will just push through the cylinders anyway. In fact, this could be good, as it will push out the exhaust gases and cool things down. So a blow-off valve won't be any good with a diesel.

I suppose you could set the blow-off valve for a max psi pressure...but I don't think they're designed to leak off a little pressure over a long period of time...I'm not sure.

I think you would have to experiment with pulley diameters and control the speed of the supercharger to find the right boost pressures at the right rpm.

Edit: after re-reading your posts, it sounds like you already know this...I jumped the gun in posting. Oh well.

Casey

[convert2diesel]

On a diesel, there are no throttle plates, so the engine is ingesting as much air as possible at all times. When you mash the go pedal on a diesel, all you are doing is adding fuel and advancing the timing a bit. When you let off the go pedal suddenly, the supercharger is still producing boost, but that's not a problem, as it will just push through the cylinders anyway. In fact, this could be good, as it will push out the exhaust gases and cool things down. So a blow-off valve won't be any good with a diesel.
Casey

Casey:

The reason you want a blow-off in this case is to un-load the compressor. At 10PSI and 10,000 RPM compressor speed, the blower is pulling off 40HP from the engine. While this works with the throttle mashed, it would be a serious drain on engine resources at part throttle/load. The Eaton only needs about 1.5 HP to maintain 1 PSI and that is all you really need at cruise or just popping around town. The Whipple even less. In other words, we have to come up with some method, other then compressor speed, to regulate blower out put. Thus the blow-off valve.

My thoughts on this would be to install a double reference vacuum pot with one side open to atmosphere and the other to upper deck pressure. This pot could be set to maintain 1.5 PSI upper deck pressure at all times. You could then use the vacuum regulator that was used for the 400 autos along with the vac pump to pull the blow-off shut when throttle angle went over say 75% allowing the compressor to operate at full pressure. Already spooled up, no lag just unbridled fun.

Bill

[merlot566jka]

Cool idea! Sounds like you have a lot of the basics covered.

One problem that I see and that you are aware of concerns the blow-off valve: there are no throttle plates or intake vacuum on a diesel. On a gasser, when you mash the go pedal, the throttle plates open up and the intake vacuum disappears as the engine starts to ingest as much as air as possible. When you suddenly let off the go pedal at high rpm, the throttle plates close, but the supercharger is still producing boost, but it has no place to go, so it goes out the blow-off valve (relief valve).

On a diesel, there are no throttle plates, so the engine is ingesting as much air as possible at all times. When you mash the go pedal on a diesel, all you are doing is adding fuel and advancing the timing a bit. When you let off the go pedal suddenly, the supercharger is still producing boost, but that's not a problem, as it will just push through the cylinders anyway. In fact, this could be good, as it will push out the exhaust gases and cool things down. So a blow-off valve won't be any good with a diesel.

I suppose you could set the blow-off valve for a max psi pressure...but I don't think they're designed to leak off a little pressure over a long period of time...I'm not sure.

I think you would have to experiment with pulley diameters and control the speed of the supercharger to find the right boost pressures at the right rpm.

Edit: after re-reading your posts, it sounds like you already know this...I jumped the gun in posting. Oh well.

Casey

lol, Its ok man. It never hurts to share what you know, you may tell someone that doesnt know! Lotsa people read these forums.

[merlot566jka]

Casey:

The reason you want a blow-off in this case is to un-load the compressor. At 10PSI and 10,000 RPM compressor speed, the blower is pulling off 40HP from the engine. While this works with the throttle mashed, it would be a serious drain on engine resources at part throttle/load. The Eaton only needs about 1.5 HP to maintain 1 PSI and that is all you really need at cruise or just popping around town. The Whipple even less. In other words, we have to come up with some method, other then compressor speed, to regulate blower out put. Thus the blow-off valve.

My thoughts on this would be to install a double reference vacuum pot with one side open to atmosphere and the other to upper deck pressure. This pot could be set to maintain 1.5 PSI upper deck pressure at all times. You could then use the vacuum regulator that was used for the 400 autos along with the vac pump to pull the blow-off shut when throttle angle went over say 75% allowing the compressor to operate at full pressure. Already spooled up, no lag just unbridled fun.

Bill

Could you go more into detail here? I don't know what a double reference vacuum pot is. Kinda sounds like a mechanical manometer.

Vacuum regulator for 400 autos...?? Were talking turbo 400 trans, right? And I am assuming there is a vacuum regulator. What does it regulate to and from, and is it adjustable?

thanks

[convert2diesel]

Could you go more into detail here? I don't know what a double reference vacuum pot is. Kinda sounds like a mechanical manometer.

Vacuum regulator for 400 autos...?? Were talking turbo 400 trans, right? And I am assuming there is a vacuum regulator. What does it regulate to and from, and is it adjustable?

thanks

What you would be looking for (or to fabricate) is a dual chamber pot. On one side of the diaphram you would vent it to atmosphere and that side is responsible for closing the blow-off valve. On the other side, upperdeck pressure will force the valve open. By incorporating an adjustable spring tension bolt, you could adjust this side to open at 1.5 PSI.

In the 80s, the 400 auto was used alot on these engines but as you may well know, this tranny needed a vacuum source for the modulator. They controlled this with the vacuum pump and a vacuum switch that attached to the throttle quadrant and looks like a TPS with hoses. This would have to be re-worked to function in reverse from it's intended use, but allows for venting to atmsphere or full vacuum routing for the vac. pump.

This is just one way of skinning this particular cat as there's a miriad of ways to accomplish the same task. This one just uses readily available bits and pieces.

Bill

[merlot566jka]

Another way to skin the cat....

electronic controlled bypass valve. using a servo recieving a signal from the tps's varying voltage.... .045v = full bypass and 5v = full boost.

[merlot566jka]

ok so just a rough, throw it in there and take a look.

looks like it needs to be about 5 inches max from the top of the hummer intake manifold. there is plenty of room in the back of the charger towards the firewall. the cruise control has to be moved (its ok, doesnt work anyway). i think im going to start with the stock intake manifold, find a heater core or oil cooler that will work for the water to water aftercooler.

I talked to magnuson superchargers, and they say that the bypass opens at 5'' of vacuum. Now without seeing what conditions cause 5'' of vacuum in a gas car, i dont know how much throttle this usually happens at. I have a buddy that might beable to get a datalog on his car and spit out the data.

I really think that electonic opening is going to be the best.

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[convert2diesel]

Was wondering how you were going to clear the water cross over. Looks like your in the market for a serpentine belt set-up for that engine.

While your idea of electronic control of the dump valve is elegant, I feel it is over kill. The TPS vacuum control I talked about would be perfect. 75% of throttle travel would supply vacuum to the valve. 75-100% no vacuum, valve closed, big power.

Bill

[merlot566jka]

While I like your idea, I don't fully understand it!
lol, I am more of an electronics guru. I am an electronics tech (component level) for the navy (and prior engineman/diesel tech). And all other cars I have owned have been completely ecm controlled, and I have even upgraded their ecms to newer frankenstien like ecms. Electronics are my forte, but I would really like to know another way to do it. I just dont really grasp what youre trying to say.

things are looking good, minus my starter eating sh!t today before work. Got a new one going on when im down with this post.
I have found a 94 6.5l td thats being parted out, I am looking to get its ecm, wiring harness, IP and serp belt set up. That should get me pretty far. I also found (on this board) an ecm tuning program for the 6.5l ecm. Ive been tuning obd1 cars for a few years, so it should be pretty easy to combine diesel knowledge with ecm tuning and get some promising results.

Im going to attack the planning and placement of the heat exchanger realitive to the charger and intake. I may have to have something cnc'd, as a matter of fact, im pretty certain Ill be calling a mill soon. It doesnt look like I am going to be able to weld up an aluminum peice for this project in my apt!

[Rafedial1]

looks like you got a plan.


Good luck with the project. I used to have an M90 laying around. matter of fact it was right around when I was just starting my Camaro project. shoulda kept it!!!

I will be following this build closely. I like it!

Cody

[convert2diesel]

While I like your idea, I don't fully understand it!
lol, I am more of an electronics guru. I am an electronics tech (component level) for the navy (and prior engineman/diesel tech). And all other cars I have owned have been completely ecm controlled, and I have even upgraded their ecms to newer frankenstien like ecms. Electronics are my forte, but I would really like to know another way to do it. I just dont really grasp what youre trying to say.

The TPS used on the 6.2s and the 400 tranny is the method used to emulate mainfold vacuum in a gasser. They routed the vacuum pump through the TPS to give the modulator valve in the tranny a vacuum source that varied with throttle position. By the time it got to 75% throttle angle (or there abouts...it is adjustable), vacuum had been cut-off almost entirely to the modulator valve, like stomping on your gasser, forcing a downshift. The same function could be used to control your dump valve.

Unlike gassers, diesels cannot run too lean, thus they don't have a throttle plate. In NA form, they have all the air they require to operate. Power is modulated by fuel delivery. Less fuel=less power. You make power in a diesel by adding fuel. If you add too much fuel and the mixture runs out of air, then all you do is create lots of black smoke and dangerous EGTs. There is a finite point where more fuel has no effect on power output. Adding air allows you to add more fuel and subsequently more power.

The trick to getting power out of a diesel is adding both fuel and air, thus the blower. In all likelyhood, your configuration would not need any more air at the lower power levels so you would only need boost above a certain point. Remember you can't over air a diesel so the boost levels are un-important up to a point. Its unlikely you will ever reach that point with a M90.

More importantly, boost pressure will only need two settings. In normal driving, the blower is just along for the ride, venting most if not all of it's output. When you put the load pedal down, the blower is now active and pressure is controlled entirely by RPM.

As you intend on installing an electronic pump and ECM, you will have the ability to finely adjust fuel rate and timing to suit the upperdeck pressure, and as a result, maximize your power output.

Prepare yourself for a steep learning curve as the fuel and advance maps, comparative tables, component references and function perameters differ greatly from any gasser you have encountered, especially the advance tables. Things can go wrong in a big hurry when you are running a boosted engine with a 22:1 compression ratio (increased proportionally with boost pressure) and no spark plugs. Knock sensors don't work on diesels :D so the ECM depends on its O2 sensors and TPS for advance information.

Good luck on your project.

Bill

[merlot566jka]

Brilliant. I will def do that. I may have to rig some sort of linkage to use the vacuum tps, because right now I have the tps for my 700r4, and the 6.5td has one also. Shouldnt be a big issue at all.

Something else that was running through my mind was cruising rpm. Right now the truck has to downshift to make it over a mild hill. Its embarrassingly weak. Perhaps the sensor could be adjusted to allow just a little bit of boost at low 'throttle' angle? Just enough to give me some more usable power where I need it.

I agree with you, tuning will be a real challenge coming from the gasser tuning world. I will start conservitive and look for inputs from other members who have tuned thiers themselves. I am pretty confident though.
What do you mean knock sensors wont work? hahaha:D

Well 5 hrs of replacing the starter, wiring, HID headlights and a few other things, Im too tired to work on the intake stuff. Thatll be a weekend deal.

Thanks for all the help, its good to get things from other people whose ideas are very creative and worthwhile.

[Kcustom73]

This stuff is great. I've always been more of a fan of superchargers then turbo's (personal preference). Please keep us informed on your project. It's something I would love to do in my 75 Toyota FJ40 Landcruiser project. I would love the power band of the supercharger when I start off-roading the truck but would also be great when I daily drive it.

Bill, wow, it will be great to have a local guy too talk shop with who has this much knowledge and maybe turn a wrench with ;). I will get in touch with you soon to talk local shops.