actually twin m90s. I just need some info about how to size things correctly. As in airflow, boost, and the like.

I want to use one per bank, max rpm on the engine is 3800rpm. Its mechanically limited in the injection pump.

will these move enough air?

what kind of boost am I looking at, assuming I match the crank pulley to the same as the 3800's (approx. 7in dia.)

If its not too much trouble, can someone show me some math to back up the sizing? Turbos have flow maps, as i am sure the superchargers do, but they have to be really different. I mean they dont work the same at all.

Diesels dont have a throttle blade, how would the bypass from the supercharger work? How does it work in the first place? would I even need it?

I am only looking for about 8psi, the engine is 379 cu.in., max rpm 3800, and the engine has an overall low VE.

all the extra stuff that will go into this is already planned out and doesnt really need to be covered here (i.e. fuel, mounting, intake manifold, cooling, belts and routing etc)

thanks folks

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i gave away my fiero to americasfuture2k. 6 engines and thousands of dollars were put into it in two years. hes enjoying it, im missing it.

M90 moves 90 ci of air per revolution. Two will move 180 ci. In one revolution, the 379 cid diesel will move 189 ci of VOLUME. I'd guess the VE of that engine to be 50% at best, so a 1:1 drive ratio would probably give you boost.

There are LOTS of pulley options for M90's. Start with the stock drive ratio and see where you need to go from there. It's not like you can blow the thing up from running it lean...

What were the stock power and torque ratings of the engine?

The M90 was used on 240 HP engines stock, and goes up over 300 WHP modified. Do you really need two? Would ONE larger blower work? You should be able to pick up a 112 from a Cobra cheap.

Lemme think about the bypass for a bit... Need to figure how that interacts with a diesel.

[This message has been edited by Will (edited 03-08-2009).]

The only reason a bypass or blow-off valve is present on a Petrol motor is that when you close the throttle the pressure could force it's way into the motor past the throttle blade or pop off hoses. Because there is no throttle blade on a diesel there is no need for a bypass. More over there's no way to operate it because it never has vacuum .

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Red 86GT 4 Speed

Bypass is in no way similar to a blowoff valve, as it all happens inside of the throttle blade and does nothing to protect the blade, but it does prevent compressor surge.

Will, there are a bunch of non street use diesels out there that use turbos with no wastegates even, but you should still need to use the bypass on any motor, as all you have to control surge at idle type situations, where very low airflow is used and the blower is still spinning fast, moving more air than the motor needs.

1 m90 blower should be enough, it will flow roughly 40lb/m of air at reasonable efficiency, its flow ratings are slightly lower than the passenger truck turbos, like the 5.9. I know commonly the 5.9's use hardly 75% of the h1c turbo they used too.

quote Originally posted by Will: M90 moves 90 ci of air per revolution. Two will move 180 ci. In one revolution, the 379 cid diesel will move 189 ci of VOLUME. I'd guess the VE of that engine to be 50% at best, so a 1:1 drive ratio would probably give you boost. There are LOTS of pulley options for M90's. Start with the stock drive ratio and see where you need to go from there. It's not like you can blow the thing up from running it lean... What were the stock power and torque ratings of the engine? The M90 was used on 240 HP engines stock, and goes up over 300 WHP modified. Do you really need two? Would ONE larger blower work? You should be able to pick up a 112 from a Cobra cheap. Lemme think about the bypass for a bit... Need to figure how that interacts with a diesel.

Stock power 130-165 and torque 240-280. Depends on years and engine codes, but really low hp & trq!

I was thinking twins cause I have an m90 just sitting around, and didn't know if the m112 would move enough air by its self.


Since there is no throttle, the engine tries to move 100% of its volume from idle to redline. But per rotation its only half of the displacement. You say 1:1 drive ratio? Stock 3800 drive ratio is like 2:1 (sc to engine) wouldn't I want to start there and possibly go to a higher ratio? Or are you saying since im using twins, I should start on the lower ratio being that they are only working on about 3.1L of volume.

Yup, going lean wont do anything, just lower the rpms. Diesels are kinda more fun than gassers as far as that goes!

damnit, i wanted that M90 to slap on the aveo. your lucky i didnt find it in storage.

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First LX9 Fiero GT, 1987
If you can't fix it with a hammer, you've got an electrical problem
Fiero's are people too. We pay just as much attention to them, if not more than our loved ones
screw paying those bastards. im not going to become rich by paying for things.....
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ill sell it to ya for $500 :P

The m90 is really similar to the h1c in terms of flow....

the problem I see now is pressure... the M90 is horrid for efficiency past 14psi... I know for a fact you wont have any issues running the flow of the m90, or even a m62 to max out the pressure ratio requirements.

You may actually be required to run 2 m90's, but in a sequential boost configuration, where you could see PSI over 14.

quote Originally posted by darkhorizon: The m90 is really similar to the h1c in terms of flow.... the problem I see now is pressure... the M90 is horrid for efficiency past 14psi... I know for a fact you wont have any issues running the flow of the m90, or even a m62 to max out the pressure ratio requirements. You may actually be required to run 2 m90's, but in a sequential boost configuration, where you could see PSI over 14.

Well I was aiming for 8-10 psi to start with. Maybe more later...

Included in my planning is an after-cooler under the supercharger, I know this will help the charge temps, but I doubt it will correct any of the sc's inefficiency.


So basically 1 m90 will flow enough air for this engine, (at the stock 2.06:1 ratio) and compress enough air to hit about 14psi before charge temps sky rocket and things just go south??


I want to make a note, my CR is 23.1:1, thought that may help anyone doing some thinking here....

[This message has been edited by merlot566jka (edited 03-09-2009).]

Which diesel motor is this?
you may have some better luck looking aorund for marine diesel applications and engine sites. Most all of the new gen marin diesels are at least turbo inter cooled, and there are a couple that have SC and turbo setups for full rpm coverage.
The unfortunate part is most come that way, so I am not sure how much info there is for after market modification.
Some of the mfg sites do have very detailed graphics for power and fuel, not sure if they cover airflow, never really though of looking for that. A word of warning tho, if this was an automotive base diesel, like the cummins type used in the dodge trucks, they do not hold up well in that trim, for conversion to higher duty marine use, the pistons all need tobe changed out to handle the extra compression and strain.
just a thought for some sources for info, may find a site that will have true experience with diesel mods.

quote Originally posted by tjm4fun: Which diesel motor is this? you may have some better luck looking aorund for marine diesel applications and engine sites. Most all of the new gen marin diesels are at least turbo inter cooled, and there are a couple that have SC and turbo setups for full rpm coverage. The unfortunate part is most come that way, so I am not sure how much info there is for after market modification. Some of the mfg sites do have very detailed graphics for power and fuel, not sure if they cover airflow, never really though of looking for that. A word of warning tho, if this was an automotive base diesel, like the cummins type used in the dodge trucks, they do not hold up well in that trim, for conversion to higher duty marine use, the pistons all need tobe changed out to handle the extra compression and strain. just a thought for some sources for info, may find a site that will have true experience with diesel mods.

its the stock 1986 6.2 diesel that came in the chevy burbans (tanks). im sure jonnys idea is to use what he has on hand without spending gobs of money on other stuff.

------------------
First LX9 Fiero GT, 1987
If you can't fix it with a hammer, you've got an electrical problem
Fiero's are people too. We pay just as much attention to them, if not more than our loved ones
screw paying those bastards. im not going to become rich by paying for things.....
My Fiero Fuel Economy
Videos of My GT
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MPG Display for OBD I

This is the GM (detroit diesel) 6.2l. Its in an 86 suburban. It is naturally aspirated, doesn't like more than 21lbs of boost and is a real dog of an engine with out forced induction.
Banks makes a turbo kit for it, and it actually improves gas mileage and provides a 60% increase of power at 8psi.

A few of the marine apps have been supercharged, and many of the hummer's have been supercharged with whipple superchargers. As far as I understand, Whipple doesn't make the kit anymore, and I have yet to contact them about the kit they had for information. I dont think this engine has ever been sequentially charged yet.
As far as after market, there are several forums I belong to, but they arent really into the same kind of mods I am looking for. They are mostly into repair, function and offroad.

This is a mil-spec engine and I have a good amount of info for the engine. But as far as performance data, its very limited.

As far as the application, they offer some lower compression pistons, main web girdles, different types of pre-cups, turbo injectors and high flow injection pumps. I don't intend to get to a level where those are required. Not yet anyways. Boost is like crack, I may need more later

As an Mechanic in the Army, I've seen these develop very lound rod knock in there measly 150hp output, of course these where all on 'rebuilt units' that we have recently received. Have you looked into building the bottom end of the motor up?

looked into it, and at the price of almost $2000 for a rebuild, once it grenades, its done. I'll look into a duramax or something extremely retarded to put in there (can we say a twin blown marine 12v71?)

They have been known to develop some knock, but it has mostly been related to crank warp-age due to a failed dampener/harmonic balancer. But rod knock? that sounds like someone tried to grind the crank, they really cant be ground.

Do you work in the motor pool? can you get your hands on any extra cucv or humvv parts?

quote Originally posted by merlot566jka: This is the GM (detroit diesel) 6.2l. Its in an 86 suburban. It is naturally aspirated, doesn't like more than 21lbs of boost and is a real dog of an engine with out forced induction. Banks makes a turbo kit for it, and it actually improves gas mileage and provides a 60% increase of power at 8psi. A few of the marine apps have been supercharged, and many of the hummer's have been supercharged with whipple superchargers. As far as I understand, Whipple doesn't make the kit anymore, and I have yet to contact them about the kit they had for information. I dont think this engine has ever been sequentially charged yet. As far as after market, there are several forums I belong to, but they arent really into the same kind of mods I am looking for. They are mostly into repair, function and offroad. This is a mil-spec engine and I have a good amount of info for the engine. But as far as performance data, its very limited. As far as the application, they offer some lower compression pistons, main web girdles, different types of pre-cups, turbo injectors and high flow injection pumps. I don't intend to get to a level where those are required. Not yet anyways. Boost is like crack, I may need more later

Based on this information, bolt on a M90 and have fun... Try to do some type of intercooling, air/air works fairly well if you want to keep it simple.

quote Originally posted by darkhorizon: Based on this information, bolt on a M90 and have fun... Try to do some type of intercooling, air/air works fairly well if you want to keep it simple.

My idea is to use an aftercooler that sits beneath the charger. a water to air type, and a small radiator in front of my stock radiator. And a bilge pump to move the coolant. To me, this sounds easier to package.

I should have some results soon. I will reply to this thread with pics of progress as it happens.

[This message has been edited by merlot566jka (edited 03-09-2009).]

quote Originally posted by merlot566jka: Stock power 130-165 and torque 240-280. Depends on years and engine codes, but really low hp & trq! I was thinking twins cause I have an m90 just sitting around, and didn't know if the m112 would move enough air by its self.

quote Originally posted by merlot566jka: I'd love to bite on to the idea that 1 m90 would be sufficient, but really? Its intended for a gas 3.8l that spins up to 6k rpm. I'm working with an engine that's almost double that size yet doesn't spin as high... I dunno, you could be right, I just want more info.

The naturally aspirated 3800 SII's make 200 HP, so they flow a lot more air than your diesel, yet they carry a single M90 when supercharged. One will be just fine.

You'll still need the bypass in unthrottled operation on a diesel. The drive ratio is what determines boost. The blower's going to keep trying to make boost at idle. This will result in a large parasitic loss from the blower as well as unecessary heating of the intake charge and stress on the engine in terms of continuous high cylinder pressure.

This really intrigues me, I have an '83 pickup with the 6.2 diesel, and know a guy with a used M112 from an '03 Cobra Mustang. Mine makes 130 hp @ 3600 rpm, and 240 ft-lbs, but gets 24 mpg empty without being lowered, with a shell on it, with no airdam, and with a 3.42:1 axle and 235/75R15 tires, and the overdrive not working. I haven't checked mileage since replacing the 700R-4 and airdam. One thing I do know, the stock Stanadyne injection pump will allow you to get to 5000 rpm IF you know how to adjust it. I have the whole story on this, filed away.
If you want a serious 6.2, headers do exist.

The stock c-code pump will net those rpms, but wont really flow the fuel. the db2 4911 pump is what ill need.

I got 26mpg in an 86 burb with the 700r4, and 3.08 gears and 265/75r15....untill i hit the mountains and hills, milage dropped to about 14mpg! thats why im looking for some boost. And probably bumping the gears up to 3.42.
You have the info how to change the governer settings? Ive already turned the fuel screw up about 1/8th of a turn and got enough fuel to give me some black smoke at wot. with my open aircleaner its just right.

yeah, i found those headers, theyre short tube, ceramic coated and from stories ive heard from folks over at the diesel page, the guy who makes them is horrible for customer service and the headers dont fit right. and they warped in short order. Id rather make my own.


Will, about the bypass, how is it controlled? vacuum I assume. Since a diesel doesnt make any vacuum, what are my options to control it? if i could make like 1-2 psi at cruise part throttle, id have like 100%ve!! and the parasitic loss wouldnt kill all hopes either. Would i be looking at some sort of boost controller?

jonny, arent you on duty today? is this what AT's do on the ship? its what i do on base

------------------
First LX9 Fiero GT, 1987
If you can't fix it with a hammer, you've got an electrical problem
Fiero's are people too. We pay just as much attention to them, if not more than our loved ones
screw paying those bastards. im not going to become rich by paying for things.....
My Fiero Fuel Economy
Videos of My GT
Google Videos of My GT
MPG Display for OBD I

The BBV works sorta like a wastegate, to the point where it uses a spring to default it to a close position. The vacuum on a gas motor pulls it open to allow for it to bypass.

without vacumn before the rotor blades, there really is no way for you to open it out of boost... So you need some way of tellng the valve that you want to make boost, and not bypass.....

If I was to try to make this (not knowing a darn thing about diesels) I would have it on a switch via a vacuum source for testing....

I have always been a fan of air/air cooling... but I just picked up bolts for my air/water setup going into my fiero..... I would try to do air/air if at all possible, as it would be much simpler for a street car.

[This message has been edited by darkhorizon (edited 03-09-2009).]

Ok, if it's really a detroit diesel, the marine types are almost unkillable. But that is sorta a loose term.
in your app, I don;t really think you will need much in the way of bypass, as the motor will outrun the sc at high rpm, which is why they usually turbo them. All the marine ones are turbo'd, which just use internal bypass to shut them down. for a quick let off on throttle tho, you could likely just rig a simple blow off to limit boost and rig it to your throttle linkage.
To get any decent power and efficiency you need large exhausts on them with no restrictions. typical 300 hp ones run 10" final outputs, and are deafening loud while cruising, not really practical in a car. they love alot of air in and out to get power, true of any diesel motor, moreso for the detroits.

.

quote in your app, I don;t really think you will need much in the way of bypass, as the motor will outrun the sc at high rpm,

Technically it wouldnt if the drive ratio is configured correctly.

quote Originally posted by darkhorizon: The BBV works sorta like a wastegate, to the point where it uses a spring to default it to a close position. The vacuum on a gas motor pulls it open to allow for it to bypass. without vacumn before the rotor blades, there really is no way for you to open it out of boost... So you need some way of tellng the valve that you want to make boost, and not bypass..... If I was to try to make this (not knowing a darn thing about diesels) I would have it on a switch via a vacuum source for testing.... I have always been a fan of air/air cooling... but I just picked up bolts for my air/water setup going into my fiero..... I would try to do air/air if at all possible, as it would be much simpler for a street car.

Interesting, OK, and I dont have the tools to route pipes everywhere....

quote Originally posted by tjm4fun: Ok, if it's really a detroit diesel, the marine types are almost unkillable. But that is sorta a loose term. in your app, I don;t really think you will need much in the way of bypass, as the motor will outrun the sc at high rpm, which is why they usually turbo them. All the marine ones are turbo'd, which just use internal bypass to shut them down. for a quick let off on throttle tho, you could likely just rig a simple blow off to limit boost and rig it to your throttle linkage. To get any decent power and efficiency you need large exhausts on them with no restrictions. typical 300 hp ones run 10" final outputs, and are deafening loud while cruising, not really practical in a car. they love alot of air in and out to get power, true of any diesel motor, moreso for the detroits.

Designed by detroit as a light-medium duty truck engine. It is not a marine or industrial engine (not indestructible!)
The turbos most put on these cannot flow what the m90 does. The engine redlines at 3800 and has a ve like a retard in a spelling be (yeah, kinda not doing so good) like 50-65%. So this charger will out run this engine stock, and up to about 14psi. Even then I wont beable to get enough fuel to support anything above 12psi.
Thats an interesting way to use a blow off valve, ill keep it in mind. that may become very handy.
10'' final outputs....huh?
I was a diesel mechanic for the navy for years, I can vouch for how loud the detroits actually are. (and to be 100% honest, I would kill for the sound of a 12v71 twin blown diesel romping away in my engine bay.)

quote Originally posted by merlot566jka: looked into it, and at the price of almost $2000 for a rebuild, once it grenades, its done. I'll look into a duramax or something extremely retarded to put in there (can we say a twin blown marine 12v71?) They have been known to develop some knock, but it has mostly been related to crank warp-age due to a failed dampener/harmonic balancer. But rod knock? that sounds like someone tried to grind the crank, they really cant be ground. Do you work in the motor pool? can you get your hands on any extra cucv or humvv parts?

Yea, I work in the motor pool, and if this was 6 months ago, I would be swimming in free cucv parts and tools, but now since the army is 'rebuilt' its wound pretty tight. We have two cucv's that are off the books and are eating parts pretty hard. SInce I'm only a weekend warrior snaking parts would be pretty hard.

gotcha. I was looking for the CDR valve. I did an individual augmentation (also called IA, TAD, TDY, farmed out, etc etc) in Alaska in 2006 and I didnt have a 6.2l back then, and I was making weekly trips to the motor pool and picking up pallets of DRMO stuff. One was boxes of cdr valves, and damned my luck, mine is stuck right now.

quote Originally posted by tjm4fun: in your app, I don;t really think you will need much in the way of bypass, as the motor will outrun the sc at high rpm

Diesel VE falls off dramatically at high RPM; blower VE does not. The blower will build higher boost at higher RPM.

Will, thats exactly what I want, electronic control. but Ill need some more info to make good decisions of when to kick it on. Like boost gauge, rpm etc etc. I have a non-ecm truck. would be nice if i could find an ecm to put in there that will just monitor things and not worry about fuel and spark....

quote Originally posted by merlot566jka: Will, thats exactly what I want, electronic control. but Ill need some more info to make good decisions of when to kick it on. Like boost gauge, rpm etc etc. I have a non-ecm truck. would be nice if i could find an ecm to put in there that will just monitor things and not worry about fuel and spark....

Haha... that's the RIGHT attitude... turn a non-ECM car into an ECM car. Doing things the other way is soooo backwards.

But in this case, getting the bypass to be correctly controlled via a computer will probably be tough. I'd suggest simply using a throttle switch (such as used for N2O apps) to operate it. The bypass should stay open until you go to WOT or something close to it. That will take some creative calibration of the injection pump, however.

The later 6.5l had an ecm and electronicly controlled IP. perhaps a look into thier capability is warented here.

As far as having it only make boost at WOT using a nitrous or simliar micro-switch sounds good, untill like youve said, IP tuning. It would work best to have it make boost at all times varying with rpm and low to no boost at idle/part throttle.

At idle, i would want 0 boost, or full bypass. but at like 1600-1800 rpm part throttle id want some boost, cause thats my cruise rpm at 70ish mph. that would decrease my down shifting to make it up a hill!

IDEA....use varying tps voltage to control a servo attached to the bypass. .045v =full bypass, 5v = full boost. My truck has a tps for trans control.....

[This message has been edited by merlot566jka (edited 03-10-2009).]

quote use varying tps voltage to control a servo attached to the bypass. .045v =full bypass, 5v = full boost. My truck has a tps for trans control.....

That seems to be the key here.... but the bbv is not nearly as linear as a wastegate would be, so keep that in mind....

I would do it more so as a on/off deal, and just flutter it for part boost... it would be much easier to do this with a off the shelf electronic boost controller, that was enabled with a switch.

quote Originally posted by merlot566jka: The later 6.5l had an ecm and electronicly controlled IP. perhaps a look into thier capability is warented here. As far as having it only make boost at WOT using a nitrous or simliar micro-switch sounds good, untill like youve said, IP tuning. It would work best to have it make boost at all times varying with rpm and low to no boost at idle/part throttle. At idle, i would want 0 boost, or full bypass. but at like 1600-1800 rpm part throttle id want some boost, cause thats my cruise rpm at 70ish mph. that would decrease my down shifting to make it up a hill! IDEA....use varying tps voltage to control a servo attached to the bypass. .045v =full bypass, 5v = full boost. My truck has a tps for trans control.....

You want to stay OUT of boost in cruise to keep your fuel mileage up.
Can the electronic injection pump be retrofit to your engine?
If the ECM that controls the electronic injection pump has been hacked, that would ABSOLUTELY be the way to go with your control system.

www.tunercat.com
www.tunerpro.net

[This message has been edited by Will (edited 03-10-2009).]

Darkhorizon,

Not as linear? Meaning partial opening of the bbv does not equal partial boost....?
Fluttering a valve with some pressure on one side of it may be tricky for a dc servo.

Tell me more about how these off the shelf electronic boost controlers work, or where I minght find some info on them.

Will,

Now this is where things are wierd.....

The 6.2l actuall IMPROVES gas mileage when boost is applied at cruise. Something about diesels making more trq as a load is applied?? (I would say more, but I feel a little retarded when it comes to how exactly making more power saves fuel. It can be read about on the banks website under the gm/6.2l sidewinder kit. I just dont want to sound like an idiot, cause I dont understand fully.)

Its been proven on the Banks turbo kit increases fuel economy by 10% at cruise, and I believe even better mpgs while towing (towing vs towing turbo'd). While others who have installed the kit have seen up to 2.2mpg increase AFTER installing a turbo, some say thier mpgs went unchanged. But no one has ever said it went down. Odd, I know. Instead of researching it, I just accepted it and went after some boost....

The 6.5l pump is a direct bolt in. No retrofitting. (The 6.2l and 6.5l can be compared to the stock fiero V6 and the 94 camaro V6...in that they are the same basic engine, with a few upgrades like computer control, injection control, dis...bla bla bla)

I am working on the angle of the hacked ecm. As of 2006 It looks like some one hacked it and offered tuning sultions for both obd1 and obd2. But with a price of $895 and $1300 respectivly, I feel that it has to have been done on an end user level somewhere.
I am at work (in the navy, on an aircraft carrier, 24hr duty today) and the internet is painfully slow. When I get home tomorrow I should beable to find some more info on the ecm. I do belive it will be a key player here. Whether it be obd1 or obd2.

[This message has been edited by merlot566jka (edited 03-10-2009).]

so much diesel talk. im lost. ill poke my head around in my 3500 n/a GAS powered fiero.
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still lost. ill just dik around with the wiring...

------------------
First LX9 Fiero GT, 1987
If you can't fix it with a hammer, you've got an electrical problem
Fiero's are people too. We pay just as much attention to them, if not more than our loved ones
screw paying those bastards. im not going to become rich by paying for things.....
My Fiero Fuel Economy
Videos of My GT
Google Videos of My GT
MPG Display for OBD I