icanfixall
Official GMM hand model
Talk with Huff on the other site. He is the turbo expert around these parts.
supercharged 7.3?
- Thread starter LCAM-01XA
- Start date
Ironman03R
Full Access Member
Detroits had superchargers w/ turbos. I'm not sure on how they went together, and the old Detroits were 2stroke, but it might be possible. Probibly cost big $$$ but it would be cool!
seawalkersee
It needs a turbo...
The idea of twin charging is not new. As stated before, there are diesels that have done in. AFAIK they were two stroke engines (but I do not know what that means). The gasoline market is now starting to twin charge vehicles now. I can explain it but it will not be 100% correct if I put it to where it makes sence. You spin a blower fast enough, the air will cavitate. Now there you have your lower end boost. You add a turbo that will take effect at higher RPMs and you can actually improve the boost because the air coming in is already under compression. It is also cooler than high boost from the SC because it is a lower boost level. It depends on the style blower used for the outcome after that. The eaton style blowers actually do not smash the air like some other superchargers. They push the air through the case with a paddling effect. With positive displacement on the inlet side, you can actually push air past the rotors where as in high boost levels with the same SC, the boost will bleed back through the case heating the incoming air. Make sence? There is a company doing it for the new mustang and I BELIEVE the 03-4 cobras. If you want, I will try to find a link of one of the Aussies who did it to a Toyota or some kind of import.
Chris
Chris
No but you can feed the supercharger into the turbo....kinda like compound turbo except faster cause it's belt driven then exhaust under load!
detroit diesels were made this way--8vt92--turbo and supercharger both--supercharger for down low--turbo as the r's came up---theyd hummm!!!!!!!!!
rumdumb
Registered User
Detroits blowers are not clutched they simlpy there to provide positive air box pressure for the intake. Detroits were an open crankcase design for a two stroke with exhast valves and ports for intakes at least on 53 ,71,92,110, 149 series the blower for the most part was to supply positive air pressure in the air box . Some were not even bypassed straight turbo into the blower . Turbos were added to further boost air box thus intake pressure or provide boost as thought about on a four stroke / cycle diesel. Now EMD's Detroits bigger cousin had some clutched gear driven centrifical blowers and make the hair on your neck stand up when they came up to enough rpms for the centrificals to engage .
BigRigTech
Diesel junky
You can't have a 2 stroke Detroit without the blower - the blower was not there to make boost, it's job is to scavange the cylinders...Remember the 4 stroke power sequence....Intake, compression, power exhaust....A 2 stroke only has to strokes....Compression and power - hence the need for a blower to push the exhaust out and refill the cylinder with fresh air...Probably very little or no boost effect from the blower and that's why they added turbo's to it....Buy a turbo, less rpm - more boost and better power per dollar.
RKOCH
Fellow Oil Burner
I saw a 7.3L @ a truck pull last year running a paxton and it feed a Large turbo. He said it worked well because the turbo was so big it had a lot of lag but the paxton totally eliminated the lag because it is a pos displacment induction system. It was all custom machined pullys and brackets and looked good. Had propane and water injection also. He could move that sled like no tommarow.
93turbo_animal
Registered User
See that is what is confusing me. Why when you triple the rpms with a blower does the boost go up more. That to me makes no sense. Why wouldnt it be linear, its running off the crank, so as rpm's go up the blower speed goes up. Why would it push more air up top (more efficiency maybe) that what it should.
And I would say your EGT thinking is false. I can see it easily with my truck. If I lug it with no boost (say 1300rpm's in 4th gear), I'll be roaling the coal and my EGT's will go up to 1000*. Now take for instance me going down the road, say 2000rpm's 3psi of boost and 600* EGT's, if I step on it it will take me almost triple the time to get to 1000* compared to lugging it, and this is with hardly any smoke output (because I would be at almost 8psi boost).
because the supercharger is not a 1:1 ratio its over that so the more RPMs the farther off it gets then you have to figure in efficiency. I don't see any reason why a supercharger won't work just think of it as a non wastegated turbo if you can get it pulleied right so the max boost was at what you wanted for max RPMs be it 3000 or2750 or where ever you shift at when pulling then no need for a blow off valve or anything . I also don't think egt's will be a concern just like a nonwastegated turbo they don't build max boost until max rpms under load. Yes the heat does make a difference in driving the turbo but with the supercharger he should be able to back off the throttle to let the egts come down some with out loosing any boost if he doesn't loose any rpms besides the amount of time where that could be a concern is so little why worry about it
aussiedave
TOKEN AUSSIE
check this out
i know its not a 7.3 but it looks interesting
http://flashoffroad.com/Diesel/supercharger/supercharge.html
i know its not a 7.3 but it looks interesting
http://flashoffroad.com/Diesel/supercharger/supercharge.html
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seawalkersee
It needs a turbo...
Well, I can tell you this. With the exception of the hardware, pressure is pressure. Sure, that sounds simple, but no matter how it gets in, belt or exhaust, the results will be the same. With a SC like the one in the link, you will also want a bypass valve to cut the boost back to the intake side when you let off of the throttle. This is done in gasoline vehicles to eliminate idle pulsation and to keep the air from reverberating when the throttle plates close after full throttle. On the IDI, I think this would need to be done to keep it from going lean, WAY LEAN when you let off of the throttle. I may try this the more I think of it. I could throw one of my spares on the thing and call it a day. Anyone have any good turbo links that tell you what you have to upgerade the fuel system?
Chris
Chris
sootman73
Registered User
tru you dont have to worry about a diesel going too lean. i doubt it would lean out too much to kill the motor liek you do when you throw too much nitrous in it. plus it would help to cool it off quicker wouldn't it?
seawalkersee
It needs a turbo...
I do not know what the effect will be with no bypass valve. I wonder if it will continue to stay at the RPM of which you let off of the throttle. I do not think it will be a problem, but it may cause a problem of pulsation at idle. I do not know, I do not know, I do not know. What I do know is that you can run more boost off of smaller turbo's on a diesel than you can on a gas engine. So if I am looking at this correctly, I do not need a huge SC to make it pump a small amount of boost. I am going to look at this further when I get the fan off of the front of the engine.
Chris
Chris
93turbo_animal
Registered User
you can't lean out a diesel the way you slow down is to reduce the fuel but all the air it can flow always goes thru the motor. So if you let off the throttle no fuel no run so the motor would drop back to idle it would just have a little more air going thru for a few seconds. You have to look at CFM's your motor has a lot more cubes but turns about half the rpms so it kinda equals out. So yes you don't need a big charger to get your boost but it does need to turn the right amount of RPM's
