Turbo alternative
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Posting Guru
Joined: Aug 2006
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From: Kent WA
Turbo alternative
Has anyone installed one of those belt-driven superchargers like a vortech?y Here's the type I'm talking about
http://cgi.ebay.com/ebaymotors/Power...21789774QQrdZ1
Seems like with the right pulley sizes it would provide as much boost as a turbo, without near the complicated exhaust plumbing. What would be the drawbacks? I know that (in theory) a turbo is driven by "wasted" energy from the exhaust flow, but in the real world anything in the flow path of the exhaust HAS to restrict the flow somewhat - which has to rob power. Especially on a diesel where free airflow is such a critical component of making more power. There's no free lunch.
So why wouldn't this work as well as a turbo? Or would it?
http://cgi.ebay.com/ebaymotors/Power...21789774QQrdZ1
Seems like with the right pulley sizes it would provide as much boost as a turbo, without near the complicated exhaust plumbing. What would be the drawbacks? I know that (in theory) a turbo is driven by "wasted" energy from the exhaust flow, but in the real world anything in the flow path of the exhaust HAS to restrict the flow somewhat - which has to rob power. Especially on a diesel where free airflow is such a critical component of making more power. There's no free lunch.
So why wouldn't this work as well as a turbo? Or would it?
Fleet Mechanic
Joined: May 2005
Posts: 1,575
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From: Puyallup, WA
There have been many supercharged diesels over the years. But, the current stste of the art in forced induction, at least in diesels, is the Turbo. With a supercharger you give up horsepower to make horsepower. IE if you loose say 30 - 50 hp compressing air in the supercharger, then that is not hp that you have available at the rear wheels to drive the truck.
A supercharger can however provide more snappy acceleration as there is no lag. Much like a current state of the art dual turbo setup.
There have also been marine diesels set up with both a supercharger and a turbo. Trying to get around the lag issue, componded in the marine environment by having "only" one gear ratio, even though there is some slippage in the fluid medium.
David
A supercharger can however provide more snappy acceleration as there is no lag. Much like a current state of the art dual turbo setup.
There have also been marine diesels set up with both a supercharger and a turbo. Trying to get around the lag issue, componded in the marine environment by having "only" one gear ratio, even though there is some slippage in the fluid medium.
David
Post Fiend
Joined: Nov 2003
Posts: 21,285
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From: Nutter Fort, WV
I just did a searck of Powerdyne and did come up with the BD-11A makes 12 PSI max boost on a 3.8 liter Mustang at what ever RPM they turn.
That unit would be lacking CFM on a 6.9 that only turns 3300 RPM.
Also I was checking out some of the supercharger kits, turbo kits cost about 1/2 as much.
There is nothing wrong with superchargers, you just need to find one that is the right size to work right. The amount of work required to get the drive belts and plumbing right will probably be more than what is required to install a turbo because several people manufacture IDI specific turbo kits already.
Now I wonder if I should turbocharge the supercharger, or should I supercharge the turbocharger?
That unit would be lacking CFM on a 6.9 that only turns 3300 RPM.
Also I was checking out some of the supercharger kits, turbo kits cost about 1/2 as much.
There is nothing wrong with superchargers, you just need to find one that is the right size to work right. The amount of work required to get the drive belts and plumbing right will probably be more than what is required to install a turbo because several people manufacture IDI specific turbo kits already.
Now I wonder if I should turbocharge the supercharger, or should I supercharge the turbocharger?
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From: Kent WA
Yeah, I was wondering about the CFM issue. But if you put the right pulleys on one you could up the CFM to meet the demand. I think I read on here somewhere that the 6.9 moves 400 CFM at 3300 RPMs. Since the diese's redline at about half the RPMs of a gasser, it shouldn't be too hard to put a larger drive and smaller driven pulley on and double the speed - and therefore CFMs of one of those pumps.
I know the kits are more expensive than a turbo kit, but I'd be inclined to see if I might buy a used unit and build the rest of it myself. Doing the same with a turbo would be a lot more difficult.
It'll be a while. Gotta get 'er running right and do the basic intake & exhaust mods first to see whether I even feel the need to do forced induction. Just looking ahead and exploring options....
I know the kits are more expensive than a turbo kit, but I'd be inclined to see if I might buy a used unit and build the rest of it myself. Doing the same with a turbo would be a lot more difficult.
It'll be a while. Gotta get 'er running right and do the basic intake & exhaust mods first to see whether I even feel the need to do forced induction. Just looking ahead and exploring options....
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