Does anybody know how to convert a turbo to "wet" use. i.e.- the turbo is used downstream of the carburator and compresses an air/fuel mixture instead of just air. I believe this is the way most turbo cars from the late 70's to early 80's were setup. Can an air only turbo be converted or would I need a special turbo?? TIA
Well, laugh if you will but this is what I've been thinking about.
1)buy a late 70's big block Trans Am with blown engine 2)buy a mid 70's Cadillac 501 engine and have it rebuilt and balanced with forged rods, forged and dished pistons(for a ~ 8-1 comp ratio) and a slight beefing of the valve train. 3)the Caddy engine will bolt right up to the T/A tranny and mounts. 4)locate a used water cooled turbo from a ~ 500 cubic inch diesel engine. 5)convert the turbo to "wet" use. 6)mount the output of the turbo directly onto the intake on the engine. The carburator would sit on top of the turbo. i.e-the turbo sits right on top the intake and air flows straight down the carb through the turbo and into the intake. This ,in theory, should work because it is how most carburator/blower setups work. 7)exhaust manifolds would need to be turned upside down(or a custom setup made) to feed the exhaust up into the turbo.
I'm guessing that this setup would produce at least 600hp and 800lb-feet of torque(with moderate boost) and run on pump gas. I know I'm missing some stuff like a waste gate or blow off valve but I think I covered the basics. I got this idea from a story a friend told me. He told me he had seen a 1980 301 turbo T/A that had a 455 swapped in WITH THE TURBO!!! Most of the swap was a bolt in and the car was insanely fast. The only problem being that the turbo wouldn't last too long because it was too small. I believe that the 301 Turbo T/A has a similar setup as I described above. Feel free to shoot my theory full of holes. I don't have much experience with turbos and need some guidance.
[This message has been edited by olympic (edited 05-26-2000).]
GT Bastard Member
Posts: 2243 From: Rapid City, SD Registered: Sep 1999
I had an early 80's Buick v6 Turbo that was going into my S-10 truck. It was exactly as you described. The carb-(it had a 750 CFM quadrajet!) sat right at the turbo on the side of the engine. It was a crude setup at best, but it had potential. After an accident, I gave up and sold off the pieces. I dont think an intercooler will work because your air stream will have fuel in it. The turbo will heat and vaporize the mixture (good) but an intercooler will cool and condense the fuel back to liquid (bad) and you will have mixture problems.
Phil, Yes, I was thinking about that last night. If you used a waste gate or blow off valve you would be "blowing off" an air fuel mixture!!! Not a good thing. I'm going to do a little searching on how the carb/turbo setups work, like the one Cooter describes.
Posts: 274 From: Portland,Oregon,USA Registered: Dec 1999
A wet set up like this was used earlier for carburated cars. It is however, highly impractical and "crude" at best. I would suggest reading a book on turbo design and installation before even thinking about a setup like this. You will probably decide to go fuel injected. Detonation is too easy and all too dramatic if you don't. As far different cooling, that is not the turbos job. All you need to do is set it up with an air-water intercooler as opposed to an air-air. Extra fuel & air WILL detonate if you do not increase the cooling i.e. air density.
You know, you can use a carb with a turbo and not have to use a blow through system. either use a vacuum secondary carb with a pressurized air box srrounding it or use a mechanical secondary carb and install close tolerance bushings in it. You can then use ducting to feed air into the top of the carb.Just make sure you pressurize the fuel bowl vents in the top of the carb or the boost will blow the fuel back into the bowls.
You also don't need a big block equipped car as long as you get one with an olds or pontiac engine. Even if you don't you can just get the transmission with the cad motor. Or you could just buy the whole Caddy and suck the doors off of unsuspecting victims.
[This message has been edited by Pontiaddict (edited 05-26-2000).]
Posts: 544 From: Saskatchewan,Canada Registered: Oct 1999
That's a brilliant idea Pontaddict!! I knew I could't just force pressurized air from a turbo into a carb because that would push the fuel back into the bowls like you said. I never thought of just pressurizing the fuel bowls also. In theory this should work. I would deffinitely have to add an intercooler to keep the carb from overheating from the hot air from the turbo. I would aso need an adjustable fuel pressure regulator too boost fuel pressure 1 psi for every 1 psi of boost. I'm just trying to design a turbo setup that uses a carb because it would be waaaay cheaper than going with a fuel injection setup and a custom engine management system.
White88cpe longer registered
Posts: N/A From: N/A Registered: N/A
Report this Post05-26-2000 11:10 PM
posts Member since N/A
this may be going off on a tangent but a year or so ago there was an article in muscle muatangs and fast fords where they took a 5.0 engine and used two turbos from a couple of turbo t-birds two make a twin turbo mustang. they figured that the 4 cyl. displacements were about the same as one bank of a 5.0 v8.
so thinking along those lines you might figure a 500 ci caddy engine might use 2 buick 3.8 turbos.
in the article they used shorty headers on the wrong sides for the turbos and a cut down intercooler from a tractor trailer.
what you're thinking is just dreaming for me. i wish i had that kind of know how and funds. the vette would be a vicious thing. i have a twin turbo hood .thats probaly as close as i'll ever get.
[This message has been edited by phillip (edited 05-26-2000).]