Twin Turbos

[custom-cruiser]

Does anyone have advice on Turbo systems? I have a 76' 21' Howard custom cruiser with 454,mild cam,roller rockers,750 double pumper,performer intake,center rise exhaust w/4" tips,American Turbine jet w/droop and hydraulic place diverter. Set up currently does 55mph. I'm looking at a TO4 Air Research twin turbo system with intercoolers,10 quart Dooley pan,exhaust ect.
I would build a new motor for this set up. does any one have advice on compression,fuel pressure,cam profile,any other need to knows or tricks? what HP can be expected out of a BBC with this system?

[beached1]

Custom,
I'm in the process of researching twin turbos for my BBC also. I don't know much about them other than my neighbor, the engine builder that will be putting them on my motor said that he gets his from some place in Orange County, CA called Turbo City. I'll get a # for you and who to talk to when I get home later today if ya like. What I do know is that I'm running a 454 large oval, two bolt main. It's has an GM LS7 cam, Roller rockers, jacobs ignition, Holley 850, Edel torker II maifold. I'm at 9.5 to 1 comp. My engine builder said this settup wouldn't take more than 7lbs of pressure. Hope this info helps. I'll shoot ya an e-mail when I get the phone #.

[beached1]

Custom,
I'm in the process of researching twin turbos for my BBC also. I don't know much about them other than my neighbor, the engine builder that will be putting them on my motor said that he gets his from some place in Orange County, CA called Turbo City. I'll get a # for you and who to talk to when I get home later today if ya like. What I do know is that I'm running a 454 large oval, two bolt main. It's has an GM LS7 cam, Roller rockers, jacobs ignition, Holley 850, Edel torker II maifold. I'm at 9.5 to 1 comp. My engine builder said this settup wouldn't take more than 7lbs of pressure. Hope this info helps. I'll shoot ya an e-mail when I get the phone #.

[custom-cruiser]

Beached1,
Thanks for the tip,any info will be helpful!
Because I'll be building this as a Turbo motor specifically i'd like to get optimum specs down 1st.....

[058]

CC, do you plan on running a blow-thru or a draw-thru system? If a blow-thru, limit boost to about 9lbs, any more than that the carb metering goes south. Limit compresson ratio to no more than 8 to 1. Have a cam ground for turbocharged application [longer intake dur. shorter exh. dur.] low overlap. Comp Cams Dyno shop did mine. Build the BBC with the good parts, 4 bolt block, steel crank, good rods and forged pistons. If you keep static comp. and boost low enough [9-10lbs] you could get away with running pump gas. Hope this helps.

[custom-cruiser]

058,
Great place to start....not sure what the difference is between blow thru and draw thru systems? Would you please clarify?
Do you have Twin turbo? What kind,and specs?

[kingb36]

In a blow thru app. the turbo is upstream of the carb and forces air thru it. Draw thru has the turbo downstream of the carb and sucks air thru the carb. I'm not a turbo expert but I believe that a draw thru is a simpler setup.

[beached1]

Custom, Turbo City's Phone # is 714-639-4933. Ask for Tom. If or when you do get some turbos, please post the results in here or e-mail me with em. I'd like to know what kind of power gains you get. If I beet ya to it, i'll do the same. Good Luck!

[058]

CC, KingB is correct. The blow thru has its place though. If you need to keep the carb in its orig. position then the blow thru will work best for you. The draw thru is able to use more boost [with a carb] because the carb isn't subject to vacuume and pressure. The only modification you will need to do with the draw thru [other than jetting] is boost reference the power valve. If you don't the p/v will seldom open as the carb in a draw thru is under constant vacuume, result: little or no vacuume signal response to the p/v. Some people have blocked the p/v but that can result in a over rich codition at part throttle and/or low engine speed. I do run a twin turbo, its a Gale Banks system with single element intercooler. Its on a 466" BBF in a 18' Hondo flat. I have run both types of systems, blow thru and draw thru. I prefer the draw thru, it makes more power and the carb is alot easier to get to. One more thing, have an expert on turbochargers select the turbos for you. He will choose the proper compresson and exhaust housings and wheel trim for your application. One of the more important things when selecting turbos is the A/R ratio [area/radius] of the exhaust housing, this will determine impeller speed and exhaust back pressure. There is alot more to this and I won't get into that here as it takes too much time and space but the turbo guy will know all about it or he should, if he doesn't find another.

[turbo]

CC I had a turbo on my small block ford. used draw through method . buy this book It's in the back of summit jegs or local bookstore answers alot of your Questions, HPBooks TURBOCHARGERS by HUGH Maclnnes. the supplier I used was turbonetics www.turboneticsinc.com (http://www.turboneticsinc.com)