Should I run boost?

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mormanman

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I have a 1973 340 .040 over, J heads, KB Performance Hypereutectic Pistons, forge chrome-moly eagle rods, stock crank (i don't know if its forge or cast, I read that it was a shoot peaned* crank), small cam similar to the factory cam (couldn't tell you details on lift or duration), the motor is runnning maybe 10.5-12 to 1 compression and I don't know what else to put for specs.
I was wondering if I could run a twin turbo on it,
something like http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT28/GT2860RS_739548_5.htm.
Pushing 15 to 20 lbs of boost.
If i can't run boost what do i need to change to run boost?
if there is anything else i should know if you could let me know that would be great.
Thanks
 
well if your going to run 15 to 20 lbs of boost your going to want forged internals. I would make sure the crank is forged. Your compression ratio is way to high. 8 to 1 is ideal for boost. Oh, and you have to run blow thru or convert to efi. (huge pain in the *** in my opinion) blow thru is hard to tune and efi is hard to install( my opinion haha)
 
Forged pistons.. all forged internals.. Including a 4-bolt main block... PERIOD! Unless you want to see your engine parts all over the floor... lol I am currently running 17 PSI of boost with a centrifugal supercharger (D-1SC Blower)(Draw through design) on my 1991 Ford 5.0L.. All forged components 2-Bolt main block WITH MAIN STUD GIRDLE... Dyno'd at 601 H.P. at the rear wheels with 91 Octane fuel (Methanol Injection Kit) If you have any questions you can ask anytime.. I kind of was a pain in the *** to be honest in regards to installing/setting up the blower.. If I were you unless you have the cash to blow, i'd stick with naturally aspirated and keep away from the high compression.. Gas prices are going up so stick with 10.5:1 compression or lower with aluminum heads and you can run 91 octane..
 
15-20 lbs of boost on the engine as it is now? You would blow it up before you got to the end of the street.

And even if it did last more than a day......... Would you really want to run race fuel all the time? That gets expensive.


If you want to run a twin turbo pushing that much boost, up you will be completely starting over with the engine.
 
Good thing I asked first lol. So get aluminum heads, forged crank, forged pistons, and four bolt main. Would it be worth it to get the block machined for a cross main? Also I dont know if that's really what the compression is but I think it's higher than 10.5 to 1, I just haven't checked yet.
Again thank you
 
Y'all said all forged internals and I have a question about my hypereutectic pistons. They are 4032 aluminum alloy and what I've read is that 4032 is a forged alloy.
http://www.suppliersonline.com/propertypages/4032.asp
So I was wondering if that really counts as a forged internal or if I need a forged steel piston? Thank you
 
Good idea I've seen that just forgot his name thank burntorange70
 
What are your goals for the car and engine. Perhaps what you want and need are two different things? Not being an *** here, just there might be a better combo or lower boost to achieve your goals. Perhaps NOS?
 
A Problem you will have from the get go at 15-20PSI is you will hang your intake valves open using your current valve springs and kill the engine quickly.

You could get away with 5-7lbs of boost on a stock type engine as long as the tune is right on the money keeping you away from detonation. I believe it would live quite a long time at that amount of boost. You will want to cool the intake charge with some type of Intercooler and with your compression as high as it is you will want to use meth injection to aid in this process for sure. When tuning for more aggressive timing settings to get all the power you can out of an engine you will need to keeping the Intake Air Charge as cool as possible to stay away from Detonation which can kill an engine.

My engine is 9:1 Compression with Iron Heads, Dual Air to Water Intercoolers a Heat Exchanger with 2-10" Fans, circulation pump and I will be using a Tri Nozzle Meth Injection System. All forged internals, ARP main studs, line honed, cam journals line honed, head studs, Cometic Gaskets etc. I will be running no more than 15-20PSI as long as we can work out the tune correctly all on PUMP GAS.

Check out ........... http://www.alcoholinjectionsystems.com/
 
I think this thread can die because I think I'm going to build a 383 for a twin turbo setup. I'll just keep my 340 the way it is.
 
Can't wait to see a pair stuffed into an a-body with a big block.....
 
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