Twin Turbo 383 questions

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turbodart68 said:
I would be careful with turbos off ebay. If they are used have them disaasembled and inspected, not bad on price. I would consider even using a pair of T04s since everyone seems to throw them away these days. I built a car years ago with 2 T04s on it with a water to air intercooler and 377 inches of small block chevy. Its gone high 8s at over 160 at 16 pounds of boost and an 8 inch tire. You will be surprised at how fast you can go with a small turbo. Your combo looks good, I would use a bigger exhaust housing like the one your talking about .96 A/R.
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I have been getting a little skeptical lately. I have an old 57 trim rajay mocking up ideas. With the 383 room is minimal so twins may be out. I really do not want to cut my car up! I have been pondering this turbo,

http://cgi.ebay.com/ebaymotors/Prec...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

Considering the limited space would this particular turbo(Single) be sufficient for my application???????? Pretty big AR. of .96, 1.08 or 1.39 and states 1400hp possibilities! I am looking for 800 streetable horsepower.
 
I love this type of thread !! 1400 hp !! well there are very simple realities that often get forgotten. Regardless the type of intake charge boost used, the motor is still an air pump.. There are a couple volumetric considerations, but as a rule, 1 atmoshphere (14lb ) = 50 % horsepower increase. So your 1400 hp dream mobile would need to make 900 hp or so without a turbo... Which is fine, but probably means he has a fortune in that motor. This thread is about making 800 out of a 383.. a good running 383 is making around 400 hp so you could get 600 hp out of 14 lbs of boost.. I run 16lb ( blower
- D1SC ) through a 474 and make 790 hp.. I could probably get another 50 hp if I changed the very mild cam profile im running, but I like idling at 700 rpm. Just a reality check. Fun thread.
 
Dave_n_68383S said:
I love this type of thread !! 1400 hp !! well there are very simple realities that often get forgotten. Regardless the type of intake charge boost used, the motor is still an air pump.. There are a couple volumetric considerations, but as a rule, 1 atmoshphere (14lb ) = 50 % horsepower increase. So your 1400 hp dream mobile would need to make 900 hp or so without a turbo... Which is fine, but probably means he has a fortune in that motor. This thread is about making 800 out of a 383.. a good running 383 is making around 400 hp so you could get 600 hp out of 14 lbs of boost.. I run 16lb ( blower
- D1SC ) through a 474 and make 790 hp.. I could probably get another 50 hp if I changed the very mild cam profile im running, but I like idling at 700 rpm. Just a reality check. Fun thread.
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I believe this to be true in a Supercharged engine since the engine produces the power to move the blower from the crankshaft. However I believe that this is incorrect in the Turbo engine since there is "No" power being taken to move the Turbo. I personally seen a smallblock Chivy that produced a bit over 400hp alone. After the 2 turbo's were installed it produced well over 900hp @ 20lbs boost. This proven on a dyno!

O' a stock 383 produces 335 hp stock. This was said to be with all assys. and at the tailshaft of the trans.. Furds and Chivy's were rated at the flywheel. I have seen the 383/496 produce nearly 600hp.
 
CUUDAK said:
I believe this to be true in a Supercharged engine since the engine produces the power to move the blower from the crankshaft. However I believe that this is incorrect in the Turbo engine since there is "No" power being taken to move the Turbo. I personally seen a smallblock Chivy that produced a bit over 400hp alone. After the 2 turbo's were installed it produced well over 900hp @ 20lbs boost. This proven on a dyno!

O' a stock 383 produces 335 hp stock. This was said to be with all assys. and at the tailshaft of the trans.. Furds and Chivy's were rated at the flywheel. I have seen the 383/496 produce nearly 600hp.
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The blower certainly takes a couple hp..
In the end however it simply is a matter of fact that an engine is an airpump. The power its going to make is simply a factor of how much air and fuel can get stuffed inside. That really doesnt change depending on what method of forced induction is used. ( blower, turbo, N02 )

Turbos do steel hp as well.. There is no free lunch and the huge restriction in exhuast flow will cost something. I dont know enough to tell you what those numbers look like or how they compare to a blower.. Anyone else know ?
 
Dave_n_68383S said:
The blower certainly takes a couple hp..
In the end however it simply is a matter of fact that an engine is an airpump. The power its going to make is simply a factor of how much air and fuel can get stuffed inside. That really doesnt change depending on what method of forced induction is used. ( blower, turbo, N02 )

Turbos do steel hp as well.. There is no free lunch and the huge restriction in exhuast flow will cost something. I dont know enough to tell you what those numbers look like or how they compare to a blower.. Anyone else know ?
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Turbos restrict exhaust flow and tht is why the A/R sizing is important. Even if the turbo is a restriction the boost will be lower because of it, so with a boost correction a turbo robs very little power. Superchargers on boost rob a lot of power! No way around it and that is why it is typical to see a 100% increase in power at 15 pounds of boost. I have personally seen over 100% increase on my own car at 13 pounds.
 
Dave_n_68383S said:
The blower certainly takes a couple hp..
In the end however it simply is a matter of fact that an engine is an airpump. The power its going to make is simply a factor of how much air and fuel can get stuffed inside. That really doesnt change depending on what method of forced induction is used. ( blower, turbo, N02 )

Turbos do steel hp as well.. There is no free lunch and the huge restriction in exhuast flow will cost something. I dont know enough to tell you what those numbers look like or how they compare to a blower.. Anyone else know ?
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I know this is an extreme example, but it is an interesting read none the less.....http://www.moparengineswest.com/top_fuel_perspective.htm in particular the third line
 
Dave_n_68383S said:
The blower certainly takes a couple hp..
In the end however it simply is a matter of fact that an engine is an airpump. The power its going to make is simply a factor of how much air and fuel can get stuffed inside. That really doesnt change depending on what method of forced induction is used. ( blower, turbo, N02 )

Turbos do steel hp as well.. There is no free lunch and the huge restriction in exhuast flow will cost something. I dont know enough to tell you what those numbers look like or how they compare to a blower.. Anyone else know ?
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I just posted a read about cam choices. Take a look at it. The cam choice is critical in the process of creating the right lift-duration-overlap-timing to produce the Hp numbers. Poor choice in cam can ruin a decent setup!
 
CUUDAK said:
I just posted a read about cam choices. Take a look at it. The cam choice is critical in the process of creating the right lift-duration-timing to produce the Hp numbers. Poor choice in cam can ruin a decent setup!
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Boy you are really right on this one. I built a twin turbo small block for my buddies duster and it wouldn't clear the 300hp mark at the rear wheels! A cam change later it was a different car altogether!
 
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