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singleturbo carbed 320hp l28, looks easy please look!


hondabait

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Schwiplarkin,

 

Why do you say this type of turbo set-up wouldn't be feasible for a daily driver? Can you expand? I'm building a turbo for my 240Z (F54/P90) and I'm trying to read as much as I can about the blow thru turbo, draw thru turbo, and efi turbo set ups. I like the "Old School" style of the carb'd turbo but I don't want to continually have to tune it to keep it running right. Thanks.

 

Julius

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it depends where you live. if it always warm you shouldnt have too many problems. my engine always fires up with little effert but i have heard storys that if it isnt designed well the fuel will puddle and cause problems. im always down for different and unique things when it comes to cars, i shouldnt have said you shouldnt do it for a daily driver, i should have said you may go through some trial and error for awhile, so i would have a reliable vehicle aswell.

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Guest BradHall

How many horsepower at crank is possible with a blow through unit with a demon carb p90 head and say a t3 turbo and arizona z intake stock 280z turbo exhaust manifold and a intercooler? I'm new to the whole turbo thing and I really want a easy setup, I don't care much about driveability since it will only be an occasional weekend toy and would rather not get into alot of computer wiring and looking everywhere for a 81-83 turbo car to strip down. Just a simple old school setup. Thanks

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How many horsepower at crank is possible with a blow through unit with a demon carb p90 head and say a t3 turbo and arizona z intake stock 280z turbo exhaust manifold and a intercooler? I'm new to the whole turbo thing and I really want a easy setup, I don't care much about driveability since it will only be an occasional weekend toy and would rather not get into alot of computer wiring and looking everywhere for a 81-83 turbo car to strip down. Just a simple old school setup. Thanks

 

With even a little research you would find boost and the T3 turbo will be your limit for HP.

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Guest BradHall

I've researched on here alot and on other turbo websites. And the numbers very greatly on the same setups I just wanted someones elses opinion. Just wanted an estimate only because like this is very easy and cheap and as I said driveability isn't a major factor. And I have several of these parts available. Thanks

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I've researched on here alot and on other turbo websites. And the numbers very greatly on the same setups I just wanted someones elses opinion. Just wanted an estimate only because like this is very easy and cheap and as I said driveability isn't a major factor. And I have several of these parts available. Thanks

 

 

A stock T3 flows about 32lbs/min. Doesn't matter what carb, mani, ect. How many lbs/min to make one HP is debatable but figure ROUGHLY 1 lb per 10 hp.

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  • 1 month later...

I'm a little late finding these posts but, thanks for all the info and especially the pic's! I am considering doing the draw thru setup, and having a buddy of mine weld a custom intake for it. What kind of weld should i tell him to use and what kind of metal would do without being too expensive?

Also on the draw thru setup - Air travels thru the carb and the carb mixes feul into the incoming air, then travels into the turbo (intake side) and get's blown into the intake. Good so far? ok

My question is when the air/feul mixture hits the turbo propeller wouldn't their be a buildup of feul hiting the propeller? Maybe i'm under estemating how well the mixture is exiting the carb?

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DatsunD

My question is when the air/feul mixture hits the turbo propeller wouldn't their be a buildup of feul hiting the propeller? Maybe i'm under estemating how well the mixture is exiting the carb?

 

DatsunD, try putting a small piece of bread into a food processor and see what happens to the bread when you turn it on! The compressor wheel of a turbo will keep the fuel in suspension with the air so there will be no "build up" of fuel here. (Consider the processor spins at say 1000rpm and the turbo spins at more than 100,000 rpm):burnout:

 

What may happen over a long time is the erosion of the leading edges of the compressor wheel. The wheel isn't pushing just air but air and fuel.

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DatsunD, my plenum is all aluminum, and so is the stock intake if that is what you plan on using. the only problem with fuel is possible puddeling in the plenum under the carb if it is sitting too low. I did some tuning on my holley two weeks ago and took acouple of laps on a back road by my house, felt awsome at 20lbs!! cant wait to hit the track!

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A stock T3 flows about 32lbs/min. Doesn't matter what carb, mani, ect. How many lbs/min to make one HP is debatable but figure ROUGHLY 1 lb per 10 hp.

 

A "stock T3" What size compressor wheel and A/R?

 

That statement is much too blanket because T3s come in many different sizes that effect thier flow ratings.

 

A BOV is not used nor needed on a draw-through set-up. The only reason for a BOV is to make that the turbo shaft (Compressor wheel,m turbine wheel and shaft) don't stall from a closing of the throttle where an excessive amount of pressure is built up along with a back wave that can not only stall the turbo shaft, but bend it, causing more catastrophic problems.

On a draw-through set-up there is no differential of pressure between the compressor and intake ports, meaning there is no variable obstruction between (throttle plate), so no way for the turbo shaft to be stalled.

A draw through turbo also requires a certain compressor seal to control oil in teh high vacuum situation that a draw-through compressor will experiance.

The turbo itself will be essentially free-wheeling, and the speed is directly controlled by the amount of exhaust gasses passing the turbine, more so than the way a blow through is. The vacuum created with the closed throttle also has an effect on the turbo shaft speed, but lessser than the turbine has.

One rather large problem with a draw-through set-up has been touched on and that is compressor wheel erosion, from the fuel hitting the compressor wheel. This can eventually cause more problems than just an eroded wheel, and that could come in the form of catastrophic failure due to the turbo shaft now being out of balance. It is because of this and another point I will get to, that draw-through set-ups are not very popular for daily drivers.

The other issue is intercooling. A draw through set-up can not use an intercooler, front mount or otherwise. The fuel would end up coming out of suspension and pool at the lowest points. Throttle responce also suffers, due to the length of path from the carb to the valves. This long path can also cause poor fuel distribution issues that at times can be difficult to overcome.

The only way to cool the compressed charge in a draw through set-up is through the use of "liquid intercooling", such as alcohol or water injection.

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I restored and ran an original Turbo Tom setup on my Z for several years. It is a draw through setup which used a Holley 750cfm carb and water injection to control detonation. It dynoed at 310HP with a stock 83 turbo longblock with a P90A head.

 

Overall it ran great. The only issue was cold starting sometimes after it sat for a while. I've since changed to an EFI setup after I blew to head gasket and decided to rebuild the motor.

 

I have pictures of anybody is interested.

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71240, I would love to see some pictures of the Turbo Tom setup. Also of Texis300's setup which I believe has the adjustable boost feature. Knowing where the various vacuum, and other lines, run to and from might help other people who are thinking about a carb setup.

 

Turbo Tom's kits heat the manifold under the carb to ensure there isn't a fuel freeze up. It would be interesting to build on Tom's original good work with variable meth injection and more current technology.

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71240 pics would be awsome, i agree with dhartig, knowing where you guys run your oil lines to turbo and such would be a plus. There is a guy on youtube runing a turbo tom setup which has a seperate oil tank in the engine bay im guessing as to where he ran his lines. you can find the vid searching "turbo tom". BTW Thanks for the info guys

 

DatsunD

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Here are a few pictures of my setup. There are two systems plumbed to the carb plenum which is custom cast as a part of the system.

 

1) a coolant line from the thermostat housing to the base of the carb plenum, this line then runs out of the carb plenum and T's into the main water line leading to the heater core. The function is to preheat the fuel/air mixture as it enters the turbo.

 

2) A water injection line that also feeds into the air/fuel mixture from the back. This feed is controlled by a pressure sensitive valve that is inline with the water line that runs from the bottom of the water tank (red tank next to the battery) to the plenum. This valve is preset to open at 8-10 psi of boost. This pressure is generated by feeding intake manifold pressure to the top of the water tank. Since water is not compressible the water injection feed line is pressurized and the resulting water pressure opens the inline valve and allows water to feed into the fuel/air charge cooling it and preventing detonation.

 

The last line is oil from the block to the turbo bearing. This line taps off of the stock oil pressure sensor port adjacent to the oil filter and runs over top of the valve cover.

 

The setup does use a variable boost controller. It is plumbed as usual with a vacuum source off of the back of the intake casting. The custom exhaust manifold mounts the wastegate just below the carb. The boost controller mounts to the firewall next to the hood latch. Vacuum lines route easily and make controlling boost easy.

 

I've got the setup in my storage garage and can take more pictures if anyone wants more details.

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