draw thru carb mods????

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jonnydart440

jonnydart440

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OK, so I read about draw thru turbo systems a while ago, I just finished reading Bakerlites thread on his draw thru 318(awesome BTW, can't wait to see it finished). Now I NEED to do this to my 440! My question right now is do I need to modify anything on my carb or fuel system for a draw thru set up? I am running a holley 4150 750 cfm duel feed double pump four corner adjustable( just bought it brand new last season) and electric fuel pump at 5 psi. I currently have a used turbo off a ford 7.3 diesel. The 440 is a low compression motor and what feels like a very mild cam. Its what was in the car when I bought it. I guess the other question I have is about the turbo, I read something about the seals in the turbo because it goes into a vacuum on decel. Is this a usable turbo? Are there seals that can be upgraded if need be? Also considering using 2 smaller turbos( hopefully can find something cheap) that way I don't have to run an exhaust cross over. Any tips and advice are greatly appreciated!!! Thanks! Jon.
 
From what I've read, you want carbon seals in the turbo and a fuel pressure regulator that goes off boost. I think?

hopefully someone with solid knowledge chimes in. I've really gotten swept up in the notion as well. Might be the next dart project after my trans. :)
 
You can a lot of people have used diesel turbos. A good carb shop can modify the carb or buy a blow through carb for a good company like c&s, pro systems. And depending on boost and hp might need a better pump and for sure a fuel pressure reg with a boost reference that way it will raise 1:1 as boost goes up. Single or dual turbo lsst depends on how much fab work you want to do.

Sorry thought it said blow through my bad.
 
no boost referenced pump needed as the carb is never pressurized. Id use the largest seats you can find for the carb. Carbon seals in the turbo becasue its sucking on a carb that when snapped closed, will leave a large anount of vacuum in the impeller so it tends to draw oil out of the cartridge. Carbon seals are 360 degree seals or something like that makes them superior to standard seals.
 
No mods needed to the carb, but you may have to richen it a little. Get an Aif / Fuel meter to help you dial that in. Make sure your fuel pump can handle the extra fuel demand. As mentioned, get a turbo with a carbon seal. I don't think the diesels have them..
 
Thanks so much for the input guys. Ya, I didn't think I needed any carb mods but was getting confused reading up on it on the internet, I think sometimes the lines get blurred between drawthru and blow thru....just to be clear I'm only considering draw thru at the moment. Does anyone have any good sources for inexpensive turbos? I know u can but em on eBay, not sure of the quality tho??
 
I've seen some good prices on Amazon for turbos in the T4 family. Just glossed over them so I'm not sure the specs are right for a 440. Can't hurt to search though.
 
I think most diesels have around a 74mm turbo which is a decent size, just measure the inside of the inlet and that will give you the size turbo you have.
 
I put a normal edelbrock 500 4 barrel on the draw through setup I ran on my /6. Didn't have any issues with the carb.
 
Matts440 said:
I think most diesels have around a 74mm turbo which is a decent size, just measure the inside of the inlet and that will give you the size turbo you have.
Click to expand...

Diesel turbos usually do not have the carbon seal, so they are useless in a draw through application.
 
Also, a diesel turbo, put on a gasoline engine of the same size, will be WAY too small. Not sure if any of you watch RoadKill, but they used a PowerStroke (I *believe* a 7.3) turbo on a 4.3 Chevy V6... in a Datsun...
 
Brandon Weaver said:
Also, a diesel turbo, put on a gasoline engine of the same size, will be WAY too small. Not sure if any of you watch RoadKill, but they used a PowerStroke (I *believe* a 7.3) turbo on a 4.3 Chevy V6... in a Datsun...
Click to expand...

Ya, I saw that episode, love that show! Actually that's what turned me on to turboing my car. I don't know, I took the turbo I had at work home and tried to "dry fit" it in the engine bay...with the amount of fab work this will take I may have to wait till next fall/winter. I don't want to be without my car this spring, especially after the winter we've had in new england! But thanks for all the info guys, I appreciate it!
 
Bakerlite said:
Diesel turbos usually do not have the carbon seal, so they are useless in a draw through application.
Click to expand...

the good news is there are rebuild kits available and they have carbon seals in the kit. so if i mock it up and get it running, then i can rebuild it with carbon seals. i was not able to confirm if they do or do not have carbon seals stock, but thanks for the advice.
 
Brandon Weaver said:
Also, a diesel turbo, put on a gasoline engine of the same size, will be WAY too small. Not sure if any of you watch RoadKill, but they used a PowerStroke (I *believe* a 7.3) turbo on a 4.3 Chevy V6... in a Datsun...
Click to expand...

the 7.3 makes about 15+ psi boost, i would only be looking for 5-8 anyway. i'm not looking to drag race or anything. just want a little more kick and to have something different. i've yet to see any draw thru turbos at a cruise night around here. i will keep brain storming and see if i can come up with a solid plan to fit this in my engine bay, may have to go in front of the motor.
 
If it's from a 7.3 Power Stroke, the turbine A/R is either 1.15, or .84

If it's got a wastegate, it's .84
 
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