Simple way to turbocharge a gas engine with a carb?

[wayno]

I learned something very interesting today, I was at a car show that has invited Datsun owners with our own area to park, we had 16 Datsuns, and there were 12 roadsters, 2 Z's, a 510 and a 320 truck, they highlighted British cars this year, 26 of them showed up, a lot of american sheet metal was there also, even a 2019 Corvette was there, it is for everyone.
I was walking around and seen a big truck with a turbo on a stroked 383(350 block with 400 crank), it had a 700/750 double pumper carb and a box on top of the carb that had a tube that went straight to the turbocharger, this confused me as when people do it this way the fuel cannot get out of the carb because of the boost pressures inside the carb throat so I went over to the guy and asked him how it worked.
He had a normal Carter electric fuel pump, the diaphragm type with a vent hole in the top, it has to be this fuel pump with the vent hole, he drilled a hole in the box on top of the carb(3" X 6" X 8" box) in the back and threaded it for a fitting for a quarter inch inside diameter hose, this went to a tee, one side of the tee went to the Carter fuel pump back by the tank, he drilled the vent hole in the top of the fuel pump for the hose coming from the tee and threaded it for the same fitting that the box had and connected them together, the other end of the tee went to the auto transmission, he drilled/threaded that vacuum device on the transmission to except a valve stem, the end that you fill up a tire with, I suppose one could just tee the hose and put it very close to the transmission, this stupid valve stem is the blow off valve for the transmission vacuum devise, some how the boost in the vent hole on top of the Carter electric fuel pump makes the fuel pump push the fuel to the carb with more force, or making it work harder to create more pressure so it over powers the boost and his truck runs great, at least that is what he told me, it looks real nice and unfortunately I forgot to take a photo of it.
I do not know if you would need this valve stem blow off valve with a manual transmission, seems like it may be needed, and valve stem as a blow off valve seems crazy to me, and remember it has to be mounted on the threaded end like one is trying to inflate a tire with the boost.
Normally one has to make a box for the whole carb to fit in, this was way simple without holes for throttle cables, fuel hoses and other such things and worth looking into if you try to turbocharge a gas engine with a carb, if you have a 4spd then it may be as simple as a hose going to the top of the Carter fuel pump with a vent hole in the top as the connection, he kept saying it had to be the type with vent hole, only that Carter fuel pump would work.
I forgot to ask about the distributor mods if there were any, I will likely see the guy there next year.

 

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The way I understand it is that when a carb is under boost the venturi that makes vacuum to pull the fuel out of the bowl is under the pressure of boost, so air that is pressurized would rather go into the carb bowl via the venturi and carb vents than pull the fuel out of the carb bowl via the venturi, if the whole carb is under boost like when inside a box, then the bowl is under the same boost as the throat of the carb, so the venturi works properly again, it creates vacuum and pulls fuel out of the bowl.

Keep in mind that when I figured out my turbocharger out on my diesel engines which have a venturi to control the throttle, I had to put the vent side under boost also to get the throttle body venturi to work properly again, boost on both sides of the diaphragm cancelled each other out and the venturi in the throttle body worked properly again, it works great.

Maybe this is how it works, think of it this way, the vent side of the Carter electric fuel pump diaphragm sees boost, and the feed side of the fuel pump also sees the same boost because the boost from the running engine is trying to push the fuel back into the tank via the venturies and carb bowl vents(pressurizing the bowl not allowing fuel in the bowl), now if there is as much pressure/boost on the diaphragm on both sides, then they cancel each other out and the carb works like it should again as there is as much pressure pushing the fuel onto the bowl as there is trying to push it out of the bowl back to the tank, they cancel each other out.

What I don't understand is how it works, the only way I can think of to test this is to buy a Carter fuel pump, apply 10lbs of pressure to the vent, then have the fuel pump pull gas out of a open jar, then have the feed hose going to a closed jar with a lid on tight(hose going to the carb) piped to 10lbs of boost also(so the jar has 10lbs of pressure in it and the vent side of the fuel pump has 10obs of pressure), then turn on the fuel pump and see if it will fill the jar, then try it without boost on the vent side of the fuel pump, if a fuel pump only puts out 4psi fuel pressure, then it should not be able to fill the jar that has 10psi of pressure pushing back, does this make sense?

I think the key here is the fuel pump, boost is not always the same, it goes up and down depending on rpm, so if the pressure on both sides of the functioning fuel pump diaphragm are always the same, then the fuel should flow like normal for that pump at whatever PSI it is set to run at.

I asked the guy how he figured this out and he shrugged and said I am an engineer.

 

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I was asked if maybe the guy was just messing with me and here is my response.

 

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I do not lean on or touch vehicles at car shows except my own, they are all so clean and shiny and I don't want to leave my hand print on the nice fender, I was able to see a "Y" where the turbo exhaust feed was before it entered the turbocharger, so both exhaust sides of that 383 V8 were feeding that turbo, it looked clean but I didn't follow both them hoses to where they ended, I just approached him and asked how it worked and how did he over come the boost on the carb issue.

I reality he described what I did to make the turbos work on my vacuum throttle diesel engines and I didn't tell him about that till after he told me what he did to make it work on his gas engine, and he kept mentioning the Carter fuel pump with the vent on top, only that one would work, no other pumps would work, only that one.
And that valve stem, who would think of using a valve stem as a blow off valve, I cannot blow on a new one and force air thru it with my mouth, but that is how you fill your tires, I have never heard of such a thing before, but it makes sense if they start opening up at 7lbs of pressure as that is what he told me when I asked how much boost he was using, 7lbs.
The guy was a total stranger to me, I believe he won an award at the show for his truck(he was parked right up front at the meet headquarters), it was a nice clean truck although I don't remember a lot about it as I was interested in the turbo piping not that huge truck, I also asked about his valve covers, I didn't recall Chevy having a 383 marked valve cover but he had them, he looked at me and said it was a common modification, I asked if his 350 block had a 400 block crank in it and he said yes although I didn't even know if that is even possible and still don't, I mentioned that most manufacturers would not even be interested in making such a thing with such a small demand, and he looked right at me and said it was likely that at least 10 of the vehicles at that show had done the same modification to their engines, if that is true then there likely is a large enough demand to make them valve covers with a raised 383 in them, I wish I had taken photos now.

I am not sure if I have a way of testing a system with just 7lbs of pressure, will a glass jar even hold 7lbs without blowing up, it probably will as I have installed a valve stem in my pump sprayer and put a 100psi in it, but tires and pump sprayers are made of plastic and expand and contract as I watched my pump sprayer container expand.
I wonder if it is possible to turbocharge dual SUs if one pipes the vents of the bowls to boost, I like thinking about stuff like this.

Edited August 4, 2019 by wayno

[Turbosauce74]

This post is complete bs. 

-The guy was definitely lying to you, cause none of that would even work

- no one puts a carburetor in a "box" 

- 2 diesels don't have throttle bodies, diesels don't even generate vacuum, diesels don't even aspirate their fuel. 

 

All this has been figured out YEARS ago, with something simple called a boost reference fuel pressure regulator. It's simple, you tune your engine at idle to a set boost pressure, and then for every psi of boost you gain 1 psi of fuel pressure. 

So say in a carb set up you run 12-15psi of fuel pressure n/a. But now you want to run 14psi of boost, you need a fuel pump capable of 26-29 psi at the proper flow. 

Efi is no different. 

 

[rosso]

Not that I know anything about this, but here's this:

 

 

 

Studebaker R3 engine with supercharger and carb in a box.

Early 1960's.

[wayno]

I am not in the habit of lying or posting BS, the guy that had the truck with that turbo system won an award for his truck, next year I will get photos of his truck/engine compartment.

 

3 hours ago, Turbosauce74 said:

This post is complete bs. 

-The guy was definitely lying to you, cause none of that would even work

- no one puts a carburetor in a "box" 

- 2 diesels don't have throttle bodies, diesels don't even generate vacuum, diesels don't even aspirate their fuel. 

 

All this has been figured out YEARS ago, with something simple called a boost reference fuel pressure regulator. It's simple, you tune your engine at idle to a set boost pressure, and then for every psi of boost you gain 1 psi of fuel pressure. 

So say in a carb set up you run 12-15psi of fuel pressure n/a. But now you want to run 14psi of boost, you need a fuel pump capable of 26-29 psi at the proper flow. 

Efi is no different. 

 

 

Sadly here is proof of something you seem to believe don't exist.

Here is my extra diesel head on the bench with what I call a throttle body, call it what you want, but this is where the throttle cable goes to control my diesel engine/turbodiesel engine.

 

Note the carb/throttle body looking thing with the butterfly valve in its throat and in the photo below the throttle cable connection/bell crank on the side of it.

 

Note in the photo below looking down the throat of the carb/throttle body, it has a butterfly valve and a hole/venturi, that hole creates vacuum, when the engine is running and the butterfly is closed it creates vacuum that pulls the injection pump rack diaphragm to the idle position, when the butterfly is opening or open that hole/venturi creates less vacuum and the rack diaphragm moves to a richer position, when the diesel engine gets more air it gets more fuel.

 

A turbocharger kinda messes everything up, when under boost the injection pump rack is floored as it has pressure now instead of vacuum, it tries to run away but cannot get air so eventually it calms down, but it cannot be driven this way as when it starts running away it acts like it is floored even though I barely have my foot into the pedal, it took me a long time to figure everything out but I did figure it out, the injection pump has 2 lines, one controls the rack via vacuum that carb/throttle body venturi creates, the other line is a vent line on the back side of the diaphragm, I figured out if I piped that vent line to the boost also with boost on both sides they cancel each other out and the venturi in the carb/throttle body works properly again, I know this because I have done it, the guys on the Nissan diesel forum were very interested.

Here is my thread on my 1969 Datsun 521 turbodiesel

http://nissandiesel.dyndns.org/viewtopic.php?f=5&t=3380

 

Here is my thread on my 1980 Datsun 720 turbodiesel.

http://nissandiesel.dyndns.org/viewtopic.php?f=5&t=3474

 

Read the threads, don't read them, the fact is what that guy at that show was describing is basically what I have done to my diesel engines, but the boost controls his fuel pressure, I was unable to find the Carter fuel pump he was talking about so I bought a Holley fuel pressure regulator with a boost reference and a fuel pump, that is as far as I have got, as I have other things to think about.

I have seen photos of the whole carb in a box on a boosted engine, that guy only put a box on the top of his carb and that got my interest, I asked him how it worked and he told me, he also told me about his 383 block also with valve covers that had 383 on them, others have confirmed everything he told me on that front was true, I see no reason not to believe everything else he told me, he appeared to be a regular at that Tacoma Narrows car show, I will look at it again next year.

 

There is not just one way to do things, any painter that says the only way to paint a house right is his way is pretty narrow minded, there are lots of ways to do lots of things.

 

Edited August 30, 2019 by wayno

[datzenmike]

2 hours ago, Turbosauce74 said:

 

- no one puts a carburetor in a "box" 

 

 

 

Yeah they can and do. It's just one way of doing it is all. The entire carburetor is in a container that is pressurized. Prevents boost from blowing out gaskets. 

[Z23T]

2 hours ago, Turbosauce74 said:

This post is complete bs. 

-

- no one puts a carburetor in a "box" 

 

 

If you follow this link you can see Bert Vorgan's 510 with a turbo L20B making 300HP since the 80's with a Weber in a box.

 

http://www.the510realm.com/viewtopic.php?f=3&t=25088&start=90

[datzenmike]

I think Keith's (Bert) 510 is around 250 hp last I heard. Turns 8-9K too.

 

Funny how someone finds a way to do something and then thinks all other ways are BS.

 

With work you can find a suitable pressure cooker that will do the job of a box.

[Turbosauce74]

All great examples of over complicated solutions to a very simple problem. And it's always the "I'm an engineer", cause when you mention a way to do it easier they give you that look of "wow, I wasted a lot of time" 

A throttle body on a diesel is for the emmisions, not to actually control throttle. It's to allow the egr system to pull exhaust gasses into the intake. It's common to remove the egr and that throttle body for better flow. If you have to keep the throttle body for something like a tps, then you remove the butterfly. 

[G-Duax]

7 hours ago, datzenmike said:

With work you can find a suitable pressure cooker that will do the job of a box.

 

I once went to K-Mart, bought an aluminum frying pan lid to make an air filter top cover for my '76 Toyota Corona.

No one ever asked why I had a pan lid on my carb.

But these days, people might freak out if they see you checking your oil, and spot the pressure cooker.....

"Police, Help ! - There is a guy at the gas station with a bomb in his car!"

[wayno]

My engines I have in my trucks don't have any emissions, they never had any.

 

There is no throttle cable going to the injection pump, it is vacuum controlled, if you remove that throttle body there is no way to control the engine.

Here is the inline injection pump, it has 2 vacuum/rubber hoses, an electric controlled control rod which has 3 positions, off, start, run, that is it, it also has a manual shut down cable on it I installed when the rod setup don't work properly, the control rod at the top where it mounts to the injection pump arm has a clip I use to delete the key operated control of the engine, again it has 3 positions, off, start, and run.

 

Here is the electrically operated control rod that controls the engine in the 3 positions.

 

Here are the 2 vacuum hoses at the rear of the inline injection pump that control the throttle using the venturi in the throttle body, you can also see the little choke cable I installed as a back up when the injection pump controller acts up.

 

They do make an engine with a VE type pump that is controlled using a throttle cable that mounts on the VE type injection pump, like the Dodge, Chevy, and Ford VE type injection pumps they don't last that long, the Nissan VE type injection pump lasts under a 100,000 miles(normally around 60,000 miles), while the inline injection pumps last over 300,000 miles, this is why I stuck with the inline injection pump my engine already had.

 

Before you keep talking about stuff you appear to know nothing about you should search the SD series diesel engines that came to the USA in the 1981/1982 Datsun 720 with the

inline injection pump.

 

Here is a VE type injection pump on my  rebuilt SD22 engine, I had an engine imported from Australia with everything I needed to swap over to the VE type injection pump, but I figured it out with the inline injection pump before I went that route, that engine doesn't have the throttle body as it is controlled by the throttle cable going to the injection pump although that photo doesn't have the throttle cable installed yet.

 

Here is a photo of that injection pump from Australia with the cable in the position it would be if in a vehicle, it's in storage collecting dust/dirt.

 

In the end people believe what they want to believe, I did what I did when I turbocharged my diesel engine with the inline injection pump, it's so stupid simple I can't believe that no one else thought of it years ago, that second line needs to be piped to a boost source instead of vented, that is it.

There is another thing I do to get more HP but that is in my other threads about my turbodiesel powered trucks that I posted links to that you obviously didn't read.

1 hour ago, Turbosauce74 said:

All great examples of over complicated solutions to a very simple problem. And it's always the "I'm an engineer", cause when you mention a way to do it easier they give you that look of "wow, I wasted a lot of time" 

A throttle body on a diesel is for the emmisions, not to actually control throttle. It's to allow the egr system to pull exhaust gasses into the intake. It's common to remove the egr and that throttle body for better flow. If you have to keep the throttle body for something like a tps, then you remove the butterfly. 

 

Edited August 30, 2019 by wayno