4-71 with 4 Carbs and Mechanical Fuel Injection Help.

I'm stating a new blown Caddy flathead engine build, and I want to run 4-94's on the 4-71 blower.

I only want to use the carbs for air induction. I plan on putting jets in the carb bases, for mechanical alcohol injection.

My question is, how do I tie my barrel valve in to the ****erflys, so that I have the proper mixture?

Any idea or experiences would be appreciated!

 

Not a problem buddy just like a hilborn or enderle just a linkage arm from carb to barrel valve it will have to be fabbed but seriously not a problem you dont know a good machine shop do ya lmao


Posted using the Full Custom H.A.M.B. App!

 

Cool. We'll shoot for 400HP so!

....at least to start!

 

probably could use a set of say , eelco linkage then go off the bellcrank with another to the barrel valve... I run a similar type of deal on my chevelle....its a barry grant byp*** regulator for alcohol but is that type of design

 

Just wondering, are you going to run 8 nozzles?

 

Thanks Brandon!

Would you have a pic of the setup?

 

here ya go....

 

We'll probably run 12 nozzles-one in each carb, and one in each port. That way, the blower is cooled and lubricated, and we can get the tuning a little tighter. Blowers tend to push more fuel to the back cylinders, so we can run the front cylinder nozzles little bigger to compensate.

My Flatcad has 16-8 in the hat, and one in each port, but it makes a lot more HP.

 

Thanks Brandon-pics make it a lot clearer to me!

 

be fairly easy to add another arm up or down to link into...

 

No different from using the Hilborn throttle bodys. Just looks different.

 

what blower top is that???

 

I see Isis Engineering on it, looks very similar to the Weiand 4x2
Are they available?

 

Paul they are Very rare......I have been lucky enough to have serial # 1 of 5 made.....using mine on my coupe engine.

 

This makes me want to jump back on the flat cad band wagon. I even have a 4-71.....and a turbo layin around. I need a damn garage!

 

Gents, they are being repopped by flatheadkid1 here on the board.

Here is the link:
http://www.jalopyjournal.com/forum/showthread.php?t=778204

 

Here is another angle on the 4-71 adapter. Also a flathead blower intake that I am making for myself.

 

Are you going to use an electric fuel pump to prime your mechancial F.I. system ? Just a thought....

See you on the Salt !

 

Yes. The FlatCad is setup that way, and so will this.

See you on the salt!

 

Set both (barrel valve and carb)at wide open throttle (linkage adjustment), then adjust your idle while the motor is running....

I used a Hilborn "S" type barrel valve (if I remember correctly) feeding a fuel distribution block with #3 AN lines from the fuel distribution block to the injectors...

The Hilborn "S" type barrel valve has one inlet and two outlets, as I am not running a high speed byp***....

The electric fuel pump (with an inline one way check valve) feeds into the outlet side of the mechanical fuel pump...

I imagine you have your system set up this way...

 

it's weird to me to feed the electric into the outlet of the mech. pump.

I figured it'd be like diesels, all in series. Electric to mech. to injector.

 

Weird ? Okay....

 

Where are you planning to put the nozzles Buddy? In the carb bases or the adapter? sure would look cool on top of the Cad mill, maybe I should think of building a Cad for the ICT? ...........

 

Neil, my electric pump and check valve are plumbed into the main distribution block. If we have issues with it plumbed that way, we'll try as you suggest!

There will be one nozzle in each carb base, and one in each port on the intake. I'll probably try and run the lines and barrel valve between the carbs.

A Caddy for the ICT? Now you're talking!

The Caddy is heavy, as you know, but 400 HP in the Caddy should be as easy as 250 HP in a Ford.

 

as far as cooling the blower...

I was going to run my 4-71 dry as I figured that was the way it ran on the diesel.

I plan on running it straight up 1:1 off the crank and limiting RPM to 4000.

Should I install some injectors above the blower to cool it?

I'm going efi, one injector per port that will be mounted in a block that sits between the block and blower manifold.

I could inject a small amount of gas on top using a separate alpha-n based fuel system...but is it worth it?

 

Are you sure they are run dry on diesels? When I first planned on running mine that way, everyone warned me to run at least some gas through there for lubrication.

 

Yes they are run dry the diesel is direct injected into the cylinder and most two stroke detroits are governed about 3800 even when they are turned up I've seen them spin faster but it's rare some later model detroits had a gear reduction on the blower drive to spin them even faster for more boost most of that style had a turbocharger as well


Posted using the Full Custom H.A.M.B. App!

 

Remember that you 471 has been re-clearanced for street use, i would figure it is tighter, it wouldnt hurt to run a bit of fuel through it, certainly cant hurt.

 

Buddy, I sure hope you don't mind me stealing your thread for a bit.


I converted my blower myself using this site, some helpful people, and a DVD/parts from Rick Dean.

The only real clearance you open up to set them up for gas is the distance between the rotor tips and I set mine at the higher end of what you'd want on the diesel. This is to allow for the compression of a thicker fluid(that contains more liquid) and for the extra heat/expansion of the aluminum when pushing more boost and higher RPMs. I didn't open mine up much because the Cadillac doesn't spin that much higher than diesel and I'm not looking to push crazy amounts of air. I also have a huge cam so I don't expect to see much boost.


I do agree that putting fuel(gas) up there is better than nothing at all. The question is how much. I'd rather use gas as well other than meth just because I can tap off the fuel system that will already be in place.

I expect around ~350HP from my setup. So maybe send at most 50HP worth of fuel through the blower in a smooth exponential style based on alpha n? I'm just thinking aloud.

I can't really adjust fuel per cylinder so I do worry about the back cylinders running richer than the fronts. Maybe this wouldn't be a bad thing from a cooling point of view?

Very interesting conversation.

 

Buddy, I sure hope you don't mind me stealing your thread for a bit.

No, go for it!

I converted my blower myself using this site, some helpful people, and a DVD/parts from Rick Dean.

The only real clearance you open up to set them up for gas is the distance between the rotor tips and I set mine at the higher end of what you'd want on the diesel. This is to allow for the compression of a thicker fluid(that contains more liquid) and for the extra heat/expansion of the aluminum when pushing more boost and higher RPMs. I didn't open mine up much because the Cadillac doesn't spin that much higher than diesel and I'm not looking to push crazy amounts of air.The Caddy doesn't spin much more than diesel?

Don't kid yourself! Garry Odbert, a racer and friend of mine, routinely spins his blown Caddy to 5500+, using a stock crank and rods. I've spun mine past 6200, and routinely to 6000+.

I also have a huge cam so I don't expect to see much boost.

I doubt if your cam is any bigger, if as big, as mine. Why do you think you won't see much boost? You're lifters are open longer, and you're cramming more air in-that's the point, isn't it? You'll get all the boost you want. I ran over 21 PSI this year, Garry ran 11 with stock heads.


I do agree that putting fuel(gas) up there is better than nothing at all. The question is how much. I'd rather use gas as well other than meth just because I can tap off the fuel system that will already be in place.

I expect around ~350HP from my setup. So maybe send at most 50HP worth of fuel through the blower in a smooth exponential style based on alpha n? I'm just thinking aloud.

I run 60% through the blower, 40% into the ports, on alcohol. I run 100% through the blower on gas, so you have options!

I can't really adjust fuel per cylinder so I do worry about the back cylinders running richer than the fronts. Maybe this wouldn't be a bad thing from a cooling point of view?

I worried about that to, but the plugs say, even at 21 PSI boost, that it's really not an issue.

Good luck!