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Just another 2 bbl manifold
https://slantsix.org/forum/viewtopic.php?t=17745		 Page 1 of 1
Author:  DionR [ Fri May 26, 2006 1:14 pm ]
Post subject:  Just another 2 bbl manifold
:twisted:

Image

Image

For my turbo project, of course.

I initially wanted an Offy 4bbl, but it sold before I got there. I really didn't want this one as I was going to have to find a plate for a 4bbl.

Now, I'm planning on running the 2bbl.

Been looking at the turbo inline 6 Falcon that runs 11's with a 350 cfm 2bbl, and researching ways to make it work. Don't really like the Falcon's method as he is just running huge jets and dealing with too much fuel (15 mpg w/ a 250), so I'm going add extra fuel when under boost using a couple of cold start injectors under the carb.

Time will tell how the manifold works without heat. If it's a problem, I figure I will run a copper tube with coolant in the heat box area.

Exhaust manifold is in the works.

Just had to share.
Author:  RossKinder [ Fri May 26, 2006 1:28 pm ]
Post subject:  Re: Just another 2 bbl manifold
Quote:
Now, I'm planning on running the 2bbl.
Progressive or sync'd?
Author:  DionR [ Fri May 26, 2006 2:00 pm ]
Post subject:  Re: Just another 2 bbl manifold
Quote:
Quote:
Now, I'm planning on running the 2bbl.
Progressive or sync'd?
Just a standard 2 bbl, most likely a 350 cfm Holley of some type.
Author:  Joshie225 [ Sat May 27, 2006 9:22 am ]
Post subject: 
I'd drill the power valve channel restrictions so that you can run more "normal" sized jets and have the extra fuel you need under load when the power valve opens. You may also want to drop the power valve number so it opens a bit later and delay the extra fuel until you really need it. 2 stage power valves are available, but they are restrictive and not recommended for performance use. If you start pushing too much fuel through that carb you'll need to reduce the restriction in the booster fuel passage too. Get a good Holley carb book and learn all you can.
Author:  DionR [ Sat May 27, 2006 10:01 am ]
Post subject: 
Quote:
I'd drill the power valve channel restrictions so that you can run more "normal" sized jets and have the extra fuel you need under load when the power valve opens. You may also want to drop the power valve number so it opens a bit later and delay the extra fuel until you really need it. 2 stage power valves are available, but they are restrictive and not recommended for performance use. If you start pushing too much fuel through that carb you'll need to reduce the restriction in the booster fuel passage too. Get a good Holley carb book and learn all you can.
I've spent a fair amount of time on TurboMustangs.com where that are some guys pushing 1000+ hp through a carb.

With a 4bbl, you can get the fuel you need from the secondaries. The PV is a big part of things as well, but you can't get it all there. With a 4bbl, you can tune the primaries for good drivability (one guys is +1000 hp and claims 20 mpg on the highway), and make good power using the PV and secondaries.

The problem is, a 2 bbl doesn't have secondaries. Because of that, I really didn't want to even try. I've since changed my mind.

Maybe a little /6 making 300 hp wont need more than what the PV can deliver. My biggest goal for this is a motor that is tractable and fuel efficient when not under boost, and makes 300 hp under boost. If the PV wont make it work, I need to find another way rather than just put a bigger jet in it (Does10's method on Fordsix.com). With the cold start injectors, I can add fuel as the boost comes on (1 psi or so) and even stage the injectors if I want.

Don't mention EFI, it's the goal sometime down the road.

BTW, the big talk right now is boost referenced PV's. Seems that you reach a point where the PV is opening before boost is there and flood the motor with way too much fuel. The goal is to find a way to make the boost open the PV, instead of a spring.
Author:  DionR [ Sat May 27, 2006 10:04 am ]
Post subject: 
Quote:
Get a good Holley carb book and learn all you can.
Always more to learn.
Author:  RossKinder [ Sat May 27, 2006 10:09 am ]
Post subject:  Re: Just another 2 bbl manifold
Quote:
Quote:
Quote:
Now, I'm planning on running the 2bbl.
Progressive or sync'd?
Just a standard 2 bbl, most likely a 350 cfm Holley of some type.
Hm, some Holleys are progressive and some are sync'd. I guess you mean to use sync'd. Thanks.
Author:  Joshie225 [ Sat May 27, 2006 12:31 pm ]
Post subject:  Re: Just another 2 bbl manifold
Quote:
Quote:
Quote:
Progressive or sync'd?
Just a standard 2 bbl, most likely a 350 cfm Holley of some type.
Hm, some Holleys are progressive and some are sync'd. I guess you mean to use sync'd. Thanks.
Ross,

All common Holley 350 2bbls are synchronous opening. Only the very rare 2305 Holley 350 is staged opening.
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