Like the title says, I'm seriously considering swapping my 4bbl throttle body and carb hat, for a cast elbow and LS1 throttle body. My total height is too high for a stock hood, and I'd really love to be able to run a regular formula hood on my formula.

Do you guys think their would be any real noticeable difference in power (that couldn't be corrected by turning up boost) between the what I have now and say a edelbrock 3848/3849 elbow?

Attached is a picture before I finished all my IC plumbing and stuff but you get an idea of the total height.

-- Joe

 

On tight radius bends the na guys report power losses on their elbows. Most of those are well over 90-100 deg bends for lsx cars with stock hoods and windsheild cowls. A higher rise smoother bend to 90 deg will help distribution and cut back on flow losses.

However with boost i dont think it matters as much since whole intake is under pressure. You may need a pound or 2 more psi with flow restriction on tight radius bend but thats nothing to be worried about.

Wilson makes a nice large diameter ls style tb 90 deg low rise elbow that should clear stock hoods. Fits 4th gens well enough

From the looks of it you shouldnt have an issue fitting it

 

I just tossed and aligned a formula hood on it. I've got 4.50" exactly from the throttle body pad to the hood. (this is a high rise intake).

I'll check Wilson and a few other elbows out to get an idea of what will fit and not crash into the thermostat housing.

-- Joe

 

Any reason a 2.00 inch TB "hat" would not work?
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I have just under 1.5" from the throttle body to the hood

-- Joe

 

Fab a elbow out of cardboard. Use that template and call 6061.com for an elbow, if aaron is still making elbows. Else maybe my buddy can fab one at his shop over at FJ Performance

 

I had Aaron make me an elbow back in 2008. I noticed his website changed though ?

-- Joe

 

It changed but still think hes the one behind the effort. Can email or call to see

 

I think I'm going to try edelbrock #3847. (unless it hits the waterneck). LS1 guys are putting down over 540rwhp on blown motors with this elbow with no issues or lean cyls.

-- Joe

 

Orr,

An edelbrock 3848 elbow fits if I run it towards the passenger side, with an LS2 (4 bolt) throttle body up-side-down.

The only suck is that it's right over the valve cover, so adjusting valves requires removing the throttle body and flipping it over (to do a running adjustment).

I like the edelbrock because it has an airflow divider which should help even out the banks.

If I run a forward mounting elbow, I need something like the attached image fabricated, as I actually only have 4 1/2" at the mount pad, and an LSx flange is 5". If I run the LS2 up-side-down again, the flange can be lowered.

It also has to be right at the edge of the mounting surface because any more forward and the flange crashes into the water neck.

What do you think? I picked up two edelbrock elbows for mockup, and 3 throttle bodies (LS1 80mm, LS2 92mm, and a foxbody). Obviously I'll return/sell everything I don't use.


-- Joe

 

Hmm, being space limited is definately a problem. I'm not sure I'd like that attached tb image as its a very tight radius quick bend off the manifold. Divider will help airflow but still alot of flow loss with the quick bend. Could pose more of a restriction. IF you did have to run something like that, I would prefer alittle longer straight section after the bend. Carry it out towards the waterneck more and see if you can clear the waterneck. Sorta like those low lsx style ones. They rise up and then drop low towards front. Longer straight section could help straighten air flow out to help distribution, velocity profile thru the elbow. Then when it hits the tight radius bend, it may be subject to less flow restriction. You want the airflow uniform before hitting the divider at the bend. I think having the TB that close, the air would be kinda turbulent after entering the TB blades, esp part throttle

LS2 style tb's dont seem to have the high flange extension like the LS1's have. Something like that should work if it was cable driven. An aftermarket one may be your best bet as I'm not sure any were made cable driven? I hate Drive by Wire...

Now I assume the elbows you are looking at have the bolt patterns for the different styles of TB's?

 

Ok. So I went with the edelbrock 3848 elbow over the passenger valvecover. A 92MM LS2 throttle body (cable driven) that is flipped up-side-down. Seems like the winning combination.

92MM is huge btw. I had to order a 3" to 4" silicone to connect my IC piping to the throttle body.

-- Joe

 

I think that is a good setup. Even tho it hurts access to the valve covers it should work well. Should be better for airflow

 

Yeah. Aaron couldn't build me one facing forward, and he said even if he could it would hurt airlfow as you suggested earlier. The edelbrock elbow free flows 950cfm I believe, so on a blown motor it should be fine.

Gotta make a cable bracket, but that should be trivial.

-- Joe

 

Almost done. Just need a better ball stud for the throttle arm, I gotta swap to a SU343 IAT sensor to thread into a 1/4" npt hole, and when the silicone hose I ordered shows up I can connect the last two pipes.

For those of you wondering this is a Hurricane singleplane EFI manifold, Edelbrock 3848 elbow, and 92MM LS2 throttle body. Fits under a stock formula hood.


-- Joe