L29 454 MODS

[dzynda]

Sooooooooooo was this throttle body a waste of money too?
Will it work?
It's a Holley 85mm throttle body, 3 3/8 inches. It comes with a spacer plate that tappers it down to 3 inches 76.2mm. The stock throttle body actually measures 88.9mm that's 3 1/2 inches and tappers down to 3 inches also.
Now the flapper on the Holley is 85mm and the flapper on the stock is on the tapered end so 76.2mm.
I'm obviously no expert, my first thought is that the stock throttle body is better.
1) large entrance opening 88.9mm.
2) smoother tapper because it's one piece.
3) retains the other two ports into the intake
Is my thinking correct?
Does it really matter where the flapper is?
Again sorry if these are stupid questions, companies advertise this stuff like more hp etc.etc. you guys have are knowledgeable, not trying to sell something and have been testing these things in real life.
Thank you

 

[BeXtreme]

Sooooooooooo was this throttle body a waste of money too?
Will it work?
It's a Holley 85mm throttle body, 3 3/8 inches. It comes with a spacer plate that tappers it down to 3 inches 76.2mm. The stock throttle body actually measures 88.9mm that's 3 1/2 inches and tappers down to 3 inches also.
Now the flapper on the Holley is 85mm and the flapper on the stock is on the tapered end so 76.2mm.
I'm obviously no expert, my first thought is that the stock throttle body is better.
1) large entrance opening 88.9mm.
2) smoother tapper because it's one piece.
3) retains the other two ports into the intake
Is my thinking correct?
Does it really matter where the flapper is?
Again sorry if these are stupid questions, companies advertise this stuff like more hp etc.etc. you guys have are knowledgeable, not trying to sell something and have been testing these things in real life.
Thank you

Yep, complete waste of money in every way. You don't need a bigger throttle body unless you have stroked it, have bigger heads, and a big cam. You would also need to do some tuning for it... which you cant currently do anyways. Even then.. the manifold is going to be the limiting factor, not the throttle body.

 

[Supercharged111]

Yep, complete waste of money in every way. You don't need a bigger throttle body unless you have stroked it, have bigger heads, and a big cam. You would also need to do some tuning for it... which you cant currently do anyways. Even then.. the manifold is going to be the limiting factor, not the throttle body.

It can give a bump in throttle response. But a tune will give 10x the gains.

 

[dzynda]

Thank you guys, I can sell that stuff to put into the cam, computer and distribution.
I just painted the intake, this truck had a leaking lower intake gasket. I bought a new, thermostat 195°, coolant temperature sensor, egr valve, idle air control valve, throttle position sensor, and the new style injectors for it too.

 

[L31MaxExpress]

Sooooooooooo was this throttle body a waste of money too?
Will it work?
It's a Holley 85mm throttle body, 3 3/8 inches. It comes with a spacer plate that tappers it down to 3 inches 76.2mm. The stock throttle body actually measures 88.9mm that's 3 1/2 inches and tappers down to 3 inches also.
Now the flapper on the Holley is 85mm and the flapper on the stock is on the tapered end so 76.2mm.
I'm obviously no expert, my first thought is that the stock throttle body is better.
1) large entrance opening 88.9mm.
2) smoother tapper because it's one piece.
3) retains the other two ports into the intake
Is my thinking correct?
Does it really matter where the flapper is?
Again sorry if these are stupid questions, companies advertise this stuff like more hp etc.etc. you guys have are knowledgeable, not trying to sell something and have been testing these things in real life.
Thank you

It is not a waste. The stock 454 intake as a whole is restrictive. I had a customer do this with a 4" air intake and a 4" MAF tube with a LS3/LS7 cartridge MAF. It added about 15 hp compared to the stock setup on a mildly cammed 454.

 

[BeXtreme]

It can give a bump in throttle response. But a tune will give 10x the gains.

How? It's a smaller throttle body than stock, has no IAC provision, and is going to block off the fresh air inlet to the passenger side valve cover.

It is not a waste. The stock 454 intake as a whole is restrictive. I had a customer do this with a 4" air intake and a 4" MAF tube with a LS3/LS7 cartridge MAF. It added about 15 hp compared to the stock setup on a mildly cammed 454.

Same comments as above. How did your customer overcome those items? I'd assume you would have to just manually set a higher idle than you normally would and then just deal with higher variation when things like AC come on that would change idle load?

What is a "cartridge" MAF? Is that the slot card style?

 

[L31MaxExpress]

How? It's a smaller throttle body than stock, has no IAC provision, and is going to block off the fresh air inlet to the passenger side valve cover.


Same comments as above. How did your customer overcome those items? I'd assume you would have to just manually set a higher idle than you normally would and then just deal with higher variation when things like AC come on that would change idle load?

What is a "cartridge" MAF? Is that the slot card style?

I do not know why some are claiming the stock throttle body is larger. I have a 454 TB and it is 70mm all the way through it.

My customer had a GM IAC on his 90mm throttle body. If that unit is lacking one, I overlooked it.

Cartridge MAF could also be considered a slot card style.

 

[dzynda]

The Holley efi 85mm that is pictured
Does have an iac location there is a small hole on the inside intake side of the flapper.
As well as a throttle position sensor location.
I would have blocked off the tube coming off the 85mm throttle body which comes out behind the flapper. I was giong to use the stock location on the intake to the valve cover. I see how that wouldn't work though because the Holley would block it off.
Like Bextreme said
Maybe a breathe filter on the valve cover, idk.
The picture is a stock 1997 vortec 454 throttle body that measures
3.5" or 88.90mm at the front opening
3" or 76.2mm at the end going into the intake.
It tappers down.
The Holley is 3.25" or 85mm all the way through with a spacer that tappers down to 3" or 76.2mm to enter the stock intake.
I'm not sure what year your throttle body is L31maxExpress? I haven't paid much attention to my other trucks tb either.
I'm curious how he got 4 inches of air into the stock intake though. I was thinking of a plastic maf housing instead of metal, JET performance, Delphi, Cardone, and a few others on summits site. It looks like they use the newer style sensor with a plug adapter but I believe that they are still 3.5"

 

[L31MaxExpress]

Mine was a stock L29 454 TB and the typical one I see on 96-00 454. My buddies 1999 K3500 dually had the same unit. I measured it all out swapping the marine manifold on my 350 and ran it on my 350 for a while. The Marine unit had the same TB bore dimensions as the 454 unit. I just spent a little time looking the 454 unit, but it is MIA at the moment. I did find the marine unit used on the 4.3-454 and even some 8100s. It is basically the same as a L29 454 from prior measurements. It is just under 72mm as deep as I could measure with my calipers amd it is narrower yet at the blade. The blade itself is around 70mm when it is removed and measured. I said 70mm and the image above not even at the narrowest point is less than 72mm; so close enough as it is nowhere near 86mm.

I will add the BBK 80mm made a difference even on my L31 350. I had a 3.5" to 4" air intake and a 4" MAF setup on it. Added about 15-20 gms/sec of airflow at the 5,500 rpm shift point and increased the WOT MAP reading from 88-90 KPA to 95-96 KPA.

You must be registered for see images attach

 

[Supercharged111]

The one on my 350 necked down to 72mm at the base, but was bigger up by the throttle body. I wallered it out to about 75mm eons ago.