I have a Holley TB its a 52mm. A very nice piece but I'm wondering if I'm going to be limiting the motor or maxing out the TB.

What type of power would you say a 52mm becomes not enough. As for my car goes, its a Heads/cam and will be bottle fed.

thanks

 

...ttt

 

Best thing I can tell you is to watch WOT vacuum be that with a gauge plumbed in and taped to the windsheild or with logging software and watching the MAP. They display the numbers differently but I am sure you will figure it out. Went viewing the numbers in standard measurments the old rule was anything more than 1.5" at WOT meant you nneded a bigger carb for a street application with race applications using .5 as their guide. Now with the much more complex systems in front of the butterflies that we have you have to look at the system and determine what the restriction is it does not have to be the TB it can be anything in front of it. There is not real limit to how much power you could make with one because it will slowely become an increasing restriction with more vacuum building as the engine tries to move more air. Look at it this way boost is refered to as being how much air the engine is not flowing after the blower/turbo forces it into the intake, vacuum is much the same thing it is a measurement of how much atmospheric pressure is not getting to the intake.

 

Do yourself a favor and dis the ARE heads and get some from either AI or Lloyd Elliott. Do a search on ARE and you will find out why.

 

thanks 96capricemgr for the info. It does make since. I guess I'll try the 52mm out first. I may get a vacume guage in the car anyway so mabey I'll have a way of knowing a little bit.

While I accually do plan on swaping these heads out some time in the future. I don't exacitally like being reminded I got shafted from ARE. I mean, when I bought them 2-3 yrs ago, everyone on the boards thought they were the best thing since sliced bread. The only other real competitor at the time was GTP.

As much as I might be disapointed with these heads, w/ the EXACT same setup as me on a friends 94Z pulled 396 rwhp and pulled 117 mph in 1/4 through a 12 bolt, a bigger cam, and a home tune. And no wieght mods. I wouldn't say there the worst heads out there. But I agree I don't recommend them to others.
Not trying to be a di*k, I just don't like being reminded. It happened to MANY of us.

 

96capricemgr

I just was thinking. Would the vacume accually go down if you had a bigger TB? because its less resrictive. It seems like the smaller wouldn't flow as much and raise vacume.

Mabey I'm wrong..anyone else?

 

What vacuum does with a TB size change will depend on wether it was a restriction and wether there are other restrictions in front of it. If the TB is the restriction in the system then a larger one will cause a decrease in WOT vacuum, or a rise in manifold pressure depending on how you are viewing it. If there is a restriction before the TB then making it bigger might help a slight amount but the other restriction needs to be addressed.

 

Hey........ Nick got me too and I'm not trying to be a di*k, just offering advice based on personal experience. I had no idea of when you got the heads and you are trying to make more power right?

A 52 mm tb will sustain more power that you probably can get out of a stock block LTx regardless of what head or cam you use unless you’re planning on a very high dollar setup. 900 cfm will support well over 525 hp @ 7000 rpm.

I had Lloyd Elliot rework a pair of ARE LT1 heads for a very modest price and they are where they should be. He picked up 20 cfm virtually everywhere. I can even send you the before and after flow sheets if you would like.

For a little bit of money you can get over the ARE disease pretty easily. I’m sure AI can do the same thing.

 

thanks for the info, and is that flywheel hp your exstimating off of?

You also have a PM.

 

yep.

Thats around 425-430 at the rear with is super healthy for stock bhlock Ltx car which usually means at least real, real good LT4 heads or real good aftermarket heads turning a pretty high rpm.

Again.... I'll send you flow sheets and even a dyno sheet from the heads just off the dyno about an hour ago in which the car made 430 rwhp / 416 rwtorque with Lloyd's reported ARE heads. FYI the car is a 385 ci motor with a rather mild cam.

Waiting for my new Trick Flows and 398ci block to get done.