Professional Products tb any good?
just kidding, NO power difference. All 52mm TB are the same as any 52mm. Same goes for the 58mm. 
09-11-2011, 07:25 PM
#24
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Is that the ebay one? Mine sometimes sticks closed when I first start it but goes away as soon as the pedal is used. Also sometimes it idles higher than it should when put in park and if I pop the hood and push the blades all the way closed with my hands it will go back to normal but that may be due to the cruise control cables being removed.
09-11-2011, 11:25 PM
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Is that the ebay one? Mine sometimes sticks closed when I first start it but goes away as soon as the pedal is used. Also sometimes it idles higher than it should when put in park and if I pop the hood and push the blades all the way closed with my hands it will go back to normal but that may be due to the cruise control cables being removed.
This is the problem I was having with my holley that I was thinking about replacing. I ended up removing the tb, sanding the blades and inside of tb; this fixed my throttle sticking problem. Looks like I will not be buying a new tb after all.
09-12-2011, 12:35 AM
#28
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Really? I tried that a little bit, I guess I'll have to try more. I was confused though because I think I remembered when I took it off to see what was going on I held it up and could see daylight through the ends of the blade and the body of the TB. Is that normal?
09-12-2011, 12:56 AM
#29
I ran a PP TB for around two years before going with an AS&M (basically for the bling factor). I sold the PP maybe 3 years ago and AFAIK its still on that car working fine.
Performance wise, they are all the same. Quality wise, you will notice some differences. With the PP throttle body, I rotated the return spring one extra time for a snappier throttle return and to prevent it from ever binding - a problem that happened with the earlier models until they got broken in (not sure if they ever fixed that).
The AS&M is a work of art. It is expensive, but is perfect in every way - from the spring tension, billet construction, perfect CNC'ing, and polished finish. The bracket is a thick composite instead of the thin stamped piece of metal on the PP unit.
When it comes down to it, they both "worked" and of course made the same power...so whether or not its worth the price for a different model is up to you to decide.
For safety reasons though, I suggest anyone going with a Summit/PP throttle body(they are the same thing with different stickers) to rotate the return spring one extra time and lube it. I personally know of at least three people who have had them stick in very throttle percentages while driving, needing you to get your foot under the gas to push it back up. Not good!
Performance wise, they are all the same. Quality wise, you will notice some differences. With the PP throttle body, I rotated the return spring one extra time for a snappier throttle return and to prevent it from ever binding - a problem that happened with the earlier models until they got broken in (not sure if they ever fixed that).
The AS&M is a work of art. It is expensive, but is perfect in every way - from the spring tension, billet construction, perfect CNC'ing, and polished finish. The bracket is a thick composite instead of the thin stamped piece of metal on the PP unit.
When it comes down to it, they both "worked" and of course made the same power...so whether or not its worth the price for a different model is up to you to decide.
For safety reasons though, I suggest anyone going with a Summit/PP throttle body(they are the same thing with different stickers) to rotate the return spring one extra time and lube it. I personally know of at least three people who have had them stick in very throttle percentages while driving, needing you to get your foot under the gas to push it back up. Not good!
09-13-2011, 07:14 AM
#30
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Folks always complain about the LT1 not having any aftermarket. If you want companies to keep making LT1 stuff buy from people who pioneer parts and build them well here, rather than copying specs and sending them overseas to be made.
Lingenfelter and AS&M for me.
-Dustin-
Lingenfelter and AS&M for me.
-Dustin-
09-13-2011, 11:52 AM
#33
The big issue is making sure the PCM is programmed correctly for a given throttlebody...
There are changes required based on throttle position, ie, WOT setpoint, enrichments, shifting stuff for automatics (such as downshift point, etc) and all of those are based on TPS position percentages...
With a bigger throttlebody you need less throttle position for the same amount of air being consumed as with a smaller throttlebody.
Compensate for the changes in the tune and run whatever size you want...
09-13-2011, 05:41 PM
#34
Lets put it this way, GM put a 48mm TB on thier RAMJet502 motor, which produces 510+ hp. It isn't considered a restriction on that application, I highly doubt a 48mm on any LT1 is considered a restriction.
Now, run a solid roller cam to the point that you NEED to replace the intake manifold to gain more power and you may be in the range where you NEED a 52mm or 58mm throttlebody.
Honestly, if I ever ran a TPiS LT1 Mini-ram I would go with one of thier monoblades, for the simple reason of why not? Your spending mad cash anyway, might as well splurge a bit more...
But, in reality you try to remove as many restrictions as possible as a rule of thumb, thus going to a 52mm or 58mm throttlebody is considered a "normal" upgrade for LT1 motors. In general it jsut makes sure *if* you are going to be making enough power it isn't something you have to redo in the future. The key is, for just about any roller hydraulic build on here a stock 48mm TB or even a 52mm TB is all that is needed. Rarely is there a need for a 58mm or even a monoblade (reported to flow over 1300cfm).
Funny part is, for forced-induction applications anything bigger than 48mm is a waste, as you are forcing air through, so the "rated CFM" means nothing at WOT (ie, a stock 48mm TB is not enough of a restriction under pressurized air, as in you would need something much smaller for it to be catagorized as a restriction). But, then again, most boosted applications start out as N/A builds at some point or another, and why not put on you blingy-newer parts you already invested in instead of going back to a stock unit?
One thing of note, is that a stock TB *should* have an airfoil installed for performance applications above stock-levels. The smoothing of the airflow and reduction of turbulence has been known to have it's advantages.
So, to sum it up, stock 48mm TB with airfoil is fine for just about any buildup. A 52mm is about all anyone really *NEEDS* for a performance buildup (and the stock intake manifold will take a 52mm without modification). A 58mm is not needed until you are at solid-roller levels. A monoblade is never really *needed*. All perform the same function and all will work on just about any size hydraulic roller motor. Buy what you want and what makes you happy, but never be under the illusion that you NEED a 58mm or monoblade throttlebody.
Most people making big solid-roller motors and such will usually model thier motor in a simulator and you will know what kind of CFM is going to be pulled through the intake for a given setup, so you can use that to determine what is really needed. But, again, on a forced induction setup, nothing more than a stock 48mm TB with an airfoil is required for any power level.
09-13-2011, 11:14 PM
#36
Mathematically you would need to spin a stock shortblock to around 7K to require more air then the stock TB can flow. Since a combustion engine is a glorified air pump, you can always calculate its CFM requirements but using the CI and the maximum RPMs that it will see.
The formula is very simple and easy to remember...(RPMxCI)/3456=maximum cfm of air needed. This also assumes 100%VE, so most street engines would need even less.
These numbers are physical limitations based on strictly cylinder space and RPMs, so will usually be overkill in the real world. With a tiny cam and relatively poor heads you can get away with a much smaller TB without it being a restriction...like the RamJet 502. You put a real cam in that thing and the TB will be quite a big bottleneck! Its running a smaller cam then most of our street 350s do, but in a 502ci big block(!).
The formula is very simple and easy to remember...(RPMxCI)/3456=maximum cfm of air needed. This also assumes 100%VE, so most street engines would need even less.
These numbers are physical limitations based on strictly cylinder space and RPMs, so will usually be overkill in the real world. With a tiny cam and relatively poor heads you can get away with a much smaller TB without it being a restriction...like the RamJet 502. You put a real cam in that thing and the TB will be quite a big bottleneck! Its running a smaller cam then most of our street 350s do, but in a 502ci big block(!).
09-14-2011, 08:51 AM
#37
Be carefull with the PP TB. I ported the intake openings to the gasket that came with it and when I put the TB on the intake to check, I opened the throttle blades and could see the bores did not line up. The intake needed more material removed around the top of the bores. After checking the gasket to the TB I could see that it was just a little off. After triming about a 1/16 off the gasket and the intake everything lined up and looked good threw the throttle blades. I should have took some pictures but did not.
Last edited by 96lt4c4; 09-17-2011 at 07:25 AM.
