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Discussion Starter #1
If not, then why are throttle bodies manufactured with enough material for you to bore them? Is this an emissions deal? Gas saving deal? What's the deal? Also, what is "porting" a throttle body?

Gear heads, show your stuff. ;)
 

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The C5 throttle bodies have a waterjacket to run coolant through them so they don't ice up in cold humid climates. That's why those are kinda 'fat'.

I ported my 99 TB. It was the first mod I did on my 99. I took my time and opened it up as much as possible. It actually made a small difference. I also did a little work to the blade and the shaft. I at least picked up a little throttle response. It's in the bottom of my toolchest now since I'm running a Nick Williams 90mm.
 

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Discussion Starter #3
So all in all, it really wasn't worth the hassle, especially since you can buy something better?
 

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As long as you replace the throttle blade with one of the appropriate size, there is nothing wrong with boring out a throttle body to match the bore of your intake manifold. porting of the LS series throttle bodies typically consists of polishing it and smoothing the transition from air intake to the throttle blade itself, ie removing the casting marks and ridge just before the throttle blade.

Doing so will cause you to throw codes if you increase the airflow too much, since it will be pulling in more air than the computer thinks it should be based on throttle position. This can be fixed with a little computer work.
 

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Discussion Starter #5
I figured as much about the codes. That's one of the main reasons that I wouldn't do mine.
 

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I had a fast 90/LS2 tb sitting in my garage for several years because there isnt a quality tuner in my area to massage the computer....well, there is Carolina Auto Masters but I have heard a bunch of dis-heartening stuff about Jeff Creech...lol
 

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I had a fast 90/LS2 tb sitting in my garage for several years because there isnt a quality tuner in my area to massage the computer....well, there is Carolina Auto Masters but I have heard a bunch of dis-heartening stuff about Jeff Creech...lol
I hear there's this guy you can go see who can work miracles on anything. I can't remember his name, but his name has something to do with beef. It just escapes me right now... :D
 

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good thing that beef guy isnt near me lol
 

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So all in all, it really wasn't worth the hassle, especially since you can buy something better?
I did it a while ago before the FAST. At the time only the BBK which was 80mm was available. I can tell you I made 347rwhp/352/rwtq with just an LS6 manifold the TB and Stainless Works headers with X-Pipe and Corsa's. Before I did the bolt-on's and with just an x-pipe and corsa's with VaraRam I did 316rwhp.

I would say I picked up a few hp/tq, but yes with what's available now, I would put it in the drawer and spend the money for a larger TB. That is if you're ready to do a tune.

It was a cool project for a boring weekend at the time though.

If you do decide to do it, be careful of the lip right at the bottom of the blade in the body. Be careful to not mess with it's contour, or it will screw up your idle transition. I touched mine only a bit and it was affected, but not much, so it's a sensative area.
 

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Porting the throttle body makes a HUGE difference. I don't know about boring one. I have a ported one on my Vette and my truck. Way better throttle response.

Here is a ported one next to a stock one.





 

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Discussion Starter #12
Okay, I understand boring one but what is the process of porting? What do you do to the throttle bottle when you port it? Porting looks as if you're shaving the walls. I thought that was what boring was... :huh:
 

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Okay, I understand boring one but what is the process of porting? What do you do to the throttle bottle when you port it? Porting looks as if you're shaving the walls. I thought that was what boring was... :huh:
Well they were talking about a large throttle plate. I've not heard of that like I said. Porting takes out the large hump that is in the factory one and it creates a much smoother surface allowing better air flow.
 

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Discussion Starter #14
Well they were talking about a large throttle plate. I've not heard of that like I said. Porting takes out the large hump that is in the factory one and it creates a much smoother surface allowing better air flow.
Okay, so what does boring do and what is it? I thought boring was the shaving down of the walls, which opened up the diameter of the throttle body opening.
 

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boring it out would mean increasing the diameter of the bore, ie 78 to 80mm, 90 to 92mm, ect. they typical porting just smooths out the transition into the throttle bore
 

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Discussion Starter #16
boring it out would mean increasing the diameter of the bore, ie 78 to 80mm, 90 to 92mm, ect. they typical porting just smooths out the transition into the throttle bore
AHA! That was what I was looking for! Now it makes perfectly good sense to me. Thanks! :thumbsup:

So, I don't see that there are any real cons to doing this, no?
 

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If you bore it out larger than the intake manifold, you will hurt airflow, and if you don't get a good matchup on the new throttle blade, idle quality and throttle response will be aweful.
 

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Discussion Starter #18
If you bore it out larger than the intake manifold, you will hurt airflow, and if you don't get a good matchup on the new throttle blade, idle quality and throttle response will be aweful.
I was reading about that somewhere when I was looking all this up. I was watching You Tube videos of guys who were using a Dremel tool to bore theirs out and they were not measuring anything. I couldn't understand how what they were doing couldn't have some type of adverse effect if the TB was machined to a specification. Now I can see that these Dremel junkies could be screwing up their cars. :crazy:
 

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I was reading about that somewhere when I was looking all this up. I was watching You Tube videos of guys who were using a Dremel tool to bore theirs out and they were not measuring anything. I couldn't understand how what they were doing couldn't have some type of adverse effect if the TB was machined to a specification. Now I can see that these Dremel junkies could be screwing up their cars. :crazy:
The Dremel junkies can and probably will see increases at the strip and on the dyno, but they will suffer from idle and part throttle driveability trouble as this is when throttle blade's fit and flow are most importent.
 

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I hear there's this guy you can go see who can work miracles on anything. I can't remember his name, but his name has something to do with beef. It just escapes me right now... :D
"Where's the Beef" :laughing: His beef comes with a side of BS:laughing::laughing:
Years ago I worked for Brandywine cylinder head. Top shop back in the day for all kinds of Pro racers. One thing I learned was bigger is not always better. Air flow is funny and sometimes we would ADD material in places to improve flow in heads or manifolds depending on the application. I don't remember much of the details anymore but know that most guys porting probably are not testing with flow benches and dynos, they are just making things bigger. If I was going to port something I would take it to a professional with a flow bench and a history of such mods(someone who ports and polishes for a living...not just a tuner) My .02 :cheers:
 
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