Ported throttle body question
06-05-2009, 06:21 PM
#21
your the last person i would have expected to say this....i guess i should have left my ls6 heads alone because gm put thousands of hours and hundreds of thousands of dollars on the development of my heads...sure, GM did the hard part of engineering, but aftermarket porting of factory parts can be bettered by a dremel. porting is a proven mod.
i dont see how money can be spent much better. do it yourself for less than 10 dollars in material.
i dont see how money can be spent much better. do it yourself for less than 10 dollars in material.
I don't see how someone could notice a seat of the pants increase with such a small mod (if it was even proven beneficial) especially in these heavy trucks.
06-05-2009, 06:29 PM
#22
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porting of stock parts has proven performance gains since the engine has been around...You may not get the gains on newer heads and such that you used to get on older stuff, but gain none the less. Now if you have joe blow down the street who thinks he can port heads and throttle bodies just because he owns a dremel, you might be in for a disappointment, but if done carefully it can definitely improve power. The new boss hoss bikes that i work on for a living have ls2's and ls3's in them, we have a very good engine builder do the major work on all of our motors and he always hand ports the heads and the tb's when he does any work. He also built our 632 ci big block that makes 922 hp on pump gas. These guys know what they are doing and i doubt they would do something to decrease power when they get paid to increase. He is also the guy that ported my heads and tb.
06-05-2009, 06:48 PM
#23
your the last person i would have expected to say this....i guess i should have left my ls6 heads alone because gm put thousands of hours and hundreds of thousands of dollars on the development of my heads...sure, GM did the hard part of engineering, but aftermarket porting of factory parts can be bettered by a dremel. porting is a proven mod.
i dont see how money can be spent much better. do it yourself for less than 10 dollars in material.
i dont see how money can be spent much better. do it yourself for less than 10 dollars in material.
I think you are missing the point again. Until you open up the actual ID of the TB and increase the size of the opening you are not going to see much if any gain. What you are actually doing is "smoothing" the air path, this will improve the way the TB "processes" the air...but not how much air it will take in. What are you doing when you CNC a set of heads? OPENING UP THE INTAKE AREA!
You are NOT taking in any more air until you OPEN up the effective throttle area. Anything else is snake oil and will be a negligible gain at best.
But hey, I am an idiot.
06-05-2009, 07:09 PM
#24
I would have to say the noticed gain is probably more from cleaning the TB that anything else.
Agreed...
I agree with you. Until you open up the narrowest point, there will not be a significant increase in CFM through it. There will be a small increase from SMOOTHING the flowpath, and another small amount from grinding the throttle stop, so all told, YES, you may feel a slight difference, and a crisper throttle. However, what BlownChevy is saying is there is alot of potential for error when porting the TB, that the "risk vs. reward" is upside down here, and the money is better spent elsewhere. Now, if you are doing it yourself, then go to town, the result is free, whether its good or bad.
Agreed...
I agree with you. Until you open up the narrowest point, there will not be a significant increase in CFM through it. There will be a small increase from SMOOTHING the flowpath, and another small amount from grinding the throttle stop, so all told, YES, you may feel a slight difference, and a crisper throttle. However, what BlownChevy is saying is there is alot of potential for error when porting the TB, that the "risk vs. reward" is upside down here, and the money is better spent elsewhere. Now, if you are doing it yourself, then go to town, the result is free, whether its good or bad.
06-05-2009, 11:44 PM
#25
EDIT: Just did some rough math: If you have a 78mm TB and the part of the shaft you remove is 3mm thick, you have increased the cross sectional area 5.6%, 4mm is 7.5%.
Last edited by TX Tahoe Z71; 06-05-2009 at 11:54 PM.
06-06-2009, 12:34 AM
#28
I think you are missing the point again. Until you open up the actual ID of the TB and increase the size of the opening you are not going to see much if any gain. What you are actually doing is "smoothing" the air path, this will improve the way the TB "processes" the air...but not how much air it will take in. What are you doing when you CNC a set of heads? OPENING UP THE INTAKE AREA!
You are NOT taking in any more air until you OPEN up the effective throttle area. Anything else is snake oil and will be a negligible gain at best.
But hey, I am an idiot.
You are NOT taking in any more air until you OPEN up the effective throttle area. Anything else is snake oil and will be a negligible gain at best.
But hey, I am an idiot.
