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View Full Version : What Are Your Thoughts on Porting a Throttle Body?

Bigredmariner
11-10-2009, 12:10 PM
I ran across this last night and wanted to get some feed back from our group. I am interested in hearing what you guys think about it. Is this another gimmick or is this something worth trying? Discuss.

Port & Polish Throttle Body
http://i181.photobucket.com/albums/x251/05GTO6SPEED/0311htp_projls1_09_z.jpg
A home-ground throttle body is an easy way to get more air into the Gen. III engine. To perform this procedure, unhook the throttle position sensor (TPS) and idle air control sensor (IAC) connectors from the throttle body. The throttle cable and coolant hoses are removed also, then the three 10mm bolts holding the throttle body were removed.
http://i181.photobucket.com/albums/x251/05GTO6SPEED/0311htp_projls1_10_z.jpg
The TB was taken to a workbench and mounted in a vise; a carbide bit and some 80- and 120-grit paper rolls were waiting for it. Porting the Gen. III's throttle body is done to remove a restrictive ridge in front of the throttle blade and to generally make the contours smooth. You want to take out the turbulence and increase velocity, but don't go hog-wild because the carbide bit can burn through pretty quickly. Use the 80-grit to smooth out the carbide burr cuts, and the 120-grit to polish the throttle body smooth.
http://i181.photobucket.com/albums/x251/05GTO6SPEED/0311htp_projls1_11_z.jpg
Any sharp edge on the throttle body should be buffed down.
http://i181.photobucket.com/albums/x251/05GTO6SPEED/0311htp_projls1_12_z.jpg
don't do heavy porting in the idle air bypass area--that will force air into this spot that doesn't need any more.
http://i181.photobucket.com/albums/x251/05GTO6SPEED/0311htp_projls1_13_z.jpg
Mild port work is performed on the back side as well, and the throttle blade screws are ground down. Once the TB is cleaned up, it is ready for reinstallation.
Cowboy Cadillac
11-10-2009, 12:41 PM
Makes sense to me as long as you don't grind around where the blade touches the tb, or around idle air bypass.:dunno: I don't forsee much gain though.
dietz4ibanez
11-10-2009, 12:44 PM
Well I think the TB on my black truck was about 68mm and I always thought about getting a 72mm... But the more that you think about it I don't think that you will ever be able to justify the cost of purchasing a new one...
I don't know how I feel about honing out the stock one... I wouldn't IMO...

I'd say that you would be just as happy sticking with an upgraded cold air intake and possible an aftermarket Mass Airflow sensor followed by a BB tune and you should be pretty happy with that..
Draenor
11-10-2009, 01:01 PM
I dont think that little lip will make that much of a difference if it is ground down.Seems like a lotta work for minimal gains.

The Gen 3 TB is flow rated enough to be used on the 8.1L.
vmax2007
11-10-2009, 01:06 PM
I dont think that little lip will make that much of a difference if it is ground down.Seems like a lotta work for minimal gains.

The Gen 3 TB is flow rated enough to be used on the 8.1L.

:withstupid:

I am betting an Edelbrock sticker would net you more gains. :D
daddy
11-10-2009, 01:09 PM
That lip is designed to make the air rotate, like a built-in Tornado. Removing it actually decreases power. Dummies. :crazy:
EMS_0525
11-10-2009, 01:18 PM
I bet you wouldn't notice that much of a gain if any... my mass air flow sensor was going bad on my sonoma and i put an aftermarket high performance one on and it made a big difference, and i had a throttle body spacer and a cold air intake.
Alljackedup408
11-10-2009, 01:18 PM
For a street vehicle.. this is just a waste of time and money.. IMO. If you race.. and have strict class rules like have to have stock TB and stuff.. then porting it would make all the sense in the world. A lil gain here and there adds up. But on a daily driver... i wouldnt waste my time.
CJ Hungus
11-10-2009, 01:42 PM
I think that it increases throttle response some, but as said before, for a street vehicle with minimal other modifications, a waste of time.
mr_bots
11-10-2009, 01:52 PM
I don't think that it'll do anything at normal engine speeds just because the air won't be flowing fast enough for the turbulence caused by that lip to affect the velocity of the air. At very high rpm's there might be a slight advantage, but I doubt you'd notice it. I'd put the time and money elsewhere.
66nova
11-10-2009, 04:52 PM
For a street vehicle.. this is just a waste of time and money.. IMO. If you race.. and have strict class rules like have to have stock TB and stuff.. then porting it would make all the sense in the world. A lil gain here and there adds up. But on a daily driver... i wouldnt waste my time.

+1

This mod only works if you add 2 throttle body spacers. :jester:

Seriously, I think Justin told me the stock throttle body will support something like 500-600hp
B-rad
11-10-2009, 05:03 PM
exactly. unless your makin about 475-500 hp its a waste of time and money. if your makin
500+ its a good mod but still modest gains
Stumpuller6.2
11-10-2009, 05:15 PM
I think that it increases throttle response some, but as said before, for a street vehicle with minimal other modifications, a waste of time.

exactly. unless your makin about 475-500 hp its a waste of time and money. if your makin
500+ its a good mod but still modest gains

i have a 75mm TB (stock is 72mm TB), all i noticed was better throttle response. :dunno:

they do make 80mm bodies too, may have to try one one day on my setup just for shits and giggles, if someone gives me 300 bucks. :dunno:
daddy
11-10-2009, 05:18 PM
For a street vehicle.. this is just a waste of time and money.. IMO. If you race.. and have strict class rules like have to have stock TB and stuff.. then porting it would make all the sense in the world. A lil gain here and there adds up. But on a daily driver... i wouldnt waste my time.

+1

This mod only works if you add 2 throttle body spacers. :jester:

Seriously, I think Justin told me the stock throttle body will support something like 500-600hp

Yeah, but what would he know? :D
Bigredmariner
11-10-2009, 05:51 PM
Sounds like you guys feel the same about it as I do. If you have a high HP engine or racing that would be about the only reason I could see to even try this mod. Daily driver it is a waste of time.
daddy
11-10-2009, 06:13 PM
My guess is you wouldn't even have this TB to worry about if you were going after big horsepower for racing anyway.
99chevy7.4L
11-14-2009, 02:04 PM
this is the throttle body I put on all my big block dually's. The diff is night and day. When they say 20HP they mean it. Flows 1,000 CFM's to no check engine lights no idle issues nothing. NO AFFILIATION WITH THIS SELLER. Just a happy customer.

http://cgi.ebay.com/ebaymotors/1996-99-BBC-Vortec-454-7-4L-78mm-bored-throttle-body_W0QQcmdZViewItemQQhashZitem563706ca98QQitemZ370290379416QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories