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TB porting questions..

Bio248

Bio248

DUI BABY
im looking to port my stock l67 TB since i dont really like my northstar setup as much as i thought i would as far as pedal feel and tps problems. i also dont have cruise control, which sucks in a whole other category.

what is the main problems with the throttle body besides the maf hump? Where do i go about epoxying the top portion of the throttle body for when i break through doing the maf hump? do you port out behind the throttle blade or just on the inlet side? how many people port out the inner bore enough to use a bigger throttle blade?
 


GTP SE has been doing a lot of porting work, he might be able to help... look for his posts and pictures...
 
Brian, aka Reptile on the boards, did my TB Porting. Check out his work!!

Sorry for the blury pic in this one, but you can see the before porting of the TB and the hump in it.

DSCF0058.jpg


This is pic is when he took most of the hump in the TB. Just a little bit of shavings :)

DSCF0078.jpg


Then he used a little JB Weld to round out the TB at the hump to make a smooth trasnition.

DSCF0088.jpg


After smoothing out the JB Weld and matching to the rest of the TB. No more hump and clean shot into the intake. I like it :)

DSCF0093-1.jpg
 
There are two trouble spots. Both on the front part of where that hump is. You will break through the housing around the 1 o'clock area when you're looking into the throttle body. When looking down on top, this area is the spot between the MAF mount and the lip of the TB. You can deffinately see it. The other spot is where the screw runs down in the 11 o'clock area for the front of the MAF. A little bit of epoxy in between the first area will take care of the problem, and then a little dab from the inside into the thread, but not too much or the screw will push it right back out, and then you have the potential for a leak.
 
alright, the front portion should be easy, but the part where the maf screw goes in might take a try or two.
 
Reptile said:
There are two trouble spots. Both on the front part of where that hump is. You will break through the housing around the 1 o'clock area when you're looking into the throttle body. When looking down on top, this area is the spot between the MAF mount and the lip of the TB. You can deffinately see it. The other spot is where the screw runs down in the 11 o'clock area for the front of the MAF. A little bit of epoxy in between the first area will take care of the problem, and then a little dab from the inside into the thread, but not too much or the screw will push it right back out, and then you have the potential for a leak.
Click to expand...
I concur
Heres one I did before polishing the inside.
ThrottleBody003.jpg
 


so with the maf post sticking into the center like that, is it good to leave a little bit of a lip to ramp the air around it or just take it all the way down like you did (gtp se)?
 
I done it both the way you see in the pic, and actually ground the forward edge of the maf sensor to conform with the ramp of the TB. I did not notice any difference between those two setups.
 
After....sorta.

Rough it in, cut down as far as you need to, then after you've broken through the housing, put the JB weld down in the crevice from the outside, smooth out. If you're going to build a "ramp" up to the MAF sensor, do that after as well, and then smooth the whole thing out with an 80 grit flapper, then go up to a 120.
 


I think throttle response is improved more than anything, but it all depends on your set up. I think its more beneficial as far as the flow goes in higher HP applications. (IE Cam, headers, IC, Rockers).
 
well, its not super pretty at the moment but i wanted to make sure it worked. drove it, like it better than the northstar. i really need to just put a bunch more epoxy down and then round it out well. ill take pictures when i make it nicer looking, probably this weekend.

anyone want a northstar setup?
 


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