After a bit of pondering, I ported my throttle body couple weekends ago and when I took the truck to the track the other night, I was pleasantly surprised that it ran a 8.36 ET @83.4mph in the 1/8. Before that it was running consistent 8.5x @ 82 mph. I haven't changed anything else other than oil (Mobil 1 to Valvoline Racing Synthetic) since then.
This was with a 125 shot of N2O. It's a '08 Sierra Denali AWD with a Volant CAI and Wheatley (e-mail) tune and a ZEX kit with 125hp jets. Everything else is stock except that I have the D20 wheels (which weigh a ton!) This was a better gain than I expected, and it still feels a little flat down low, like it probably needs a retune for the additional airflow. Here are some pic's of the TB unported and ported. The Stock 08 TB has a huge "step" on the bottom and a smaller one at the top behind the throttle blade, which obviously restrict airflow, both of which I removed. Apparently, GM has removed it from the '09's (at least on the 6.2's). Best bang for the buck mod I've ever seen...

 

Awesome job on the porting mister!! Would you happend to know if the throttle body of the 09s work on a 5.3...?

 

Thanks. I'm not sure if they do. I believe all the late model trucks have the same FBW 87mm 4 bolt throttle body as mine though, so it should bolt up if the 5.3has a 4 bolt TB that lks like mine. The 09 one is otherwise identical to mine, just has the big ridge removed.

 

my buddy wants to do this on my truck with a dremel ... what exactly is the process ??

 

A Dremel would take forever. I used an air tool with a non-ferrous cutter for the rough cutting and then used sanding rolls from coarse to fine to get a smooth finish.
You have to be really careful that you do NOT touch anywhere inside the idle range area of the throttle blade. In order to accomplish this, I used a red Sharpie marker and marked the edge of the throttle blade all around the circumference of the TB. Then I pushed the throttle blade back as far as it would close and made another mark around the circumference. I then removed the throttle blade and shaded the idle area (the area in between the two lines) with the marker, so that I could see where the idle range was when I was cutting. IT IS VERY IMPORTANT THAT YOU DO NOT TOUCH THIS AREA WITH THE CUTTER OR YOUR TRUCK MAY NOT IDLE PROPERLY. Work very carefully with the cutter and remove the ridge on front bottom flange of the throttle body. When you've gotten it to like 95% removed, start using the coarse sanding rolls from there.
I would say the whole process took me a couple of hours from start to finish.
Be prepared to be covered in aluminum shavings - those suckers get everywhere - you'll get lots of silver in your hair from this! Good luck.
Please note that, like I said before, you may have to retune your truck a bit, because it has a bit of a flat spot at low throttle input, because of the sudden increase in airflow, with a small throttle input. I'm gonna try to deal with that this weekend. I will also test the truck further tonight and report back how it runs.

 

oh man this sounds a lot more confusing than i thought ... im kinda having second thoughts on letting my buddy do it .... i dont mean to bother you, but is there any way you can show me where not to polish ect ect /... sorry im really dumb when it comes to things like this thats why i uasually pay someone to do it the right way for me

 

Sorry bud, I'm kinda kickin myself for not taking some photos of what I did so that you would understand better what I'm talking about. Basically you can do 95% of what I did by just leaving the blade in and cutting the hump out from in front of the blade, taking care not to hit the blade or cut where the blade sits.
(Or, do what I was thinking I might have to do if I f@cked it up, which is buy a '09 TB!)
Hope that helps somehow...

 

ok i get it now ....

you were usign all those big words and i diddnt understand LOL

 

Just ported mine last night seems like it improved throttle response significantly.

 

Just ported mine last night seems like it improved throttle response significantly.