Originally Posted by Iraq Sucks

just ported mine last night...seems like throttle response improved significantly.

Originally Posted by m3srt

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

Originally Posted by CI DENALI

Cool! Can you feel any difference on the top-end SOTP? That's where mine seems to pull harder, and I picked up just over 1 mph in trap speed on the 1/8. I'm glad we found some kind of option for the TB since I went through that whole drama where I couldn't get the LS2/vette TB to open all the way.
I didn't get to go to the track to back up that 8.3 sec run yet, but I hope to do so this weekend.
On a different note: Which one of the Mast Cams do you have?
I'm interested in the Mast L92HO cam, but when I spoke to Horace at Mast the other day, he recommended the smaller Escalade cam since I use my truck occasionally for towing. Also, how difficult was it to get it tuned for the cam?

Originally Posted by CI DENALI

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...

Originally Posted by VMax

hey did you cut away the whole step? Because i talked to a machine shop and they said if they cut 95% of the step away then it will not seal right and that will cause it to not idle properly. And they said it is flat down low because the step was angled so the air would shoot into the top half of the butterfly. Hit me up with some feedback, cuz i am getting mine done as we speek and i need to know what to tell them.

Originally Posted by CI DENALI

I did cut away the whole step, but I did not cut it back to where the throttle blade sits at idle. My truck idles fine. The flat spot is all but gone too, so I'm now convinced that it can be tuned out altogether. I don't buy the angle of the air idea either, because I've seen a picture of an 09 L92 (actually now called an L94) TB that a guy posted on here and the step is gone, so GM must have decided it's not necessary. The air angling off the step is exactly what kills airflow through the throttle body, I think. I also think that the step is really there to give the TB and soft progressive throttle response at low throttle input. That's why some guys are seeing snappier throttle response with this mod, IMHO.

Originally Posted by VMax

They smoothed away the step almost like when you get your heads ported. But it is not totally gone. Just a nice smooth flowing look. I could tell a difference in throttle response and Charlie is re-tuning it for me soon. But thanks for the heads up on this mod.