when you do a tune do you have to do a throtle body bypass? what is the purpose of this?
thanks
Terry

 

This mod is simply to prevent hot water from flowing through an area where one would prefer to have the air colder.

I believe it's design is to help on start-up in colder temperatures.

Technically it should provide some HP because you are allowing colder air (not heated) into the engine but any effect this has is very minimal and some in the coldest areas of the country remove the bypass each year for the winter months to help with engine warm-up.

Hope this helps

 

Some will tell you that it is a worthless mod! Others sware by it. All I know is that it removes hot water from the TB and that the 05-06 C6 LS2 engines do not have the hot water flowing through the TB. I have the by-pass in mine and have not seen any ill effects. I live in New England and drive my car in the winter. Can I pin point an exact HP/TQ gain? NO!! I believe that the By pass added to other mods like the cold air induction and the TB Porting make the package complete!

There should not be any effect on tuning but any mods that you do should be done all at once prior to your tune. While your doing the TB bypass, you might as well go ahead and do the TB porting! I did mine myself! Just shape and don't hog too much out. The walls of the TB are thin in a few areas!!!! If you take too much out you will break into a void in the casting.

BC

 

Thanks Bill for this info, I happened to be considering this porting myself last few days. How did you do it ? Some kind of grind using a dremel ? Special compound used ? Any pics ?
Thanks in advance - Patrick

 

Thanks for the replys and info. wasnt sure of this little mod but now i know its ok.
thanks
Terry

 

Patric

I used a dremmel tool with a sanding roll. You don't need to remove too much. The area around the mouth is where I took off the most. Right where the walls meet the area where the blade rest, you will see a transition. I blocked the throttle blade off with some thick card board so that I didn't hit that area. The area where the Throttle blade rest is off limits and if you scar it up, get a new TB. The area between the mouth and the transition is thin in two areas. Ask me how I know? I saw a very small area where the metal got thin and started to depress. It goes into a void so there wasn't a problem just filling the small depression with JB Weld and sanding it smooth. You cant even tell there is anything wrong!

There is a depression where the intake tube for the PCV hose gets its air and a vent for something else (cant remember what it is.) some people use a Brass tube, extend the vents and fill that in so that there are only two small holes there instead of a deep depression. I just smoother the sharp edges down and called it a day.

If you imagine a molecule of air trying to enter the TB you will see all the places that it could have problems with. You want the straightest entry to the throttle blades that you can get. I also smoother out the throttle body shaft by removing a small amount from the top of the shaft , smoother the screw ends and took some metal off the bottom of the shaft. I basically made it smaller to the air flow.

You can finish the TB polish job in the mouth with 400 wet and dry, then 600 and then use some polishing compound. Mothers mag and aluminum polish works excellent! It will shine like a mirror.

This is the STOCK un-ported TB.



I will take some pics of the ported one tomorrow and post them

BC



Bill

 

 

 

Here is a pic of mine after I ported it, but before I put the plade back in...