Exotic-metal55

I originally shaft ported my 74, then my 80 and now my 82mm.. Been holding off, as with stock manifolds still on thre car, extra TB flow is now doing much.. Hope to have headers pretty soon, so I did a little pre-grinding..

I am sure we would all like to see before and after dyno numbers and bench flow numbers , as well as have a dyno in our garage.. I test what I can and when I can but this is just one of those mods I like and do regardless.

I did a very conservative grind job on this TB and only removed about 40% of the shaft material .. I still need to clean up the top inlet side and grind off the screw threads on the bottom but you can get the idea..

Mathamatically speaking, this will increase the flow area to an 85mm TB.. Just flattening off the top of a round shaft will increase flow and cut down on turbulence..

Stock 82mm inlet side, before grinding.

Stock 82mm TB motor side.


Ported shaft motor side and I left screw threads sticking through to help show material removal. I also red locktite these and then smooth off after they set for a few minutes.



Another pic; showing flow angle on ground shaft. Top screw head side is ported left and screw heads are left intact.




Here is another shot before grinding screw tips off..

shardul

iTrader: (1)

Nice work

Luke_M

You're the man. When I get mine I think I may send it straight to MaxBore to max it out.

Exotic-metal55

Be carefull having your TB (especially a $$$ 82mm) bored out.. These large fly by wire TB`s are very, very hard to bore and calibrate air flow for ECU idle.. We live on the knife`s edge of an idle code as it is and if a drop of extra air comes by at idle, you wull live with the P505 code for ever..

Cable driven Tb`s are very easy to take apart and bore out but our fly by wire TB`s are very tricky on these MB`s..

Luke_M

On his website he indicates that he has lots of experience with drive by wire so that was encouraging. Is it the "seal" that can be screwed up?

Exotic-metal55

Getting the electronics apart on most FBW is pretty easy but after they bore the TB out, they have to put a larger butterfly blade in.. This is the part that is going to be real hard on our TB`s, as most of us are at 1.4% TPS opening. This very low and on the border line for a P505 code.. They would need some way to calibrate the factory air flow and keep the new bored TB and butterfly opening the same or less (within a 2%). Maybe they have some kind of air flow measuring system and it will be fine.. Ask them, when you call.

Another option, is that one of the tuners figure out how to adjust our TPS calibration, so we can keep a smooth idle and no codes.. Maybe just raising the idle a hair would solve the problem.. Just ideas and thoughts..

Sounds like you are game to try, so please let us know how it goes and I will send mine in too..

Luke_M

Well I was game to try lol I'll have to save this info and ask questions when the time comes. Thanks Brooke! You're a weatlh of information!

ryan b

I have a stock throttle body and want to do this mod. Can the computer compensate for the extra air on it's own without getting a re-tune? Thanks