Putting on the 74mm TB shortly with NW CAI and EC Tune. Most cars I've had I've worked the TB over. On our first XF I swapped the TB but didn't work it over. Seen lots of folks here swap in the larger TB, but yet to see someone radius the intake, knife edge the butterfly plate or profile the shaft and mountng screws. Small gains but the mods are free. Figure I'll post up progress pics here. TB is due in here this week so I'll start on it right away. CAI will be a few weeks.

There's not as much meat on our TBs as others, so not sure it will make as much difference, but the price is right to try. $50 for a 74mm TB and an hour or so hacking at the TB with a Dremel and files.

Pic of Honda TB shows the effect.

 

See this thread. CLICK
There is a shaft profiling thread somewhere but I cannot find it, but here is the Mercedes version also mentioned. CLICK

 

Excellent, thanks! Looks like he skipped the gains at the plate mount. I'll take it a step further. Should be good for another 1/4hp. Or maybe just add a couple Ricer stickers. Same effect I hear.

 

Came in today, I'll start working it over this weekend.

 

I have two 05 coupes, SRT and a NA, want to mod both, got a SRT TB and sent it to MAXBORE and he punched it out to 78mm, I will put it in the SRT and use the stock one for the NA. Have the CAI for both and the SRT has the bigger chiller and isolation valves.
The MAXBORE guy does a nice job.

 

Just one added suggestion? Replace both of the 'O' rings when installing them. Too many have had air (vacuum) leakage when using the old 'compressed' ones. I used petroleum jelly to hold mine in place while assembling it, and never had a problem with it slipping out of the 'slot' or leaking air. Just a FYI.

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Will do, I will look for new o-rings too?

Dan