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Model specific boards => Golf mk3 => Topic started by: hyland770 on 03 October 2009, 20:52

Title: porting throttle body.......how much off!?
Post by: hyland770 on 03 October 2009, 20:52
today i set about cleaning my throttle body inside and out...... great success!
then after that thought i may as well have a go at porting it, so i got the correct drill and drill bit out and started sanding down the sides of the throttle body above the butterfly, but then realised i had no idea how much to grind out!!?
i searched in the search section and on none of the diy's does it say how much to take out!
so what im wondering is how much do i want to grind out?
do i want the walls of the t/b to be really thin and thus the hole bigger (if you know what i mean)
if someone could post some before and after pics of theirs so i know what im trying to achieve that would be a massive help...
p.s. i realise this would be best with pics but its dark outside and i didnt take any at the time, im guessin you know what im on about as a lot of you have already done this mod!
Title: Re: porting throttle body.......how much off!?
Post by: Khare on 03 October 2009, 21:34
at the bottom on the front there is a large hump, remove that.

At the top, on the back there is a bigger hump, remove that too. Job done  :smiley:
Title: Re: porting throttle body.......how much off!?
Post by: hyland770 on 04 October 2009, 13:25
i was trying to find these humps and couldnt see any, maybe its already been done!?  :huh:
Title: Re: porting throttle body.......how much off!?
Post by: Khare on 04 October 2009, 13:42
i was trying to find these humps and couldnt see any, maybe its already been done!?  :huh:

You must see them....post some pics.
Title: Re: porting throttle body.......how much off!?
Post by: VW BUSH on 04 October 2009, 14:01
(http://img515.imageshack.us/img515/7123/tbody.th.jpg) (http://img515.imageshack.us/i/tbody.jpg/)
Front at polishing stage
(http://img89.imageshack.us/img89/6513/photo017p.th.jpg) (http://img89.imageshack.us/i/photo017p.jpg/)
Back at polishing stage
(http://img41.imageshack.us/img41/5342/photo019h.th.jpg) (http://img41.imageshack.us/i/photo019h.jpg/)
More front  :grin:
(http://img41.imageshack.us/img41/3112/photo016wq.th.jpg) (http://img41.imageshack.us/i/photo016wq.jpg/)
Back with core shut off highlighted with cutter
Title: Re: porting throttle body.......how much off!?
Post by: axewielder on 05 October 2009, 11:35
just smooth off the steps as much as poss, you want smooth transitions, just dont take it off where the butterfly is when shut or youll get dodgy idle like khare
Title: Re: porting throttle body.......how much off!?
Post by: Horney on 05 October 2009, 11:37
Knife edge the butterfly and fill and smooth the screws in the butterfly shaft while you're at it.

nick
Title: Re: porting throttle body.......how much off!?
Post by: Baskey on 05 October 2009, 18:59
Is it worth doing? Iv found keeping them clean is vital on these engines but does going to the trouble of polishing them help the engines performance??
Title: Re: porting throttle body.......how much off!?
Post by: Khare on 05 October 2009, 20:19
Knife edge the butterfly and fill and smooth the screws in the butterfly shaft while you're at it.

nick
Don't.

I learnt the hard way. Scrappy hunting tomorrow for a new one  :sad:

As DH said, it wont make much difference if you knife edge it, yet it can cause so much trouble.
Title: Re: porting throttle body.......how much off!?
Post by: Horney on 05 October 2009, 20:28
Knife edge the butterfly and fill and smooth the screws in the butterfly shaft while you're at it.

nick
Don't.

I learnt the hard way. Scrappy hunting tomorrow for a new one  :sad:

As DH said, it wont make much difference if you knife edge it, yet it can cause so much trouble.

Yes if you do it badly and try on a spare one not one you actually need! I've done this to loads of carbs and 2 of my MKII golfs but always picked up a spare TB or carb and done it on that then fitted it. I need to pick up one for the current MKII to do.

nick
Title: Re: porting throttle body.......how much off!?
Post by: VW BUSH on 05 October 2009, 22:00
Knife edge the butterfly and fill and smooth the screws in the butterfly shaft while you're at it.

nick
Don't.

I learnt the hard way. Scrappy hunting tomorrow for a new one  :sad:

As DH said, it wont make much difference if you knife edge it, yet it can cause so much trouble.

Yes if you do it badly and try on a spare one not one you actually need! I've done this to loads of carbs and 2 of my MKII golfs but always picked up a spare TB or carb and done it on that then fitted it. I need to pick up one for the current MKII to do.

nick

Turn a new one with a 30 or 45 degree angle on it :smiley: