djnikko

anyone on here bored out a standard throttle bodie on a honda? noticed much difference in power Mine is 56mm as standard I think i can widen this another 3mm just wanna know if it worth it. Port and polish cylinder head on the way also

LeftNut

Check www.proflowdesign.com he's JHill on this board. More info on throttle BODY boring than you can shake a cam at ........ what?

djnikko

thanks for that
couldnt find much info on it thou maybe i am doing somink wrong... I was looking for figures if poss. I am porting the the intake manifold, cyl head and throttle body all at the same time so hopefully they will all compliment each other nicely anyway

JHill

There is little chance that you can successfully bore a throttle body yourself without creating major idle issues. Ask Beau.

If a port and polish is what you are referring to, that can be done, just don't get anywhere near where the plate closes the airflow. Doing the port and polish may enhance airflow, especially if you do it on the upstream side of the throttle plate at the lip. It will probably not yield any measureable result on a dyno, but it should flow more on a flow bench. A throttle body that has been rebored will flow considerably more air than a ported one. This has shown measureable gains on forced induction applications. We saw a 14hp increase on a SC S2000, going from a 62mm to a 64mm throttle body, with a 70mm ported inlet.

Jim

stevecivic

i bored throttle body on my crx zc motor with a hone tool and there was quite a bit diffrence.
steve

LeftNut

..... did it hurt?

djnikko

nice cheers for the advice Jim... I heard that little lip on the entrance ot the TB can cause a bit of turbelance but i dunno
i got a ZC too steve, well kind of its a d16a9 ... did you just do the throttle body or a bit of port polishing on the cylinder/intake manifold? did ya get any idling problems? My bro is a CNC bod so ive given him the parts to machine all properly... should come out alright with any luck i'll let you know how it goes, im off to tenerife tomorrow

LeftNut

Mating the new "larger" throttle plate to the new "larger" bore is the tricky part. Two things to keep in mind, the throttle plate is not round (not a constant radius) and I don't believe the edges of the plate are perpendicular to the plate itself (I think they're parallel to the centerline of the bore in the closed position so the leading edge is undercut and the trailing edge fat).
In any case, ENJOY!

S P E E D

I ported and polished my TB on my civic si/zc. I noticed a gain...nothing insane but still worth the time doing. Like stated above, stay about a little less than an inch away from the throtle plate then work your way out. Measure the inlet side of the TB every now and then to check how much you've taken off. If you have the right tool you can measure it on the inside also to check the surface area. Make sure You measure properly so you keep the area equal. Once you've got it down to the size you want, Polish the ****** to a mirrior finish.

After I did Port and polish on my TB and going to bigger grounds I went from 15.0 to 14.9. Like I said...nothing insane but track condition that day was good. I'll tell you more after my dyno results.