Drilling caliper orifices?

[G8White1]

So an identical '09 G8 GT pulls in next to me at the gas station - and the guy really wants to talk G8. I noticed his calipers are painted black and I eventually asked him if he knows how to decrease the petal travel. I already had SS lines to install but this guy says SS lines are not needed - that the best way to a quicker petal is to open up the caliper orifices. And I wouldn't be here if I had just asked him - what size bit? He was right about the SS brake lines - it helped a bit but I want the petal to tighten up 'faster.' After installing Centric rotors and ss lines, I am happy with the brakes otherwise - and now once they start to grip the feel is firm and linear - not spongy at all - I just want that feel at the top of the travel.
Now I have new caliper seal kits and ready to drill - but I can't find a darn word about drilling orifices on the web. I would try this but for concern about messing up the front to rear bias.
I would appreciate input from direct experience, just don't want a lot of supposition about it being a bad idea.

[Leon McJones]

That's a new one on me. Let us know what you find. Seems one could mess things up if not done right. probably best not to tempt fate for safety sake if there isn't an answer

[-Ray-]

It's new one for me.

[TooManyHobbies]

Even the Google finds nothing for that.

[WhiteHotMess]

That doesn't make any sense. The inlet to the caliper is already as large as the banjo bolt. There is no "orifice" to be drilled out. The only sort of restriction would be the two holes in the bolt, or the internal diameter of the banjo bolt itself.

[Napalm]

DON't

THE SMURF


DON"T: The only orifices that he might be talking about would be taking apart the caliper and drilling the little holes inside the body where the fluid presses out through the body into the "pots". IE taking the pots out of the caliper and relieving the holes in there - please don't bother. Now if he got them choked up with paint when he painted them - different animal.


OK so you drill the caliper - did you maybe increase the diameter of your hoses, or your lines, or those B nuts in the junctions, or the orifices at the ABS Control valve . . . . . . stem to stern.

NO you didn't


well get all that done first or well perhaps and this is an unintended consequence.

See OK he took the calipers off maybe - etc. Perhaps in his haste of what he did - he also forgot to mention how the lines leaked down - how the caliper dried back out - and how he ended up with new fluid from stem to stern and happened to also get all new fluid with no bubbles in the caliber too. Doing a full flush and fill - and getting all the air out and a good clean fluid with quality SS lines will make wonders to your brake feel. first stop, repeats stops on hot brakes either way.

But don't go drilling things. NOW about that initial travel question - that's designed in - and it's inside your ABS controller more so than anywhere and it is there to allow you to press and create some initial operting pressure incase the ABS system and the Electronic Brake Force distribution - has to activate while you are stopping. IE it's the headroom that allows that system to work even on gentle braking. (Let's the system work with light foot pressure as well as it would work if you were in a stomp to the floor situation).

Most cars with ABS, EBD and Stability assistance (IE most cars built after 2007) have this same sort of feel and it's fairly minimal. It is however not going to be like a race car or a built car without those systems. There needs to be some headroom.

[Napalm]

OH and which calipers? some have different sized orifices behind the pots on purpose so as to equalize their movement under pressure. There is a reason those are designed the way they are. It's about controllability of the brake.

[MIEngineer]

I would not touch that, there are so many factors at play here with system articulation, system & pedal tuning, etc - it will be hard to control unless you feel like spending money on replacement parts, and any sort of liability issues.

I would not try that at home, GM engineering spent a lot of time on this application and the tuning [I worked on it at the time with an export model initially]

[STL_G8GT]

Wouldn't touch it.

Sent from my LG-D851 using Tapatalk

[52WASP]

It's funny, I was waiting for MIEngineer to chime in here, and he didn't let me down! Old-school "dumb" brakes are one thing, but when you have a computer helping the brakes work, you have to tread very carefully. Drilling orifices was lost on me from the beginning of the thread though, just sayin'

[MIEngineer]

A lot of work goes into the application system, tuning and changes take time and a lot of work [and validation]