Front Caliper Orientation?
Thread Starter
Burning Brakes
Joined: Sep 2003
Posts: 1,196
Likes: 29
From: Wine Country, CA
Front Caliper Orientation?
I recently installed a pair of front calipers off of a '97 993 on my '82 928 (already had a '86.5 front suspension installed).
The 993 calipers are mounted on the leading (front) edge of the rotor while the 928 calipers are mounted on the trailing (rear) edge of the rotor. So, to make the 993 calipers work, I had to swap the bleed screws and cross-over pipes end-to-end. Otherwise, the 993 calipers bolt right up.
Since the conversion, I've been wondering why the 928 calipers are mounted on the trailing edge of the rotor while other Porsche's have the calipers mounted on the leading edge. Is it just packaging or is there a technical reason?
Anyone know the rational for the different placement?
James
The 993 calipers are mounted on the leading (front) edge of the rotor while the 928 calipers are mounted on the trailing (rear) edge of the rotor. So, to make the 993 calipers work, I had to swap the bleed screws and cross-over pipes end-to-end. Otherwise, the 993 calipers bolt right up.
Since the conversion, I've been wondering why the 928 calipers are mounted on the trailing edge of the rotor while other Porsche's have the calipers mounted on the leading edge. Is it just packaging or is there a technical reason?
Anyone know the rational for the different placement?
James
Thread Starter
Burning Brakes
Joined: Sep 2003
Posts: 1,196
Likes: 29
From: Wine Country, CA
Actually, I was just looking at photo's of the Panamera "Sport Turismo" and noted that the calipers on the Panamera are mounted on the leading edge. That's what spurred the question.
James
James
Rennlist Member
Joined: Jul 2002
Posts: 3,269
Likes: 5
From: Deep in the Heart of Texas!
Only reason I can think of might be air flow for a particular car's underbody or clearance to suspension parts. My car has true Big Reds from a 993, and it was same thing, had to reverse the cross over tube and bleeders to flip the calipers for a 928 .... otherwise identical in every respect.
Thread Starter
Burning Brakes
Joined: Sep 2003
Posts: 1,196
Likes: 29
From: Wine Country, CA
Just saw some photo's of the new McLaren P1. The P1 also mounts the front caliper on the trailing side of the rotor (albeit clamping the lower portion of the rotor - as opposed to the 928 clamping the upper portion).
Any brake engineers out there who know the rational for the different caliper placement on different vehicles?
James
Any brake engineers out there who know the rational for the different caliper placement on different vehicles?
James
Rennlist Member
Joined: Nov 2006
Posts: 14,878
Likes: 2,798
From: Pittsburgh, PA
the orientation of the caliper on the rotor has no effect on stopping. The caliper could be mounted bottom center if they had wanted. It is an aethestic issue and a clearance issue for the other things in the wheel well.
Drifting
Joined: May 2004
Posts: 2,837
Likes: 16
From: Rochester, NY
I would guess cooling has a bit of an issue with placement. Engineering wise they do the same thing, though the back up is either pushing or pulling depending on placement around the spindle and suspension axes, not sure that matters here though.
Other thought would be the positioning of the tie ro connection, in front of or behing the shock/spring.
Other thought would be the positioning of the tie ro connection, in front of or behing the shock/spring.
