In my development, I have speed bumps at most of the stop signs. At this one stop sign the speed bump is like 10-15ft before the stop sign, so I usually hit it while slowing down from like 30mph. If I am braking and have the clutch full in when I hit this speed bump, the car suddenly stops more rapidly, making a strange noise like I am dragging something, and I can also feel it on my pedals. Any ideas what this could be? I haven't gotten under the car yet, but just looking around I don't see anything. Only thing I can think of is maybe a motor mount is bad?

 

Sounds like the ABS (and/or TCS-VSA, depending on how it's equipped) activated when it saw the large variation in wheel speeds. Normal operation.

Try coasting over the bumps without touching the brake pedal.

 

I agree—you're likely feeling the ABS system working as designed (which may not be as you would like it to work). Going over the bump is causing fairly large momentary differences in the pressure the tires press against the ground with, which means the braking force available before slipping on each tire is changing. Without ABS, there's a good chance you'd be squeaking a tire a bit during this process. Driving more like a granny (a stereotypical granny, maybe not your own Granny) might not be a bad idea.

The other possibility, particularly if the speed bumps are relatively high/large, is that you're bouncing enough to hit the bottom of the car against the speed bump. I don't think that's as likely, particularly if you haven't lowered your car, but it is possible and would happen more if you have a heavy load in your car.

 

That makes a lot of sense, never thought about it being the ABS, but I think you are right, that now that I think about it, it does feel like ABS.
Thanks

 

Added to that, the jolt of hitting the bump is going to add to the pressure your foot is putting on the brake pedal. That makes the ABS even more likely to kick in once the car's weight is off the fronts.