Looking for ideas on a bumpstop for a G-body rear

[SSLance]

I'm looking for a way to gain some rear suspension travel to keep my frame off of the bumpstops during hard corners while autocrossing.

I'm running DSE 2" drop springs, and the 1 5/8" PU bumpstop that came with them on my QP 9" with the Ford racing disc brake kit with the calipers clocked low and to the front. The top caliper mounting bolt is the first point of interference if the suspension cycles too far followed very closely by the bump stop mount itself.

Here is the suspension compressed (springs and shocks removed) until the current bumpstop was up against the frame

https://static1.pt-content.com/images/pt/2013/05/DSC02121-1.jpg (http://smg.photobucket.com/user/LSVLance/media/1985%20Monte%20Carlo%20SS/DSC02121.jpg.html)

Here is pretty much the same shot with the bump stop removed

https://static1.pt-content.com/images/pt/2013/04/20120829_185328_443-1.jpg (http://smg.photobucket.com/user/LSVLance/media/1985%20Monte%20Carlo%20SS/2012-08-29_18-53-28_443.jpg.html)

This is at ride height, shows at or around 2 1/4-2 1/2" of travel with current bump stops

https://static1.pt-content.com/images/pt/2013/05/DSC02146-1.jpg (http://smg.photobucket.com/user/LSVLance/media/1985%20Monte%20Carlo%20SS/DSC02146.jpg.html)


I have a set of OEM rubber bump stops in the 2 5/8" height and today I ordered a used set of OEM rubber bump stops in the 1 5/8" height.

My thought is to trim a set of them down to 1/2-3/4" height or so just to give protection to the caliper bolt from bottoming against the frame while increasing my suspension travel at the same time. Haven't decided which set of stops to try trimming on first though?

Am I looking at this correctly? Is there a better way for me to increase my suspension travel without raising the car back up? Would I be better trimming on the PU stops or the OEM rubber stops? What do I have to be careful about in that regard? Should I trim them to a point like the OEM ones or just cut the top of them off flat?

Appreciate any help anyone can give.

Thanks,
Lance

[no go nova]

Stiffer springs maybe? Or a larger sway bar?

[SSLance]

So what I did last week was take a sawzall to my 2 5/8" OEM rubber bump stops making them about 3/4" tall and flat across the top. This gained me almost another full inch of suspension travel before the frame contacts the bump stops.

This actually made a pretty big difference in both the street driving and the autocross last Sunday. I now know just how often the frame was contacting the stops and messing with the ride\handling quality. I can't tell that it has actually got to the bump stops as they are now nor has the frame got into the caliper bolts.

I'm going to leave it like it is for a couple of weeks and see how it goes. I'm doing a 2 day track weekend with NASA at HPT this weekend then an autocross and PDX at HPT next weekend as well. Should really test the suspension travel and the stops enough to let me know if this is a permanent fix or not.

[jlcustomz]

Spraying a little fresh cheap paint in the area may help you determine contact.

[SSLance]

Everything under there is pretty freshly painted, that part of why it was hard to tell if it was contacting the bump stop or not.

I'll get it dirty this weekend though I suppose.

[Ron Sutton]

He meant applying paint to the surface of the bump stop ... where it would contact the frame ... so you could see if the bump stop touched the frame any. We use tire crayon, because it comes off easier.

[SSLance]

Ah...I gotcha... That makes sense. Thanks.

[SSLance]

80 laps of Heartland Park Topeka later, it looks like the right side caliper bolt smacked the frame only once...and bent it just a bit.

I'm pretty sure I know when that happened too, when I hit a hole in front of a rumble strip setting up for a corner that gave me grief all weekend long. I'm calling the mod a success and leaving it like it is. It certainly corners a LOT better with the frame staying off of the bump stops, I'll take that benefit over any of the other options available to me at this time.

[Ron Sutton]

Thanks for the update Lance !

Would getting the car to run a smidge flatter help the cars handling ... and provide some insurance the brake caliper bolt doesn't hit again?

If so, springs, sway bar, roll center adjustment, etc, could be options.

[SSLance]

I suppose it would Ron but at the same time that would also effect my street driving ride and the class I run in in Solo (sway bar mounting point). All things to consider, it's an ongoing process right.

My next upgrade is going to be front brakes, it needs to stop better before I get it much faster on the track.

I will point out one thing I learned this weekend with it though, when I learned to get it whoa'd down for a corner while still going straight and then turned into the corner with the suspension relaxed, the suspension really worked better at helping the tires grip the track. Was the first time I really realized just how much difference it makes in grip to have the suspension relaxed and working properly in a corner. Same with exiting a corner, get past the apex straighten out the wheel and hammer down...car would stick, track straight out of the corner and build a bunch more speed rather than fighting the wheel trying to keep the back end under it out of a corner.

[Ron Sutton]

Cool. Thanks for the updates!