tube80z

Not to be argumentative but you can increase caster and not increase trail. I also think you'll find that pneumatic trail's contribution to self centering is much smaller than that of caster or SIA. Cary

I think mostly what your seeing is a design that has less SAI (steering axis inclination) and a lot of caster. Where I think the magic is in new cars is the bushings. The can be very compliment in certain directions and very stiff in others. Cary

I used to have a severely bent race car and it always pushed in one direction and was loose in the other. When I measured the car I found the wheelbase was about 1.5 inches shorter on one side. Squaring the car made it work the same both ways so I would say this can be used. On a friends car pushing the wheels forward for more caster move the balance close to 1% to the rear. But you have to be careful with rules as a lot of sanctioning bodies require a specific wheel base. Cary

I asked Claude Rouelle in his seminar what he thought of the hyperco perches and he said there were no better than the torrington bearings and caused problems with frequency response in the suspension. He shared a few cool videos from Ohlins engineers that showed how much the spring would rotate and bend out of plan under load. I think Hyperco may have something similar on their site. In the ICP seminar (Richard was a presenter) he talked about the perches and how back in the days of IMSA GTP that they would often see shock shaft failures from the bending loads being placed on them. These perches remove most of that and allow everything to more with less friction. When I asked about struts he said that they tested in a dyno and it looked okay but on the track the side loads caused so much friction there was no real benefit to be gained. For a street car I wouldn't use these as they require frequent rebuilding unless the design has recently been changed. For Toby's BMW has you tried hanging the ARBs from heims as has been discussed before. It makes a similar contribution. Cary

Oddly I had a similar list I was thinking about. I talked to Richard Pare (he invented the hypercoil perches) and he said they offer no advantage on a strut suspension. Were you thinking about them to reduce NVH? I would add a few things. Woodward custom power rack and KRC pump to be able to adjust the steering feel to my liking. An upgraded HVAC system and a decent cruise control. I had a new 1978 280Z with factory air and it doesn't come close the to the system that was in my SER or my Titan. And for NVH I've often wondered if you could put some sand on a bare floor and run the car to see if there were wave patterns that formed (perhaps too low tech). Cary

Nothing. 14x7 is an oddball and you'd be better moving to a larger diameter that has a better tire offering. As OEMs keep going bigger the sixes for our older cars are getting much smaller. Cary

Years ago I got to watch this car at PIR (Portland) and it would outrun all the IMSA GTP cars down the straight and then get caught in the braking zone. Over and over this happened and it was very entertaining. Cary

One thing not mentioned is body size. Try them in your hand first. I bought an original Canon DLSR and won't switch because of lenses. If I could start over I might start with Nikon now and that's based on how it fits my hand. I'm not a fan of how both Nikon and Canon downsized the bodies for the lower end cameras.

MST3K

The pond is a lot bigger than you have here. Basically all the green after the straight is water. Too bad you can't see the big burn mark and tree I knocked over from a few years back. We're now entering the corner at the end of the straight in the low 90s. The last recovery should be on youtube judging from all the cell phone video I saw being taken.

3/16 like yours. These got made in a hurry and I had intended to add a gusset but ran out of time. They do flex some but seem to work okay. My tie downs aren't at a super steep angle so maybe that helps.

Sorry, I totally blew that one. They also work really well when pulling the car out of a certain pond at the end of certain track ... but I don't need to say anymore about that. Cary "three times is too many"

They are the same arms that were in one of the construction threads from a couple of years back. I have the toe-link at the rear but they are very similar to your. Cary

On a 240 be very careful hooking into the rear suspension. When I started making some toe-link control arms I found a number of these had been bent from being hooked to and cranked down. The 280 arms are much stronger but after seeing this I built toe hooks like Jon mentioned to be able to quickly tie the car down. Cary

One thing to think about is you can add a lot of weight with wheels, tires, and brakes. Those add up quicker than some of the suggestions already given. Cary

Some showroom stock racers I knew years ago told me they stitched because you can pull the damage back out. With just spot welds the parts often split making it impossible to do. So I also don't understand why you wouldn't want to have things welded up front and in back. cary

If this corner is at the end of a straight your tires will cool down. Using the brakes really hard will help get them back up to temp. If you don't have them at the operating window you may chase your tail thinking it is a shock tuning/geometry issue. Cary

You can go the old school route and used a captured spherical in place of the stock lower control arm bushing. I'd bet someone locally does those and it should be a lower total cost. Cary

Here's an example from a friends car.

I can't count the times I've almost ran over another car towing and trying to get up to speed to merge on a short onramp only to have someone barely moving or stop at the end. Cary

I drove back from Alaska and found the drivers from BC nuts. Passing on blind corners, into tunnels, etc. This was all out in the middle of nowhere but it was always plates from BC. Cary

It's odd to hear fuel running out the throat. In my experience a high fuel level will cause problems with both barrels not just one. And generally you'll have fuel coming our the air vent hole too. If you run the car when it's stationary can you see this? Things I'd check are the acceleration pump circuit (make sure one isn't leaking after they squirt) and make sure the choke circuit is turned off (I seriously doubt this has anything to do with the problem). Check your gaskets as sometimes they do fail and cause leaks. Also make sure the venturi is properly seated. A loose grub screw will allow the barrel to rotate but you'll generally have an issue with the car missing if that happens. You didn't mention anything in our post about that. Everything works fine except for the leak? It also sounds like you have other things to look for too. Cary

The penultimate and ultimate crossmembers were something I did the design work on many years ago. We were racing 510s then and wanted to reduce the rear camber gain to try and keep the wider tires flatter to the ground. Almost all of the tech that was figured out is in this thread. The big thing we found was that you wanted to try and keep the rear trailing arm level or close to level so the camber and toe didn't change as much. The trailing arm angle changes both the toe and camber curves as well as RC position. At least on the 510 the suspension seemed less sensitive to camber being changed on the inner pickup. I would expect the 280ZX to be similar but that should really be verified. Cary

Please note I have deleted a number of posts from this thread that didn't appear to add any value to a really good thread. I would like to ask that we try and keep on topic so it ranks very well in search engine relevance.

Actually I had a similar problem and when I started running limiters and it helped to fix this. The pics Jon has shown plus a number of others were showing the car on the inside edges of the inner tires. The limiters helped keep the inner tire flatter to the road (look at the yellow car example, which was the original car wear all this was tried out). Up until that point I was continuing to de-camber chasing tire temps and was seeing similar wear issues. I would at least test this to see if it helps. Cary