Spring rate, wheel well size, and lowering springs

[M_a_t_t]

I am looking at fixing/patching the rust on my mercury tracer. It is a common problem for this car to rust the rear strut towers out. I am thinking about other things I might do while working on that portion of the car.

Sample pic:


I am thinking about welding up a small frame to tie the strut towers into the clean area of the trunk. I also have a hole in the wheel well I would like to do something about.



Which leads me to my questions.

1. What is a good size tire to plan for in the future? I am currently on 165/65 14's (re92's), but I looked at tirerack's website and there doesn't seem to be many options. Different rim size possible if worth it for a good (eco-oriented) set of tires.

2. I am thinking about shrinking the wheel well with the replacement. Most super cars have little to no fender gap. I would assume having a tighter fitting wheel well is better for aero (aka filling in the gap ecomod #39/65+). Of course the other option is just cover the wheels up.

3. I bought some cheap lowering stuff awhile ago (~5/3/2020). It's a "universal" aka really cheap kit. The MOOG stock replacement coil springs are 113 lbs/in rear vs ~130 lbs/in for the cheap kit. Front are MOOG = 156 lbs/in vs ~230 lbs/in. Both MOOG are are also listed as variable rate. It sounds like it might be fine, but the replacement springs are not as long (actually about 1/2 the length of the originals). The only lowering kit I could find for this car uses the same concept, but cost 10x as much. Thoughts? Just cut a coil off the stock springs?
Cheap kit:
https://www.amazon.com/Integra-Alumi...a-6185fb77bc58


Expensive:
https://groundcontrolstore.com/colle...3-91-98-tracer

[me and my metro]

It looks like the left rear lowered itself. Sorry I couldn’t resist. Most people will tell you not to cut factory springs. I have used cut factory springs for many years on many cars with good experiences. My current Saturn L200 has rear spring with one coil removed along with half the snubber. When you cut a factory spring the effective spring rate increases making it slightly stiffer. I actually put v-6 springs in place of the 4 cylinder springs to get a little more front travel. My car sits pretty level now instead of the factory rake.

I have seen and worked with the aftermarket coil over conversion stuff on a limited basis. The spring rate is up for stiffer ride but the springs are shorter so there is less travel available. This works well on the track or autocross course but can be brutal on the street. This type of coil over equipment also make ride height and chassis loading adjustable. It depends what your plans are for the car. Is it going to be a street car that you want lower to the ground or a race car that will be hammered on on the street?

I drive my car on the street and watch other people race their toys on the autocross courses. I have raced stock cars in the past and have several years of track chassis tuning experience.

Rust is a difficult thing to deal with once it gets to the structural parts of the chassis. Be thorough with diagnosis and cut it out to good metal then build it back. You may decide to find another donor body shell for your project.

[M_a_t_t]

Yea. My towers look pretty good, but apparently they rust from the outside and I've got a line of rust working up the pass. wheel well.

Car is my DD with an ecomodding focus. I tend to mod my cars and this is the one that I mod the least intrusively (surface level might be a good way to put it). So just to lower the car for street use.

At this point I just want to make the car last a little longer. I am keeping an eye out for a cleaner car, but right now don't have the $$$. Plus I figure I can transfer any mods if/when I get one.

[freebeard]

That failure is due to vibration. Tie the tops of the struts together with a stress bar.

[M_a_t_t]

Originally Posted by freebeard

That failure is due to vibration. Tie the tops of the struts together with a stress bar.

Regardless of what that car had issues with, I have some rust issues to fix in the area. I might add a DIY strut brace as it shouldn't be too difficult to add.

Rear half of wheel well from inside the trunk:


Front half from inside the car (opposite view of pic posted in first post)



I also was looking at new(er) eco cars and the mirage still uses 165 65 14's so I should be able to get a decent set of tires in the future (if the car makes it )

[freebeard]

A piece of conduit, a hammer and a drill. If you can abide the intrusion into the interior space.

[M_a_t_t]

Something I didn't think about regarding the strut brace. There is a platform/metal shelf that runs across like an inch above the strut top. There is actually cutouts to be able to put a socket on the mounting hardware for the strut mount. You think it will still help? It's dark out right now otherwise I'd grab a picture.

[M_a_t_t]

Finally grabbed that picture. I don't think adding a strut brace here would make much sense.