Seeking advise/opinion

[Highway Man]

I have a couple of questions that I would appreciate some feedback on and the first one is that I have been considering lowering the rear of my 92. I think the previous owner lowered the front because I have less tire showing in the fender well on the front than on the back. Upon looking at the rear bolts that can be replaced with longer bolts to achieving lowering the rear I noticed that I have approximatly an inch and a half of thread showing below the castle nut. Why couldn't I just measure down one inch make a mark and then lower the castle nut to that mark and then thread a lock nut up against the castle nut to prevent it from coming off any further? My next question is that my car has the 3:07 rear differential and I have been considering going to a 3:54. Would I notice enough difference to justify this gear change or would the difference be so negligible that it wouldn't be worth it? My car has the automatic transmission. Thanks in advance.

 

[boomdriver]

Your front may be lower by a worn spring. Fronts are different. When any crack they just settle down and drop. You can take shims out to lower it some...not a inch.

Rear....you can drop the castle nut to the bottom of the rod as long as there is some pretention on the bolt. Dont back it out so far that its loose. This allows the full arc of the spring...which is not near enough to help at the very beginning of the spring travel but people think so, so why not......

Lower the ass end by replacing shims in the center spring mount. swap the shims around. There should be some in over the spring and some below. Move them all to one side to lower. Thats 1/2" or more. Just make sure the clamps are snug against the mounting blocks so the spring is not loose in the mount.

 

[Hib Halverson]

(snip)

Rear....you can drop the castle nut to the bottom of the rod as long as there is some pretention on the bolt. Dont back it out so far that its loose. This allows the full arc of the spring...which is not near enough to help at the very beginning of the spring travel but people think so, so why not......

(snip)

In the rear, DO NOT run the castle nuts to "bottom of the rod". If you do, the bolt will fracture at the cotter pin hole, the suspenson will collapse and the spring will contact the gound. If this happens while you're driving loss of control of the vehicle is possible.

The only way to safely lower the rear suspension is to replace the OE bolts and castle nuts with longer, aftermarket bolts and "nylock" nuts.

 

[boomdriver]

Your front may be lower by a worn spring. Fronts are different. When any crack they just settle down and drop. You can take shims out to lower it some...not a inch.

Rear....you can drop the castle nut to the bottom of the rod as long as there is some pretention on the bolt. Dont back it out so far that its loose. This allows the full arc of the spring...which is not near enough to help at the very beginning of the spring travel but people think so, so why not......

Lower the ass end by replacing shims in the center spring mount. swap the shims around. There should be some in over the spring and some below. Move them all to one side to lower. Thats 1/2" or more. Just make sure the clamps are snug against the mounting blocks so the spring is not loose in the mount.

CYA ----CMA in everyway.

 

[Highway Man]

Thanks for the feedback

I was wondering about that cotter pin hole being a weak spot in the bolt and the possiblity of it snapping off. Oh well, a new set of bolts isn't expensive and for sure less of a question about safety. I didn't think about the front setting lower because of weak springs but it rides good and as far as having any issues with the front end I haven't I would still appreciate some feedback about my rear gear swap question. Thanks guys.

 

[John Robinson]

Here is the formula for figuring gear ratio to rpm at road speed I believe you can just plug in the gear ratio you are asking about and do the calculations,

Here is the formula for figuring the rpm for the different gear ratio

RPM=mph x final drive ratio x gear ratio x 336
________________________________________
26

So lets use the final drive ratio and gear ratio for my 93 for this example

75 x .70 x 2.59 x 336 = 456876 Divided by 26 = 1752 RPM

Now all you have to do is plug in what ever ratio you want

Using a 3.73 instead of a 2.59 will have the following results at 75 MPH the RPM will be 2530 or 778 RPM more per mile.

You can simulate this by dropping the trans into a lower gear that puts the rpm in that range at 75 to see if you would like that on the road.

As others have said the MPG and the traction will be big issues but this would give a lot more low end performance without touching the engine.

If the engine has any miles on it this will increase the piston wear factor by about 7% because of the increase in what is called feet per minute.