Lowering Procedure Question

[1969Fstback 58]

For those of you who have lowered your own car. What procedure did you follow. My plan is to lower the rear 2 inches first. Then lower the front to match. I want the car to be level. I plan on cutting the factory springs. I know its a cut, reinstall, check process.

 

Any tips to help me either not screw up, not get hurt and/or not do something stupid. Normally one of the 3 happens, but part of the fun.

[barnett468 418]

determine how stiff you want it to ride.

 

buy reverse hey springs in the weight you want detroit spring can also make them . . drive it for a few days because they well settle.

 

you can NOT cut stock springs, you need lowering springs.

.

[1969Fstback 58]

I was gonna use blocks in back and cut the front coils springs.

 

So I don't want to cut the front springs?

[barnett468 418]

I was gonna use blocks in back and cut the front coils springs.

 

So I don't want to cut the front springs?

 

 

you can NOT cut stock springs, you need lowering springs.

 

...........................

[1969Fstback 58]

I tried to fined 2 inch lowering springs and could only find 1 inc lowering springs. I'd much prefer buying new ones instead guessing and checking anyway.

[barnett468 418]

I tried to fined 2 inch lowering springs and could only find 1 inc lowering springs. I'd much prefer buying new ones instead guessing and checking anyway.

 

ok, you CAN cut lowering springs because they are stiffer than std springs . . if you cut std springs your front end will bottom out.

 

the lightest 1" lowering spring is around 480 lbs . . your stock spring is around 220 . . it will be noticeably firmer with the 480 springs but will not ride like a rock . . you need good shocks to keep the front from bouncing with stiffer springs . . after you install .lowering springs in the front the rear will feel even softer.

.

Edited December 15, 2014 by barnett468

[1969Fstback 58]

gotcha, I seen a 2 inch lowering spring last year can't find it now.

[barnett468 418]

gotcha, I seen a 2 inch lowering spring last year can't find it now.

 

its sometimes better to get the 1" and cut it but if you get a 2" and its too low you can buy thicker spring pads so its easily adjustable fortunately.

.

[Guillaume69 150]

I cut my front stock springs about 10 years ago. I removed 1 coil. Drove the car 60,000 miles since, to include a couple (gentle) track days, and lots of mountain driving. Never had a single issue. Car is a GT.

 

For what it's worth.

 

G

Edited December 15, 2014 by Guillaume69

[barnett468 418]

I cut my front stock springs about 10 years ago. I removed 1 coil. Drove the car 60,000 miles since, to include a couple (gentle) track days, and lots of mountain driving. Never had a single issue. Car is a GT.

 

For what it's worth...

 

G

 

your spring rate is higher than a non gt so this is why you could get away with it . . my other guess is that you do not have cheap $10.00 shocks on it . . high damping shocks reduce the potential for bottoming.

.

[Guillaume69 150]

I have Koni Classics all around.

[barnett468 418]

I have Koni Classics all around.

 

lol, i knew it...

[Guillaume69 150]

As far as I am concerned, best shocks for a driver, hands down. ;-)

[barnett468 418]

As far as I am concerned, best shocks for a driver, hands down. ;-)

 

nope, although they are certainly xlnt shocks, dual adjustable ones are but they start at $200.00 each and run to around $1,000.00 each.

[SA69mach 39]

I have done the same as Guillaume69, with GT springs cut down. They run around 520lb I think, so they can handle a small cut.

The lowering effect was minimal though. I made the cut primarily because the front was too high. I lowered around an inch. I cant exactly recall if I cut one coil or half of one coil - which is the important information I guess - sorry.

 

My engine is a 302 with aluminum heads, so, not a lot of weight up front.

 

The car does not look "lowered" at all. The ride is firm but not harsh, Never bottoms out. I have a big front stabilizer bar and Bilsteins all round.

 

I regard Koni and Bilstein as very high quality shocks, just different approaches to the body roll issue. Koni is stiff compression and mild rebound. Flat cornering effect

Bilstein Mild compression and stiff rebound - gives slight roll in on cornering, which loads the outside tire, and gradual re-balance on exit.

Both make for an exciting drive in spirited driving.....

 

Two inches drop would need a well calculated lowering spring, based on front end weight, and in combination with all the other suspension components

The condition of your suspension, ball joints and idler/pitman arms, front stabilizer bar, control arms, perches, and all rubber bushings is important, and critical with a large drop. All those parts need to be in top condition.

 

I agree with Barnett on 480lbs front coils for a small block and a 2 inch drop, with a quality shock to match.

A 2 inch drop on a GT coil I think will not work, the spring will just be too short and be way out of spec for bind and compression rate.

 

Edit - The work I describe was on my 302 powered T5 trans 1970 coupe, not the Mach 1. The coupe is a far better driving experience. The Mach 1 is just old school cool, haha

Edited December 15, 2014 by SA69mach
clarify vehicle as not on signature line

[SA69mach 39]

I have done the same as Guillaume69, with GT springs cut down. They run around 520lb I think, so they can handle a small cut.

The lowering effect was minimal though. I made the cut primarily because the front was too high. I lowered around an inch. I cant exactly recall if I cut one coil or half of one coil - which is the important information I guess - sorry.

 

My engine is a 302 with aluminum heads, so, not a lot of weight up front.

 

The car does not look "lowered" at all. The ride is firm but not harsh, Never bottoms out. I have a big front stabilizer bar and Bilsteins all round.

 

I regard Koni and Bilstein as very high quality shocks, just different approaches to the body roll issue. Koni is stiff compression and mild rebound. Flat cornering effect

Bilstein Mild compression and stiff rebound - gives slight roll in on cornering, which loads the outside tire, and gradual re-balance on exit.

Both make for an exciting drive in spirited driving.....

 

Two inches drop would need a well calculated lowering spring, based on front end weight, and in combination with all the other suspension components

The condition of your suspension, ball joints and idler/pitman arms, front stabilizer bar, control arms, perches, and all rubber bushings is important, and critical with a large drop. All those parts need to be in top condition.

 

I agree with Barnett on 480lbs front coils for a small block and a 2 inch drop, with a quality shock to match.

A 2 inch drop on a GT coil I think will not work, the spring will just be too short and be way out of spec for bind and compression rate.

 

Edit - The work I describe was on my 302 powered T5 trans 1970 coupe, not the Mach 1. The coupe is a far better driving experience. The Mach 1 is just old school cool, haha

Edited December 15, 2014 by SA69mach
clarify vehicle as not on signature line

[Guillaume69 150]

nope, although they are certainly xlnt shocks, dual adjustable ones are but they start at $200.00 each and run to around $1,000.00 each.

 

I was just giving a personal opinion here. Nothing more.

 

G

Edited December 15, 2014 by Guillaume69

[Guillaume69 150]

nope, although they are certainly xlnt shocks, dual adjustable ones are but they start at $200.00 each and run to around $1,000.00 each.

 

I was just giving a personal opinion here. Nothing more.

 

G

Edited December 15, 2014 by Guillaume69

[barnett468 418]

I was just giving a personal opinion here. Nothing more.

 

G

 

oh all i meant was that shocks with separate adjustable rebound and compression are better simple because you can tune them . . also when you get into the 1000.00 shocks they have a different and better type of valve but who has 1000.00 each for a shock . .yes the bilsteins and konis are very good and koni does made a shock with adjustable damping and the hotchkiss shocks are just revalved bilsteins or konis . . i forgot which . . the orig konis used on the shelbys have mega damping . . cshelydi shocs are better in that

Edited December 15, 2014 by barnett468

[barnett468 418]

I was just giving a personal opinion here. Nothing more.

 

G

 

oh all i meant was that shocks with separate adjustable rebound and compression are better simple because you can tune them . . also when you get into the 1000.00 shocks they have a different and better type of valve but who has 1000.00 each for a shock . .yes the bilsteins and konis are very good and koni does made a shock with adjustable damping and the hotchkiss shocks are just revalved bilsteins or konis . . i forgot which . . the orig konis used on the shelbys have mega damping . . cshelydi shocs are better in that

Edited December 15, 2014 by barnett468

[DarkBuddha 107]

BTW, it should be noted that cutting a spring will increase it's rate. Mathematically, the formula for calculating spring rate can be found here: http://www.ajdesigner.com/phpspringrate/spring_rate_equation.php

 

This is a caution for cutting both stock and aftermarket higher rate "lowering" springs. In some case, cutting a stock spring would be preferable to installing a higher rate lowering spring, especially if ride quality is a consideration. However, as mentioned above, cutting a stock spring enough to provide SIGNIFCANT lowering can reduce the amount of available compression to the point of bottoming out or hitting the bump stops, despite the amount of rate increase created by cutting the spring. And in a lot of case, trimming or removing the bump stops may be required with any lowering spring or cut coils.

[DarkBuddha 107]

BTW, it should be noted that cutting a spring will increase it's rate. Mathematically, the formula for calculating spring rate can be found here: http://www.ajdesigner.com/phpspringrate/spring_rate_equation.php

 

This is a caution for cutting both stock and aftermarket higher rate "lowering" springs. In some case, cutting a stock spring would be preferable to installing a higher rate lowering spring, especially if ride quality is a consideration. However, as mentioned above, cutting a stock spring enough to provide SIGNIFCANT lowering can reduce the amount of available compression to the point of bottoming out or hitting the bump stops, despite the amount of rate increase created by cutting the spring. And in a lot of case, trimming or removing the bump stops may be required with any lowering spring or cut coils.