[Murf'sDad]

Hi Guys:

I tried this question in the Suspension Forum but no response so I'll try here.

I'm in the process of installing the 1LE front discs on my '76, no problem. I want to drop the attitude of the nose just a bit. Probably about 2". I've did the HA mod in the rear when I converted it to S10 discs which dropped the rear ride height by about 3/8" , so I need the nose down from stock. I never liked the level or slightly nose-up look of stock TA's.

My problem comes in when I have to factor in the weight reduction in the front with the installation of the '70 Endura bumper and sheet metal valance in place of the way heavier '76 bumper and composite valance/grills. I'm saving between 85# - 100# there; the battery is in the trunk, another 25#; plus about 15# of iron crossover and other bumps removed from the intake. I figure the lighter weight has raised the front end an 1" in ride height over stock.

If I cut a full coil from the stock '76 TA front springs (335#/in) and re-flatten the bottom I will lose 1" in free length plus the flattening of the bottom coil is about another 1" length loss. According to all the searching and reading I've done here and elsewhere, that will drop me about 3" in ride height (2" for the cut coil plus 1" for the flattened end) and increase my spring rate to about 370#/in.

Are my thinking and calculations making sense? I would have gained an inch over stock height with the weight loss and lost 3 inches from the coil cut so the net lowering of the front end from stock height is 2", which is what I want. Plus a little higher spring rate will improve the handling a bit.

Any advice or constructive criticism is appreciate.

Stewart

[trauschu]

On my '69 I cut 1 coil, and I flattened the bottom coil back down. I dropped at least 2 inches, if not more.

Info here: http://www.1969fb.com/Firebird.asp?myPage=Modifications

Remember, you can always cut more off a spring, but you can never add it back. You might start at 1/2 or 3/4 coil, and move up as necessary.

Thomas

[Keith Seymore]

Ditto; typically the ratio is 2:1 - that is, if you cut 1" off the coil you'll get two inches at the fender lip.

K

[Murf'sDad]

Originally Posted by Keith Seymore

Ditto; typically the ratio is 2:1 - that is, if you cut 1" off the coil you'll get two inches at the fender lip.

K

This is the basis of my calculations. A measured 1" in spring free length is 1 coil. Should give me 2" drop, plus the flattening of the coil for another inch.

Stewart

[71 Ventura II]

Man that sounds different to me, I was told 1/2 a coil will settle in at a 2" drop! Remember just measuring an unsprung spring down, where you have 1" of material removed, is about 1/2 a coil down. If you look at the coil spring starting at the top then following the spring as it coils down you'll see what I mean.

I guess what I'm saying is the 2 for 1 makes sense but if you cut a full coil off it will remove more than 1" off the height of the spring. JD

[77 TRASHCAN]

Stewart,
Just my personal experience, as mentioned above.
I'd go buy some aftermarket springs, cut on them first. I've seen too many F body spring changes, that went goofy.
Your O.E. springs may not be EXACTLY where you want them, but you can go back to them if you try something else...

I've never seen after market springs that duplicate the O.E. ride height. Go cut on some other new or used spring before you ruin your original set...
Jeff

[Murf'sDad]

Originally Posted by 71 Ventura II

Man that sounds different to me, I was told 1/2 a coil will settle in at a 2" drop! Remember just measuring an unsprung spring down, where you have 1" of material removed, is about 1/2 a coil down. If you look at the coil spring starting at the top then following the spring as it coils down you'll see what I mean.

I guess what I'm saying is the 2 for 1 makes sense but if you cut a full coil off it will remove more than 1" off the height of the spring. JD

2 for 1 is the basic premise. I've measured the free length of the spring, open coils not flattened coils. Moving around the coil until the freelength is 1" less is just under one full coil.

Stewart

[scorpio ps]

Where do you cut. Top or Bottom.

[Murf'sDad]

Originally Posted by scorpio ps

Where do you cut. Top or Bottom.

Bottom and re-flatten half the last coil.

Stewart

[chuckies76ta]

Stewart: I cut one full coil from the top of my springs as per Brian B, and as I can recall it dropped the car almost 2"

Charles

[Murf'sDad]

Originally Posted by chuckies76ta

Stewart: I cut one full coil from the top of my springs as per Brian B, and as I can recall it dropped the car almost 2"

Charles

Hi Charles:

Was that with the '76 or the '68? And who is Brian B?

Two inches might be enough for my purposes but I think I need a little more. Did your cut include re-flattening the coil?

Stewart

[chuckies76ta]

Hi Stewart: that's on my 76 T/A.. Brain Baker.. Thanks Brian..

I cut the top of the coil , so no re-flattening required..

Charles

[chuckies76ta]

pic

[Murf'sDad]

Originally Posted by chuckies76ta

Hi Stewart: that's on my 76 T/A.. Brain Baker.. Thanks Brian..

I cut the top of the coil , so no re-flattening required..

Charles

Thanx Charles. My springs are flattened on both ends with a rubber donut on top.

Stewart