'91 Formula

iTrader: (1)

Any body know what they are?

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'91 Formula
383CI Supercharged
5-speed
3.42
12.34@117.04, 1.91 60Ft.
on Drag Radials

Justins86bird

The fronts are 548lbs.

'91 Formula

iTrader: (1)

Thanks Justins86bird. Anybody know rear spring rates?

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'91 Formula
383CI Supercharged
5-speed
3.42
12.34@117.04, 1.91 60Ft.
on Drag Radials

89FirebirdUK

According to this webpage, they are 204lbs

http://www.1le.net/~1le/formula/

Geoff

'91 Formula

iTrader: (1)

Yeah, I saw that too. I think that is kind of high. 1le springs in a 4th gen are 130-180lbs variable rate. I think they are 130lbs single rate. I found some info in Automobile mag. back in 1987.

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'91 Formula
383CI Superram, Sportman II's
SLP Cam 214/224 .470/.490
Vortech V1 S-Trim
5-speed
3.42
12.34@117.04, 1.91 60Ft.
on Drag Radials

98_1LE

That's my site, and to be honest I got the 204# number from a member of this site as a reply to a similar post I made. While I agree that 204# seems a little stiff to me, my '87 is a tad stiffer than my '98 1LE. Fourthgen 1LE front springs are 360# linear springs, and rely on stiff shocks for suspension dampening. My '87 still has the original shocks at 57K miles.


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87 Formula 350 13.94@96.67
98 Z28 1LE 13.15@107.59
1LE Owners Association

[This message has been edited by 98_1LE (edited September 06, 2001).]

RB83L69

Are you asking what they are, or what they were when the car was new?

Too many times I see people looking for junk springs and thinking that's the answer to their handling or bottoming out or whatever problems. Well, those springs are all now a decade old, and they're just as worn out and useless as any other old, worn-out springs.

548 lbs/in sounds believable for a "hi-perf" factory spring; with the shocks they use, anything more than that would be intolerable to most of the public. With properly matched shocks the ride isn't so much of a problem though.

Moog has a part # that fits these cars with a rate in the 700 lbs/in neighborhood. That's what I have in my 83. I strongly recommend them. The Moog ones for the rear are somewhere near 200 lbs/in IIRC, maybe 185 or so.

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"So many Mustangs, so little time..."
ICON Motorsports

[This message has been edited by RB83L69 (edited September 07, 2001).]