I have been running my 88 with stock springs that have had 1 coil removed at all 4 corners. It rides real nice, but I want to firm it up a bit.

Bone stock 88 front coils have a spring rate of about 201lbs/in.
With 1 coil removed the new spring rate is 235lbs/in (17% increase) and I am wanting something stiffer.

I happened to have an 86 GT parts car and was curious about its springs. People always say the 84-87s ride rougher than the 88's so maybe they have stiffer springs that might be interchangeable with the 88.

Here are 3 springs. The one on the left is the stock 86 GT spring, the middle is a stock 88 (C) spring and the one on the right is one of my 88 (D) springs with 1 coil removed.

The 86 GT spring is about 13" tall, the thickness of the rod is thicker than the 88's (0.499" vs. 0.490") , but the coil diameter is slightly tighter (3.706" vs. 3.860"). The estimated rate of the stock 86 spring is about 215lb/in. So the 86 is stiffer and smaller diameter and looks like it would fit an 88 if it was shorter.

I cut 2 1/4 coils off the 86 spring to retain the same wheel well height of 25 1/4".

The new spring rate due to the cut coils is right at 300 lbs/in and I am very pleased with its ride.

Something else that "should" be possible is to lower an 84-87 car about 1" just by switching to 88 coils up front. They are shorter and just slightly softer, so it might be something for someone to try.

Were the identification tags on your 86 springs? I have been wanting to increase the spring rate on the rear of an 88. I have a set of FJH springs from the front of an 85-86 that I am considering cutting and fiting to the rear.

It has been my observation that the earily front springs are about one inch longer than the 88. Thus, using an aftermarket 2" drop spring that is made for the 84-87 (e.g. Suspension Techniques) should drop the front of the 88 by 1".

If you don't mind, please list the mathmatical formula to determine the spring rate after cutting.

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FierOmar

I am looking at using some front springs to stiffen the rear as well. The 88 rears are in the 150 lb/ft range and I would like something much stiffer without going to coilovers. The lower spring perch looks to be fine with the front springs, it will just be an issue getting the upper spring perch setup for the smaller diameter springs.

I will have to check the tag again. They were FJ(something).

I would agree that a 2" dropped coils for an 84-87 would probably drop an 88 about 1 inch.

Here are the formulas for spring rates. Just be sure to use a precision caliper to measure coil thickness.

[This message has been edited by fieroguru (edited 09-06-2005).]

quote Originally posted by fieroguru: The lower spring perch looks to be fine with the front springs, it will just be an issue getting the upper spring perch setup for the smaller diameter springs.

In looking at the lower spring perch, it appears to be offset from the shock tube. Since the FJH spring is a smaller diameter, I have some concerns about the possibility of contact. I am considering making a lower seat. I would be interested in seeing how you handle the top seat.

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FierOmar

[This message has been edited by FierOmar (edited 09-06-2005).]

quote Originally posted by fieroguru: I have been running my 88 with stock springs that have had 1 coil removed at all 4 corners. It rides real nice, but I want to firm it up a bit. Bone stock 88 front coils have a spring rate of about 201lbs/in. With 1 coil removed the new spring rate is 235lbs/in (17% increase) and I am wanting something stiffer. I happened to have an 86 GT parts car and was curious about its springs. People always say the 84-87s ride rougher than the 88's so maybe they have stiffer springs that might be interchangeable with the 88. [Photos omitted] The 86 GT spring is about 13" tall, the thickness of the rod is thicker than the 88's (0.499" vs. 0.490") , but the coil diameter is slightly tighter (3.706" vs. 3.860"). The estimated rate of the stock 86 spring is about 215lb/in. So the 86 is stiffer and smaller diameter and looks like it would fit an 88 if it was shorter. I cut 2 1/4 coils off the 86 spring to retain the same wheel well height of 25 1/4". The new spring rate due to the cut coils is right at 300 lbs/in and I am very pleased with its ride.

I have measured a FJH spring (from the front of an 85 or 86 Fiero) The FJH is supposed to be one of the two stiffest springs offered on these years. I measured (with micrometer) the wire diameter of the coils was measured at 0.505" and the mean average diameter of the coils was measured at 3.9" (4.405 - 0.505). I counted 8.5 active coils which resulted in a spring rate of 181 lbs.*

Assuming for the sake of discussion that you are using the same spring that has had 2.25 active coils removed, it would result in 247 lbs. Cutting to leave 5.5 active coils would yeild 280 lbs., while cutting to 5 active coils would yeild 308 lbs.

Applying the same formula to the 88 front spring would result in a 280 lb. spring if cut so as to leave 5 active coils.

Not quite sure if I want to remove that many active coils from either spring. I plan on comparing my calculations to a couple aftermarket coilover springs that I have lying around.

*It is important to count only the "active" coils as well as the mean average of the spring coil diameter. For additional information on rating springs, see: http://www.bluecoilspring.com/rate2.htm

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FierOmar

[This message has been edited by FierOmar (edited 10-26-2005).]

I met a guy with a 84 fiero with a 500 ci caddy engine and he said to make his car not squat so much and to stiffen it up in the rear he used a set of Chevy Lumina mini van springs and cut them dowm. I don't know how much he cut them down, but when the car took off it didn't squat very much.

quote Originally posted by FierOmar: I have measured a FJH spring (from the front of an 85 or 86 Fiero) The FJH is supposed to be one of the two stiffest springs offered on these years. I measured (with micrometer) the wire diameter of the coils was measured at 0.505" and the mean average diameter of the coils was measured at 3.9" (4.405 - 0.505). I counted 8.5 active coils which resulted in a spring rate of 181 lbs.*

The 86 front springs I used are the FJF springs. These are suposedly less stiff then the FJH, but I am not convinced about that.

The difference in wire diameter gives the FJH a +9 lbs over the FJF (keeping active coils and coil diameter constant).
The difference in the average coil diameter gives the FJF a +30 lbs over the FJH (keeping active coils and wire thickness constant).

So with the same # of active coils (8.5 used) the FJF would be 20lbs stiffer than the FHJ. In fact to get the FJF to have the same rate as the FJH, the FJF would have to have 9.5 active coils and from the picture above it ONLY has 9.5 to begin with and we know at least 1 will not be active.

If the FJH is truely stiffer than the FJF, then there is something wrong with one of our measurements or estimates of active coils.

quote Originally posted by fieroguru: The 86 front springs I used are the FJF springs. These are suposedly less stiff then the FJH, but I am not convinced about that. The difference in wire diameter gives the FJH a +9 lbs over the FJF (keeping active coils and coil diameter constant). The difference in the average coil diameter gives the FJF a +30 lbs over the FJH (keeping active coils and wire thickness constant). So with the same # of active coils (8.5 used) the FJF would be 20lbs stiffer than the FHJ. In fact to get the FJF to have the same rate as the FJH, the FJF would have to have 9.5 active coils and from the picture above it ONLY has 9.5 to begin with and we know at least 1 will not be active. If the FJH is truely stiffer than the FJF, then there is something wrong with one of our measurements or estimates of active coils.

Take a look at this list which I am assuming is correct: : http://www.geocities.com/MotorCity/Garage/5007/fiero_osg/springs.html

Indeed the FJH springs are supposed to be stiffer than the FJF. You may not have measured the coil diameter correctly. As I understand, the coil diameter is measured at the centerline of the wire coil. This is accomplished by measuring the inside diameter and adding the diameter of one wire, or alternatively, measuring the outside diameter and subtracting the diameter of one wire.

I rather suspect that the outside diameter of both springs is nearly identical. On the FJH, I measured 4.405" - 4.410" as the outside measurement. Subtracting the diameter of one wire yeilds a coil diameter of 3.9."

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FierOmar

[This message has been edited by FierOmar (edited 09-08-2005).]

quote Originally posted by 2m6turbo: I met a guy with a 84 fiero with a 500 ci caddy engine and he said to make his car not squat so much and to stiffen it up in the rear he used a set of Chevy Lumina mini van springs and cut them dowm. I don't know how much he cut them down, but when the car took off it didn't squat very much.

And that 472-500 ci Caddy engine is one big mofo. Might be a good alternative. Anyone have any experience with these springs?

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FierOmar

Have any of you put the front springs from a pre-88 onto an 88' ? If 87's front springs fit the 88' fiero that would make my life much simpler.

quote Originally posted by jchad: Have any of you put the front springs from a pre-88 onto an 88' ? If 87's front springs fit the 88' fiero that would make my life much simpler.

I think that is what fieroguru is planning to do with his 86 springs. Since the 87 front springs are similar, they could be made to fit as well. Check the code tags on your springs. Alternatively, check the wire diameter and plug the numbers into the formula to compare to the spring rate for the 88 front springs.

I have been looking for a replacement for the 88 rear springs. Based upon my observations, I can adapt a front spring from an early Fiero to fit the rear of the 88.

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FierOmar

quote Originally posted by jchad: Have any of you put the front springs from a pre-88 onto an 88' ? If 87's front springs fit the 88' fiero that would make my life much simpler.

Yes, the front springs from an 84-87 will fit an 88. They will be too tall (unless you want a monster truck/fiero), but they are easily cut to suit your tastes in ride height.

Thanks, I thought it sounded like you were useing 86' springs on your 88', but I wanted to be sure before I spent 150.00 buying a pair for myself to put on my 88'
West Coast Fiero sells 87' 1.5" drop springs with a 350lb/in rate which in my 88' should be only .5" with that same spring rate. Perfect!!!! for what I want.
Thanks again,
Jchad