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Blues n Brews
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498 Posts
Discussion Starter · #1 ·
Boy, does the stock Mustang rear suspension suck or what? I've just got my roadster on the road and the rear suspension bottoms out very easily. Its way worse with a passenger. I was going to wait until this fall to upgrade to coil overs but the car really is not driveable as it is now. So I'm going to do it now. The rear suspension is just way too soft. Is the Koni coilovers that Factory Five sells a good deal? The price seems right, it doesn't look too hard to install them, and Koni seems to have a good reputation for their probucts. So I'm interested in input from those who have upgraded and what your experience is with them so far ( ease of install, if ride was improved, reduced or eleminated bottoming, any other helpful info ), or if you used coilovers from another manufacturer and why. I'm going to place an order this coming week so I'm going to make a decision soon. My roadster is a MKII, 5.0L, carb, T5, 8.8 4 link rear, 17 inch Halibrand replica rims. Thanks in advance for the help.

ewh123
 

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1,581 Posts
not sure what your budget is but I would buy the 3 link bundle and install it over the weekend. You will be very happy.


just my $.02
 

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1,358 Posts
I upgraded from the Mustang donor springs to Koni coil overs last year. I had the donor springs on for six years, 22K miles. My donor springs were pretty well dialed in but they still bottomed out with a passenger on sharp bumps like bridge expansion joints.
The Koni's were a great upgrade. They give a much nicer ride with no bottoming and they make adjusting the ride height MUCH EASIER. I put them on my Mark I in an afternoon. I'd highly recommend them.
 

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FFCobra Craftsman
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24,732 Posts
I have driven my friends car w/ VPM's Carrera and can say that they must be the king of good ride in a solid axle FFR when ordered w/ the 200# springs. I haven't had a chance to ride in a car w/ the FFR Koni's but they seem good from many posts here. Choice could boil down to price. Either will be a big improvement from the donor springs. On my MkI the donors were a tremendous pain to adjust and ended up needing to make the car higher than I wanted to get rid of the bottoming.
 

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FFCobra Fanatic
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1,835 Posts
I also have the VPM coilovers, and am very pleased. Their customer service is excellent to boot.:001_rolleyes:
 

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Blues n Brews
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498 Posts
Discussion Starter · #8 ·
Thanks for the input, I've got some research to do before placing an order. The Carrara setup looks interesting, I'll call and see about them. And I'm going to call Factory Five about the Koni's. I remember something about the Bilstein's having a breakage problem, so I'm a little wary of those. Thanks again!

ewh123
 

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Senior Charter Member
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6,800 Posts
Rear Spring Rate

I don't know if I'm missing something here,..but...why don't you add a little more spring to the stock coils?

On my MK-II, which I'm not driving yet, I can turn the springs to put more of them below the curved plates and thus increase the spring tension giving more resistance to bottoming out.

If I've missed the boat here, please let me know where.

I have nothing against switching to coil-over shocks, but if the stock Mustang springs can be adjusted, why not?

Regards, Rick.
 

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Premium Member
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968 Posts
As Rick stated, try adjusting the stock rear springs. My MKIII is a roller and I have adjusted the springs to make the suspension softer. Reason - When I stood on the rear trunk section and bounced to test suspension reaction, it would only compress an about inch - and I'm 200 lbs. I treaded the rear springs another 1/2 turn to make suspension softer (compresses about two inches now) and will make final adjustment when road ready. The stock Mustang setup works well on the Mustang which is a lot heavier.

Regards, Rocky
 

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Charter Member
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972 Posts
Rick - rotating the stock springs does reduce the bottoming-out, but it also raises the ride height. I installed the Konis and am very happy with them.

Dennis B.
 

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FFCobra Craftsman
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1,273 Posts
I installed the Koni's on my MK-1 and it cured the bottoming problem but the ride was too stiff. I replaced the 350# springs with 250# springs from Jegs and I now have a great ride. I think the 350's would be idea for autocrossing or the track.
 

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Blues n Brews
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498 Posts
Discussion Starter · #13 ·
I've tried to adjust the coil springs but they won't stay in position. They keep creeping back up on the mount. Its not too bad without a passenger but with me and the wife in the car its impossible to drive on the highway, bottoms out on even the small bumps at speeds over 55 mph, really bad at 65 mph. I'm around 275 pounds and the wife is ??? but together its too much weight for the rear suspension. I talked to a Factory Five rep at the London show on Saturday and he suggested the stock springs may be just worn out. His reasoning was if the donor had a lot of miles the springs could be weak. I have already bought the tubular upper and lower control arms for when I was going to convert to coil overs, so my timetable has just been moved up somewhat. So I'm going to decide on Monday and try to have the new coil overs to install when I'm on vacation at the first of July. Thanks guys.

ewh123
 

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ASE Master Tech
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136 Posts
Hello, switching to FFR Koni coil-overs was the best thing I've done for the ride and handling of my MKIII. No more fighting with the cut coils to adjust ride height, every other day. No more suspension bottoming out period. Can't say enough good about them. Do it, you'll be glad you did.
 

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82 Posts
The stock Mustang springs are variable rate and on the FFR the soft rate is in play. I changed to linear rate 250lb/in springs from a 2001 Mustang Bullitt, (also the 03 and 04 Mach 1 had them). Solved the problem big time
 

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Blues n Brews
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498 Posts
Discussion Starter · #16 ·
I called Factory Five today and talked to Brian about the Koni's. Asked him about mounting hardware and spring rates. He was very helpful, checked to see if the hardware kit and coil overs were in stock, which they were. I told him about my hope to have them by the first week of July so I could install them while I'm on vacation. He said they could be shipped today and I would have them by the end of this week. So I ordered the Koni's. So I can't wait to get them installed. Thanks to all for your advice. Looks like a better riding roadster is in my future!

ewh123
 
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Blues n Brews
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498 Posts
Discussion Starter · #18 ·
The fronts will have to wait till this fall, I just had to replace them. They were Proshocks, which I got from Forte's. I'll run them for the rest of this season then replace them with Koni's. I just paid 370 dollars for the Proshocks without springs, I reused the old springs. Sure it's easy to spend money on these cars, I'm doing fine on my own!

ewh123
 

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Junior Charter Member
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900 Posts
At the time of my build I used the basic stock cut springs.. I wasn't going to spend the dollars for the 4 link coil overs... Yea, I have adjusted them because they were soft. I put those knuckels in the spring to change the spring rate also. It works fine for now.

Just a note, your car may feel stiff when you build it, put the body on it and fill up the tank and go out on the street--give it the gas and that back end will squat like you were gym... You will have to keep it still, the car will do the rest..stevo
 

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Blues n Brews
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498 Posts
Discussion Starter · #20 ·
Success!!! I have the Koni coil overs installed and what an improvement! No more bottoming, and the ride is firm but much better than the way it was ( too soft ). I also installed the tubular lower control arms from Factory Five. I have the tubular upper control arms to install but I have to figure out how to get the bolts out without screwing up the aluminum panels. I guess the control arms are installed before the aluminum is riveted in. There's no way I can see to remove the bolts. But I'll figure it out. I've been driving around and even at 65 mph no bottoming, and that was with me and the wife in the car. Now its really fun to drive! Thanks to all for your input.

ewh123
 
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