FMS M-5300-L Springs - Low Rear End Fix

[SteveWK]

I'm in the process of removing most of my open track parts and decided to replace the Eibach Pro springs with the FMS L springs for what I hope is a softer ride. Nothing wrong with the Eibach springs, just experimenting. One thing I read concerning the L springs was that the rear sat lower than the front for some people. I didn't want that and really want a bit of rake to it. I decided to double up on the top and bottom spring isolators and it now sits at 29.5" on both sides LOL. Too high for me, almost stock height. I will be removing at least one of the isolators. Just thought I would pass this info on to anyone who thinks their rear sits too low.

 

[Catmonkey]

All springs will settle after a few days, so you might give it time to do so.

 

[SteveWK]

Thanks. I'm going to drive the piss out of the car over the next few days trying to get my 4.10 gear install to start whining. Hopefully they will settle about 1/2".

 

[Catmonkey]

If you're having difficulty setting you rear ride height at a specific amount of drop, using coil over springs with the rear spring adjusters will allow you to set it just where you want it. You just need to know the right spring height based on the desired spring rate.

 

[SteveWK]

I have a set of Griggs double adjustable coil overs. They have adjustable spring perches, but the springs are pretty darn stiff and they transmit a lot of road noise. I had them installed when I thought I was going to be running a lot of open track events, but that didn't materialize. Tomorrow I'm getting the front springs installed and I will assess the relative heights then. The rear has settled about 1/8" but I think I'm going to pull out one of the isolators on each side. I'll give it a few more weeks to settle though.

 

[kcobra]

I have a 14 PP 500. I purchased the L springs and only installed in the rear due to having had done this with P springs on my BOSS with perfect level stance results. I was somewhat happy but found it to still sit a bit high in the rear at times and sometimes, the front seemed a bit higher due to the lower profile tires in front vs backs. Anyhow, today I installed the front springs also and re adjusted the perches in the rear. I had the pigtails of the bottom of the rear springs pointing basically front to back of the car. I read MM instructions on there springs saying to have the pigtails point left to right or in line with the axle, basically cradling the rear perch, which made sense. So after doing everything, I am totally happy. Level and I am not sure if it is because the front is a bit lower now or because I re positioned the rears, the back seems lower also.

 

[tomshep]

I am running L springs on a PP 2014 and very happy with the stance and ride. From past research they are the same rate as the OEM PP springs, just lower.

That pic is with 275/35 front and 315/35 rear.

Tom

 

[biminiLX]

Tom is right, same rate used in the SVTPP and used in the cars development, so they work with the Bilsteins dual modes and same rate as stock, just a bit lower.
They lower the rears more than the front, my front only went down about 3/8-1/2”
-J

 

[SteveWK]

Yep, I knew they were the same rate as stock. I'm just trying to maintain the same rake as the stock springs but with it lowered overall. I didn't find any spring spacers online, and I over corrected with doubling up the spring isolators on each end of the spring. Remember LethalChem? He and I met up at an open track event about 6 years ago and he didn't like how low the rear sat with his L springs. As with just about every single mod I have made to this car, I end up doing it twice lol.

 

[SteveWK]

I have a 14 PP 500. I purchased the L springs and only installed in the rear due to having had done this with P springs on my BOSS with perfect level stance results. I was somewhat happy but found it to still sit a bit high in the rear at times and sometimes, the front seemed a bit higher due to the lower profile tires in front vs backs. Anyhow, today I installed the front springs also and re adjusted the perches in the rear. I had the pigtails of the bottom of the rear springs pointing basically front to back of the car. I read MM instructions on there springs saying to have the pigtails point left to right or in line with the axle, basically cradling the rear perch, which made sense. So after doing everything, I am totally happy. Level and I am not sure if it is because the front is a bit lower now or because I re positioned the rears, the back seems lower also.

Hmmm, I didn't put the springs in. I'll have to look at the pig tail. Good info.

 

[kcobra]

I had a guy send me a picture of his non PP 13 GT500 with the same wheel and tire set up as mine and with the same L springs. His sits quite a bit lower than mine. The PP makes the drop, especially in the rear, not as low. I prefer the drop on the non PP cars personally. Oh well.

 

[SteveWK]

I wonder what it is about PP cars that makes the drop different.

 

[kcobra]

I am guessing the Bilsteins.

 

[SteveWK]

Hmmm, good point