Question on H&R springs and isolators

[98 svt]

I ran (and still do out back) Tokico HPs and H&R SS springs. When I had the same on all 4 corners I was amazed at how well the car handled the shitty roads around here. It was smoother than stock, IMO.

I currently run coilovers up front, that's the only reason I removed the Tokicos and H&Rs.

I don't know why they discontinued those Tokicos. They were a fantastic daily shock/strut. I still have the struts laying around somewhere.

 

[Mark99GT]

I ran (and still do out back) Tokico HPs and H&R SS springs. When I had the same on all 4 corners I was amazed at how well the car handled the shitty roads around here. It was smoother than stock, IMO.

I currently run coilovers up front, that's the only reason I removed the Tokicos and H&Rs.

I don't know why they discontinued those Tokicos. They were a fantastic daily shock/strut. I still have the struts laying around somewhere.

Which coilovers are you running? Are they linear or progressive springs?

 

[Boost or Bust]

Yes, you are right. It’s koni srt, not KYB.

 

[98 svt]

Which coilovers are you running? Are they linear or progressive springs?

Right now I'm running MMs coilovers kit with hypercoil 325(?) 10" springs. I bought the kit used here on SVTP. Unsure if they are progressive or not.
I have the correct 12" springs that MM recommended for my setup, I just forget the rate.

 

[Mark99GT]

I'm all over the place here. I have Koni yellows and some other stuff in the garage waiting. I just can't decide on springs or if I should just go with coilovers since I'm so hung up on ride height. I considered front coilovers with non-coilover rear springs, but am unsure about mixing progressive and linear springs.

 

[Cobra Jet]

I have the H&R Race springs on my 94 Cobra, with Bilstein struts/shocks, 2003-04 Cobra front A-arms, 1995 Cobra R front sway bar, rear Hotchkis lower control arms, Steeda rear boxed upper control arms, and Energy Suspension urethane components

As others have said and as you have observed, the H&R Race springs have a very high spring rate which = almost no jounce/rebound. I can press the front end of my Cobra and there’s almost no give at all. There’s practically no roll going into tight curves or corners. It’s a very aggressive/stiff spring.

If you tend to drive the car to enjoy it, and depending on your local road surfaces:
- You must have a high tolerance for a very tight ride
- Must have a high tolerance for any additional NVH
- Expect to be jarred if you hit road imperfections - even with decent strut/shock combo.

I bought what I bought because I researched what I wanted and knew what I was going to be up against. This type of suspension or Race Springs isn’t for everyone.

I’ve had the different versions of Eibach springs on prior Mustangs, and the H&R Race springs are THE firmest I have ever experienced, even compared to an Eibach or Ford Motorsport/Racing/Performance equivalent.

Using urethane spring isolators will add back at the minimum 1/4” to 1/2” to overall ride height. That type of isolator was great for BACK THEN on most of these SN95’s and Fox Mustangs in general, where 98% were driven daily. Urethane was good then because it didn’t break down or deteriorate like the factory rubber - again when driving as a daily and the car is being used 24/7/365.

Today, most SN95’s and Fox Mustangs are no longer driven daily, therefore even if replacing with new rubber isolators, the rubber will last much longer than the originals due to less miles driven.

Urethane does add back NVH, don’t let anyone tell you otherwise. Urethane doesn’t compress as much as rubber does, but since it’s a denser material, it’s going to add NVH to the ride quality. Whether it’s the brand Prothane, or Energy Suspension.

If you want my recommendation for TODAY’s SN95s still around - go with the rubber isolator replacement, it’s pliable, less NVH and it’s not going to wear or deteriorate any faster (NOW) than the urethane counterpart, because many SN95’s are barely on the road….

Don’t go with the H&R Race springs, UNLESS you’re a tolerable person and can live with a very stiff suspension ride quality. Don’t get me wrong, the handling is great if you’re into twisties and able to drive on roads without imperfections. I’m not going to blow sunshine and push H&R Race springs, I’ll tell you exactly what to expect - not what anyone wants to hear…