Street/Strip suspension setup

[sutyak]

I'd like some help selecting a decent street/strip suspension. Car is mostly a street car, but won't see any corner-carving at all.
Here is the current (untested at the track) setup:

Tubular K member and A-arms. No front sway bar. Stock full-sized battery in stock location.
Front: Coilovers UPR? 250lb springs. Unknown brand non-adjustable struts.
Rear: Coilovers UPR? 150lb springs. Unknown brand single-adjustable shocks. Poly lower CAs. Spherical upper CAs.

To-do: full length subframes, weld torque box seams, and 6 point bar. I mention these because of added weight, strength, and rigidity.

Tires will be 28" slicks with tubes on a 15" wheel and skinnies up front.

I don't want to pour a lot of money into a suspension. Ideally I'd like to be able to drive to the track, click a couple settings on the struts/shocks, and pull a consistent 1.5-1.6 60'.
I'm leaning towards leaving the rear as-is, and swapping out the front springs for 150# or 175# and going with adjustable struts. Thoughts?

[Dickbag 5.h0]

My 2000 Fobra does pretty well on both the street and the track with my suspension set-up and its a fairly simple set-up. Upper and lower control arms, subframe connectors, poly bushings, KYB AGX adjustable struts and Tein S-Tech lowering springs. Ive ran 1.52-1.57 60's pretty consistently with this set-up on 275/50-15 ET Streets. With a slick and a wide open launch I know it would go 1.4's. I switched from Eibach Pro kit springs to the Tein's to lower the car more, people said it would effect the launch being lower, but it launches exactly the same. Eibach's were 1.5" drop, Tein's are 2.4". It does well on the street as well, and if I get the itch to carve some corners, I still can.

Im planning on installing a tubular K-frame and a-arms this summer for weight reduction purposes, has yours changed the handling at all? Any pro's or con's street driving?

[sutyak]

My 2000 Fobra does pretty well on both the street and the track with my suspension set-up and its a fairly simple set-up. Upper and lower control arms, subframe connectors, poly bushings, KYB AGX adjustable struts and Tein S-Tech lowering springs. Ive ran 1.52-1.57 60's pretty consistently with this set-up on 275/50-15 ET Streets. With a slick and a wide open launch I know it would go 1.4's. I switched from Eibach Pro kit springs to the Tein's to lower the car more, people said it would effect the launch being lower, but it launches exactly the same. Eibach's were 1.5" drop, Tein's are 2.4". It does well on the street as well, and if I get the itch to carve some corners, I still can.

Im planning on installing a tubular K-frame and a-arms this summer for weight reduction purposes, has yours changed the handling at all? Any pro's or con's street driving?

Thanks for the info. Do you know the spring rates? I'm surprised lowering springs pull that good of a 60'!

I bought this car with the tubular setup, but I can tell you it's noisy/squeaky and a rough ride. I think part of it is due to the poly bushings in the A-arms desperately needing lubed. I've bought some lube from energy suspensions, but haven't used it yet.
I had a 2003 Mach 1 which I bought new, and the stock ride was far more pleasant than this car is set up.

[Dickbag 5.h0]

Thanks for the info. Do you know the spring rates? I'm surprised lowering springs pull that good of a 60'!

I bought this car with the tubular setup, but I can tell you it's noisy/squeaky and a rough ride. I think part of it is due to the poly bushings in the A-arms desperately needing lubed. I've bought some lube from energy suspensions, but haven't used it yet.
I had a 2003 Mach 1 which I bought new, and the stock ride was far more pleasant than this car is set up.

Front spring rate is 538, rear 269.

[Ares]

Front coil over spring I use is a 14" x 150lb. I've used a 14" x 175lb in the past. Both I find to be nice on the street. A 250lb coil over spring is gonna be rough. I'd try the 175 up front with your car.

Never messed with coil overs in rear. So not any input I can offer there.

[sutyak]

Front coil over spring I use is a 14" x 150lb. I've used a 14" x 175lb in the past. Both I find to be nice on the street. A 250lb coil over spring is gonna be rough. I'd try the 175 up front with your car.

Never messed with coil overs in rear. So not any input I can offer there.

Thanks. Is your ride height in the front basically stock height with those 14" springs? What front strut do you use?

[Ares]

Think I have it setup with fender lip 27.5" from ground. Lower if I use my cut stock rear springs.
Strange struts up front. No sway bars since 2004

[Mark Aubele]

Thanks. Is your ride height in the front basically stock height with those 14" springs? What front strut do you use?

As Ares was saying, 250lb coilovers are quite stiff. Same wheel rate as a stock location 1000lb spring.

[SlowSix]

As Ares was saying, 250lb coilovers are quite stiff. Same wheel rate as a stock location 1000lb spring.

While 250 is relatively stiff, I don't think that is right. At least the math I used was based on MM's recommendations -
"The spring rates must be converted into wheel rates. The wheel rate is the spring rate measured at the wheel. The conversion is done through the use of what's called the motion ratio. For a stock Fox Mustang front suspension, the wheel rate is 25% of the stock location spring's rate. For example, an 800 lb/in stock location spring has a wheel rate of 200 lb/in. For a coil-over suspension, the wheel rate is approximately 90% of the coil-over spring's rate. For example, a front coil-over spring rated at 350 lb/in would result in a wheel rate of about 315 lbs/in. Note: The exact motion ratio conversion of the wheel rate for a front coil-over suspension is determined by the angle of the strut. That angle is the result of the camber and caster settings, and by the SAI (Steering Axis Inclination)."

I run a 275# spring, which equates to a wheel rate that is pretty close to a lot of conventional placement lowering springs, maybe slightly stiffer. I'm sure the basic math they give there isn't completely accurate but still.
i

[sutyak]

Thanks all. I'm leaning towards a 12" 175# front springs, but haven't decided on a strut yet. Maybe a Lakewood 70/30 or Strang 10-way? I should be able to slip the coilover setup over either, right?
I also looked at the MM calculations, and yes I think a 250# coilover would be approaching a 1000# equivalent. Definitely stiffer than I need.
Stock Mach 1 is 600# front and 250# rear. Technically these 150# rear coilovers are stiffer than stock (more like a 300# on a control arm?), but I think I'll try them at the track before switching. I think the front needs the most work. Feel free to correct me if I'm wrong.

[Ares]

Thanks all. I'm leaning towards a 12" 175# front springs, but haven't decided on a strut yet. Maybe a Lakewood 70/30 or Strang 10-way? I should be able to slip the coilover setup over either, right?
I also looked at the MM calculations, and yes I think a 250# coilover would be approaching a 1000# equivalent. Definitely stiffer than I need.
Stock Mach 1 is 600# front and 250# rear. Technically these 150# rear coilovers are stiffer than stock (more like a 300# on a control arm?), but I think I'll try them at the track before switching. I think the front needs the most work. Feel free to correct me if I'm wrong.

Lakewood you need to cut/grind off plate that is spot welded to top of strut body. Strange it is just a gold metal cap that pops off. Then sleeve for spring can be placed on strut.

[SlowSix]

I definitely wouldn't run a 250 if you're more interested in straight lines, I'll say that. 175 might not be a bad choice.
I have heard the strange struts are really noisy but don't have any personal experience.

my 275 is relatively stiff, but stil pretty soft for autox/road course purposes

[Ares]

Strange struts I have run two sets. First set was quiet put I blew out one. The second set has a slight noise due to C/C plates. Strange are not gas charged.

[Martin0660]

My strange is noisy on the drivers side, not as bad on the passenger side. On my list of stuff to get off the car when I can

[Mark Aubele]

While 250 is relatively stiff, I don't think that is right. At least the math I used was based on MM's recommendations -
"The spring rates must be converted into wheel rates. The wheel rate is the spring rate measured at the wheel. The conversion is done through the use of what's called the motion ratio. For a stock Fox Mustang front suspension, the wheel rate is 25% of the stock location spring's rate. For example, an 800 lb/in stock location spring has a wheel rate of 200 lb/in. For a coil-over suspension, the wheel rate is approximately 90% of the coil-over spring's rate. For example, a front coil-over spring rated at 350 lb/in would result in a wheel rate of about 315 lbs/in. Note: The exact motion ratio conversion of the wheel rate for a front coil-over suspension is determined by the angle of the strut. That angle is the result of the camber and caster settings, and by the SAI (Steering Axis Inclination)."

I run a 275# spring, which equates to a wheel rate that is pretty close to a lot of conventional placement lowering springs, maybe slightly stiffer. I'm sure the basic math they give there isn't completely accurate but still.
i

I wasn't 100% accurate as I was using Fox body standard spring motion ratio which I have always known to be .23, and S197 coilover geometry which is damn close to 100%, while the Fox/SN coilovers are around .9. So a 275lb coilover is equivalent to a 1000lb conventional. His 250s are equivalent to a 900lb conventional spring. Still much too stiff for his intended purpose. And your coilovers are much stiffer than the available lowering spings, most of which are around 600lb. H&R super race and a couple others being 1000lb and the exception.

[SlowSix]

I wasn't 100% accurate as I was using Fox body standard spring motion ratio which I have always known to be .23, and S197 coilover geometry which is damn close to 100%, while the Fox/SN coilovers are around .9. So a 275lb coilover is equivalent to a 1000lb conventional. His 250s are equivalent to a 900lb conventional spring. Still much too stiff for his intended purpose. And your coilovers are much stiffer than the available lowering spings, most of which are around 600lb. H&R super race and a couple others being 1000lb and the exception.

yeah, a 275 x.9 is about a 250 wheel rate roughly. Which would be about a 1000# conventional, you're correct. I must of been thinking when I was running a 200# spring, which is closer to a conventional lowering spring at about 180 or about a 720# conventional.
I think the eibach's I had previously were around 650#.

[sutyak]

My strange is noisy on the drivers side, not as bad on the passenger side. On my list of stuff to get off the car when I can

Bob are you staying with Strange struts? This sounds like the best option for me, and won't break the bank.

[sutyak]

Decision made for the front. I split the difference and went with 160# 12" coil over springs from Aldan American (new from ebay), and Strange 10-way adjustable struts through Summit.

[Martin0660]

It's a shame that after all of these years of Fox / SN95 / new edge stuff, we still cant get a decent strut at a reasonable price .... either Lakewood or Strange on the bottom end, then it's all high end stuff (I'm lusting after a set of Vikings for mine).

[yeahloh95]

yeah I want the Vikings too I love my rears from them