Suspension Recommendation ~$2,500

[BmacIL]

500s are not that much cheaper than Conti Sports, and they SUCK in the rain. All 3 are pretty similar in the dry, but it's hugely erroneous to say they are even remotely close to a PSS in the wet, let alone a Conti Sport or PS4S.

BmacIL - 71s are great on autox or in cold weather, but on hot tracks, in 90* weather, they don't hold up very well.

Yup. They're an autocross compound. I do quite a bit of that.

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[TheLion]

I'm going with either the Conti's or the PS4S's. PS4S's are the top of the top. It's not just outright grip, how a tire breaks loose towards its limits, how it feeds back as you load it etc. all affect it's performance or at least the driver's ability to tap into it without going past that last 1% of remaining grip. That's where I think the Conti's fall short, their feedback isn't as good, it's more isolated compared to the Pilot Sports and that shows up in how much of their available traction you can safely tap into. Their steering is more light and with less effort, that might be good for slolm type driving or auto x courses with lots of abrupt turns, but I don't think I'd want light steering at high speeds, I'd wanted weighted feedback.

PS4S's resistance builds as you load the tire, the edge isn't razor sharp but they more slowly let go instead of suddenly (a criticism I have of the Pilot Sport AS3+'s is that they do let go very suddenly at the edge of grip where the P Zeros are more gradual, however the AS3's offer better feedback than the P Zeros so it's easier to push closer to the limits as I know more of what the tire is doing). Sure, AS3+'s and P Zeros are different tires, one is all season, other is a max performance summer tires. However the AS3's are so good despite being all seasons, they have high outright grip than the P Zeros. It's more or less a Super Sport with a more temperature stable compound that can be used in temps down to 0F.

RE71R's aren't just super sticky auto x tires, they also provide good feedback to the driver on what's actually happening with the tires and are the best in their category in both feedback and outright grip. However I'm interested in street performance and a few times a year HPDE, not auto x (I was for while but lost interest when I got a taste for back road "tracking" at higher speeds, similar to actual track). If I had a Mazda MX-5, BRZ or other momentum car, Auto X would be my choice as those cars transition very well. But the Mustang is a big power car with a long stable chassis. It's architect-ed more for HPDE than auto x and that's where it excels.

It's said that the Pilot Sport 4S's are half way between the Super Sports and Sport Cup 2's. About as good as your gonna get on a tire that's actually enjoyable on the street, can hold up to periodic track use and will last more than 5k~7k miles while providing close to "dedicated track tire" performance. RE's are a 160 UTG tire while the PS4S's are 300 UTG, sure they are listed as 200 currently (RE's), but they "magically" became 200 all of the sudden once SCCA rules required a minimum of 200 UTG for certain classes when they were previously listed at 160 utg. They just don't last long if you drive them on the street and I like to Grand Tour as much as I like to "track" the car.

Quality costs money and tires are 80% of your suspension. No joke, it doesn't matter how good you suspension is if the only thing between your car and road is sub-standard. I'll bet a PP GT with Pilot Sport 4S's and stock PP suspension could out handle the same car with SP083 springs, PP Struts and GT350R front bar but running something like the Firehawk Indy 500's despite it's superior suspension tuning (both cars having same engine, gearing etc.). Maybe I'm wrong, but suspension and power mods have little effect without tires to match.

I think my current setup is a very good corner carver street setup. SP080's, PP Struts, BMR CB05 IRS Lockout, FP Spherical Bearings in the toe links (both inner and outer), Power Pack 2, Cat back exhaust and some RTR Tech 7 light weight (23 lbs per wheel, stock PP wheels are 32.5 lbs each) that the Max Performance Summer Tires will go on next spring.

Currently I'm burning up my factory P Zero's on factory PP wheels. I miss the lightweight Tech 7's, both in feedback (larger scrub) and looks (flush, spoke design, more open to see the brembos), but I don't miss my now bald AS3+'s as they were growling quite a bit and well past the wear bars. They are shot, so the PS4S's will go on the Tech 7's for the warmer months and in November I'll scrap the P Zero's for some Geforce Comp 2 AS's (did better in light snow handling than all the other all seasons).

 

[TheLion]

Here's another question. If the rear is so sensitive to ride height compared to the front, why did BMR increase the rear drop from 1/2" to 3/4"? Would running 1/4" rear spring spacers be advantageous? It would give the car a little more rake and give the rear end slightly more optimal ride height. Or could one even use GT350R rear springs and BMR SP083 fronts? Aren't the rear's on the GT350R same design despite MagneRide? Then you could run GT350R front and rear bars, GT350R rear springs and BMR SP083 front springs. You'd have nearly identicle rake and spring rates to the GT350R, just not the adjustable damping of MagneRide, but that's about as good as a static suspension is going to get.

 

[TheLion]

Order of below heights are front drop, rear drop and rake in inches.

GT350R/TP 0.70 0.38 0.33

SP083 (revised) 0.88 0.75 0.13

I realize the ride frequency of the SP083's on FP Track Struts is VERY close to the GT350R's on it's stock springs and struts. However it has a little less rake and a little lower sitting rear.

Maybe the SP083 setup with R front bar and PP rear bar is the way to go, but I'm not 100% convinced yet a 22.2 mm stock PP rear bar is enough with the 980 lbs/in rear springs over the 24 mm GT350R rear bar with 920 lbs/in rear springs and more rake. The R's rear ride height is slightly more optimal over BMR's.

Prices of mixing and matching parts isn't really an issue as it's all about the same giver or take a hundred bucks. What matters is the balance and tuning. I'm just very cautious about upsetting the tuning and balance of the GT350R's suspension when porting it over to a PP GT.

 

[Bluemustang]

Here's another question. If the rear is so sensitive to ride height compared to the front, why did BMR increase the rear drop from 1/2" to 3/4"? Would running 1/4" rear spring spacers be advantageous? It would give the car a little more rake and give the rear end slightly more optimal ride height. Or could one even use GT350R rear springs and BMR SP083 fronts? Aren't the rear's on the GT350R same design despite MagneRide? Then you could run GT350R front and rear bars, GT350R rear springs and BMR SP083 front springs. You'd have nearly identicle rake and spring rates to the GT350R, just not the adjustable damping of MagneRide, but that's about as good as a static suspension is going to get.

My understanding is that it was done to improve the overall stance and not for performance reasons. The difference between a 1/4" is small enough that it doesn't make much of a difference. IMO the stance is perfect and I wouldn't change a thing (I have previously had SP080 and FRPP track, so I know what the stance looked like before).

I have the GT350 (non-R) bars in my garage waiting to install. I decided not to buy the R rear bar due to the fact that SP083 rear spring has a higher rate than the GT350R. So my theory is that with the higher rear spring rate, one does not need as much roll control as the R bar would give. Currently I have the BMR bars on full soft front and rear. As of now I suspect I have a little bit of oversteer behavior because the BMR rear bar is much stiffer than stock, as is the SP083 rear spring rate. I would probably be happy putting the front bar onto full stiff and not even bothering with the GT350 bars. However, I do think the GT350 bars would suit better overall. I don't think it needs stiff bars once you've gotten stiff springs.

 

[BmacIL]

Here's another question. If the rear is so sensitive to ride height compared to the front, why did BMR increase the rear drop from 1/2" to 3/4"? Would running 1/4" rear spring spacers be advantageous? It would give the car a little more rake and give the rear end slightly more optimal ride height. Or could one even use GT350R rear springs and BMR SP083 fronts? Aren't the rear's on the GT350R same design despite MagneRide? Then you could run GT350R front and rear bars, GT350R rear springs and BMR SP083 front springs. You'd have nearly identicle rake and spring rates to the GT350R, just not the adjustable damping of MagneRide, but that's about as good as a static suspension is going to get.

Kelly's words:

We wanted to get a little more drop out of the fronts, so naturally going down "a touch" in the rear was the right thing to do to retain the balance for the guys who are going to be tracking the springs.

The rake on our SP080s is desired..and works, and is well accepted.

At the end of the day, the SP083 is really a "track" spring and being so, we wanted to make sure it is widely accepted among the racers out there.

You will see me posting about this from day 1 on this forum that, we really are not fans of going much past 3/4" on the rears of the S550 - and the 1/2" was done for a few reasons, to include geometry and ALSO for the guys who do the larger staggered and taller rear tires. ;)

There's a balance between roll geometry and pitch geometry (as well as rake, which changes static load on the tires...not hugely but some). Also, the original rears for the SP083s sit at ~0.6" drop. This is what I have.

 

[TheLion]

My understanding is that it was done to improve the overall stance and not for performance reasons. The difference between a 1/4" is small enough that it doesn't make much of a difference. IMO the stance is perfect and I wouldn't change a thing (I have previously had SP080 and FRPP track, so I know what the stance looked like before).

I have the GT350 (non-R) bars in my garage waiting to install. I decided not to buy the R rear bar due to the fact that SP083 rear spring has a higher rate than the GT350R. So my theory is that with the higher rear spring rate, one does not need as much roll control as the R bar would give. Currently I have the BMR bars on full soft front and rear. As of now I suspect I have a little bit of oversteer behavior because the BMR rear bar is much stiffer than stock, as is the SP083 rear spring rate. I would probably be happy putting the front bar onto full stiff and not even bothering with the GT350 bars. However, I do think the GT350 bars would suit better overall. I don't think it needs stiff bars once you've gotten stiff springs.

That's the direction i've been heading and been discussing with @BmacIL , SP083's, FP Track Dampers, GT350/R Front Bar (34mm) and a PP GT rear bar (22.2 mm). The 83's rear springs are a bit stiffer than the Ford OE R Track Pack rears (920 lbs / in). The GT350R just has such balanced handling characteristics it ran within .39 seconds of a car making 125 HP more (the ZL1) on the same track, same day, same driver. That's impressive to me. It was also by far the more enjoyable car to drive.

 

[BmacIL]

@TheLion I think you need a ride in one of these cars so as to not overthink it too much. @Demon Coyote did, and I know he's pleased!

 

[TheLion]

@The Lion I think you need a ride in one of these cars so as to not overthink it too much. @Demon Coyote did, and I know he's pleased!

I'll stop speculating now, lol. I just try to be as certain as possible before committing to a change, especially one that affects reliability / warranty of a major component (engine) or handling (suspension) in a big way that can end up in disaster and large sums of wasted money if not done carefully. I'm sure there are many, many cars out there that actually handle worse than stock due to poorly chosen alterations (high school kids and their dragging on the ground Hondas come to mind).

Sounds like the first pass is going to be FP Track Dampers, BMR SP083 front and rear springs paired with a 34 mm GT350/R front bar and my stock 22.2 mm PP rear bar next year. Already have the BMR IRS Cradle Lockout and FP Toe Link outer Spherical Bearings. Also already running MM caster / camber plates I'll re-use with the FP Track dampers. We'll see how that works out and plays with the Tech 7 wheel / PS4S tire combo and current mods. Should be one heck of a car!

I'm more or less trying to keep it sleeper, mostly stock looking besides the wheels. I really like the simplicity of the S550 body. It has all the right curves and creases in just the right areas, not too much, not too little. Awesome looking car (both first gen and 2nd gen).

 

[Bluemustang]

That's the direction i've been heading and been discussing with @BmacIL , SP083's, FP Track Dampers, GT350/R Front Bar (34mm) and a PP GT rear bar (22.2 mm). The 83's rear springs are a bit stiffer than the Ford OE R Track Pack rears (920 lbs / in). The GT350R just has such balanced handling characteristics it ran within .39 seconds of a car making 125 HP more (the ZL1) on the same track, same day, same driver. That's impressive to me. It was also by far the more enjoyable car to drive.

With my setup, I would not be surprised if it would beat a GT350R. Lower center of gravity and higher rate springs, and monotube dampers, same as GT350. Another tip I learned from @BmacIL - our cars don't have front camber gain that the GT350/R has, so alignment settings are important. The suspension geometry of the GT350/R is slightly different from our cars, so it's probably not as easy as throwing GT350R parts on our cars and be the same.

@TheLion I think you need a ride in one of these cars so as to not overthink it too much. @Demon Coyote did, and I know he's pleased!

Tell him how many G's you hit on your last autocross LOL

I wouldn't be surprised if your car would beat a GT350R on a track with a good driver.

 

[TheLion]

How would the GT350R have more front camber gain? It's a double ball joint lower with coil over strut front dampers. The physical sheet metal uni-body is a standard S550 production body. Unless the hubs are different and the strut angles are different?

 

[TheLion]

I guess not: https://www.motortrend.com/cars/for...16-ford-mustang-shelby-gt350-steering-knuckle

Looks like the knuckles are different in the front. I'm guessing they alter roll center. So would there be a benefit to using Steeda's front links to correct roll center in the front? Or is not necessary with the SP083 ride height?

 

[BmacIL]

With my setup, I would not be surprised if it would beat a GT350R. Lower center of gravity and higher rate springs, and monotube dampers, same as GT350. Another tip I learned from @BmacIL - our cars don't have front camber gain that the GT350/R has, so alignment settings are important. The suspension geometry of the GT350/R is slightly different from our cars, so it's probably not as easy as throwing GT350R parts on our cars and be the same.




Tell him how many G's you hit on your last autocross LOL

I wouldn't be surprised if your car would beat a GT350R on a track with a good driver.

Let's not get ahead of ourselves . There's still a lot that the GT350R has that would make it quicker, but without a doubt this handles very well and is quite quick. 1.17G lateral, 1.31G braking.

 

[BmacIL]

How would the GT350R have more front camber gain? It's a double ball joint lower with coil over strut front dampers. The physical sheet metal uni-body is a standard S550 production body. Unless the hubs are different and the strut angles are different?

The GT350 and R both have ball joints that are raised compared with the standard Mustang. They do similar to what Steeda's extended balljoint arms do, and are a valuable piece. The flip side is: lowering the car by about this amount without changing that increases anti-dive significantly, which is a big part of the reason the car stays much flatter after lowering.

 

[TheLion]

I wouldn't expect this setup to beat a GT350 and certainly not the R handling wise. However I believe handling wise it may come CLOSE to the regular GT350, which still an awesome street / track variant. There are a lot of small tweaks to he geometry of the Shelby that make it what it is, including going so far as vehicle specific variants of tires, just like the SS 1LE that has tires specifically altered for it's use and suspension characteristics. The sum of parts that make it what it is.

However I think a PP GT has an immense potential and can come close to these much higher tier cars even if it cannot match them outright. And I believe it can be done for just a few thousand dollars with the right tuning choices (both engine and suspension). I am a huge fan of the Power Pack 2 for it's balance of performance, drive ability and reliability. It's like the car came this way from the factory (in a good way). But my suspension and tires are now lagging the power and tires are first so I can really see what it's current weaknesses are.

The SP080's rates are more or less a softer variant of the SP083's, very similar balance. I'd say that with some decent tires what I have now is a good street / corner carver setup, but not necessarily track worthy if you want to really push the car. There's still some body roll and the front still pushes a little too much in my opinion, but then again wider and stickier front tires can have a substantial impact on that aspect. I've seen where just changing tires altered a car's very mild push into almost flat, so that's why I want to get tires first and I'll wait until next summer.

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