J.P.B.
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Review of BMR handling springs (SP083) paired with the Ford Performance track shocks and struts (M-18000-F)
Now that I have these installed for a few weeks, I am able to review them for both the street and road-course. But, some background information is required.
First, both springs and dampers were installed at the same time as a set of other suspension upgrades that were carefully selected to complement each other. While it’s not possible to strictly isolate the individual affects, I believe that I can comment on “major effects” of the springs and with the FP track dampers in the context of the overall suspension upgrade. I got valuable advice from many folks when researching these upgrades, but forum-member BmacIL deserves particular thanks for his comprehensive and thoughtful advice. Also, thanks to BlueMustang for his very helpful impressions of this pairing.
So, for the record, here are the modifications that I made to my base model 2017 GT.
• BMR: handling springs (SP083: front: 250lb; rear: 980lb)
• Ford Performance: track struts & shocks (M-18000-F)
• Steeda: rear billet shock mounts (555-8151)
Other upgrades:
• Ford Performance: rear toe links (M-5972-M) and toe link to knuckle connector bushing (M-5A460-M)
• Steeda: IRS subframe bushing support system (555 4447)
• Steeda: IRS subframe alignment kit (555 4437)
• Steeda: K-member 4-pt chassis support brace
• Steeda: Strut tower brace
• Performance alignment
Second, there are inevitable tradeoffs between street and road-course performance, and in the interest of full disclosure, I favor road-course performance. Prior to my GT, I tracked a 2015 Ecoboost Mustang; and prior to that I raced motorcycles at the same track. FYI, my local is the Atlantic Motorsports Park, and it is widely considered the most technical road course in Canada. I daily drive my GT, so I am sensitive to the tension between the tradeoffs of suspension performance.
OK, on to the review. I will break it down into separate points, and I will start with the street. I will also make direct comparison to the Ecoboost Mustang, and in a few cases to the 2012/2013 BOSS 302 Mustang.
Street performance:
1. Both the stock GT and the Ecoboost Mustang suspension have a lot of soft rubber bushings, and the IRS can sustain a lot of deflection in some circumstances. These cars are softly sprung “grand tourers” by design. With the factory springs and dampers, both cars felt disconnected from the road; specifically they had delayed and un-intuitive reactions to changes in the road surface. The upgrades (in large part due to the springs and dampers, but also due to IRS bushing support system) have almost completely CORRECTED this problem in the GT. The car is now “hunkered down” and predictable.
2. These springs and dampers result in a much more FRIM ride compared to stock. But, it is NOT TOO HARSH; it’s still a largely confortable ride. The road surface is now transmitted to the driver, but in an informative way. You will feel all the road imperfection, but this is “knowledge” you do not have as a driver in the stock setup.
3. Some road conditions are transmitted more than others to the cabin and to the driver. However, it was not what I predicted… Rough and broken pavement is not as harsh as I expected, and, oddly, minor “undulations” seem to be the biggest challenge to the suspension. However, the car is never unsettled. It is never skittish (which I had been worried about). Indeed it’s extremely effective at dealing with a broken surface: ONE-DOWN then ONE-UP and it’s all done.
4. Unexpectedly, the suspension gets BETTER WITH SPEED. There is a bridge joint I have to cross on a regular basis, and it was very harsh on both the stock GT and the Ecoboost. I gritted my teeth on my first approach to this bridge joint with the new suspension, and low-and-behold it was actually better! And, the faster I go the less harsh this joint feels!!!
5. STEERING RESPONSE is very noticeably improved. I chalk this up to the combined effect of the 250lb front springs, the strut tower brace, and the 4-point chassis brace to (i) reduce the amount of flex in the front end, and (ii) maintain a stable wheel alignment during cornering. The effect is that steering response is immediate, and the car changes direction much more quickly. This makes the car really fun to drive on twisty roads (but with unexpected consequence on the track; more on this later). The Ecoboost Mustang, with 200lbs less weight over the front wheels, had a real advantage over the GT Mustang in terms of steering feel and response. For street driving, these upgrades corrected that discrepancy.
6. There is now noticeably less tramlining on the highway (it’s not entirely gone; I do run 275s up front after all). But, this might not be attributable to the suspension changes. The reduction in tramlining could be a consequence of the extra weight of the GT over the front wheels and the alignment changes I chose after the suspension upgrades. I can’t be sure about the source of the improvement.
7. A final note about the effect of tires on the firmness of the ride. I run 18x10 wheels and a 275 square tire stance. Tire pressure and temperature have a noticeable effect on ride quality. I found that running just a little less pressure, 29-30psi rather than 32psi, made a noticeable improvement on ride quality for my setup.
Road-course performance:
1. The ride is now VERY FLAT. Even with the stock sway bars (more about this later) the car has much less lean during hard cornering. There is also much less nose dive under hard breaking and the car no longer rocks back on its haunches during hard acceleration. The effect is that there is much less weight transfer during hard driving, and this leads to (i) a more “planted feel” at speed and (ii) smoother transitions that minimize disturbances that unsettle the suspension.
2. The car now communicates everything to me, as it should. In addition to feeling the road, I can instantly feel how the suspension is reacting to my inputs. This is why you want “TRACK FRIMNESS”. By the way, it’s not too firm; the car has yet to react unexpectedly and is easy to apply power smoothly.
3. There are some unexpected consequences of the sharp steering response. The effect is that even very small mistakes get quickly transmitted to the chassis. As I approached the limit in my car (which is now MUCH FASTER than before) it demanded much more technical skill. This suspension simply demands more precision. It's not that car gets dangerous, or jittery, when I make a mistake; it's just that it communicates my mistakes instantly. That delightfully crisp steering response on the street becomes “hypersensitive”; if you are just a little too abrupt on turn in, you will feel it in the chassis. The EcoBoost, and the stock GT, were much easier to drive at their limit (albeit slower). The BOSS 302 under the same conditions over the weekend, was also easier to drive at the limit. The good news is that the upgraded GT suspension will help teach you to be a better driver… if you are willing to listen to it (and your instructor). For this reason, I feel this is not a suspension setup for a beginner (more thoughts on this later).
With my general impressions out of the way, I thought I would break the review down into the basic stages of a road course turn.
Maximum braking on approach: The car is very stable. Since there is much less nose-dive it feels more settled, and this gives you confidence to go deeper. I suppose the back brakes could now be more efficient leading to shorter stopping times, but I can’t be sure that I actually was stopping any more effectively. But, stability leads to greater confidence and smoothness, and this encourages you to go deeper.
Turn-in / transition to cornering: This is where the increased sensitivity has pros and cons. The cons: the margin for error is smaller. If you are off a little on your input timing, or you are too abrupt, you will feel that mistake. The car will NOT soak it up for you. You need to pay attention. The pros: (i) You will feel your mistakes instantly. Yes, this was also a con because it can be distracting. But, this is how you learn to be precise and smooth. (ii) You will feel that you have made a mistake but it will not punish you; the car was never unpredictable or jittery. (iii) Precision and smoothness are rewarded with more speed throughout the rest of the turn!
Cornering on a balanced throttle: There is MUCH LESS body roll. As with the turn in, there will be less weight transfer (if you have done it right), and the car feels like it maintains more speed. There is also LESS UNDERSTEER. The car still understeers, but I was surprised how much less I was fighting it. All this said, for me, actual improvements in speed were gained by avoiding mistakes during the transition to cornering. That is where I have some work to do.
Transition to acceleration and exit: This is where it gets interesting. I had struggled with a particular decreasing radius turn going down hill with less than ideal camber. There is no consensus opinion on the best line for this turn, and it slows a lot of folks down, including me. Not only was I able to carry more speed, but I was able to build a surprising amount of acceleration on the transition to exit. At one point I swore that the throttle caused the front end to tuck in. On the next lap I realized that I was actually getting very progressive, and manageable, throttle steering. A turn that had once been a problem for me was now delightful to manage with partial throttle and a touch of oversteer. I am sure than any well tuned suspension can delver this. That is not the interesting point. The interesting point is that I am still on the stock sway bars; I am seriously thinking of staying with the stock bars.
Critiques: As expected, nothing is perfect and there are some issues. Three things stand out at this point:
(1) Some people say that, with an “upgraded” suspension, the GT mustang “shrinks around you” once you get it on the track. I disagree. The car still feels big. If still feels bigger that the Ecoboost Mustang (on the same track), and it feels bigger than the BOSS 302 (on the same track). It's still a 3700lb car with a lot of weight over the front wheels.
(2) The suspension is not perfect. Under cornering conditions much faster than what was possible with the stock suspension, the suspension can very occasionally shift in a way that is delayed relative to my inputs or changes in the road surface. Either way, it seems to be localized in the rear, and I think there may still be some deflection in the IRS. It’s distinct, very noticeable, and somewhat distracting; fortunately, it does not happen often, and the car can still be driven quite easily. This does not seem to be the fault of the spring and damper pairing; rather, I suspect there is still something in the IRS that needs correction.
(3) My upgraded GT rides flatter than the BOSS 302 and yet it feels less planted. I believe this is related to issue (2) above. Both cars communicate a lot of information about the road and the cornering dynamics to the driver; let’s call this “signal”. My current suspension still shifts in a way that is unrelated, or delayed from, my inputs; let’s call this “noise”. I think the BOSS 302 feels better because it has a little better “signal to noise ratio” than my car does right now.
Overall impressions: If you are interested in road course performance, you would be very hard pressed to find better value for money in the pairing of BMR handling springs (SP083) paired with the Ford Performance track shocks and struts (M-18000-F). With a small number of supporting mods the changes in the handing are PROFOUND.
The advantages of this suspension improve with speed. If you spend most of you time in traffic, and at lower speeds, then you are simply not going to appreciate the amazing engineering that went into these, and you are certainly not gaining anything in terms of comfort. This pairing is perfect for those driving hard in autocross or on a road course. I love this set up! But it’s not for everyone. Here is my very subjective sense of the spectrum of different damper and spring pairings.
(1) Very soft grand touring car:
(2) Moderately soft grand touring car:
(3) Daily driver, performance driving mostly below the limit (a corner carver), with occasional track days:
(4) Daily driver and high performance driving at frequent track days or autocross, but with slightly more preference for a softer street ride:
(5) Daily driver and high performance driving at frequent track days or autocross, with more preference for a track spring. Specifically, a flat ride with road surface and suspension dynamics clearly communicated to the driver, predictable weight transfers, and optimized reactions to weigh transfers.
Now that I have these installed for a few weeks, I am able to review them for both the street and road-course. But, some background information is required.
First, both springs and dampers were installed at the same time as a set of other suspension upgrades that were carefully selected to complement each other. While it’s not possible to strictly isolate the individual affects, I believe that I can comment on “major effects” of the springs and with the FP track dampers in the context of the overall suspension upgrade. I got valuable advice from many folks when researching these upgrades, but forum-member BmacIL deserves particular thanks for his comprehensive and thoughtful advice. Also, thanks to BlueMustang for his very helpful impressions of this pairing.
So, for the record, here are the modifications that I made to my base model 2017 GT.
• BMR: handling springs (SP083: front: 250lb; rear: 980lb)
• Ford Performance: track struts & shocks (M-18000-F)
• Steeda: rear billet shock mounts (555-8151)
Other upgrades:
• Ford Performance: rear toe links (M-5972-M) and toe link to knuckle connector bushing (M-5A460-M)
• Steeda: IRS subframe bushing support system (555 4447)
• Steeda: IRS subframe alignment kit (555 4437)
• Steeda: K-member 4-pt chassis support brace
• Steeda: Strut tower brace
• Performance alignment
Second, there are inevitable tradeoffs between street and road-course performance, and in the interest of full disclosure, I favor road-course performance. Prior to my GT, I tracked a 2015 Ecoboost Mustang; and prior to that I raced motorcycles at the same track. FYI, my local is the Atlantic Motorsports Park, and it is widely considered the most technical road course in Canada. I daily drive my GT, so I am sensitive to the tension between the tradeoffs of suspension performance.
OK, on to the review. I will break it down into separate points, and I will start with the street. I will also make direct comparison to the Ecoboost Mustang, and in a few cases to the 2012/2013 BOSS 302 Mustang.
Street performance:
1. Both the stock GT and the Ecoboost Mustang suspension have a lot of soft rubber bushings, and the IRS can sustain a lot of deflection in some circumstances. These cars are softly sprung “grand tourers” by design. With the factory springs and dampers, both cars felt disconnected from the road; specifically they had delayed and un-intuitive reactions to changes in the road surface. The upgrades (in large part due to the springs and dampers, but also due to IRS bushing support system) have almost completely CORRECTED this problem in the GT. The car is now “hunkered down” and predictable.
2. These springs and dampers result in a much more FRIM ride compared to stock. But, it is NOT TOO HARSH; it’s still a largely confortable ride. The road surface is now transmitted to the driver, but in an informative way. You will feel all the road imperfection, but this is “knowledge” you do not have as a driver in the stock setup.
3. Some road conditions are transmitted more than others to the cabin and to the driver. However, it was not what I predicted… Rough and broken pavement is not as harsh as I expected, and, oddly, minor “undulations” seem to be the biggest challenge to the suspension. However, the car is never unsettled. It is never skittish (which I had been worried about). Indeed it’s extremely effective at dealing with a broken surface: ONE-DOWN then ONE-UP and it’s all done.
4. Unexpectedly, the suspension gets BETTER WITH SPEED. There is a bridge joint I have to cross on a regular basis, and it was very harsh on both the stock GT and the Ecoboost. I gritted my teeth on my first approach to this bridge joint with the new suspension, and low-and-behold it was actually better! And, the faster I go the less harsh this joint feels!!!
5. STEERING RESPONSE is very noticeably improved. I chalk this up to the combined effect of the 250lb front springs, the strut tower brace, and the 4-point chassis brace to (i) reduce the amount of flex in the front end, and (ii) maintain a stable wheel alignment during cornering. The effect is that steering response is immediate, and the car changes direction much more quickly. This makes the car really fun to drive on twisty roads (but with unexpected consequence on the track; more on this later). The Ecoboost Mustang, with 200lbs less weight over the front wheels, had a real advantage over the GT Mustang in terms of steering feel and response. For street driving, these upgrades corrected that discrepancy.
6. There is now noticeably less tramlining on the highway (it’s not entirely gone; I do run 275s up front after all). But, this might not be attributable to the suspension changes. The reduction in tramlining could be a consequence of the extra weight of the GT over the front wheels and the alignment changes I chose after the suspension upgrades. I can’t be sure about the source of the improvement.
7. A final note about the effect of tires on the firmness of the ride. I run 18x10 wheels and a 275 square tire stance. Tire pressure and temperature have a noticeable effect on ride quality. I found that running just a little less pressure, 29-30psi rather than 32psi, made a noticeable improvement on ride quality for my setup.
Road-course performance:
1. The ride is now VERY FLAT. Even with the stock sway bars (more about this later) the car has much less lean during hard cornering. There is also much less nose dive under hard breaking and the car no longer rocks back on its haunches during hard acceleration. The effect is that there is much less weight transfer during hard driving, and this leads to (i) a more “planted feel” at speed and (ii) smoother transitions that minimize disturbances that unsettle the suspension.
2. The car now communicates everything to me, as it should. In addition to feeling the road, I can instantly feel how the suspension is reacting to my inputs. This is why you want “TRACK FRIMNESS”. By the way, it’s not too firm; the car has yet to react unexpectedly and is easy to apply power smoothly.
3. There are some unexpected consequences of the sharp steering response. The effect is that even very small mistakes get quickly transmitted to the chassis. As I approached the limit in my car (which is now MUCH FASTER than before) it demanded much more technical skill. This suspension simply demands more precision. It's not that car gets dangerous, or jittery, when I make a mistake; it's just that it communicates my mistakes instantly. That delightfully crisp steering response on the street becomes “hypersensitive”; if you are just a little too abrupt on turn in, you will feel it in the chassis. The EcoBoost, and the stock GT, were much easier to drive at their limit (albeit slower). The BOSS 302 under the same conditions over the weekend, was also easier to drive at the limit. The good news is that the upgraded GT suspension will help teach you to be a better driver… if you are willing to listen to it (and your instructor). For this reason, I feel this is not a suspension setup for a beginner (more thoughts on this later).
With my general impressions out of the way, I thought I would break the review down into the basic stages of a road course turn.
Maximum braking on approach: The car is very stable. Since there is much less nose-dive it feels more settled, and this gives you confidence to go deeper. I suppose the back brakes could now be more efficient leading to shorter stopping times, but I can’t be sure that I actually was stopping any more effectively. But, stability leads to greater confidence and smoothness, and this encourages you to go deeper.
Turn-in / transition to cornering: This is where the increased sensitivity has pros and cons. The cons: the margin for error is smaller. If you are off a little on your input timing, or you are too abrupt, you will feel that mistake. The car will NOT soak it up for you. You need to pay attention. The pros: (i) You will feel your mistakes instantly. Yes, this was also a con because it can be distracting. But, this is how you learn to be precise and smooth. (ii) You will feel that you have made a mistake but it will not punish you; the car was never unpredictable or jittery. (iii) Precision and smoothness are rewarded with more speed throughout the rest of the turn!
Cornering on a balanced throttle: There is MUCH LESS body roll. As with the turn in, there will be less weight transfer (if you have done it right), and the car feels like it maintains more speed. There is also LESS UNDERSTEER. The car still understeers, but I was surprised how much less I was fighting it. All this said, for me, actual improvements in speed were gained by avoiding mistakes during the transition to cornering. That is where I have some work to do.
Transition to acceleration and exit: This is where it gets interesting. I had struggled with a particular decreasing radius turn going down hill with less than ideal camber. There is no consensus opinion on the best line for this turn, and it slows a lot of folks down, including me. Not only was I able to carry more speed, but I was able to build a surprising amount of acceleration on the transition to exit. At one point I swore that the throttle caused the front end to tuck in. On the next lap I realized that I was actually getting very progressive, and manageable, throttle steering. A turn that had once been a problem for me was now delightful to manage with partial throttle and a touch of oversteer. I am sure than any well tuned suspension can delver this. That is not the interesting point. The interesting point is that I am still on the stock sway bars; I am seriously thinking of staying with the stock bars.
Critiques: As expected, nothing is perfect and there are some issues. Three things stand out at this point:
(1) Some people say that, with an “upgraded” suspension, the GT mustang “shrinks around you” once you get it on the track. I disagree. The car still feels big. If still feels bigger that the Ecoboost Mustang (on the same track), and it feels bigger than the BOSS 302 (on the same track). It's still a 3700lb car with a lot of weight over the front wheels.
(2) The suspension is not perfect. Under cornering conditions much faster than what was possible with the stock suspension, the suspension can very occasionally shift in a way that is delayed relative to my inputs or changes in the road surface. Either way, it seems to be localized in the rear, and I think there may still be some deflection in the IRS. It’s distinct, very noticeable, and somewhat distracting; fortunately, it does not happen often, and the car can still be driven quite easily. This does not seem to be the fault of the spring and damper pairing; rather, I suspect there is still something in the IRS that needs correction.
(3) My upgraded GT rides flatter than the BOSS 302 and yet it feels less planted. I believe this is related to issue (2) above. Both cars communicate a lot of information about the road and the cornering dynamics to the driver; let’s call this “signal”. My current suspension still shifts in a way that is unrelated, or delayed from, my inputs; let’s call this “noise”. I think the BOSS 302 feels better because it has a little better “signal to noise ratio” than my car does right now.
Overall impressions: If you are interested in road course performance, you would be very hard pressed to find better value for money in the pairing of BMR handling springs (SP083) paired with the Ford Performance track shocks and struts (M-18000-F). With a small number of supporting mods the changes in the handing are PROFOUND.
The advantages of this suspension improve with speed. If you spend most of you time in traffic, and at lower speeds, then you are simply not going to appreciate the amazing engineering that went into these, and you are certainly not gaining anything in terms of comfort. This pairing is perfect for those driving hard in autocross or on a road course. I love this set up! But it’s not for everyone. Here is my very subjective sense of the spectrum of different damper and spring pairings.
(1) Very soft grand touring car:
- Base GT suspension
(2) Moderately soft grand touring car:
- Factory Performance Pack suspension
(3) Daily driver, performance driving mostly below the limit (a corner carver), with occasional track days:
- Factory Performance Pack dampers with BMR min-drop springs (SP763)
(4) Daily driver and high performance driving at frequent track days or autocross, but with slightly more preference for a softer street ride:
- Ford Performance track shocks and struts (M-18000-F) with BMR min-drop springs (SP763), in combination with supporting suspension and chassis mods. (Done right, I expect this might feel a lot like the BOSS 302.)
(5) Daily driver and high performance driving at frequent track days or autocross, with more preference for a track spring. Specifically, a flat ride with road surface and suspension dynamics clearly communicated to the driver, predictable weight transfers, and optimized reactions to weigh transfers.
- Ford Performance track shocks and struts (M-18000-F) with handling springs (SP083) combined with supporting suspension and chassis mods.
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