Say im trying to decide on a suspension set up and some wheels and tires for my 2014 mustang that has 115k miles and still the original shocks and control arms. I was going to go with Koni sport and eibach springs but was told today that SR performance coil overs which even cost less would do better at the track. It's not my daily driver and I only plan on like 8 weekends a year at the track but I want the tightest feeling I can get on the street but not to harsh ride quality. I was told Koni can adjust from ultra comfort to track but there will be the springs. SR coil overs are on sale this weekend for $767 to the door. Would you guys go with that over 1k for shocks and springs?
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SR performance coilovers VS Koni sport/Eibach?
- Thread starterDarrylS76
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Dave_W
Cones - not just for ice cream
I believe SR Performance is American Muscle's in-house private label Chinese garbage shocks. As Nancy Reagan said, Just Say No.
Koni Sport (aka Yellow) shocks are good for the price. When adjusting, don't leave them at the end of the range or the adjuster can get jammed - turn to full soft or stiff and then go back 1/8 - 1/4 turn. I also happen to like Bilsteins -- they're not adjustable but they're good quality monotubes with a digressive damping curve.
For the Eibachs, avoid the Sportline, as they have too much drop, especially in front. The Pro-Kit is okay. Generally, you want to drop the front about 1/2" to 1" max to avoid detrimental changes to the McStrut geometry. You can drop it more, but you'll need extended ball joints and a properly adjusted bump steer kit.
Take a look at the S197 spring & bar compendium --
trackmustangsonline.com
Something that costs a bit more but gives you ride height adjustability and the ability to easily change among real race-type springs (available in different free lengths and differences in stiffness of 25 or 50 lbs/in) is Ground Control's coilover conversion kit.
groundcontrolstore.com
Their tech line is very helpful. Don't order online, give them a call and talk to them about your mix of street / track, the roughness of your local streets, ride comfort, etc., and they can help pick spring rates custom to your needs. And they sell the Eibach ERS springs for $82 each, so it's relatively cheap to swap in stiffer front springs later if you decide to do more track days.
Koni Sport (aka Yellow) shocks are good for the price. When adjusting, don't leave them at the end of the range or the adjuster can get jammed - turn to full soft or stiff and then go back 1/8 - 1/4 turn. I also happen to like Bilsteins -- they're not adjustable but they're good quality monotubes with a digressive damping curve.
For the Eibachs, avoid the Sportline, as they have too much drop, especially in front. The Pro-Kit is okay. Generally, you want to drop the front about 1/2" to 1" max to avoid detrimental changes to the McStrut geometry. You can drop it more, but you'll need extended ball joints and a properly adjusted bump steer kit.
Take a look at the S197 spring & bar compendium --
S197 Spring and Sway Bar Rates
S197 Springs Front/Rear: OEM: Boss 302 ................... 148F/186R lbs/in Boss 302 Laguna Seca 137F/191R lbs/in Brembo GT/ GTPP ...... 131F/167R lbs/in GT and V6PP............... 123F/156R lbs/in P Springs (1" drop) 230-260/202 (est - may be same as published K below) K Springs (1.5" drop)...
trackmustangsonline.comSomething that costs a bit more but gives you ride height adjustability and the ability to easily change among real race-type springs (available in different free lengths and differences in stiffness of 25 or 50 lbs/in) is Ground Control's coilover conversion kit.
2005-14 Mustang GT Coilover Conversion Kit
Coilover conversion kit for 2005 Mustang GT with stock shocks. Optional spring seat allows added range of front adjustment (same price, specify when ordering) Expected ride height change from 0 to 2.5 inches front and rear Includes upper perches and bearings, instructions and ride height specs...
groundcontrolstore.com- Thread starter
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I think these two are the no-brainer EASY button. You won't have adjustment, but you will have completely reasonable damping control. I'm not really a fan of Koni's. I find them harsh and not particularly good for grip. YMMV. Some people swear by them.
Dave_W
Cones - not just for ice cream
The worst would be spending money and having no improvement, or actually being worse. Yes, and yes, potentially -- I don't have first-and experience with the SR so i can't definitively say, but I see the signs in some of the reviews.
Springs are relatively easy to engineer well. They provide a force based on length displacement (position), the mechanical calculations for design are simple and well-known, and the level of quality control needed to turn out a consistent product isn't too much.
Dampers, on the other hand, can be difficult to engineer well. They provide a force based on speed of length displacement (velocity). They rely on fluid dynamics around small parts and dynamic material properties (e.g., shim washer flex under various loads). The level of quality control needed for good, consistent units is probably at least one or two magnitudes greater than springs, and more even if adjustable. You need to factor the sprung mass being controlled, and the spring rate being used, to determine the ideal damping needed. By default (wavy hands), shocks have a linear damping curve, but many drivers prefer the low-speed support of a digressive curve, so that's another design decision.
Shocks generate heat, and the oil used in them should not significantly change viscosity from that heat. That requires another entire area of engineering all its own (Penske shock oil is $30-40 per quart). And the shock oil should not cavitate on its way through the shock valving, so added pressure is typically used in shocks -- enough to prevent cavitation but not so much it's adding noticeable spring force to the suspension.
A couple (older) articles from the force behind creating SCCA's Street Modified autocross category, whose day job was a shock builder for a race team. Note that he worked with real racing shocks, where you often adjust them by opening them up and changing the internals instead of using a external knob. And then dyno them to see if you got the shim stack right, open up again because you didn't, adjust the stack, and dyno again.
Autocross to Win (DGs Autocross Secrets) - Shocks
Autocross to Win, a technical discussion of preparing winning autocross cars.
farnorthracing.com
Autocross to Win (DGs Autocross Secrets) - Buying Shocks
Autocross to Win, a technical discussion of preparing winning autocross cars.
farnorthracing.com
You didn't pay an extra $800 for what you have now. And there is a non-zero chance the SR shocks could be worse.
I think Bilsteins shocks and Ford Performance springs are both high-quality, have good engineering behind them, and would be a nice improvement for a daily driver through mid-level HPDE without being overly harsh.
I'm on Koni yellows and Steeda Boss springs. I haven't used Bilsteins yet, but these 2 brands are the most popular non-coilover design shocks on TMO. The impression I get is that Konis tend to be little overdamped and tend to not last all that long but they work well, give you rebound adjustability and have a good warranty program. Bilstein's seem more refined, will be more comfortable on a wider range of springs, will last much longer but have no adjustability. I went with the Konis because the Boss originally came with adjustable shocks and I just wanted to retain that capability. I'm only street driving for the time being, but the Koni's work well for me. They're certainly much stiffer than the OEM Boss shocks. If I want to make things a little more comfortable in the future I might try the Bilsteins.
One thing about Koni yellows that I think many people may misunderstand is that people talk about setting them to, "full stiff," etc. Understand that the rebound control adjusts how quickly the shocks return to ride height, and not how much they resist compression. Koni says that this is best used to control body roll. It's also important when doing WOT pulls for datalogs. I find that if the rear shocks are on a, "stiffer" setting, that you lose some stability on launches. It makes sense that drag racers prefer shocks that are less dampened.
Buying coilovers seems much more tricky and much more pay-to-win. But I have seen some fast guys on TMO on cheaper coilovers like Ground Controls or Konis. Vorschlag seems to have some well regarded setups also.
Shocks are expensive. If you don't have the time or money to experiment, and you want to be fast, find some fast guys on TMO and duplicate what they've done. Easiest way to get a good result.
Regarding the springs, lowering the rear will also change the suspension geometry. You'll need an adjustable panhard bar and if you go really low you'll need an adjustable upper rear control arm to correct the pinion angle.
Here's an MM chart about pairing springs and shocks that I like:
One thing about Koni yellows that I think many people may misunderstand is that people talk about setting them to, "full stiff," etc. Understand that the rebound control adjusts how quickly the shocks return to ride height, and not how much they resist compression. Koni says that this is best used to control body roll. It's also important when doing WOT pulls for datalogs. I find that if the rear shocks are on a, "stiffer" setting, that you lose some stability on launches. It makes sense that drag racers prefer shocks that are less dampened.
Buying coilovers seems much more tricky and much more pay-to-win. But I have seen some fast guys on TMO on cheaper coilovers like Ground Controls or Konis. Vorschlag seems to have some well regarded setups also.
Shocks are expensive. If you don't have the time or money to experiment, and you want to be fast, find some fast guys on TMO and duplicate what they've done. Easiest way to get a good result.
Regarding the springs, lowering the rear will also change the suspension geometry. You'll need an adjustable panhard bar and if you go really low you'll need an adjustable upper rear control arm to correct the pinion angle.
Here's an MM chart about pairing springs and shocks that I like:
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- 554
I’ve used Bilstein sports and Koni yellows. Anecdotally I feel like the Bilsteins are stiffer on compression and a little harsher on the street. But no real data.
Bill Pemberton
0ld Ford Automotive Racing Terror
The SR ( Shanghai Racing ) Performance will give your car the " China syndrome " and hence it will be slower and have " ill handling ." Listen to your fellow TMO members and go Koni or Bistein.
Autocrossers seem to go much more often with Konis, the adjustability comes in handy on various road courses and does seem to help plant the rear end better under power.
Have a nice day!
Autocrossers seem to go much more often with Konis, the adjustability comes in handy on various road courses and does seem to help plant the rear end better under power.
Have a nice day!
blacksheep-1
Epic Contributor
IMO find one of the Ford Performance kits, install it, and enjoy. Decent coilovers will run north of $5K, the ones on the S197s are Penskes at over $10K. The disadvantage far outweigh the advantages in maintenance alone, plus with a FP suspension you can't tune yourself out of the setup, You will also need to rebuild the coilovers at least once per year. In IMSA they get rebuilt after each race.
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Thanks for the feed back man! That all black is sick on the Boss. I love the wheels on that green one in your pics. I think ill go with shocks and springs instead of cheap coil overs
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- #12
Thanks for the recommendation im looking on American muscle now at some of the kits . That way ill have the sway bars too. Sounds like ill need the pan hard bar and control arms as well. Only thing is the ford performance kits springs only lower by one inch and I really wanted to get rid of some of that gap between the tire and wheel well. Its awful stock . Really is a shitty suspension set up when you dont get a shelby. I m wondering what shelby does? Guessing ford performance as well ?
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Eibach is a 2 inch drop in the rear right? Seems like that would be perfect . I cant really justify doing it with only 1 inch
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- #14
That sounds like the way ill go but can I get more then 1 inch of drop with ford springs ? Although it sounds like if I only go 1 inch nothing else will be needed?
When you read lowering spring drop measurements, know that the result on every car will vary somewhat. Think of them as an estimate rather than something you can count on.
Here's a pic of 2 very nice TMO cars that I think is a good comparison in regards to fitment:
On the left, @TymeSlayer's Sweet Loraine. He's on FRPP "T" springs and 19x11 wheels.
On the right is @cholmes1's 302SX. He's on the same springs as me, Steeda Boss springs and he's also on 19x11's.
(edit: correction, cholmes1's car appears to be on the stock Boss wheels in the photo, so 19x10's or thereabouts)
For reference, I'm on 18x10's.
TymeSlayer's car is lower to the ground and his wheel fitment is tighter. cholmes1's car is just a little lowered from stock height. For me, this is the reason I chose the Steeda springs. I was already scraping around town with what I had previously and I wanted to remedy that. Most of the popular lowering springs will look more like TymeSlayer's setup. FRPP "T" & "P" springs and Eibach Pro Kits I think will all be similar. The rates will probably be a little different.
In regards to fitment, you have to think of your suspension setup and your wheels and tires as a package. This is a bad idea but, most people could easily get nice looking fitment by throwing on a set of 20" wheels. The smaller your wheels, the lower you have to go to achieve nice looking fitment. Most people on here wouldn't recommend anything over 19" and I'd agree. 18's are the most versatile I think, and that's what I have. I can put a wide range of tire sizes on my car because of the 18's. But the fitment looks kinda stockish. I think a combo like what TymeSlayer's got there is probably what you're looking for.
Here's another nice setup:
This is @Adam Ginsberg's Boss. He's also on FRPP T springs with 19x10 wheels and 295x35 tires. This is max tire meat without spacers.
That green Boss next to mine in my photos is also on T springs, but he's on 20x10 wheels and 285x35 tires. This gives him very tight fitment, but a stockish ride height. He says he has no rubbing but I find that hard to believe! Probably not the best for performance. But the guy who owns it has no plans to track it so he only cares about fitment. Actually, there's an old classified ad on TMO for that exact set of wheels if you really like them. Not sure if they're still available or not. But I'd recommend 19's for you.
Another thing you want to keep in mind is your revs/mile. The car's computer expects the wheel/tire combo to be around a certain size and if you change it significantly then your traction control and speedometer will be a little off. This can be corrected with tuning though. That green Boss in my photos would definitely be outside of the normal range. Here's a calculator you can use to look at revs/mile. Just put your car's original wheel and tire size in the top box and put what you're thinking of changing to in the bottom.
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blacksheep-1
Epic Contributor
Well, if you just want to lower it, that's one thing, the Ford kits are designed to work together, you may want to look at Cortex, they sell kits as well and in some cases they provide parts for Ford (painted blue). Project Superbeater has the Ford kit, 18x 10s, it doe shave the stock GT sway bars but they are in urethane bushings. I always go back to what was run in World Challenge, basically non adjustable FP trailing arms, a stock or GT500 center link, a FP adjustable Panhard bar, then of course, the high zoot Penskes, which were probably the real key, as far as the front same deal, all stock but sway bars and Penskes, There's no magic there, the spring rates are proprietary, and you wouldn't believe them anyway. 18mm bar on the rear and the old Ford adjustable Blue bar on the front. Pretty standard stuff. My gt500 has Ford FP springs on it,
blacksheep-1
Epic Contributor
Project Superbeater page 13 if the link doesn't work.
trackmustangsonline.com
Project Super Beater
I love that MM uses nice hardware, including hardened washers.Where did you put that thing? -3.5?I don't want to say because if someone else tries it and it doesn't work, I'm gonna take the heat. I'm sort of a low buck version of Sal Molinare @Fabman when it comes to experimenting.
trackmustangsonline.com
I had Bilsteins with FP springs in an 07 GT I owned. Good handling and control and very predictable on track, a bit harsh on the street on rougher roads. My 12 GT500 got Koni yellows and FP springs last year. I leave them set fairly soft for the street and it rides better than the factory Performance Pack dampers and springs. For Mosport I turn the shocks up a bit (more so the front) and it works decently for a nose-heavy turd.
- Thread starter
- #19
Man that world challenge suspension sounds hooked up ! Stock shocks tho huh ? Kinda surprising. Not sure i know what trailing arms are exactly? Im looking for the best handling not too too harsh on the street . Then maybe 5 or 6 track days a year being im lucky to live 10 minutes from Summit point raceway. Half the reason why i got the car
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- #20
Hey man , thank you so much for the reply on the info. You nailed it.I do like that ride height one time slayer , and the other one that you posted , and I also need tires and wheels , so thinking maybe bill stevens , shocks or koni i can't decide and then go on with ford performance racing springs. Is there anything else that won't break the bank suspension?Wise , that really makes a drastic improvement? Sway bars or control arms maybe ? I don't plan on doing much at all in the power category juust really want a different handling car other then this boat like floaty stock ride. Im looking at a really cheap big brake set up that I saw a couple videos. I believe their power stop rotors Hawk pads and some kind of inexpensive 4 piston calipers. So a 2 inch drop on a eibach springs would be to much huh ?
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