KB AGS-4 Suspension Install

[Eric]

Jimmy,

Verified the current LCA orientation is correct.



r/
Eric

 

[Jimmy Pribble]

Jimmy,

Verified the current LCA orientation is correct.

r/
Eric

Well, glad to hear it. The picture threw me off, but I guess you were right about their instructions being detailed and precise.

I'm almost certain I will be going with some KB stuff. The only thing now is that I'm hearing these hybrid LCAs are still noisy. If that's the case, I'm not sure why I wouldn't just move on to the double heim-jointed version. In for a penny, in for a pound...ing in my ears.

 

[Roadhouse]

Mine are pretty noisy. They just clank around a lot going over rough streets. Which is every street in Oklahoma... :

 

[Champale]

Jimmy - you should consider these Steeda billet LCAs. They make them in a variety of configurations, including ones with spherical bushings on the axle end like I have (3rd one down on the list). I had them on my '12 for about 5k miles and then yanked them off and installed them on my '13 LS when I switched cars. About 7k miles total with nary a clunk or squeak. Plus, they are light and beautiful!

http://www.steeda.com/store/steeda-mustang-billet-lower-control-arms.html

 

[Jimmy Pribble]

Jimmy - you should consider these Steeda billet LCAs. They make them in a variety of configurations, including ones with spherical bushings on the axle end like I have (3rd one down on the list). I had them on my '12 for about 5k miles and then yanked them off and installed them on my '13 LS when I switched cars. About 7k miles total with nary a clunk or squeak. Plus, they are light and beautiful!

http://www.steeda.com/store/steeda-mustang-billet-lower-control-arms.html

Thanks for the recommendation! Those do look like nice pieces.

 

[Dig-It]

I ran the KB RCRK at VIR this last weekend - with no rear sway bar, Steeda Boss springs, stock struts and shocks. I was able to get a full course lap time of 2:20 on the stock Pirelli Corsas and 2:17 on Hoosier slicks. I'm sold on the KB parts.

 

[boro92]

I ran the KB RCRK at VIR this last weekend - with no rear sway bar, Steeda Boss springs, stock struts and shocks. I was able to get a full course lap time of 2:20 on the stock Pirelli Corsas and 2:17 on Hoosier slicks. I'm sold on the KB parts.

Sadly, I'm unfamiliar with VIR as I've never been. Do you have time comparisons to when you took the car there before you had the RCRK installed?

 

[further]

2:17 is pretty darn fast.

 

[VoodooBoss]

I ran the KB RCRK at VIR this last weekend - with no rear sway bar, Steeda Boss springs, stock struts and shocks. I was able to get a full course lap time of 2:20 on the stock Pirelli Corsas and 2:17 on Hoosier slicks. I'm sold on the KB parts.

What were your times the last time you ran there?

 

[Dig-It]

Not sure as this was my first time with a timer.

 

[drano38]

Reading this thread has me wondering why I've got a Whiteline Watts link laying in a box in my garage. :-\
Oh well, I'm ready to start its install tomorrow.
But the KB kit panhard relocation kit does look like a good solution.

 

[Eric]

Quick update on the AGS-4 suspension after 3000 miles...

Performance. Much more balanced than stock. Turn in, brake dive, cornering, neutral roll...all much better. Very satisfied with the KB spec Eibach coil overs...not jaring or hash riding.

Maintenance.
- Check torque. Went through the entire car and retorqed anything that had been replaced (struts, k-member, rear suspension). Noted some of the k-member fasteners had loosened up. All torqued to spec now; will re-check again.
- Rod Ends. After 3000 miles and the ever present "clunk/clunk" noise over expansion joints and other road irregularities, I took the back end apart to see what the problem was. Ended up replacing all of the rod-ends as they were sloppy. Figured they would last longer than that, but Pegasus Racing sells a very high quality 3/4 x 3/4 Aroura rod end for $75.00 ea.
- Hardware. Also noted during the tear down/build up that the OEM hardware is slightly smaller in diameter than the inside diameter of the aluminum inserts that are used in the rod ends. This was also true for the bushing/steel insert on the axle side of the UCA. Replaced all the hardware with 9/16 (course pitch) Grade 8 bolts and nuts. Had to bore out some (not all) of the aluminum inserts to accept a 9/16 bolt. The UCA bushing/steel insert is already 9/16". Now there is no slop between the rod end and attaching hardware.

End result...no more clunk/clunk. Even more impressed with the performance level and ride quaity now.

r/

 

[boro92]

Quick update on the AGS-4 suspension after 3000 miles...

Performance. Much more balanced than stock. Turn in, brake dive, cornering, neutral roll...all much better. Very satisfied with the KB spec Eibach coil overs...not jaring or hash riding.

Maintenance.
- Check torque. Went through the entire car and retorqed anything that had been replaced (struts, k-member, rear suspension). Noted some of the k-member fasteners had loosened up. All torqued to spec now; will re-check again.
- Rod Ends. After 3000 miles and the ever present "clunk/clunk" noise over expansion joints and other road irregularities, I took the back end apart to see what the problem was. Ended up replacing all of the rod-ends as they were sloppy. Figured they would last longer than that, but Pegasus Racing sells a very high quality 3/4 x 3/4 Aroura rod end for $75.00 ea.
- Hardware. Also noted during the tear down/build up that the OEM hardware is slightly smaller in diameter than the inside diameter of the aluminum inserts that are used in the rod ends. This was also true for the bushing/steel insert on the axle side of the UCA. Replaced all the hardware with 9/16 (course pitch) Grade 8 bolts and nuts. Had to bore out some (not all) of the aluminum inserts to accept a 9/16 bolt. The UCA bushing/steel insert is already 9/16". Now there is no slop between the rod end and attaching hardware.

End result...no more clunk/clunk. Even more impressed with the performance level and ride quaity now.

r/

Eric, thanks for your notes on these great parts!
Can you also comment on the rebound control with the KB spec Eibachs?
Specifically, I've driven things like KW V1 and Bilstein PSS and they exhibit distinct lack of rebound control for circuit work. The car is sloppy and transitions weight too swiftly. Clearly, those 2 mentioned setups are more ideal for street use (and they would ride better with softer rebound). How is the KB?

 

[Eric]

Boro...

I can only compare it to the stock LS package on my car and the Boss car I drove at Track Attack...my impression is that the KB/Eibach set up is far more balanced in both compression and rebound. On my stock LS, I was running the fronts on 3 and rears on 2 and the car seemed "jittery", if that's a technical term, where as the KB/Eibach set up is not. When I spoke with Rich and Kenny about upgrading the spring/shock/strut set up they were not pushing the $4000 and up JRZ coil over packages. Their opinion was for the enthusiast with a street, occasional track car that the KB/Eibach was the ideal way to go...you dont need to pay for adjusability that you won't use. KB did spend a lot of time developing this package with Eibach....compression, rebound, and spring rates are all built to KB spec. It is certainly an upgrade over stock. Finally, as a component of the AGS-4 suspension system, it certainly feels very integrated and sorted out....and we've all driven cars that were a mix parts cobbled together based on magazine articles billed as the latest set up... Two thumbs up from me!


r
Eric

 

[isrboss]

I wish KB would confirm what spring rate/dampening changes KB and Eibach came up with for KB's kit. I am running the 05-10 Eibach pro street s kit (KW dampeners) on my Boss and it's great. I don't see Eibach messing with this particular spring design too much(it's not your standard spring design). I'm betting KB just did a frankenstein kit from Eibach's spring/dampener combos. The secret is not impressing me with KB's spring rates etc. just makes it fishy to me. If it's street driven it will not be over 425-450lbs/in front ( so KB is using the 400lbs/in GT500) and he might be using the softer 246lbs/in rear depending on the sway KB balanced the kit with. This is probably the confidence you are feeling. Understeer gives more confidence, just tighter everywhere. The Boss factory setup was more neutral most likely, the way you describe the feeling, leans more toward someone describing a looser setup.

 

[Eric]

ISR,

Yep. Hard to speculate on what KB did or didn't do with Eibach...they did spend time developing the kit and were quite pleased with the way it turned out. The AGS-4 doesn't use a rear sway bar and I am running a 36mm (Eibach) 3-way adjustable bar on the front (currently on the middle setting) with the stock LS wheels and tires. In the end, the KB/Eibach set up works very well with the AGS-4 system....and if you want to move to the KB/JRZ set up that is the only change....sway bar, control arms, k-member, etc. all remain in place. I'm not selling anything...just a satisfied owner.

r/
Eric

 

[isrboss]

I understand your point, and without a doubt, I know the KB/Eibach coilovers are better. I just don't understand what the secret is with the Eibach pro street s from KB's direction. It's not a damper or spring that KB would be competing with or their customers ( makes it seem like hype ). It's just weird and would make it difficult for me to do business with KB. I want to know everything about a product prior to buying it. I feel releasing spring rates on a daily driver coilover setup to be pretty standard.

 

[boro92]

I understand your point, and without a doubt, I know the KB/Eibach coilovers are better. I just don't understand what the secret is with the Eibach pro street s from KB's direction. It's not a damper or spring that KB would be competing with or their customers ( makes it seem like hype ). It's just weird and would make it difficult for me to do business with KB. I want to know everything about a product prior to buying it. I feel releasing spring rates on a daily driver coilover setup to be pretty standard.

I agree with you here. KB stuff intrigues me, but without knowing more about the actual specification, it's really difficult to justify a purchase. It's a shot in the dark...and without having the specs, we won't actually know what the affect to the car will be until it's mounted. Clearly, a good thing for those who want something better and tuned by someone who is in the know...but for those who are after altering their car's specific handling balance to suit their tastes...we are out of luck without that info.

What I didnt know was that the Eibach pro street kit uses the KW struts??? I think you mentioned that in your previous post--is this a change which you made (ie: swapped to KW struts) or do they infact come with struts made by KW? I thought all Eibach coilovers were monotube (and KW V1/2/3 are all twin tube)....thus my asking.

Oh and Eric - thanks for your review. Your insight is most helpful!

 

[Jimmy Pribble]

Does KB obfuscate the Eibach p/n that is printed on the spring?

 

[Eric]

Jimmy,

Nope....here're the numbers. I'd have to look under the car to verify front and rear.

343257 // 35115.701
355301 // 35115.702

ISR and Boro,

Concur with the secrecy thing...makes you wonder why. Having said that, for me it was less about spring rates and more about how the system worked. What I didnt want to do was create an ill handling car in an effort to correct ride height and rear roll center. Ford spent some serious R&D coin on developing the Boss, so in my mind simply swapping springs was problematic. I had a similar experience with my 70 Boss as I experimented with different springs, lowering front A-Arms and such only to end up with a car that handled poorly on the street and track. I finally settled on a fully engineered and tested set up from Global West....and the difference was night and day in both environments. So, for me KB's approach was similar to GW...they race what they sell....and its a fully engineered and tested system with each component compatable with the other components.

r
Eric

r/
Eric