In search of perfect coilovers - Eibach Multi-Pro R1's

[xpystchrisx]

Why some guys rip all the factory perfection out for aftermarket stuff on these cars is a little beyond me, its takes a highly modded Mk5 like my own to keep up with one of these in stock form with just good tires.

Didn't you know that aftermarket parts are always better than OEM? Dur... :wink:

As you were. Great thread bostonaudi, I'm enjoying every bit of your research. I just moved back to FL which helps with the spring rate choice on a daily driver. The roads here are flat as glass.

 

[telaio]

The thing with spring rates is they are a part of a mechanical system with damping, and have to be tuned with car's weight and unsprung weight taken into account.

How does reducing unsprung weight affect spring rates?

 

[bostonaudi]

Just not if somebody gets this wrong:

Dampers work only on bumps and when you turn the wheel > on turn in or on corner exit.
They are already settled less than as second after you're finished with this. In no way the
dampers have any influence on balance and roll at mid corner. It's the job of springs and
sways only.

:wink:

With older or basic dampers that might be true. With more advanced race shocks aggressive setting of the low speed compression circuit of the shock contributes to preventing roll. Ride in a car with Motons set stiff sometime and you will not experience a whole lot of roll. Course the sways contribute a lot too.

 

[bostonaudi]

How does reducing unsprung weight affect spring rates?

You can generally tweak rates up a bit. Part of the reason my car gets crashy with high rates is I run the stock 18" Huffs for DD and they're heavy.

 

[the bruce]

With older or basic dampers that might be true. With more advanced race shocks aggressive setting of the low speed compression circuit of the shock contributes to preventing roll. Ride in a car with Motons set stiff sometime and you will not experience a whole lot of roll. Course the sways contribute a lot too.

subjective feelings versus objective data :attention_whore:


Try to get hold of some race car data recording. :wink:

 

[RRacerguy717]

You can generally tweak rates up a bit. Part of the reason my car gets crashy with high rates is I run the stock 18" Huffs for DD and they're heavy.

When the front spring is too stiff there not enough cross weight transfered to the front to help it turn. This is even more important IMO with our suspensions that use high caster rates. Prob whats happening with your DD setup is because you don't push it like when your at the track that transfer of weight is a lot less making it feel less front grip. I always look at it that your springrate controls how MUCH cross weight is transfered and a good shock controls how FAST the weight is transfered IMO.Bob G. :thumbsup:

 

[jmk007]

I did a massive round of spring testing over the last couple of days. The R1's work best near the rates they supply as that's what they are valved for. I ran at Road Atlanta a couple of weeks ago with 450/350, the increased rates did not lower lap times, and made the car unsettled when taking lines over rumble strips. So I'd suggest sticking near the rates they supply, and use 8" springs front and rear. I also ran the car with 350/300, and 350/350 for a while, which will tighten it up a bit, but I wouldn't venture much above that. I installed a 300/250 combo last night, both with 8" length, and I like the way it rides and handling still excellent. If you change the front springs you can fit an 8" 300 lb spring and still lower it a full inch.

To run a more aggressive track setup its better to buy a setup like a KW Clubsport kit that already comes with higher rates and matched valving, or order a custom setup from GC, or Vorshlag etc..

All the above isn't to say the Eibach R1/R2 setups aren't good, they are, when used as designed with supplied rates. For anyone getting an aftermarket kit, once again get the best damping you can afford, spring rates are secondary. Any kit based on Koni shocks is going to be pretty good. The important thing is keeping the tires with the best contact on the road they can have, especially over bumps and rumble strips, and that is what great damping accomplishes.

I drove another local members car the other day with the AST 4100 kit, they supply the kit with relatively moderate 350/250 springs, but the dampers are fantastic, car stuck like glue. Its another $700 or so to step up to this kit, but IMO the AST kit has to be on short list as best kit in its price range of around $2300.

In the other Ohlins thread the right questions were raised about whether those shocks will control the higher 350 rate springs H2Sport is shipping. Mismatches makes for a car that is not fun to drive. Your track car should be fun, and inviting to drive, not a punishing car that no one wants to get in.

Bostonaudi,

How would you compare the Eibach R1's in 350/250 to the AST's in 350/250 in terms of: a) performance on the rack; and b) ride on the street? Is there a material difference in either category between the two?

 

[bostonaudi]

Bostonaudi,

How would you compare the Eibach R1's in 350/250 to the AST's in 350/250 in terms of: a) performance on the rack; and b) ride on the street? Is there a material difference in either category between the two?

I can't speak to the AST performance on the track as I haven't driven a car with that setup there, but I'm sure they are awesome. For the short street drive I took them on they felt great, smooth and totally composed. The R1's are very good too, the AST's about another $700, how fast do you want to go? If you can afford the extra coin the AST's are excellent, if not the R1's not a bad choice at all, I've been running hard with them for last 3 yrs and no complaints.

The interesting choice would be R2's, then you get separate damping settings and external resevoirs.

 

[jmk007]

Since you do have experience with the ASTs on the street, how do they compare to the Eibachs on the street?

 

[bostonaudi]

My car was riding on 450/350's at the time I drove the car with AST's with 350/250, so obviously the car with softer springs rode better. The AST car also had GC camber plates and you almost couldn't tell they were on the car, it was still very smooth, the AST's are excellent in their ability to control car with glue like grip and still ride smooth. The AST's were not bouncy at all, just smooth, controlled and firm, exactly what you want. IMO the Eibach's very good too, that same controlled firmness, but perhaps a tad less refined than the AST's.

The Eibachs R1's are a great deal for $1700, if you can afford the $2400 for the AST kit you won't go wrong. Both feel similar in that they are high pressure gas monotubes so both get the advantages of that design. Again at the price range of the AST you also gotta look at the Eibach R2's, for $2200 you get external reservoirs and separate rebound and compression adjust. For the track junkie the split adjustment gives more fine tuning and they'll resist heat better.