420 front suspension upgrade ??s...

[northNH]

Comparing standard front 500E vs EuroSportline spec 420:
EPC shows 420 Sportline upgrades to standard 500E struts and ASB, but calls for stiffer springs (-4204s vs -3504s) than standard 500E.
Huh?

Why might this be?
Because the 420 SL spec calls for the stiffer-bushed LCAs (-36/37,07) vs. the no-LCA-upgrade-shown 500E?
Does not seem to have to do with SLS vs. non...

Weight differences? Track differences from wheel/tire sizes?
Just another official printed inconsistency?

 

[gsxr]

The .034 Sportline had stiffer springs than 6-cyl Sportline, due to the higher weight of the V8 models vs non-V8. The #42 springs are different than 500E, but not stiffer than 500E springs. Probably because the .034 weighs less, and the .034 Sportline has a higher ride height than the .036 chassis. Specs for all the 124 the coil springs are on my website in the "suspension" directory, including the wire diameter, free length, and number of turns/coils.

The Sportline LCA bushings were stiffer through roughly early facelift production, then MB switched back to standard bushings... I suspect there were some complaints of harshness, but I really don't know for sure. All late Sportlines had standard / soft LCA bushings, same as all .036 chassis.

 

[northNH]

I know the useful spring #s/values you've provided, tho' just enough info missing (i.e. deflection) to be provocative but non-definitive...

Based on #ing convention -4204 SHOULD be for a heavier car than -3504, no?
You are saying a set of 3504s on a 430 will be lower/stiffer than the 4204s, right?

How much lower/stiffer you reckon (disregarding spacer factor), compared to typical ~1" Sportline change?

Re: Later 124 Sportline LCA change to standard bushings:
FWIW When I Sportlined my Coupe (struts, springs, ASBs, steering box, front LCA and rear bushings, etc.) my sense is that the stiffer bushings had the least effect on the much-improved result.
Maybe thusly discontinued?

 

[gsxr]

Part number sequence does not correlate to either stiffness or length... while some series are in numerical order, others are random. For example the 036 standard rear springs are #30, while the 036 Limited #38 springs are both shorter and softer. Deflection numbers were sourced from the TDM and this data was not published for 1990-up springs (Sportline, 400E, or 500E).

The #35 front springs are slightly stiffer than the #42 based on the specs. The #35 springs in an E420 may result in a slightly taller ride height than the #42. The only way to find out is try both of them. You can fine-tune with the rubber spring pads. In this particular scenario I wouldn't have a problem using either front spring on the .034 chassis as I expect the performance to be similar. I'd wild guess a 1/4" difference in ride height between the two (maybe) which you can tweak with the pads. Both seem to still be available new, and the .034 Sportline rear springs should be available new as well. The 036 rears might be NLA... uh-oh.