Improving performance and handling

[chassis87]

Hi there all,

we currently have got a 280sl California in our hands, which we would like to participate in classic rallies with. The question is rather simple hehe, what improvements and upgrades would you suggest for such usage?

any racers there that can point me in the right direction please?


Many thanks

Chassis

[Cees Klumper]

Welcome Chassis. May I suggest you do a search of previous topics? There've been many discussions on this so it'd be a shame to have to do those all over again.
I think the main conclusions have been, though, that the car does not need much alteration to be fit for rallying; just make sure all suspension components are in good condition and the engine is well tuned.

[chassis87]

Hi Cees Klumper,


we did an engine overhaul and gbox haul, changed all bushing, brakes, suspension components to new OEM parts. only non original item is ignition 123. Power wise Im not reallt looking to increase.

However I do feel this car needs sway bars, or harder springs on race day those tight chicane's with no run off area are going to be challenging

I did a search for sway bars and nothing came up

is there an aftermarket one stop shop for suspension setup for this car please? I need a good source to buy stuff from.


Thanks in advance

chassis

[Cees Klumper]

Years ago I bought a set of poly bushings for the sway bar (there is or should be one) at the front, and for the rear trailing arms. The vendor name was Cox Racing.
Tires may be another thing for you to look into, as well s special purpose shocks, and heavier duty springs.

[Garry]

Welcome to the Group.

As Cees said there is a mass of topics on the site that can be found by doing a search under verious headings such as,

Suspension improvements, 15 hits,
Progressive springs, more than 15 hits
Alloy wheels (lightweight) more than 30 hits
Rallying over 10 hits

Then there are the modified pagodas that have been detailed here by a few such as GGR

Just keep searching by key words and you will be rewarded

[GGR]

Hi, welcome to the group.

In my experience, in terms of chassis performance, the car really benefits from a stiffer suspension, especially in the front. You can then lower the car and get bigger wheels and bigger tires.

Mechatronik did develop a kit with stiffer and shorter springs together with fully adjustable shock absorbers. I do not have direct experience with it, but I heard good things about it and it's kind of one stop shopping when it comes to the suspension. You can also adapt bigger sway bars from w108/109/111 chassis cars, but I would do that only after swapping the springs, as stiffer springs will already be doing part of the job.

Cox Racing indeed developed a complete kit of poly bushings. I have them all round on my Coupe and I'm happy with them as the chassis and suspension is much more precise and responsive. However they do transmit road imperfections much more than the rubber bushings, so there is a loss of comfort.

You can also stiffen the lateral strut bushings to reduce lateral play in the rear end. You will need that if you go with bigger tires.

Lowering the center of gravity by lowering the car will also significantly improve handling. You can do that by fitting the thinnest shims you can find on top of the springs, and by deleting the rubber shims on each side of the compensating spring in the center of the rear axle. If you want to lower more, you need to cut the springs. In the back, this will translate by some additional positive camber. If you want to reduce that camber, you will need to lift the rear end center mount. You can go up to one inch or so. After you may run into clearance problems.

You can fit some 15x7 steel wheels. You can get some from Germany as they were used for winter tires on the w126 chassis. The best tire compromise with these wheels is 215/60-15. They really make a difference. Bigger than that will get you into clearance problems.

You can fit w108/109/111 V8 brakes in the front, as they are vented and they are a straight fit. if you go with 15' wheels you can fit 300mm brakes, but it's a bit more involved. With a stock engine the same diameter vented brakes and some race pads (Porterfield) may be more than enough.

Then come chassis adjustments. The more camber all round and adding caster in the front (with shorter front axle leaf springs) will also help. However, a lot of camber will ruin your tires on long distance trips. 

   
Group member Peter Lesler did race a Pagoda so he may be able to give you additional tips.
 

[jeffc280sl]

Welcome,

I have a 1970 280SL with a 4 speed manual tranny.  I have installed many performance upgrades and can say they makes for great handling improvements.  Here is a summary.

230 SL front sway bar.  It's stiffer and requires minor bushing change
123 ignition.  You have already.  Good choice.
Progressive springs. May require some minor cutting to achieve required rear camber.  Measure twice and cut once. Be precise
15 inch wheel with 60 or 65 series tires.  Handling change is amazing.  Top it off with 15 inch painted hub caps for stealth look.
New bushings.  You have already.
Tune injection system with air fuel ratio and map sensor to MB on road dyno specs.  Very challenging but worth it.  Alternative is to send injection system off for calibration.
Upgrade front brakes with V8 components.  Check out 327 rear axle.

Car is exciting to drive.

Enjoy

[garymand]

What is the diameter of the 230 swaybar?  I have a 300sel swaybar, memory says its 24mm?  I couldn't find a way to do a rear sway bar, old timers told me the camber spring serves the same purpose but infact its the opposite: up on the right = down on the left. 

I ride on 16" rims.  There is no reason why you can't go to 17 or 18.  I wanted to keep the daily driving cost of tires down with 245 16.  I like good cornering and its surprising how much better these cars handle with modern wheels and tires. 

Install an O2 sensor and tune the FIP.  you could gain an amazing increase in performace for the type of diving you are looking for, depending on how your FIP was setup on the bench.  I had one that was way too rich through the whole range. 

There are standard shocks and heavyduty use shocks that are 2x stiffness from Bisstein.

The bad news is there are very few commercial aftermarked mods for these cars, Good news is there are few temptaions to spend good money on that won't be worth it.

[jeffc280sl]

I think the 230 SL is 21 mm versus 19 for the 280 SL

[garymand]

Interesting, the cornering flatness much better with a bar up around 1" , 24.5mm but the ride is harsher on bumpy roads.  I have racing suspension 944T, the front sway bar is a hollow tube bent in the same shape as a solid bar but its really light for about 24mm.   If I had to do it again, I would try to fit a porsche hollow bar to the front because it is so stiff and mounts very similarly.

[Raymond]

I have Bilstein sport shocks on my BMW E30 and they are very nice.  On the Pagoda, I have Koni Classic shocks.  They are adjustable so you can make the front stiffer than the back.  I've put stiffer linear coil springs all around and I like the combination.  I tried the progressive springs first but didn't like the way they transitioned from soft to stiff in a hard corner.  I prefer the predictability of the linear springs  For tweaking the ride height and rear camber with the new center spring, you can use rubber flange gaskets as spacers above the spring rubbers at each wheel.   

Search for the many good threads on this topic.

[GGR]

also to be noted that the stock Bilstein shocks are filled with gas. As a result they increase the height of the car by a good one to two inches. Replacing them with different shocks will lower the car without having to fiddle with the rubber shims on top of the springs, which can be a lot of work. So if your car is still equipped with stock Bilsteins and you want to lower it, a good place to start is to replace the shocks and then see where you get. 

[jameshoward]

+1 for the koni classic adjustable shocks.

[Cees Klumper]

What do these Koni shocks go for? Vs Bilsteins?