getting the detune out of a 560SL

[cabrioal]

Looking at an 86 560 SL, and understand that the U.S. models were detuned down to 227hp, when they have capability of upwards of 280hp.

how do I get this detuning back to normal?

[donbryce]

This thread might be a good starting point. Infamous Programming Resistor Upgrade (107) - Results
My take on this subject is that the engine was designed for typical available octane and emissions requirements in the country where it is sold, hence the different timing chips (?) installed.
The picture is a european EZL, I think, with variable resistance options, I suppose for adaptation to the available octane available.
Try posting your question in the 'Performance Paddock' section.

[dugald]

This mod is said to liven things up but I haven't tried it yet.

http://www.benzworld.org/forums/w126-s-se-sec-sel-sd-sdl-class/1372807-remove-resistor-advance-timing.html#post2843516

[donbryce]

While waiting for a response from the OP.....I read the Benzworld thread, and got the impression that the 1986 and up SL's received this resistor to allow for less than premium/high octane gas in NA. Does this mean that I can now safely switch to mid-grade gas instead of premium, if I leave it in? Am I buying high te$t for no good reason?

[dugald]

Originally Posted by donbryce

While waiting for a response from the OP.....I read the Benzworld thread, and got the impression that the 1986 and up SL's received this resistor to allow for less than premium/high octane gas in NA. Does this mean that I can now safely switch to mid-grade gas instead of premium, if I leave it in? Am I buying high te$t for no good reason?

Good questions.
Yesterday I put in mid-grade 89 octane. No problems evident.

[UT_Tech]

The euro version had different camshaft, a higher compression ratio, and a better exhaust. I think the USA 560SL had an incredibly low compression ratio of about 9:1. That's more than low enough for 89 octane. Raising the best was to get that power back and the compression ratio will be easy to increase if and when you have to remove the heads ($$$). Depending on where you live a better camshaft is not an option because of pollution requirements. The exhaust backpressure can be tested but the stock system is already good.

[Strife]

I did this by installing a different fixed resistor in the standard plug package; the performance is SLIGHTLY better, but from a seat of the pants point of view, first gear start is more important. BTW, after this mod, I ONLY use 93 premium. the 86 560SL has no knock sensor.