500E faithful,
After talking with Benzmac, readling literature, and finally messing with my own car while it was in the air I can say this....the 500E DOES have a limited slip differential.

While we are on the topic of rear diffs, doing a rear diff change to something lower would hurt top end potential as long as we are keeping with the 4-speed automatic. Pop in the 6-speed manual and then the 3.27 or 3.08 isn't a bad idea, but doing either would bring top speed down some. After pegging my 500E's speedo past 160mph that is about your top speed with stock gearing and the 4-speed auto.

The fuel and the ignition are both computer controlled. Reprogramming one aspect is easier than reprogramming both. This is not saying you can't reprogram the fuel/air and ignition... The stock fuel management tends on the lean side so you should be able to get some gains just from that. I've also been told that when the engine gets to 100C, then progressively after that, it takes out timing in 2 degree increments. That is why keeping that engine temp down around 80-85 C is worth 30-45HP.

As was discussed earlier in this forum...the OEM exhaust system is pretty close to optimal on its own. To get any kind of measureable gains you would have to replace 100% of it and/or make some compromises. If you do a 6.0 engine, then it probably becomes a good idea. Before then, you can get much better "bang for the buck" elsewhere.

Example: the Renntech complete exhaust sytem is $12,600. You can buy a 420+HP 6.0 engine conversion from Brabus for $19K. Personally I would rather kick in the extra cash for the real 6.0 engine. To match the Brabus engine you would need a Renntech stage three 6.0 conversion for a sticker of $41K-$50K. (depending on engine #)

Now that we have discussed unlimited budget 500E upgrades here are some "poor man's" tricks that might work on 500E's.

First: replace the clutch fan with an high speed electric of similar size, that ought to free up some bottom end and perhaps improve low-speed cooling.

2nd: put a second 4-prong coolant temp sensor in while leaving the original in the block. The computer will read the underhood temp which is significantly less than the coolant itself. This should enrich your fuel/air mix. Do not use 24/7 as you may over-richen the fuel/air mix. You could also wire in a resistor that corresponds to the temp when the engine feels to be making the most HP.

3rd: pop in some K&N air filters. If there is some restriction in the breathing, they should help. Just keep them cleaned and oiled every 1-3K miles.

4th: put on stickier tires. 235/50/16 or 245/50/16 on the OEM 16x8" rims or 245/45/17 (european OEM) with some 17x8.5" rims. That will let you use much more of what the car has. Actually, putting 235/50/16 front and 245/50/16 rear would let you dial in some more rear wheelspin before ASR grabbed you. The two sizes are only 1.6% different and either isn't very far from OEM RR.

5th: ASR seems to be "less" active while the brakes are applied. Lightly holding the brake or a switch into the brake circuit...

6th: watter wetter can never hurt, previous mention to temperature and HP.

7th: buy a chip from PAD, PMG, or Superchips (anyone who provides a 30 day guarantee) then take your car and the new chip to a dyno. Run before and after. If it works to their claims, keep it. If it does not, return it. When you find the "hot ticket" let us know!

8th: shift the car manually via the stock shifter. As Lou said, you have a great car...now become a great driver. Learn to use all of what you already have at your disposal.

9th: NOx. Okay, that isn't cheap at $750 to $1,500 but for 100HP-150HP at the flip of a switch the results are not either.

That is about it for those. Conventional press states that 500E supercharging is not possible because of underhood clearance issues. What if I said there IS a way to fit a blower under there without major re-engineering... If anyone is interested, email me.

Just my take on tuning these cars...Lee

Lee: Great summary! Thanks.

How many 500E's do we have in the group? Are there any others out there that have experience with mods/parts to share?

I just got a big Adobe document from Brabus North America with pages of bits for the W124 line. They have the least expensive Engine tuning kits and exhuast, but perhaps the most expensive chips and ASR defeats.

I also read on the mercedes list server archive that there is a fellow who claims he had a chip programer make a chip for him that defeated the ASR and gave performance gains. Is this possible? Many e-mails professing to the skill of Conforti as well. Any word from him?

Eric:

I have a '92 500E... no experience with mods, etc... I'll probably go with Lee's suggestion on the tires however. I am also a little concerned with the engine temperature. I rolled into work this morning in Austin, Tx. where the outside air was 78.. No problems... Engine ran at about 87-92. Last night was the same. But given one of the 100+ days we've been having, its hard to keep the temp below 100. The air conditioner stresses it on those hot days also. Therefore, I might consider the 'turbo' engine fan that Lee suggested as well.

EricH,
A single chip would not defeat ASR and up engine HP. What that individual probably did was to send in the "brainbox" aka LH control unit, ABS/ASR control unit, electronic accelerator control unit, and the base module in for a "sport" reprogram.

After talking with Brabus it is my understanding that they do not do "chips". If you buy a cam kit then of course they can reprogram your engine to take advantage of the new mods. However, I do not think they do "chips" by themselves. For BMW tuning, Jim Conforti is by far the best. We have talked with him trying to get him to do some MB work but no progress yet. Adrian Eckenrod (RAE190) is trying to get him to tune his 190_16v. Have not heard from either RAE190 or Conforti as to progress. If he were to do MB you could count on his stuff being first class.

After much research, it is accepted that the 500E just runs "hot" when ambient temps get 85-90+. When I find a solution to that, I will surely let the board know. So far people seem to have experienced some minor success with Redline Watter Wetter.

Lee

Thought I'd chime in, as a 500E owner. Mine's completely stock, with the exception of running Water Wetter in with the coolant. I saw perhaps a 10 degree drop in average coolant temp.

As regards mods, I'm waiting for the OEM air filters to need replacing, then I'm going for K&Ns. I also picked up a second coolant temp sensor and will employ it as Lee suggested. That's about it, and I've run 14.1 in the 1/4 on a 100 degree day!

------------------
Best regards, Michael
'92 500E
'88 300TE

Lee:

You're right about the temperature affecting performance. Now that I've had a couple of weeks and some hot days with my car, I can see the big difference in power between 75 and 110 degrees indicated.

As you and others have recommended, I put in some water wetter this weekend. I didn't notice a huge difference, maybe a few degrees. Has anyone tried straight water and the WW as the bottle suggests? Is there any benefit to running coolant too beside the obvious antifreeze property? My car seems to get the hot pretty fast, especially if I'm doing the Berkeley hills. I used to ride my ducati over and around these hills and I'd say I might be every bit as fast with my 500E. I tried these hills with a 560SEC with no luck! Too BIG!

Question 2: Do all 500E's have dual electric fans in front of the radiator? I have never noticed mine in action, and am wondering if there is a relay or something blown. When should they come on? Is there an easy test?

thanks

Eric, obviously the first place to look is the fuse box. There is a resister mounted inline with the fans, it is right behind the drivers side headlight assembly. I have seen alot of these get rusty where the wire connections are and have bad or even broken connections. I've had a bunch of 400e's come in with fans inop due to a broken wire at that resistor.

hey eric!

maybe i'll see you buzzing the berkeley hills sometime... look for a pearl black 1992 500E...

------------------
john
'77 6.9
'87 2.3-16v
'92 500E

AlainV: Thanks for the tip...I replaced the fuseable link by the firewall today since it was broken and did some hard driving to get the temp up (110deg) but still no go on the front radiator fans. I did look for a resister by the headlamps but did not see it. I'll trace the wires in tomorrows light.

John: Kept an eye out for you tonight as I ripped through the hills. I hope someday i run into you and your 500E. That way we can tell how much difference the AMG chip makes :-)

It should be behind the light on the drivers side,under the alarm sys horn. It has a shiny metal cover over it with a bunch of little holes in it. If you loosen the alarm horn and remove the air duct behind the drivers headlight,it should be easily visible. Wiggle the wires to see if they are still connected or if one is broken off. Alot of times the wire breaks off because of the heat generated because the connection was bad. One way to see if the fans work is to turn on the ignition,disconnect the high switch wires at the ac dryer and touch tham together,this should activate the fans. Or you can remove the plastic cover in front of your air filter housing and pull the 212 switch wire o

Alain: as per you post, I checked the resister behind healight...seems okay. Why a resister anyhow? Hmmm....looked for the 212 switch...is it the 2 wire connector on the top right side of engine under the front plastic piece? I see the 4 wire temp sender in the middle and there is a one wire something on the left. To check the aux fans, I am supposed to disconnect the 212 switch and jumper the two wires?

Thanks,
Eric

The two wire connecter should be the 212 switch. Disconnecting the plug from the switch (w/key on) should activate the fan relay thus turning on the fans. Also, you can try jumping the high switch on the a/c dryer. It is the one with the "pig-tail" on it.

Wow! I've just come back from a really great drive in local hills! This car kicks A**! But boy do I need better tires....no scratch that, 4 wheel drifts and throttle steer might be more fun, but that Damn ASR! It ruins throttle steer. Its on so much, I think i'm going to burn out the bulb. Its a machine...it cannot be reasoned with, it can not be stopped!

Eric,
The solution to the constant ASR is better rubber. If we are keeping the stock 16x8 rims then 235/50/16 is a good size. Michelin makes the Pilot HX MXM in that size, Dunlop might have the SP9000, Pirelli has the 6000, and Toyo has the T1s. Personal experience with the Pilot HX MXM's is good....the car is still a very comfortable touring machine but with more grip. Treadlife probably wont be stellar and if you are looking for ultimate handling that setup may still be a bit soft. You may want to give the Toyo's a try. Have heard good things about that tire. Also, another 500E owner has been happy with his Toyo's.

If we are going to the next level of handling the recommendation would be 245/45/17 tires on new rims. (BBS or tuner wheels IMO but that is individual taste...) That size was OEM in europe for the E500. There are many good tire choices in that size as well. I've also heard that the W129 "Sport" package will "bolt on" nicely. Give Tirerack a click/call and check with them. Let me know where you are looking to get it between mild to wild, and I'll get right back to you.

Hope this helps...Lee

What's Water Wetter and where do you get it? Are there considerations for its use, like type of radiator, type of anti-freeze, etc.?