M104 performance from an M103! (Information given not questions asked!) - PeachParts Mercedes-Benz Forum

400Eric · #1 04-16-2017, 01:17 AM

Video of my 300E (Benzer1) running dead even with a genuine mid-90s M3 that had over 100,000 fewer miles on it: https://www.youtube.com/watch?v=6QDtIV-N7dI&index=1&list=PLF1UzjxFeX0AKzGCO5dqxy7rTirj_1xpM

Sorry it has taken me so long to do this. I did a thread on my 400E but never did one on my 300E. This is a much shorter mod list. My 300E is rather unique as it's an '89, which is the first year for the wide ratio trans, which gives a lower first gear ratio than the pre-89 trans did (3.87 vs 3.68), but it is also the last year of the 3.07 rear gears, because starting with the '90 M.Y. the rear-end ratio was changed to 2.87. So unique one year only gearing is part of it. Next is the removal of all of the exhaust after the cats (just like my 400E and in both cases still smog legal), followed by the cutting back of the plastic cover/shroud at the entrance to the air intake just behind the grill (still stock cold air intake). Also installed a stock '86 CIS-E ECU in place of the stock '89 ECU. I did a few other things but none of them showed any improvement in 1/4 mile E/Ts. The mods listed here did the trick. For the record, everything I'm saying here about gearing only applies to the 3.0 liter M103 W124, not the 2.6 M103 W124. Trans and rear gear ratios are totally different with that car.

This car's best ever E/T is a 15.924. There is a '93 300CE at that same track where I run Benzer1 that is owned by a track official that also occasionally runs 15.9s but that car has a 24 valve HFM managed 3.2 liter M104 six that has over 100,000 fewer miles! (It seems like EVERYTHING has at least 100,000 fewer miles than Benzer1 has!) My 300E is just a CIS-E 12 valve 3.0 M103! I'd sure like to line up with that 300CE sometime! All E/Ts are uncorrected BTW. The D/As at this knappy track are usually in the 3,500 foot range, often worse!

I wish I could post some pics of the intake mod, maybe I can get my son to help me some time if there is any interest.

Post up any questions you may have. I hope there are at least a few people out there who still want to play with M103s!

party · #2 04-16-2017, 11:09 AM

Interested in the intake mod.

Ask Junior for assistance or someone here can walk you through the process of posting pics on the board.

400Eric · #3 04-16-2017, 06:41 PM

OK, will do but it'll have to wait a week or two cause I'll have to rig up a "before" shot.

Something else I just remembered is that I played with tranny shift points. Some cars will need this, some will not. Benzer1 originally did not need this, Benzer2 definitely did. Benzer5 did not. You can read more about it here: http://www.peachparts.com/shopforum/performance-paddock/245997-tuning-cis-21.html#post2792781 and here: http://www.peachparts.com/shopforum/performance-paddock/245997-tuning-cis-21.html#post2793540

400Eric · #4 04-16-2017, 07:35 PM

I also need to mention that '90-'92 300Es are generation 5 CIS-E while '86-'89 are generation 3 CIS-E. It is best to not try to interchange stuff between the two. (There is some stuff like ECUs that you can't interchange even if you want to.) 93 300Es are actually HFM managed M104s that are entirely different animals altogether. (Except for 93 300E 4matics which are still gen 5 CIS-E M103s.)

Now maybe some of you out there also have a '90 or '91 V8 W126 and you are thinking: "Hey, my V8 car is still gen 3 CIS-E, what gives?" Well, you'll have to ask the factory that one. My theory is that since the W126 was slated for replacement in '92, MB figured it wasn't worth the trouble and expense of changing anything on those cars.

party · #5 04-16-2017, 08:44 PM

Quote:

Originally Posted by 400Eric

OK, will do but it'll have to wait a week or two cause I'll have to rig up a "before" shot.

Sounds good. Until then, is what you did cut off the big J-shaped dustpan looking part on the front?

400Eric · #6 04-17-2017, 02:00 AM

Yes, but I didn't cut it perfectly flush, I left a bit more material on that side. I basically cut it where that parting line is, maybe just a little beyond it. ("Beyond" meaning a little more material was removed, including the parting line itself.) You still want a bit of material there to insure that the air is coming from in front of the radiator, not behind it. When you look at that part installed you will see what I mean. You then need to try to smooth the whole entry area. It's too bad we can't have a proper "flare" there, but I basically let the stuff in the surrounding area there dictate how I cut that part, and that "stuff" actually helps form a bit of a flare if you do it right. What this means is that dual cooling fan equipped cars will have that part cut a bit differently than single cooling fan equipped cars, and remember, the air conditioning plumbing is configued differently between these two cars as well. (I can't address how this mod would be done on a W201.)

The value of this mod should not be underestimated. When installed in stock form, the open area of that part is blocked by air conditioning plumbing.

Before I did these few mods, the best I could get out of Benzer1 was an uncorrected 16.9 E/T!

400Eric · #7 04-17-2017, 11:49 PM

I just remembered another very important mod that I forgot to mention. Pulling the R16/1 resistor! LOT'S of passionate opinions on this mod but I firmly believe in it. Having that knappy resistor in place kills so much low end torque that it even jacks up my reaction times. The reason why I forgot to mention it is because that was the very first mod I ever did to my very first W124 (Benzer1!) over twelve years ago! Sorry for the oversight. Here is more info on removing R16/1 as well as a whole lot of info on the topic: http://www.peachparts.com/shopforum/performance-paddock/32224-read-free-hp-w201-w124-owners-pictures.html

oldsinner111 · #8 04-18-2017, 10:13 AM

My 99 w140 m104,I removed the plastic that covered the grille inside.This way a 100% airflow thru grille. I then sawsalled,plastic around radiator to let more air in.I removed stock snorkel,and used a section of downspout drain hose to funnel air in.Then drilled holes in bottom of air box so if driving in rain,water would drain.I use a KanN filter,with no problems ever.I wash,air dry,lightly oil one side.

party · #9 04-18-2017, 01:33 PM

Decided to have a go at the intake this morning. This is on a W201 M103. When I got the car it didn't have the full scoop on it. There was only the first segment at the air cleaner from a W124 with the sensor holder. When I installed the correct scoop it struck me as constrictive. The bottom of it was pretty much closed off against the elec fan.

"Before":

After:

The cut isn't as bad as it looks there, but I'll sand it smooth after decide if I'm gonna leave that little piece at the bottom or take it off too.

Thoughts?

400Eric · #10 04-20-2017, 03:14 AM

I would take off a little more on the side next to the headlight. Especially down towards the bottom. Not a bad start though!

I have to elaborate some on the ECU swap. It could very well be that the performance improvememnt provided by the 86 ECU was because it was a non-Calif ECU, not because it was an older ECU. There are several different ECUs with several different part numbers for both the pre-90 W124s (CIS-E gen 3) and the 90-93 W124s. (CIS-E gen 5). Some years Calif cars had their own unique ECUs, other years they didn't. And remember, just cause you're not in Calif doesn't mean your car's not from Calif!

I also don't know if W201s ever got CIS-E gen 5 or did they just stay CIS-E gen 3 like W126s did.

So anyways here is a thread where I talked more about this ECU stuff: http://www.peachparts.com/shopforum/performance-paddock/271612-m103-cis-e-performance-ecu-module-thread.html

party · #11 07-23-2017, 08:39 PM

Had the headlights out, so came back to this as the duct was staring at me with them off the car.

My thinking was for it to kinda follow the headlight when I cut it on 4/18 above. Followed 400Eric's advice and cut it straight across. The side by the radiator is untouched.

Sorry for the way overexposed images. Needed to capture the detail on dark, black parts and the sun was going down by the time I had the lights back in.

400Eric · #12 09-22-2017, 01:20 AM

That looks fabulous!