SL/R129: R129 M113 Modifications




No improvement on performance, but the sound was slightly raspier.
A couple of my videos ( undercarriage of my car and exhaust sound )
I honestly believe I could have gotten into the 13s if I had some more runs to dial in my launch technique. I was spinning way too much off the line especially after the tires got cold.
All stock ‘99 except for the M113k intake and muffler delete. Not bad for a 20 year old luxo barge with 111k miles.
EDIT: Run was with the Hardtop off, 1/3 tank of gas, everything else all stock.
Last edited by SLGuy408; Oct 27, 2022 at 02:46 AM. Reason: More info
I honestly believe I could have gotten into the 13s if I had some more runs to dial in my launch technique. I was spinning way too much off the line especially after the tires got cold.
All stock ‘99 except for the M113k intake and muffler delete. Not bad for a 20 year old luxo barge with 111k miles.
EDIT: Run was with the Hardtop off, 1/3 tank of gas, everything else all stock.
oh hell yea, that’s solid. Yea your 60ft was horrible. It would be well into the 13s.
I honestly believe I could have gotten into the 13s if I had some more runs to dial in my launch technique. I was spinning way too much off the line especially after the tires got cold.
All stock ‘99 except for the M113k intake and muffler delete. Not bad for a 20 year old luxo barge with 111k miles.
EDIT: Run was with the Hardtop off, 1/3 tank of gas, everything else all stock.
I have a heat shield for it now also. When I get some free time, I will dyno this, and then throw a 113k intake on it and see what the difference is.
My car feels really strong, and the same setup on my 210 E55 made 20whp and 20tq, through the whole rpm range.
Also, for anyone that does the M113K intake & baffle mod, you're going to have to change your air filters every oil change. I usually change air filters once a year, I happened to check mine after like 3-4 months and they were filthy.
Last edited by SLGuy408; Oct 27, 2022 at 08:24 PM.
V12 intake helper.
Cutting out the dual fresh cool(er) factory intake system for a single under the hood intake system is a step backward; otherwise the real tuners (RENNtech, Carlssen, AMG, Brabus, Kleeman, etc.) would have done so.
Fresh, cooler air (in abundance), a resonator delete and attention to the throttle body are the time honored paths to increased performance.
The Best of Mercedes & AMG
From your picture it appears that your intake baffles have been removed from your car as well (those two holes in your rad support in front of the hood latch is where the baffle clips on to).
I agree with everything else you said though which is why I went for this factory parts bin cold/ram air setup. I'm running the m113k air intake as described in this picture.
Last edited by SLGuy408; Oct 27, 2022 at 08:56 PM.
I also got some RENNtech larger airbox intakes to help with airflow.
Extra air damming plus baffle. Pure SL600 MB and AMG.
Larger RENNtech airbox intakes.
Resonator delete increases exhaust flow and adds a little (very little) more bass.
Stainless resonator eliminator pipe and genuine AMG muffler. The AMG and V12 mufflers have a larger inlet than the V8 or 6 cylinder cars.
If anyone is interested, I have a resonator delete for a V8 car (90-98 cars) and a AMG muffler. Not inexpensive, but a noticeable improvement in sound and performance.
I disagree with your interpretation for the purpose of the baffle. With the baffle in place it blocks the air dam from getting air directly from the grille, it does not pool the air or create "high pressure", if anything it creates a low pressure point. Without it, the air from the grill funnels directly into the air intake tubes and into the engine.
Put it this way, if you stand behind a wall on a windy day, how much of the air wraps around the wall and hits you, almost none. So why would a wall in front of the air intake tube not be different?
Ram air = HP.
Last edited by SLGuy408; Oct 27, 2022 at 10:43 PM.
The air intake (dam) on either side of the car, behind the headlight, inside the core support which connects to the air intake tubes which then connect to the airbox is all still in place on my car. And it gets ram air from the grill with the baffle removed.
The baffle, circled in red, 3x4 inch piece of plastic placed directly next to the headlights does nothing but obstruct the airflow from the grille to the air intake. It does not create a high pressure point or "pool" the air.
You got a Renntech airbox, you seem to like HP, take 2 minutes and remove the baffles and drive your car around for a while, I guarantee your throttle response will improve.
Last edited by SLGuy408; Oct 27, 2022 at 11:31 PM.
Now, If you look at the w220 S500 it has its air inlets without baffles so that it gets ram air from the grille. As does the CLK55 and pretty much every Merc designed after 1996. However, the airbox on top of the engine is also the resonator to keep the noise down. As far as the ram air from the grill, I'm not doing anything Merc engineers aren't already doing but I'm also adding a smooth 1 way airflow for the air directly into the intake manifold with the m113k air boxes.
EDIT: This picture is also a primary example of why it might not be a good idea to remove the baffles if you don't meticulously maintain your vehicles.
Last edited by SLGuy408; Oct 28, 2022 at 02:46 PM.
V12 intake helper.
Cutting out the dual fresh cool(er) factory intake system for a single under the hood intake system is a step backward; otherwise the real tuners (RENNtech, Carlssen, AMG, Brabus, Kleeman, etc.) would have done so.
Fresh, cooler air (in abundance), a resonator delete and attention to the throttle body are the time honored paths to increased performance.
Moreover, number 7 (which actually should be #1 as that is the beginning of the path) is a rather big offender in my opinion. It acts as a wall preventing the air from going into the intake, so the engine has to suck the air in through all those bends. When that wall is removed the air is forced into the intake, rammed if you will.
This is backed up by the fact that my SL ran a 14.1 in the 1/4 mile with nothing other than this intake mod and a muffler delete. If I had some traction I would have been into the 13's. Factory stock the SL runs a 14.5 as noted by multiple automotive magazines at the time.
No one is saying you have to do this mod to your car, BUT why not remove the baffles and give it a try for a few days instead of bashing me for doing something new.
Last edited by SLGuy408; Oct 29, 2022 at 01:48 PM.
Moreover, number 7 (which actually should be #1 as that is the beginning of the path) is a rather big offender in my opinion. It acts as a wall preventing the air from going into the intake, so the engine has to suck the air in through all those bends. When that wall is removed the air being forced into the intake, rammed if you will.
This is backed up by the fact that my SL ran a 14.1 in the 1/4 mile with nothing other than this intake mod and a muffler delete. If I had some traction I would have been into the 13's. Factory stock the SL runs a 14.5 as noted by multiple automotive magazines at the time.
No one is saying you have to do this mod to your car, BUT why not give it a try for a few days instead of bashing me for doing something new.
He’s just hating. I’ve dynoed over 30 m113/114k cars. 113k air boxes are known to make power, so is my single intake set up. If brabus, or renntech doesn’t do it, then most Mercedes tan boys think it isn’t cool or doesn’t work. My e55 210 made 370whp. That’s 10 less than a stock 113k E55. Sooooo I might know a little about making power on an NA 113 engine. Just wish these cars had me 2.8 not 2.0
And actually, I shouldn't have said that I was doing something new. I copied the idea from TechTune and some other forum guys that modded these cars when they were new. That isn't even my car in those pictures lol, that's the forum guy who initially did this mod.
And actually, I shouldn't have said that I was doing something new. I copied the idea from TechTune and some other forum guys that modded these cars when they were new. That isn't even my car in those pictures lol, that's the forum guy who initially did this mod.
Talk to MBswapshop. He can convert your car easily to me2.8 with a harness and a me2.8 ecu
And actually, I shouldn't have said that I was doing something new. I copied the idea from TechTune and some other forum guys that modded these cars when they were new. That isn't even my car in those pictures lol, that's the forum guy who initially did this mod.
Although, we should also acknowledge that not all questions come from a place of general curiosity.
Not implying that you weren't being genuine in your question btw.
Last edited by SLGuy408; Oct 29, 2022 at 03:06 PM.





