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So yesterday I removed my throttled body in order to clean the circuit board contacts just for preventive maintenance (and I enjoy tinkering). Anyway, when I removed the intake Y pipe elbow, I opened up the throttle plate by hand to see how clean the intake was (I just installed new PCV system).
Low and behold, I proceed to see that the throttle Body Gasket has a lip that protrudes into the stream of the intake air. The lip is around 5-10 mm and goes all the way around the diameter of the throttle body. I replaced this gasket as part of the work I did recently and ordered from MB dealer. I have checked all part numbers and I did order the right gasket. I also checked to see if the s600 vs s65 changed anything and according to EPC, they use the same gasket. Even the black series and the new 65 use the same gasket.
Essentially, the gasket is a smaller diameter than the throttle body and a smaller diameter than the intake port on the manifold.
So my question is, has anyone else seen this? Is this normal? Doesn't this hurt airflow? The problem is that when the throttle is opened at partial angles, lets say at just above idle, then the lip is severely blocking the path of air. I dont understand how this can be normal.
Any input is appreciated.
As an example, look at our gasket thickness vs a 80mm upgrade gasket from an e55.
My part number as per EPC is A2750980380
(the pic I used is a stock photo but is representative of the part number for Cl65)
Interesting find. I have never looked into this but now that you have discovered this I will try to take a look in mine after Memorial weekend and see. If it is as bad as you say it might be worth a few HP to open up the gasket.
So I installed new larger gasket yesterday. Measured new gasket, and it is 82mm. I measured the intake opening on our manifold and it is 82mm. I measured the throttle body and it is 80mm. I measured original gasket and it is 74mm.. The gaskets are made from the same material and are of the same design so no issue should be present with sealing effect.
Part number A1371410780 ( from pre-2003 e55)
The original (and new) gasket is made of metal (can test with magnet) so cutting it and reshaping was not an option. The pic I previously posted of an e55 gasket was in fact a 80mm throttle body kit sold by Kleeman. I found more pics of this kit and with a little digging located a pic with a part number for that gasket. Bought yesterday from mercedes dealer and installed. All driving well. I don't know if there is any gain, (maybe part throttle response), but I just can't stand that there was a restriction here that could be rectified with a gasket that costs 10 bucks.
While your at it, I would highly recommend popping the plastic cap off the throttle body and cleaning the contacts on the board if you haven't done so already. Just use some good electrical contact cleaner that wont hurt circuit boards.
The small metal clips pry off fairly easily and just press back on when done. When opened mine I had a check at the gears as well but looks like they don't wear much at all. Was expecting wear as gears like this on the M6 I use to own get ruined and need replacing.
Post up when you got the gasket installed, glad I could help. Not that these 65's need a whole lot more power hahah.
So I installed new larger gasket yesterday. Measured new gasket, and it is 82mm. I measured the intake opening on our manifold and it is 82mm. I measured the throttle body and it is 80mm. I measured original gasket and it is 74mm.. The gaskets are made from the same material and are of the same design so no issue should be present with sealing effect.
Part number A1371410780 ( from pre-2003 e55)
The original (and new) gasket is made of metal (can test with magnet) so cutting it and reshaping was not an option. The pic I previously posted of an e55 gasket was in fact a 80mm throttle body kit sold by Kleeman. I found more pics of this kit and with a little digging located a pic with a part number for that gasket. Bought yesterday from mercedes dealer and installed. All driving well. I don't know if there is any gain, (maybe part throttle response), but I just can't stand that there was a restriction here that could be rectified with a gasket that costs 10 bucks.
Very nice find, it can't be helping things being in the way. There are so many E55s running bigger throttle bodies, surprising there isn't much talk on this platform, since its typical across all other makes. Only thing I can think of is the limits of the stock exhaust manifold.
Originally Posted by Dr Matt
Well, I'm hoping to leap over a few guys on the "list" for ET's so a cheap mod like that looks good to me! Thanks again.
I feel like I'm walking around with a target on my shirt and you are in point blank range. LOL There are only a few things I will/want to do to help with my current setup, but it won't be for a while. I think my MPH should be good for another tenth. That being said your car ran real strong before removing the cats. I don't see how you won't pass me up with the extra massaging since last year. It just shows you don't need to spend $30k in mods and turbo upgrades to get decent power and times out of these cars.
Lol. Well my goal is usually to go just a little faster every year. My best run to date is a mere .044 seconds behind you sooooo, if I can pick up just a little.
Lol. Well my goal is usually to go just a little faster every year. My best run to date is a mere .044 seconds behind you sooooo, if I can pick up just a little.
I totally understand, nobody want to arrive and go slower. So why can't you just be happy going .0429 seconds faster? won't that make you happy? LOL, I admire what you do and if your car runs 100% and gets the job done I will truly be happy for you. You are a good guy and an asset to MBworld. You got a week to go, so in the mean time I hope its a record high of 80 degrees next weekend in Alaska, I'm gonna need all the help I can get.
Thanks for the kind words. You know I'll just be giving you a new goal to shoot for if I happen to run quicker, lol. Wish I would have been there today. DA was 1.44'. Yeah a DA of about 15". I never seem to hit it on those days. we all know that not every day at the track goes as planned. If things work, and the weather is good, and the track is good,....... Then maybe......
Ordered this gasket today. I think $7.95 is no doubt going to be the cheapest single performance mod ever on my CL, LOL. Of course in the end I'll also take off the intercoolers, replace the bolts that hold them down with studs and add phenolic washers above and below them to isolate them from, heat conduction. AAAAnd as long as they are off I might as well spray them with Lizard Skin insulation, and wrap them in neoprene, and..... Yeah, so much for an $8 mod.....
Anyway, hoping it arrives in time to install before Memorial weekend races. I'll post up what I find about my gasket's size to confirm if mine is another small gasket restricting the intake flow.
Ordered this gasket today. I think $7.95 is no doubt going to be the cheapest single performance mod ever on my CL, LOL. Of course in the end I'll also take off the intercoolers, replace the bolts that hold them down with studs and add phenolic washers above and below them to isolate them from, heat conduction. AAAAnd as long as they are off I might as well spray them with Lizard Skin insulation, and wrap them in neoprene, and..... Yeah, so much for an $8 mod.....
Anyway, hoping it arrives in time to install before Memorial weekend races. I'll post up what I find about my gasket's size to confirm if mine is another small gasket restricting the intake flow.
Please do post up about your install. I could be wrong but you may have problems with studs on the intercoolers. When installing and removing, I find that they have to be slid sideways and cannot really be lifted prior to removing from Y-pipes. If you can do it, and add phonelics, this would be interesting so please let us know how it goes.
Just for anyone else that wants to put these on, the intake Y pipe that connects to the throttle body and to the intercoolers cannot be removed and installed without loosening both intercoolers and moving out of the way slightly. The angle of the Y pipe restricts the ability to install without moving the intercoolers.
Very nice find, it can't be helping things being in the way. There are so many E55s running bigger throttle bodies, surprising there isn't much talk on this platform, since its typical across all other makes. Only thing I can think of is the limits of the stock exhaust manifold.
I agree, I couldn't believe it when I saw it but after checking part numbers I see that it is indeed smaller. I agree with you that ultimately, the size of the exhaust manifold is the restriction on these cars. However, If you look at the airflow around this restriction at small throttle openings, you will see that it is substantial. Heck, at small throttle openings more than half of the space is taken up by that gasket in terms of the path of airflow. (air must hit the gasket and then flow around it). It must provide better throttle response for small openings.
FWIW So far after my install, I don't know if its just me, but I feel that there is an added smoothness and sharpness to my throttle input especially at small openings.
For 8 bucks and an hour on a saturday, it just makes sense.
Last edited by MooksM275; 05-23-2016 at 03:57 PM.
Reason: Trying to fix quote
Mooks, I've had my intercoolers off a couple times and yeah, I'm thinking it's going to be a pain to do, but not impossible. The spacers are probably going to have to wait until after Memorial, but not the gasket!! Thanks again for sharing your find.
Got my gasket today, but since I don't have much time I'm going to try and put it in tonight without fully removing anything, so sorry, I will not get TB and manifold pics like the OP. Hoping I can just unbolt the intercoolers, loosen the clamps on the turbo-intercooler coupler hose, unbolt the TB, and slide it back far enough to swap out the gasket. It should only need to move a mm or so. If I can do it that way it's like a 10-15 minute job, depending on how easy it is to unbolt the TB. I'll try to get a better look when I remove the intercoolers to paint them with Lizard Skin.
Got my gasket today, but since I don't have much time I'm going to try and put it in tonight without fully removing anything, so sorry, I will not get TB and manifold pics like the OP. Hoping I can just unbolt the intercoolers, loosen the clamps on the turbo-intercooler coupler hose, unbolt the TB, and slide it back far enough to swap out the gasket. It should only need to move a mm or so. If I can do it that way it's like a 10-15 minute job, depending on how easy it is to unbolt the TB. I'll try to get a better look when I remove the intercoolers to paint them with Lizard Skin.
You can do it without much fuss. No need to slide it in as you can just unbolt throttle body and move out of the way. Good Luck man!
Unbolt Intercoolers
Loosen Hose clamps on Y pipe (for throttle body)
Loosen Bolt for Charge Pipes (the one with the Horseshoe bracket-just loosen slightly)
Loosen Bottom Hose Clamp at Charge Pipe to Intercooler
Pull Intercooler Aside (for Both Sides)
Pull off Y pipe from Throttle Body
Removed Throttle Body.
Replace Gasket.
Yep, that's basically it, but I also removed the MAP sensor's bracket. They are so fragile mounted to the hose from the intercooler I wanted it to move freely. I took pics but not going to load them tonight. You are correct that the gasket is too small though. The TB is 80mm, the intake is 80 mm, and the gasket is 73.72mm. New gasket is 82mm. Bye bye restriction.
Sadly, I broke a clamp (I/C to Y hose) on reassembly though. Sucks because the plan was to drive the car to work in the morning and go from work to the track tomorrow. I don't have a clamp to replace it and not sure I'll have time to get one with my busy schedule tomorrow. oh well, may have to head out Saturday instead.
Would this be a restriction of max. Airflow at Full-Throttle? What do you think?
It must be. The only point may be that the exhaust restriction is the bottleneck of the system and therefore at max flow does not change much. However, I am more interested in turbulence created at partial throttle openings and at max opening.
More testing would need to be done. However, look at the e55 market and upgrades to bigger throttle bodies. In our system, we are effectively running a 74mm throttle body. Lucky for us, the upgrade to 80mm costs 5 bucks hahah.
Car has not had any issues idle or running with this in. My long term fuel trims are very good and all seems fine.
FWIW, I reset all the adaptions through STAR DAS for the Engine and Transmission and performed adaptions as needed. May be good to do given that the new throttle body gasket size may affect some adaptions.
05-15-2016, 05:42 PM
. The gaskets are made from the same material and are of the same design so no issue should be present with sealing effect.
It just shows you don't need to spend $30k in mods and turbo upgrades to get decent power and times out of these cars.
