Trouble sleeping, read on...

The absolute last thing this board needs is another exhaust thread, there have been several excellent ones already written using a variety of different systems – mine is a combination of a few and as far as I know, the only one to so far use AMS headers on the CLK. In other words, I’m only posting this up because it’s different and I have some interesting dyno numbers to go along with it.

Here in Dubai cars are inspected every year before registration can be renewed, this inspection includes a full visual check much like what we get back home when we take a car into a shop for a pre-sale inspection, it’s very comprehensive. The car is also run on a set of load bearing rollers (like a dyno) and the brakes as well as an O2 reading are taken. If the vehicle is deemed to be performance ‘modified’ or it fails the O2, it will not be granted new registration. Taking the above into account, it is logical to say that long tube headers would immediately raise a red flag and would definitely risk an inspection failure, thus the reason I chose to go with the AMS tubular exhaust manifolds. The reason that I will refer to these as manifolds and not headers is purely from experience and personal views, I have been building engines and cars since ’91 and in my opinion and ‘true’ header has a collector – these do not. If anything, the term used to describe this design would be ‘log header’ or more accurately, ‘tubular exhaust manifold’. Again, this is purely personal opinion.

After exchanging several emails with Omey of AMS and reading a review of the manifolds I felt like they would be a very good alternative to a set of long tube headers given the situation regarding inspections here. I ordered a set and they were shipped to Canada to be sent in a container full of other goodies for my CLK build project, they were shipped out in time and arrived as expected. When I received the heavily delayed container months later I was able to get a look at them first hand, the initial thought was ‘very impressive’. The flange is thick, very thick, better than most others which is great because it greatly reduces the chance of warpage and exhaust gas leaks. The quality of the exterior welds was also very impressive, they were very consistent and without pin-holes.



When I turned my attention to the inside of the first manifold I was equally impressed, the finishing was very good, very little flashing, well machined and smoothed ports and deep weld penetration. However, the second manifold was quite different, it almost looked like it was done in a totally different facility with different quality control. There was excessive flashing remaining on the inside, it was obvious that the same time to clean up the joints properly was not spent like it was on the other manifold. Additionally, the ports were not all consistent, they were not smooth like the first. The weld themselves were fine but a lot of cleaning/grinding was needed inside.



I made an appointment to have the AMS manifolds installed along with a Magnaflow muffler but first ran the car on a dyno to get a baseline number, it was a paltry 221hp in complete stock form.

At the exhaust shop, I dropped the car off and was told it would take a day to complete, they were going to install the AMS manifolds, delete the secondary cats and MB resonator and replace it with a Magnaflow muffler then run new piping to the rear with tips. Before anything though, they spent a while cleaning up the inside of the one manifolds to get it as close to matching the other as they could. A few hours after I dropped the car off I got a call saying that the AMS manifolds were installed but the factory down-pipes would not bolt up to them, the flange angles were wrong. In disbelief I went to the shop after work to see what the problem was – it was in fact true that the manifold flange was at a fairly sharp angle compared to the down pipe. To get it to work, they had to cut the down-pipes off the primary cats, rotate them then bolt them on. The pipes were then angle cut and re-welded to the primary cats. Later, when I ended up speaking to Omey about this he said that I was accidentally shipped a set of manifolds for a W210 in W209 box, the flange angles are obviously different between the two.



Because of the extra work the car was delayed a day. When I collected the car the following day everything was in place, manifolds, Magnaflow and some new piping.



When the car was started up the exhaust note was glorious! Very meaty mellow sound with a fantastic controlled snap when blurping the pedal. My enthusiasm turned into a migraine by the time I got home. The volume and drone inside the car was unbearable, my ears were actually painfully ringing after the 20 minute drive home. I called the exhaust shop and made an appointment to go back in and have the factory piping (secondary cats, resonator and chambered muffler) put back in place while I figured out what I was going to do about suppressing the volume. When I got back to Dubai after a week the OEM system was put back on but the AMS manifolds were left in place – perfect time to run a dyno and see what they did on their own.

The car was run on the same dyno, the same corrective values were used, the result was 223hp. The AMS manifolds provided an increase of 2hp over the OEM manifolds. I didn’t expect to see significant gains but both the dyno operator/tuner and I were still surprised that we didn’t see at least 5hp. There is another AMS review done on a SLK55 AMG and IIRC the gains on an OEM exhaust system were 6 or 8hp.

Moving on, I decided to take the car back to the exhaust shop with a new system in mind. New 2.5” piping off the primary cats back to the Magnaflow muffler originally used (dual inlet, single out), from there 3” piping past the axle to the axle, a flange, then into another Magnaflow muffler (single in, dual out) into the Fox exhaust tips. All the piping was to be stainless, mandrel bends with no clamps, only welds. When I went back to collect the car the following day I was very impressed, the workmanship was fantastic, the tips were straight and even and at start-up the sound was still fantastic – oh oh… Driving away I was expecting another drone induced migraine but it ended up being perfect, probably the best sounding exhaust on any car I’ve ever owned.




Time to get it back to the dyno.

Same dyno, same corrective values, same operator – 239hp. Wow. Keep in mind this is still with the factory ECU tune, air-box and paper filters, just a free flowing exhaust with the AMS manifolds. Now, what I did next was just to satisfy my own curiosity, to see if a true dual exhaust set-up would in-fact flow better than my dual to axle single then dual after muffler system. We unbolted the flange before the axle and disconnected the rear section and ran the car again, results, and average of 239hp. The free flowing Magnaflow rear muffler and extra snake piping did not affect the power at all (but god almighty was it ever louder), a testament to Magnaflow and mandrel bends to say the least.

Since then I have added the E55K air-box, BMC filters and the AMS crank pulley, then had the car custom dyno tuned, the result, 277hp. Fantastic.

So, my thoughts? First and foremost, you just can’t buy a better sounding and free flowing muffler/resonator than Magnaflow – period. I’ve used them for years and can’t see a switch anytime soon. The Magnaflow is a far heavier muffler than an equal sized Borla, this is due to the stainless mesh wrapped around the perforated inner pipe with dense sound suppression material behind it. This is done to keep the sound suppression material from burning out over time which happens with other mufflers. The Magnaflow design results in a very deep, mellow and consistent tone.



As for the AMS manifolds, they seem work well on a high flowing system and add to the enhanced exhaust note but in regards to performance gains, at least in my case, on their own there just wasn’t much there. For those who are looking for pure performance and are able to run actual headers, I suggest spending the money on a set from Kleemann. For those who are unable to run Kleemann headers, well, you need to decide if spending $1,000USD is worth an enhanced exhaust note and a few horsepower.

As for AMS itself, Omey has been a good guy to talk to and he certainly has stood behind his products. Even though it cost me a considerable amount of money for the cleaning up of the one manifolds and the custom work to have them fitted, Omey made amends by shipping me an AMS crank pulley at no charge. For a guy living in Dubai and not use to getting much response from overseas suppliers concerning workmanship issues, I was satisfied with Omey’s gesture. And as it goes for the pulley, no problems whatsoever so far, I had MB install it and the shop manager was impressed with the build quality and the initial results from the test drive.

After this massively long winded review, if anyone has questions, I’m all ears. Hope this was helpful.

 

I love exhaust thread. Really enjoy your post. Thanks.

 

Awesome write up Kev. Still waiting for that sound clip.....

 

Great write up !!! everything looks good,though remove the factory primary cats and replace them with 100cell stainless have the tune adjusted accordingly and you will see a 10 to 15 hp gain .



regards sonny

 

Thanks, appreciate the comment.

Thanks Wes. Took a long time to get it posted put I wanted it to be complete with pics and dyno numbers. As for the sound clip, I took a vid today but the audio on my little camera recorded nothing deep, just tin sounds. I'll take a HD vid with my Canon 5D MKII later this week.

Thanks for the comment and suggestion. If I was back in Canada I would definately have 100 cells in place, however, here in Dubai the car would not pass yearly O2 emissions testing with them, I know guys who have tried.

 

PM me and i,ll fill you in on how make it pass...been done many times

regards sonny

 

Just wanted to ask if you remove the factory cat won't it show up as an error on the computer? I've been wanting to do this but was unsure if it would create problems... Spewing your located in Sydney though because I'm from Melbourne.. Do you have any contacts in Melbourne? Or can you recommend any workshops here..
Thanks

 

With the bolt on " generic" tuner who buys one fits all tunes,sure you will get a check engine light,come down for a drive one day and i,ll do the work..and guranteed no error lights...custom tuning..you gotta love it !



regards sonny

 

Thank you for writing such a comprehensive review, Kev!

I believe you and I have similar situation, here in California we have a Smog inspection with a visual check and long tubes are just not an option. I'm leaning towards getting custom shorties and experimenting with High Flow primary cats (although, I wouldn't even know which ones to use), since the most important thing is to pass the sniffer test (friendly shops would gloss over the visual check).

So you ended up using 2 mufflers resulting in drone elimination, but without sacrificing Hp? This would be a great solution to fellow W209 member Amiricanmade.

The Magnaflow pic showing the inside of the muffler (showing the strait through design with the perforated muffling on the outsides) is EXACTLY how the Borla I have looked and since the Borla cost $100 more (but weighs a little less), the Magnaflow would be the better buy.

 

Thanks S/Carlos (what an ingenious play on words eh?).

Yeah, unfortunately you and I are just SOL when it comes to using Kleemann headers, that being said, I had a set of equal length shorties custom made for a 350ci years ago and they were awesome. I'd be interested to hear what kind of costs you get quoted if you go that route. In regards to 'high flow' cats, keep in mind that dropping to a lower cell count to increase flow could cause the car to fail the sniff. I know a guy here that put 200 cell high flows onto his C63 - it failed.

As for the second muffler, yes, it worked perfect and being that it's free-flowing, there was absolutely no power loss - this fact was dyno proven. I forgot that you had a Borla, I hope you weren't offended by my comments, it's a great company but the build of the Magnaflow and the cost have really made me a fan of their products.

 

I plan on emailing a few companies like DynoComp and figure out what the options are for shorties (since the exhaust will be custom, I also want 3" tubing and X-Pipe included). As far as the replacing the primary cats, maybe a 300 cell high flow would work? I'm also hoping the custom exhaust will drop my SC Boost (at 6-6.5lbs right now) so I can run a smaller pulley (don't want to run more than 6lbs of boost since I don't have forged internals).
I will definitely let you know what I find.

No offense taken with the muffler comments, brother. Nobody had tried the Borla on the CLK and since I had one on my Mustang (gone now, but it sounded great), I wanted to give it a shot. I was just surprised that the design was practically the same as the Magnaflow.

 

Looking forward to hearing about your findings mate, going to be a fun summer for both of us.

 

I thought the 500 made 302 HP already so why is it only 221? thats a 81 HP loss at the wheels

 

at the crank not the wheel.

 

well that sucks. loss of 80 hp I guess my 350 only makes around 190 at the wheel thn...

 

As Andy said, these are whp numbers, not bhp. Additionally, each dyno reads differently as well, a Dynapack will read a number far higher than a Mustang or Dyno Dynamics system. At the end of the day, dyno numbers don't really mean anything other than the difference from stock to modded, it allows you to see the gains. The story in this thread in regards to the dyno numbers is gains of 56whp with mods.

 

Hey Brotha, good lookin out. I actually ordered your Borla muffler, it's sitting in Pepe's shop. I'm gonna go have it installed in place of my muffler after my finals. I too was thinking that if the drone does not go away, i will add another Borla muffler and re-do my exhaust to exactly what Kevwood has. While having 2 mufflers may seem like a bad idea since i don't have a free flowing exhaust liek Kev, i think it'll be ok as the two Borlas would be more free flowing than the OEM muffler. Trial and error will start next week.
I'm glad this was dyno-proven, because if i find that the Borla is still too loud/drony for me i will do EXACTLY what you're doing. Q, does the piping coming out of the 2nd muffler wrapping around your spare the same size as all your other piping? Someone recommended i get a slight smaller 2' in order to even up the flow a bit.

BTW, GREAT write-up. Love your car.

 

That's good to hear. I wonder how much different the tone is. I keep hearing Borla sounds more euro while Magnaflow sounds more american-but i think it'll sound the same as the design is pretty much the same.

 

Magnaflow is definitely a lower tone, the dense design of the muffler is why. Also, over time the Borla tone will get slightly higher pitched where as the Magnaflow will not. They are both very good mufflers, I just prefer the very deep Magnaflow sound.

 

Haha Nice Kevwood for the info. I think ima do the Magnaflow route. A magnaflow 13256 and some tips. total cost only 140 uninstalled.

 

Nice, I paid a heck a lot more than that just for my muffler here, I had one sent from Canada in my container but had to bring the other one in through a local retailer - ouch...

 

Very good thread Kevwood. Thanks for sharing. Wondering how restrictive the oem muffler on the 500 is? Does anyone have a pic of the insides or peak into pipes of OEM muffler?
Very curious as I have done second cat and resonator delete and wondering if I should ax the OEM muffler and get an aftermarket one for more HP.

 

Definitely go for it

 

You are not going to get much, if any, HP gains changing the muffler (removing your 2nd cats probably netted the most HP in your current setup). Doing this mod only upgrades your exhaust note.

 

doooo iiit lol