My main goal was to get 40% to 60% of the power of long-tube headers for 20% to 30% of the price. After quite a bit of research, I decided to go with AMS short-tube headers. They are manufactured in thick stainless steel mandrel-bent TIG welded tubing as opposed to mild steel. Also the one-piece CNC machined flange ensures a spot on seal to the head. AMS provided all the hardware needed as well as the exhaust gaskets. The headers are ported and polished both inside and out which makes for nice engine jewelry. Because they were manufactured for strength and longevity, they are not much lighter than the stock units; which is a good thing.

I put the car on the dyno before installing the headers to get a base HP reading. As you can see from the graph, it put down 297.6 HP on a Dyno Dynamics machine on a 68 degree December day. From what I understand, this type of dyno machine runs about a 20% to 22% difference vs. crank HP. The car has K&N filters, Powerchip software and AMS lightened pulley. I am also running a bit of fuel enhancement (NOS racing formula 6 oz.) to get it to 92 octane (I live in CA…).

Installation of the headers was performed by my independent mechanic. It took him about 3 to 4 hours to install. He had no issues installing the headers; they bolted up in the stock location directly to the head and to the primary cats.

The initial reaction on start up and driving away from my mechanic was a glorious exhaust note. How could a set of short-tube headers make such a difference? It was not considerably louder, but rather a more enriched tone. I really was a nice surprise. I have always done cat-back systems on my cars – this is the first time starting on the front end of the exhaust system.

After driving the car around for a couple weeks to let the ECU adapt, I headed back for a post- install dyno run. Unfortunately it was a very hot day. Who knew it would be 90 degrees in Southern CA in the middle of January? In any event, the car put down 304.3 HP. I figure that the 22 degree difference was good for 2 to 4 HP; perhaps less, perhaps more. I'm figuring around 12 to 14 HP gain at the crank which lives up to AMS' claims and met my initial criteria. The change in torque was the most impressive result at around the 2,800 rpm mark; it is now difficult to hook up in 1st and 2nd gear with anything more than ½ throttle.

I have since changed the secondary cats to 200-cell metallic cats (see my other post), but have not done another dyno run. The sound is even more enriched now. Not too loud; very refined.

Overall, a great modification. Reasonable price, easy install, excellent fit and finish, excellent customer service, HP gains, and that glorious sound…

Here are a few sound clips (best to click on "watch in high quality"):

http://www.youtube.com/watch?v=YiC4C...eature=channel

http://www.youtube.com/watch?v=Nn_0I...eature=channel

http://www.youtube.com/watch?v=XnLxB...e=channel_page

 

nice review

 

nice sound. the header really makes a huge difference. by the way, how much does the 200-cell metallic cats cost u? after installed the kleemann header on my 55, i'm thinking either replace the 2nd cats with a 200 cells or straight pipe to get nicer sound. which one u guys prefer?

 

I got the ECT cats from ebay for $100 each plus $15 for shipping (Arizona to CA) from seller ppe. Email him and ask for a multi-buy discount. The install cost me $350 cash (see my other thread), and worth every penny. AAA performance exhaust did a fantastic job. The trick is to get the new exhaust tucked up as far as possible, and avoid using the pipe-squishing technique and 90-degree bends that the factory does. You can go with full secondary cat delete, but you won't pick up much HP by doing so and the secondaries aid in refining the sound of the exhaust IMO. Here is an info link to ECT metallic cats.

http://www.ect-catalyst.com/02metallic.asp

 

Hello Ala,

Glad you are happy with the results from the headers. Those are very healthy gains especially considering a 22 degree disadvantage on the after dyno. You definitely have one of the best sounding SLK55s out there, clean, classy, refined. Great job! The videos sound great, can't wait to see more .

Thanks
~AMS~

 

straight pipes will not sound good, You need something to refine the sound out a bit. Your other option is running compete stock system on the back half (resonator & mufflers) and then running and X-pipe in place of the secondaries.

Two things though, One, this will weld both mid-pipe pieces into one solid piece so keep that in mind. Second, it will reduce resonance compared to just straight pipes and you will pick up more power and improve scavenging effects, however it will still be louder than high flow secondaries.

Hope that helps.

 

Thx for ur help

 

IMO, best to keep resonator and mufflers in place and drive it around for a while after installing the headers. Then adjust if it is still too quite for your taste. I will post a couple more vids shortly.

 

Here is a short drive-by clip with the AMS headers and 200-cell secondaries. About 1/8th then to 1/4 throttle tip in to kind of simulate real world driving. Again, cheap Casio Exlim digital camera - sounds much better live.

Best to "watch in high quality"
http://www.youtube.com/watch?v=5bCjV...e=channel_page

 

sounds great even under part throttle. Thats definitely one of the most refined sounding slk55s I've heard, To many try and make their SLK55s sound like 60s muscle cars, and not classy exotics.

Nice work A'la.

 

Sounds good on the drive by. Going to rid the 2nd CAT this week and get rid of the sharp bend b/f the same. Will try to post vid in next week or so. Too bad a 200 cell primary would get into MIL issues, or I'd be tempted to swap the same.

 

stop me if i'm sounding a bit pessimistic and omey, perhaps you can chime in here, but seven rwhp for a set of headers seems like a pretty insignificant gain

 

Weather conditions probably stole 2 to 4 HP I figure + or -. Then grossed up to get to crank HP is about 12 to 14 HP. Which is in line with the original goal; 40% to 60% of the gains of long-tube headers for 20% of the cost. It was a cost benefit/noise/staying green analysis for me; I was not searching for the last drop of HP. Yes, long tubes will deliver more HP, but at a far greater cost (and noise) and will require a complete rework of the rest of the exhaust system.

The increase (upfronted and increased) in torque was the biggest improvement, and it is what you feel first and foremost since the torque curve comes on much stronger and earlier now. Difficult to hook up in 1st gear now when I give it heavier throttle.

Also want to note that the scaling on the graph is off. The left hand side is scaled to 320 while the right hand side is scaled at 465, so the intersect of HP to RPM is not at the 5,250 where it should be. I need to drive back to Autowave and get a reprint when I have a chance, then the results will be a bit more clear.

 

You are looking at absolute peak numbers, plus even those numbers are not necessarily 100% accurate b/c the AMS headers peaked 100rpm after the stock ones so its actually a bit larger (at the AMS peak gains were around 10HP, vs stock peak 7.X HP). This because the power continues on after the peak and remains higher with the AMS headers, whereas the the stock headers the drop off in power is pretty abrupt.

Even with the 22 degree disadvantage throughout the power band there were gains of up to 13HP at the wheels (on a loading dyno, which is about 16 crank HP) which are stellar gains considering the circumstances in our opinion. We are very happy with the results as is A'la.

Both between 2800-3500, and 5800rpm+ There were gains of 13 rwHP in these key areas of the power band. In addition the torque gains were even more impressive in the lower portion of the power band.

Peak numbers are irrelevant when taken out of context, and mean very little. It is the total "meat" under the curve that matters.

Once A'la posts the updated dyno chart which is easier to read we will post a direct comparison analysis of before & after dynos for very precise readings of before & after to get a much better picture of exactly whats going on at each 100rpm.

Ala': You are correct regarding long tube headers, and most people forget to mention long tube headers are illegal in most parts of the US because they delete the primary catalytic converters. At AMS we do not condone the removal if necessary emissions components and they exist for a reason (for both environmental & legal reasons). Ours are 100% compatible with the stock system and do not remove any essential emissions components which are crucial to keeping the car street legal.

Thanks and have a nice day.
~AMS~

 

Westchester Parkway, howdy neighbor
I want my CLK sounding like that, god damn, thats just right.

 

Yes, Westchester Parkway! About 6:45 am with no one around except for two LAX off-duty cops jogging that heard (not saw) me do a 75 foot burnout who then proceeded to radio me in (which I saw them do, so I bolted). I'm kind of afraid to post that clip due the fact that my friend caught a piece of the front plate that was not taped over....

Very nice CLK55!

 

Thx, wanna trade?
Ha, that street is dangerous i've already got a speeding ticket on that street and i was not intentionally driving fast.
Roughly how much did it all finally cost you? Near summer once i finalized what i want, i will most likely have AAA do mine as well.

 

All in cost was not too bad:

AMS Headers; I preordered the headers way back in summer so I got a bit of a discount, but I think the list price is around $1,500 now - check with AMS
Mardikian Automotive install of headers; $300 - about 3.5 hours labor
200-cell ECT Metallic Cats on Ebay; $200
AAA Performance Exhaust install of cats with custom piping; $350 cash price

So only $1,700 on parts at full list price. As opposed to Supersprint headers and cats which are a whopping $5,000 before install add in mufflers and you are up to $6,600. And you run the risk of not passing smog in CA and the car sounding like a Messerschmitt BF 109 fighting over Calais.

Also want to note that AMS' customer service is top notch. He always kept me informed of manufacturing progress, timing etc. He also went well out of his way to help me chose the appropriate cats and overall exhaust layout. He steered me away from useless mods and mods that would make the car too loud for my taste such as an x-pipe or aftermarket resonator. The results are as expected in HP improvement, but well in excess of expectations on sound improvement and torque improvement. I really have to thank AMS for that.

Here is an example of alternatives:
http://www.supersprintna.com/categor...ategory_id/139

 

MSRP price for the headers is only $1250, that is our standard price available to all first time customers. You can save another $100 if you participate in our Dyno Rewards program (of which A'la did participate as well). Compared to the competition it is MUCH cheaper and the results speak for themselves.

Glad you were happy with our products and our customer service. AMS really does try to go the extra mile for our customers as much as we can because at the end of the day the most important thing is making our customers happy.

A'la let us know when you get the revised dyno charts, hopefully they are much easier to read since the one above can be a bit confusing b/c of the scales.

Thanks,
~AMS~

 

So what HP do your different Stages make.?

Jim

 

Hello Jim,

To get an idea as to what our stage 2 performance package will make (Pulley & Headers), you can simply add the results A'la F1 got with the independent C55 dyno (hooleyboy) on our website to get a basic idea. We are currently doing much more dyno testing as well, however most people still prefer independent results.

If you would like to participate in our dyno rewards program and test the stage 2 performance package on a Dyno Dynamics dyno, then you will be eligible for a substantial discount on the overall cost. I am assuming you have a W209 CLK55 AMG correct? If interested contact us via PM/Email for more information.

Thanks,
~AMS~

 

nice write up...
headers FTW

 

Thank much. It has been a fun project. Like Heather Locklear, AMS headers' looks improve with age. Here they are with a bit of age on them - a beautiful blue tone.

 

Yes, SS tends to change color with shades of blue,purple & gold as they age. Many like them more as they age b/c the headers really do look better with age.

Glad you like them Ala. Best regards,
~AMS~

 

Finally received the revised graphs that has the same scaling for both HP and Torque. This one is a bit less confusing.