y420

thanks for the reply AMS. how much of a pain is it to swap the primary cat out also?

-anyone know good shops in the boston area?

AMS Performance

The W208s are a real pain, but the W209s are slightly better. The W208s have a weird crossover pipe for the drivers side bank which makes it very difficult to weld in a high flow primary where as the W209s tend to run the banks on separate sides making is easier. Its still a tight fit and you will have to get a angled cat instead of normal straight high flow cat (they are roughly 3" shorter than the regular high flow cat.)

FatTony001

AMS,

Are you saying we could change (weld) the primary cats from OEM
to the new high flow ones you suggested? W209 = easy

Soo option 1 : replace the secondary cats with high flow = ~10WHP

option 2 : replace the secondary and primary with high flow = ~20WHP?

option 3 : replce sec. cats and your headers (has primary included) = ~ 25WHP ?


My question was more about option 2 beacause we already discussed option 1 and 3...

thx

AMS Performance

Hello Tony,

Each pair of high flow cats will free roughly 10 HP. Our headers make roughly 23HP/25TQ by themselves. How much they make all together is tough to predict exactly since nobody has done a direct dyno with all 3 combined but the gains should be very impressive to say the least I'm sure. However, you can't simply add 23 + 10 + 10, its not that simple. Realistically though 35-40HP should be possible for all three combined.

M-bENZ

AMS,

Do you have any idea where my second cat is ?

Andy

y420

thanks AMS, i have an 03 clk 55 amg which only has the singled side exhaust so im guessing my hp gains would be a little less..? so i can get this one from ebay for 75 bucks to replace my OEM secondary cat, can you recommend me a quality product to replace my primary cat? also.. i heard that sometimes there were electrical issues or errors of some kind when replacing the primary cat? sorry for all the questions.. i appreciate the help!

AMS Performance

Here is diagram of the W209 exhaust system. You can clearly see the secondary cats in the middle of the exhaust system (After the numbers #10 & #20). The cats before those are the primaries. The W209 primaries line up in a straight line so you can easily get the normal high flow cats and just cut off the extra ends and fit it in between the two OEM welded O2 bungs. Hope that helps.

M-bENZ

so mine should be the same as in the diagram ? I thought that for CLK55 AMG ?

Andy

AMS Performance

My bad, didn't realize you have CLK320... btw... they share the same front half of the exhaust system as the CLK55 (if you can believe that)...

CLK320:

M-bENZ

is that my resonator after number 150 ? ok so I guess I have the same front end as CLK500/55. Thanks AMS.

Andy

FatTony001

WOW, this is sweet ! Your header + primary cats + sec. cats = ~35WHP

Do you know if the Primary cats are easy to weld, install? looks like a toff
spot to do some work down there...

Always good infi on here

AMS Performance

Correct, All the front ends are the same, which is why AMS always recommend to the V8 customers to especially upgrade their catalytic converters & exhaust manifolds because that is where most of the power is freed up.

Yes, #150 is your resonator, the W209s CLK55s do not appear to have a resonator where as the W208 CLK55s do. (according to the MB EPC catalog)

AMS Performance

The best route to take is to do the Headers & secondary cats first... and then once the car has adjusted and you have determined whether you need more power or need more sound you can then do primaries. Primaries are the hardest to do since there is very little room, so it is recommended to save that to last (if ever, most never do because headers & 2nd cats are more than enough).

Hope that helps,
~AMS~

MarcusF

The front half of the exhaust is the same on a CLK320 and a CLK55? That's odd, because according to the Mercedes-Benz Electronic Parts Catalog (EPC) 2034905219 and 2034905319 are the part numbers for pre-resonator pipes on a W209 CLK320. 2094901119 and a 2094901219 are the front pipes for a 2003/2004 W209 CLK55 (no resonator). I cross checked the part numbers at one of the online MB dealerships (not a parts house, a dealer) that sells parts onine. The dealer claimed the cars take different parts and there's a big difference in prices. The CLK55 pipes list for $3710, while the CLK320 parts list at $736. How did you determine they use the same parts? Or are you saying the parts can be "made to fit" either car?

AMS Performance

They are the same basic design, the angle of where the stock manifolds meet the mid pipes are slightly different but other then that they are the same basic 4 cat design and in most cases even the cats are the same. The difference in part number is b/c of the angle of the flanges at the manifolds. hope that helps...

GiZzO

Interesting that the W209 have no resonator cause they sound the same.

Tump43

Hey, what do you think, with my intended set up (post#49) no primary cats and then adding high flow secondary cats (I've ordered them), will I loose low rpm torque (under 3500 rpm), or would these mods simply increase my useable torque and hp across the board (2000 rpm to 4000 rpm)?

AMS Performance

No, you won't lose any torque, it will provide power at all rpms. 300-cells still provide plenty of backpressure while still allowing for higher airflow. Go ahead and install them, you should definitely like the results.

Stiggs

I know for sure there is no resonator on the 2003 W209. I put my car up on a lift to find it and it doesn't have one!

speedybenz

AMS,

You have been saying that the AMG muffler and resonator are not a restriction to exhaust flow. Have you measured the backpressure of these two items under a full load?

Without that information it would be hard to say if they are restrictive or not, or are you basing your comments off of other data.

You mention the 200 cell metal core cats. Do you have a source for those? As I take my car to the roadracing tracks in my area, I could take advantage of the slightly higher flowing cats.

Thanks

Jeff

Tump43

Thanks AMS.

Jeff, the cat's recomended by AMS were 300 cell highflow metal cores. I ordered two of the ones he recomended from Magnum exhaust off of ebay: http://cgi.ebay.com/ebaymotors/ws/eB...SA:MOTORS:1123

Didn't receive them yet but will post dyno results after installed. My set up will be no primary cat's (per your recomendation) with Kleemann headers & down pipes and high flow 300 cell metal core secondary cats to replace the OE cats. I note that the OE primary cat's were really heavy, about 10-15lbs each.

Others, Hooley mostly, noted that he found 15 to 20 hp by deleting the secondary cats and replacing them with straight pipes. AMS notes that the w210 E55 guys realized about 10 to 12 hp by replacing the OE secondary cats with highflow secondary cats. So far I have not found a dyno on this board showing the increased hp/tq of a na 55 engine with no primaries and high flow secondary cat's. We will see if this does anything over my previous shorty headers ecu mod's.

Jeff, by the way, can you descibe to me here or by pm how to modify the intake elbow and throttle body? I am working on getting the MAF body bored out to 80mm, that leaves me with possibly deleting the separation slats in the intake elbow (or whatever else you recomend) and either having the throttle body bored out to 80mm or modified per your 5 degree post (which I don't yet understand).

speedybenz

AMS,

I measured the backpressure of the resonator and got no more than 2.5 psi from the stock AMG C43 piece on a 55 liter motor. And at the exhaust muffler I coudn't get anymore backpressure than 1 psi.

So based on that info I would say there is little restriction to exhaust flow from those two items which is cool because I like the quiet mode when I am blasting up through the canyons and track. Still interested to know if you have a scource for 200 cell cats?

Tump43,

On my Throttle Body I just bored a nice smooth 10 degree angle to the blade to help smooth out the airflow and the transition from the 80 mm tubing to the throttle body. I aslo took the manifold off and ported a nice rounded entry to the manifold so when the air reaches this point it will flow better.

I would cut out the elbow flow directors as they are not a real help on our larger motors. But you will need to fill in to indents on the sides and make the elbow inside smooth. If you want you could leave the airflow director on the shortside bend as it may help a little with airflow as the turn is really sharp. IF you sned me your MAF housing I will take care of it and also do the elbow too.

PM me for details.

Jeff

riarm

I say, delete the the 2nd cats and the resnonator.

Sound great- and cheap

AMS Performance

The stock AMG resonator & mufflers are straight through perforated core so there is virtually no restriction therefore theres no point in removing either of the components. The real bottlenecks are the exhaust manifolds, primary cats, secondary cats (basically the whole front half of the stock system).

The 2nd source I posted has the cats listed for $75 shipped instead of $90 shipped for a little bit more savings, both links are same brand thunderbolt OBD2 49-state legal 300-cell metal core cats, so its merely price difference.

The difference between 300-cell cats & zero 2nd cats is 10hp/12TQ vs. 13HP/19TQ (our dyno vs. hooleys dyno). Therefore its a differential of only 3HP/7TQ, which isn't much when you consider the actual difference (200cell cats will be only marginally better). Therefore in that regard, the 300-cell cats will get you roughly 77% HP & 63% TQ compared to no cats at all. And since they are street legal and will save lots of legal headaches and they clean up the sound while still giving improve exhaust not... seems like its worth it to just keep the environment a bit cleaner and give up a few HP.

For the record, I run high flow secondaries & AMS headers (obviously).... everything else is bone stock and the car sounds amazing, clean, OEM refined, smooth, deep.

M-bENZ

Ok so have anyone actually installed the high flow cats already ??? Report back please...

Edit:

Does anyone know ?