Primary pipes are 1 3/4".

Yes I did. In fact, my lovely wifey let me have most of the weekend to work on the car, so I did an oil and filter change, replaced all 16 spark plugs, dropped in a new SC belt, refreshed the air filters, and did the header install. Basically lived in my garage this weekend. A tip for those planning to do a header install is to change out the spark plugs at the same time because the access is so easy. With the two exhaust manifolds removed, there was lots of room to remove the plugs, and more importantly, be able to actually use a torque wrench to torque them to their correct 25 Nm specification for the install. The new NGK IridiumIX plugs (see https://mbworld.org/forums/w211-amg/...omparison.html) have a very snug connector fit and it took some decent leverage to snap the spark plug wires onto the plugs.

I was very fortunate to have planned to replace my downstream O2 sensors as part of the header install. With the high flow cats ordered as part of this system, you most definitely need to extend the wiring harness of the downstream O2 sensors. I was able to use the wiring from the old sensors and splice it into the harness of the new sensors. A quick trip to Radio Shack to pick up some shrink tubing and I was ready to start surgery on the O2 sensors. Easy way to not screw up the wiring was to do one wire at a time. Soldered the connections, slipped the shrink tubing into position, and used a heat gun to shrink the tubing down. I then reinstalled the original outer insulated wiring jacket. Almost looked "factory" when finished. Here's a shot with the headers already installed and the passenger side mid-pipe being fitted into position. Note the longer rear sensor wiring harnesses.



The next picture is the front end all buttoned up with also O2 sensors connected and secured in place. What's great about this system is that the rear belly pan (lower splash cover) can still be used. Plus, there is excellent ground clearance.



Here's a shot viewing towards the rear of the car. In the interest of time, I just connected to the factory rear exhaust for now. With this configuration (cats, factory resonator, factory mufflers), there is ZERO drone in the cabin at any RPM. But give it throttle and it's freaking amazing!!!



Initial impressions upon the first drive after buttoning everything back together was i) my car was really due for new spark plugs; it's purring like a kitty now. Before it was idling a little ragged; ii) There's no noticeable or perceived loss of low end torque. That was my biggest worry. The improvement was stunning and acceleration seems completely effortless. Up on 70 mph in the blink of an eye; iii) build quality is really nice. It was great being able to just bolt the stuff in and be good to go. And finally, no check engine lights with the cats in place and extended downstream O2 sensors. The ECU is happy and so am I.

I know these headers aren't the least expensive alternative out there, but one drive was all it took to confirm to myself that I made the right choice.

 

Gorgeous, the floor that is. Same as my garage floor. No reallly, the headers are first class workmanship!

You going with a h or X pipe to balance Ex gases?

 

Thanks! Yeah, absolutely love the garage floor coating.

The plan is to go with a resonated X-pipe when time permits. You probably already know that the factory resonator contains a crossover, but it's not ideal for max performance.

 

Maybe for some applications, but an E55 with the "cats" option most definitely requires extending the wiring harness of the downstream sensors. A very minor inconvenience, though, for the gains these make.

 

great purchase and pics of install. Can you provide the part #s for the Bosch 02 sensors? Race cats replacing the primary cats, and secondary cats are gone and no CEL codes!!! FTW

 

Sure can. Part nos. are Bosch #'s for North American market.

Upstream with OE connector (plugs into engine wiring harness): 16272
Downstream with OE connector: 16328
Universal for both upstream and downstream: 15733

If I had it to do over again, instead of buying the 16328s for downstream, I would have saved myself some cash by buying the universals (15733) for downstream because if you're installing the high flow cats with the MBH headers, you'll need to extend the rears sensors anyway. The headers were advertised as no extensions needed, but that's not the case. No big deal, though. The only thing I don't know is how much cable length is supplied with the universal sensors, but I assume it would be at least as much as the OE type. If that's the case, then you would have sufficient wire to extend to the needed length. You would simply reuse the original connector and splice the universal sensor at the end of the original wiring (i.e., right before the actual sensor).

 

Thanks again for the part #s. I have 62k miles on mine and will eventually need new plugs/o2 wires (will have them handy or will wait little longer) when i get my headers installed. I'm planning keeping the secondary cats and rest stock. But now seeing your setup with race cats and no CELS, might change up and go your route.

 

It's a shame something so amazing looking will rarely be seen.

Has anyone been talking about a group buy price? And what is the waiting period on a system like this?

 

If there is an interest (5? 10? more???) I'll give a great price.

 

1. Denroll
2.
3.
4.
5.
6.
7.
8.
9.
10.

 

I forgot to post some additional data points from when I installed these.

I actually weighed everything coming off and going on because it seemed fairly obvious that the SS headers would weigh more than the puny factory exhaust manifolds they were replacing and I didn't really want to add any more weight to the car.

Factory manifolds (combined weight): 12.65 lbs.
MBH headers (combined weight): 20.85 lbs.

Other than maybe being made out of titanium, I don't think you can avoid this result given the size difference between the parts.

Factory center section (R & L catalyst sections): 48.25 lbs.
MBH cats and straight thru mid-pipes: 23.7 lbs.

Total factory pieces: 60.9 lbs.
Total MBH pieces: 44.55 lbs.

So the net weight savings from this system is 16.35 lbs. I thought going in it might be a bit more of a weight savings, but it's really not too shabby given the fact that the MBH pieces are all quality heavy gauge stainless steel. How can you argue against less weight and huge performance gains from some bolt-on parts?

 

Maybe start a new thread so its easier to see/jump on the group buy???

 

Agreed

 

Excellent write up!


Good idea on replacing the plugs while you are there. Another would be to change out the motor mounts before bolting on the new headers. Lot's of room in there without the exhaust in the way.