Ugly-Nugget

Hello guys, I was trying to find and older thread I was reading on a discussion about the best set up for MBH headers and what to actually install. I cant find it in the search so sorry I am going to ask again.


I am looking to buy the MBH header set up and I am wondering about the add ons you can purchase.


Mid pipes
X-pipe
High flow cats
Removable test pipes


Now before I buy and start to get into the exhaust what is really needed and or required as far as the mids and x-pipe and what are the removable test pipes..


I only want to do this once and order once, so I am calling on the forums membership and experience. Final question is the MBH header the right way to go.


I know there has been a discussion on this in the last couple months but I can not find the thread.


Thanks in advance
Doug

CarHopper

MBH is a great choice for headers and arguably the best. However, when you want the best setup it really depends on what you're going for.

Two main questions really...

- Do you need to pass emissions?
- Do you care how loud the car is?

Ugly-Nugget

I am really looking for some extra power gains and setting up for future mods.


Emissions testing is not a concern here in Alberta, so no issues there.
I would like some more sound obviously but I don't really want it stupid loud and annoying. Just a nice symphony of power so to speak.

BLKM3

Haha I have the exact same questions as you. I will be talking to MBH tomorrow.

BLKROKT

I have the MBH setup with the high-flow cats and x-pipe. The sound is amazing - not at all loud just driving around town or highway cruising. But at WOT it sounds crazy. To be honest, if you don't have to pass emissions and are interested in max power, I would go with the straight pipe instead of the high-flow cats. I'm going to get straight pipes made myself. But it will be stupid loud.

DVC

Just another perspective, albeit from an E55 guy...I have the full MBH modular setup with their cats and test pipes. Even if you don't have emissions, you may want the hi-flow cats to remove the unburned fuel smell...especially if you park in a garage. Even though I live in an area with no testing, I run my MBH cats most of the time for that reason. Makes it slightly quieter as well.

ld63

I don't have MBH but have headers with an x-pipe (no cats) and its a marvelous symphony of power

I was thinking of adding cats to reduce fuel smell, but it wasn't too bad and eventually got used to it.

Ugly-Nugget

Just so I understand the set up correctly the LTH will remove the stock manifolds and the primaries then the new hi flow cats, the x-pipe replaces the resenator. What is the application for the test pipes?

So if I get the LTH and the hi-flow cats will the car throw any codes?

BLKROKT did the set up come complete as in no extra parts needed, like sensor extensions.

BLKROKT

LTH replaces the stock manifolds and cats. Then the MBH cats come after (relocated). Then the X-pipe replaces the secondary cats and goes back to the stock resonator.

Won't throw codes, but you need your tuner to adjust the program for the deletion of the secondary cats. Still have to plug in the secondary O2's (unless you made simulators like I did). The MBH kit has places for all of this. No extensions needed.

CarHopper

I know contradicting information gets confusing here, but this is not correct. Secondary cats have no o2 sensors associated with them at all and will never throw codes.

A lot of this, however, is correct. The LTH's will replace your OEM exhaust manifolds (which are log style) and also eliminate your Primary cats. Your NEW primary cats that come with MBH will be relocated to the end of the LTH's. Then it will go back from there through the x-pipe, res, and out the mufflers.

And YES, you WILL throw codes if you're catless. Just always anticipate this to be the case. Some people may not get codes even if they are running catless, however, I am skeptical of those claims and will always assume codes happen when catless. Now, because you're in an area where emissions doesn't matter, just get a tune and tell the tuner you are running LTH's. They will provide you with a tune that will eliminate the CEL for no cats, however, it will not pass inspection with that tune.

Catless will give you more power and sound obviously. However, you will get a kind of gassy fuel smell and it is very loud. Such as if you're cold starting in your garage and someone is asleep, well, they won't be anymore. Others have had neighbors complain. That is really up to you and your preference. More power + gassy smell and maybe be a little too loud vs Less power but the gassy smell is much less severe or not there at all and the car is a little quieter. But, quieter is relative because it will still be quite a bit louder than stock and these cars are pretty loud stock anyways.

BLKROKT

I didn't say the secondary cats had secondary O2 sensors associated with them. Re-read. We said the same thing.

CarHopper

The bold is what I was referring to that seemed confusing with the secondaries. Maybe you're talking upstream and downstream o2's on the primary cats? Anyway, lets just call it reinforcement then.

BLKROKT

You're right. I totally misspoke on that and didn't even realize. Second cats aren't monitored. Good catch.

Ugly-Nugget

So basically with this set up you are leaving the resonator in tack, and this is all going in up stream of the factory res.?


So these test spools as they call them are basically knock out spools for the hi flow cats if you want to remove them quickly or semi quickly?

BLKROKT

Yes, this is all upstream of the resonator.

Test pipes. They're not super easy to remove once the exhaust is in place. The pipes all slide into each other and are held on by clamps, but the rear of the exhaust from the cat-back is on rubber mounts and pushes on the rest of the exhaust with quite a bit of force. When I get around to it I'm going to flange everything with gaskets to make removal easier. Plus my exhaust tips stick out about 3" further due to the sections not sliding completely into each other. The welds, bends, and general construction are great, but I'm not a huge fan of the pipe connections.

Ugly-Nugget

Thanks guys, I think I have all the information I need to make the order. That's the beauty of these car specific forums, all the combined experience and knowledge.


Thanks again for the help and patience from a question that probably gets asked a lot. I just couldn't find the right combo of info in the search area.





Ugly

Wobble64

I have LTHs and X-Pipes, catless. I ended up not daring to cold-start the car with the garage door open, for peace in the neighborhood. My wife did not dare to start the car once for 15 minutes near horses, because she did not want to put riders at risk and cause an accident.


I ended up replacing the stock mufflers with Akrapovic slip ons and now the sound is still way louder than stock but reasonable, cold start is dampened and the tone is back to the AMG deep rumble again.


I prefer it that way, but sound is subjective.


On the other hand, I dynoed the car before/after and LTHs brought 40 rwhp, about 50 crank hp. They made a big difference!

Ugly-Nugget

I am going to order with the Cats and X-Pipe and go from there as far as sound goes, adjust accordingly from there.