Z99

I know there are some here that have seen excellent gains wuth he MHP long tubes. I currently have K2 package. I believe that the results on this forum have all been with long tubes and cat delete. Is it worth making the change if I want to retain cats (versus my current K2)? How much are the MHP long tubes with cats?

Thanks

c63beastdriver

Z99 - PM me your number and I will call you about MHP.. Jim

Z99

You have PM.

Thanks

Savoy6

what about cel's these turn them on constantly? every video ive seen has the cel illuminated or is that just them driving in esp sport or off.

mthis

i have MHP LT's with no cats. and i have 0 lights poping up. (NO CELS WITH MHP HEADERS WITH NO CATS)

Z99

Nice qrtr mile times. Those headers work. But, I wonder if I would get significant difference if I installed with cats versus K2. Maybe better off installing the Kleeman throttle bodies. Wish there was more data on the throttle bodies. Maybe I will need to become a data point.

hhughes1

The MHP long tubes feature three sections, the midpipe is interchangeable with high flow cats. I don't know what the power difference is (with vs without the cats) but my catless system picked up 44 whp and 32 tq versus the K2, same dyno next day. Keith had similiar gains as well. TB's seem to be a question mark at the moment at least until some data comes available.
The catless version is loud when accelerating but not unreasonable. At WOT on the track it howls like a Banshee and really ups the ante on the intimidation factor.

Hans Delbruck

hhughes,

Do you know your total WHP gain with Kleemann tune and MHP LongTubes, vs stock?

hhughes1

Stock was 368 whp taken in Jan. Current is 458 taken in July( 95 degrees and 70% humidity). I will dyno again on a cold dry day because I don't believe the software really makes enough adjustment. Waiting for track results with the right weather and some drag radials.

Z99

Good info. Thanks. So with the mid pipe I can take out the cats for the track and put them back for the street? Will I be flagged for the noise at the track?

Dads C63

You have NO idea how funny that is!! Ask HHughes1

IF you think thats loud try the new complete 3" Race version. Its mind blowing loud. How can a 4V 6.2L V8 make that much noise at WOT and be silent at idle??? Its amazing!

Merc63

Doesn't the MHP tune remove the CEL light for the headers??

I want to use the MHP headers with my renntech tune, will I get a CEL light? Or is there a stop to plug the sensors back into the exhaust??

Merc63

I purchased my ECU upgrade from Renntech. I am almost certain they don't make a "header file". They use the stock primary cats in their header system.

Do the exhaust sensors mate back up with the MHP LT headers? I'd assume the CEL would be a check cat code because of the emissions readings..?

Is it possible for them to delete that code on my ECU if I were to purchase the headers and still use my renntech tune?

JonMBZ

Im sure renntech can remove the CEL warning if you need, but how much gains did you even get with them? MHP gets like 65whp with their tune and I would imagine 50+ more with headers.

c63beastdriver

Yes. You should get about 45rwhp and 30rwtq with MHP headers alone...

otoupalik

if you keep the cats, you will not see the gains.

If you don't delete them you will prohibit the increased gas velocity from the LT's from getting out, which creates back pressure, which minimizes the gains!

thanks
Brad

Dads C63

MHP offers high flow cats for their system. That way you will get the gains you want and keep the cats.

otoupalik

There is no high flow cat made that will give you the same flow and HP as you would get from the LT's without cats. This is just fact, it is not about what vendor is offering it. Anyone that tells you otherwise is trying to "sell" you something rather than "tune" your car to meet your goals.

That being said, the addition of a cat (the properly matched high flow metallic substrate cat) can be a benefit in some set-ups. What they will do is to re-shape the curve and generally add more TQ at the expense of HP. The curve will move "down" or to the left if that makes sense. On low TQ cars (such as BMW M cars) this can be advantageous. On torque monsters like the AMG cars though, it is generally not of any real benefit.

This is JUST a discussion about HP, not about the benefits or legality of cats.

thanks
Brad

C63 Guy

No X-pipe? Really? Interesting...

Also, I worked at evosport for a good while there, and we had to make the headers with individual flanges to be able to install them without any cutting or removing any pieces other than the forward bottom shroud. How do these go in and what has to be removed or cut? Not a hater question, just interested in the process.

Thanks,

Josh

Dads C63

Josh,
The X-pipe goes after these pipes in place of the resonator because the stock cross over is in the resonator. I should have taken pictures before I installed the cat back, sorry.

The only parts you need to remove are the normal plastic undercarriage guards and the steering box/shaft. Otherwise they take less than literally 5 minutes to install after those parts are removed. Macedo Motorsports did the install and Larry said they were one of the best fitting and highest quality headers he had ever installed. The performance is incredible!!

dacls63amg

Any long tube headers for a cls63?

F360

Does the MHP header fit the CLK63 black series?

a_Y

How about for the SL63 AMG? I want long tubes but I just can't find anyone making long tubes for the SL63..