After independently testing PLM Exhaust Manifolds, the GT PRO Single X-Pipe and my own 2.5" catless bolt-in down/midpipes on the dyno and at the dragstrip, I've moved on to Long-tube Headers.

I sent my ECU off to Cory @ Kleemann to update the file to the same K2 version avengerboater is using with his MHP long-tubes. Got it back in 24-hours. Thanks, Cory!

Install was done by Sound German Automotive in Bellevue, WA this morning. The process was straightforward and took about 6-hours. Thank you, SGA!

The only issue we ran into was unexpectedly having to trim back a very slim portion (no more than a 1/4 of an inch) from the drivers side plastic under tray. Slightly annoying not knowing about this potential issue. Apparently it can and has happened to "some C63s". No big deal in the end.

As I already knew from hearing avengerboater's and nrgy's car, these headers make the car insanely loud at Cold Start and Wide Open Throttle. It just sounds angry. In a couple weeks I'll have my "sound reduction" solution. MHP is working on a custom configuration to help me quiet down those cold-starts during non-track use. More to come on that subject when testing is complete.

So you ask, "How does it feel?". The best possible answer to that question is ->

Videos, dyno pulls and some new 1/4-mile time coming in the next few weeks.

On to the photos!

The 1 7/8" 4-into-1 Long-tube headers:


The complete system w/ 3" mid-pipes:




Close-up of the TIG welding:


Close-up of the laser-cut flange:


Installed:


The high-velocity merge collectors:








Extra O2 bungs pre-installed on the mid-pipes for optional wide-band monitoring:


Close-up of the clamps used in the system:


Close-up of the steering shaft clearance:


How it bolts to the factory resonator:




Shot showing the ground clearance:


That's it for now. I'll post more data as I get it.

 

Looks great, congrats. Any pics of the undertray mod? Where do you plan on placing the HF cats in relation to the collector? Did you use new manifold gaskets or sealant?

 

Awesome. Thanks for posting the pics. I'll be checking back for further updates.

 

The quality of the MHP headers looks great. Do you even have the room to install a set of cats? Congrats.

 

Welcome!

 

looking forward to the dyno results

 

Looks really nice... I tried my headers with no cats but that was just too loud... have 200 cell cats now...
Are you going to install resonator or cats?

 

As usual From you


Great job and clean work

we waiting for dyno results and video

Thank you for shearing

 

Great write up. Looking forward to clips and dyno results.

Enjoy!

 

Looks great super.

The dyno results should be interesting.

 

Looking good and as always a great write-up. Hope my set turn out as well...I am sure Andy will pull through for meHow loud is loud as I am going cat-less and from what I seen/heard that this could prove too much. I can always get cats later, but if it is way over the top then I might as well add cats during install of headers.

 

I've said it before, with catless LTs this is the single loudest street car I've ever heard at cold start and WOT. I've been drag racing and dynoing for years and have been exposed to a ton of different high-performance cars. Nothing has come close to this kind of "bark". That first cold start will freak you out so bad that you'll think something is wrong . . . even if you know it's coming.

I'm hoping the solution Jim/Andy come up with does remedy this. Civility when not racing is something I strive for. More to come when testing is complete.

Until then, I'll be driving my Ford Ranger 4x4 to work.

 

Is there a section long enough for you to add some cats? That is the main thing that turns me off with catless LTs is the noise. I like Bhamg's MBH setup; however, I am waiting to hear his car with only 1 set of cats vs. the 2 sets that I have heard.

 

Ever consider the vibrant sound deadeners, not sure how they compare versus 500 count cats.

 

MHP makes a bolt-in 3" cat solution now. It replaces the mid-pipe portion that connects to the collectors. nrgy runs these on his car but it's still too loud for my taste.

MHP is working on something custom to address my needs. More to come when testing is complete.

 

Thats SICk i really Like how it looks .. its MEAN !

 

Wow....a single cat on each bank is still too loud? I think you and I have the same sound level requirements. Chubbs kind of touched upon this; I have seen some kind of noise reducer that looks like a mesh funnel for a lack of a better term.

 

Track worker once recommended that I stuff the tailpipes with Brillo pads after being black flagged for being over the decibel levels......again

 

great write up super thanks for the info.. can't wait to install my headers as soon as i have them here

 

Very nice header+midpipes! And great pictures as usual! Thanks!

 

I NEED MHP DELIVERED TO OZ!!! hahaha Tempting!!, does MHP make for RHD car?

 

 

Wayne your car is becoming insane (in a good way!!!) I heard NRGY's when he took me for a ride in his car and I agree that Bark is something to be heard. I think my neighbors would shoot me if I did something that loud. Tossing around the idea of the K2 package, knowing it doesnt make the power that the Long Tubes do but might be a good compromise I think for the reduced noise levels.
Thanks as always for the great reviews and all the info you pass along. Much appreciated.

 

^ Go all in..get the longtube headers. Especially if it's not your only car. It is ridiculously loud, but only at cold start and WOT. Otherwise, you're already noticed anyway with stock levels(at least my neighbor at the bottom of the hill--he likes it), so why try and be subtle about it? I don't think you'll regret it...And if even if you did, you could probably follow Super's path and get his sound reduction plan.

 

NICE SET OF HEADERS!