You mean to say that using *naturally aspirated* scavinging techniques post *turbine* increases backpressure??

Not surprising at all and thanks for the data! Peak power is only part of the story, less backpressure means lower EGTs and more power over time, something you may not capture on a chassis dyno pull.

 

I always have to laugh when folks talk about exhaust "making power". This is just NOT possible...LOL

If someone wants to collect data properly to determine factor effects, I would be happy to assist in designing an experiment (factorial) and nest a measurement system study in there to account for measurement uncertainty.

 

OK, not making power what about "free the power". But what do I know my car have straight pipes

 

guys i think we're missing something. i think the key lies in the way the x merges. tim was explaining it to me on the phone a couple of hours ago. i dont have pics of my set up, but the 'x' is different than the markski (and i assume others).

 

I am the owner of the 997tt that AMS referenced in their blog. My goal for the build was a car with awhp in the 6xx range and flat torque curve on pump gas. This car will be used on multiple road trips so I did not want a 3" non-catted exhaust, but something much more noise/gf friendly. I had fitment issues with my Europipe and asked 911Tuning to fabricate a street friendly exhaust (catted). Mark suggested a 2.5" exhaust x-pipe and I was eager to have one of his exhausts for my build. Mark went out of his way to expedite the completion and delivery of the exhaust we discussed.

The unfortunate situation with the exhausts during the build was obviously not what I had hoped for. After contacting Mark regarding the exhaust issues I realized there was a miscommunication in the more conservative exhaust build/design that I asked Mark to originally build versus the expectations that AMS had for the power they wanted for this build.

To be clear I am just a car enthusiast and do not have extensive knowledge in tuning / muffler design / etc. I do not hold anything against 911tuning/Mark and respect his knowledge on this forum.

Clarification: There was nothing wrong with the EP quality or fitment alone. The combination of the exhaust with the new turbo kit caused had some sort of interference when mounting the bumper. I believe they said something regarding the size of the cats.

 

Sounds like just a problem of a good product but bad application. I personally have never thought the X-system looked that promising but I'm not a scientist.

 

I believe Tim showed me some pictures of your exhaust when he was making it..
Is it a 2.5'' with a 180 bend on each pipe butted together,welded, with no connection between the two sides?? So really its not an X-pipe,sharing both sides in the middle..
Todd at Protomotive makes his two pipes criss cross from one side to another on his exhaust..

 

More glad that I have an AWE tuning exhaust now... even though mine does have some drone at part throttle between 2-3k rpms, and they swear their exhaust should have no drone... Shrug. It's not bad enough to really bother me.

 

Just going to chime in and say that I am perfectly happy with my QUALITY 911tuning 3" x-flow exhaust. I don't have a highly modded car like a lot of you guys, but I can attest that the craftsmanship and sound quality of my exhaust is more than enough to make me happy.

 

ummmm.....did AMS promised you XXX awhp with their setup that couldn't delivered? and now the blame is on the 911Tuning exhaust.....great way to explained that to a customer

With all the respect here to all members, as I done on previous thread. There's no doubt in my mind that there's no person or vendor with better skills in communication that Markski. Not only 911Tuning products are superior than other here, his customer service is outstanding and professional. My Seal Grey Project is a full testimony of that, my car not only have great power but is very...very...reliable.

In the past I had various type of exhaust but never the one from 911Tuning 3" Custom X-Pipe Catless..... that exhaust is just perfect with excellent quality fabrication and end results.

Watch the video and proof me wrong

 

Absolutely -I would assume your setup is more of a blended pair of U's than an X? Other than volume control (which IS important to many), there is no good reason to slam the post turbine sides into each other in a traditional X. I think this was discussed in the EBWerks thread when they did some CFD on a bunch of X designs and arrived at a blended U bend for least backpressure.

 

HEY I thought I would throw this out there..
If anyone wants to see how good their X-pipe is compared to a 100 cell Milltek system on my K24/18g car,my combo on signature,I am willing to Dyno it...But it can not be a full race system,non mufflered.. Street worthy..
I will pay for Dyno time and swap...If it makes more power with a nicer power curve I will buy it,if not I return it to you..
I have dyno time on May 15 on AWD Mustang Dyno at a shop called Boostin..

 

Some good discussion here and some are just oblivious to the fact that a full on X creates back pressure and will not get most performance that way. It does sound the best IMO.

I find it funny how someone blamed AMS for not making enough whp through a restrictive exhaust system and then "blaming poor Dyno results" on it. Air in, air out its almost that simple.

 

What was the back pressure after cutting off the X? I am small potatoes HP wise to you guys but love the X sound!

 

What back pressure ?