Jasonoff

You can make it worse and lose power. That's fact. Isn't that what he thinks is happening because of having the X and H pipe? Upset balance resulting in power loss.

jptaylor

Here is my "theory"....

x-pipes and h-pipes do 2 totally different things for an exhaust....thats why technically they are CALLED 2 different things, an x-pipe is also known as a MERGE pipe and an h-pipe is known as a BALANCE pipe...the h-pipe allows the pulses to equalize between firings and an x-pipe crosses the streams(no GBusters jokes here ya *******s!) so that when merged the pulses create a pseudo-vacuum to promote scavenging which smooths out the flow, but at the cost of reduction in flow rate. By doing both it would "seem" to me that whichever was 1st in line would "balance/merge" the flow rendering the 2nd one useless(except if the x-pipe is 2nd it only reduces flow rate as pulses are already balanced between firings).....of course this is all conjecture but it is ok, I've got my Nomex on and am fully prepared for the fire!!!!

BLKROKT

I stopped caring. I'm perfectly happy with my setup, and I've seen enough testing on all kinds of cars to know that it makes just about zero difference either way. To say that you can feel whatever the incremental difference is between the two - 5wtq maybe - is kinda ridiculous, but whatever.

Here's an interesting video I stumbled upon though.

Jasonoff

You can't just slap stuff together and expect it to work. Replacing restrictive components with the same type of less restrictive components in an already properly designed system "should" work though.

http://www.superchevy.com/how-to/exh...for-your-ride/

bentz69

As we all know, or should know, the stock exhaust system has an h-pipe already. I like to think that MB did enough testing to figure out if they should use an X or H pipe and WHERE to place it. Now yea, we add headers with different size tubing, cut out 2nd cats, remove resonators and most importantly, add custom tunes that completely change timing, A/F, throttle position etc. With all these different options you'll need to experiment to see what works best. The butt dyno aint gonna cut it. Do an exhaust mode, throw the car on the real dyno for 3 pulls (75$ around my area) and go from there. It will be money well spent if your in the search for each last bit of horsepower and you want your car to drive its best.

I dont think theres any reason to have both the X and H at the same time. Is it causing a noticable loss in power? Thats for the real dyno to say, not the butt dyno.

Infiniti

i would love to see facts on our cars on running both x and h to only running one of them. for a while i've been thinking how this is affecting my car, if its 5-7whp then i'm doing something about it lol. i need every last bit of power i can get, i just cant imagine it being that much but maybe i'm wrong. i know if i take off the stock resonator the sound will probably get 30% louder.

Vladds

In case of the Subaru, it depends what you do:
It was discovered that there is an accelerated learning procedure that the factory devised, in order to get to max in one 10 minute drive. That includes a specific set of parameters, drive at 2500 rpm, then floor it, etc.
If you don't know and don't do this, the learning takes a day on average, say a commute in which you drive spirited in one segment of it.


However, it is considered that being able to start with maximum multiplier after a tune is an important tool for the tuner, as they can gage where they are with the power gains.


This is complete speculation, but if one tuner makes more power than other tuners, they may have better tools. Restart with maximum multiplier (which they may disable after they sign off on the tune, for safety and longevity) and real time tuning. real time tuning means that you don't have to stop the engine to dial in the parameters.
Normally you set the parameters, you save the rom, stop the engine, reflash, restart and log.
With this, you don't reflash until you get where you want to get. You want less timing? the engine runs, you reduce the timing, in the same interface as the logging and then continue the pull.
Once you feel you have something, you stop, save and reflash.
This saves hours and hours and usually is reverse engineered from the factory tool.

skratch77

Car feels a little better with more miles on it and I'm finally at a point where I feel like I didn't spend money for nothing.

Before I didn't even want to dyno it because it felt so flat and wanted to change up stuff to get the car to respond good on the but dyno.now I feel good about the headers and actually want to see what it's making

I'm going to add 300 cell cats but not for performance issues trying to add mid range but for smell.

There is too much traffic and it's so bad that I put the windows up.

Can't imagine what the car behind me feels like.im also going to try without xpipe because it's a direct bolt on and just curious how it will run without it.

I like how it sounds now but it has a pitch that reminds me of a gtr or a g37 and want more of the amg vroom back.

And for everyone including me who was asking what setup to run you have to just try them out and I'm willing to bet everyone tried different things after there initial headers install.

Like trying with resonators,h vs x,catts mufflers etc.

One good thing with my setup is zero drone off throttle and hope I don't get it when I take the x pipe out and put cats in.

BLKROKT

Takes a good amount of time for the headers tune to set for some reason. Glad it's feeling better now.

NotABaller

Good stuff OP.