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  • exhaust gains?

    Im trying to find out if anyone here, with a 2.5, has experienced significant gains with any exhaust systems. I have the stock system with simply a muffler for my exhaust. I wanna know if its gonna be worth it to get headers, and full exhaust. Thanx-hugh

  • #2
    oh man! I just got the joke in your sig. First I thought it meant you weren't driving it hard enough and it was bored with you....but now I get it (bored cylinders) I feel dumb :sosad:
    "It is needless to say that self-propelling vehicles, like other machines, will never do as much for one who does not understand them as for one who does."

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    • #3
      When I had my motor built I had the header installed at the same time, so I can't comment on the header being an improvement or not, although I would hope so for what I paid!

      I had the stock cat with a Borla muffler for a while, and then ordered a Raven Performance dual 2.5" header-back system and noted a huge gain in lower end performance. Up top there isn't much of a difference but the toirque down low is quite an improvement.

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      • #4
        shyea...hence the awkward silence after the joke hehe

        thats good enough for me...how much did your header system cost/was it the motorsport headers? Ijust get pissed that all these brand name exhausts don't dyno test their shit...maybe they do ijus cant find the evidence.

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        • #5
          a muffler will not do much, nor will a header unless you are finishing up your motor. replacing the stock cats with high flow units or a resonator will help much more even when your motor is fairly stock as it is a larger bottleneck.

          i installed the VSR x-pipe at the same time as an evo 2 intake cam. my motor is a fairly mild 2.3, so i chose a unit with high flow cats versus a catless some backpressure was desired. i cant elaborate, but i can say the powerband felt beefier throughout. no loss in low-mid rpm torque whatsoever, but much more up top. i believe the cam helped move the powerband upwards about 500 rpm, while the x-pipe helped a tad everywhere(0-5hp). not the best upgrade for $700, but ive been happy with the drop in weight (75lb? probably not, but it is significant.), and the sound with a borla muffler.

          i suggest considering somehow integrating higher flow cats into a custom exhaust system utilizing the stock cat section. a little more effort and you will see similar gains for much less. again, not sure, but likely under $300.

          i also recommend replacing the afm before any other modification besides a jc chip.

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          • #6
            What is the pipe diameter of the VSR cat system???

            88 M3 - LACHSSILBER/M TECH
            89 M3 - ALPINEWEISS II/SCHWARZ
            85 323I S52 - ALPINEWEISS/SCHWARZ
            91 M TECHNIC TURBO - MACAOBLAU/M TECH


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            • #7
              Originally posted by BijanH
              a muffler will not do much, nor will a header unless you are finishing up your motor. replacing the stock cats with high flow units or a resonator will help much more even when your motor is fairly stock as it is a larger bottleneck.

              i installed the VSR x-pipe at the same time as an evo 2 intake cam. my motor is a fairly mild 2.3, so i chose a unit with high flow cats versus a catless some backpressure was desired. i cant elaborate, but i can say the powerband felt beefier throughout. no loss in low-mid rpm torque whatsoever, but much more up top. i believe the cam helped move the powerband upwards about 500 rpm, while the x-pipe helped a tad everywhere(0-5hp). not the best upgrade for $700, but ive been happy with the drop in weight (75lb? probably not, but it is significant.), and the sound with a borla muffler.

              i suggest considering somehow integrating higher flow cats into a custom exhaust system utilizing the stock cat section. a little more effort and you will see similar gains for much less. again, not sure, but likely under $300.

              i also recommend replacing the afm before any other modification besides a jc chip.
              awesome, thanx. Yea ive heard somewhere that headers arent near as productive as they should be for their cost. So i presume creating custom high flow cats should be my best bet? hmm

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              • #8
                custom high flow cats would be hard

                unless you mean buying a high flow cat and custom mounting it (ie: welding flanges on the ends and bolting in)

                also how can you replace the AFM on the car without a full engine management to replace it with a map sensor?

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                • #9
                  Originally posted by ///Frestyle

                  also how can you replace the AFM on the car without a full engine management to replace it with a map sensor?
                  Could do a MAF conversion, either a custom setup or the SS kit.

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                  • #10
                    correct me if i am wrong...but AFM and MAF are the same (air flow meter , mass air flow sensor).....just different terms


                    anyways....info for the solutions?

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                    • #11
                      i am not a genius on the subject, but i think i can explain a little.

                      AFM = old flapping door mechanism used to measure airflow entering throttle bodies.

                      MAF = heated wire mechanism. better for the reason that.......ugh, it isnt a flapping door mechanism. flapping door is significant bottleneck. especially hindering lowend torque and throttle response.

                      well, when replacing the AFM, there are two choices i know of. MAF, or alpha N maxx (via john, here at s14.net. check the for sale forum), maybe someone else can elaborate, but I will try with these two.

                      -split second has a MAF system you can purchase and install. I am unsure, but think it is around $600. less if used, which you can often find. as far as i know, a bit quirky with aggressive cams. not the best solution for replacing afm, but for $600, or less if used, a great upgrade. + ~12-15hp over entire powerband. s14 finally has noticeable lowend torque, and now better throttle response.

                      -alpha N max kit could recently be had for $850. that includes everything needed to get it running, like the split second kit. i only have the illusion of understanding the basics of how this system works, so i wont try to confuse anybody. there are a few threads on the subject here at s14.net already. all of my knowledge has come from these threads, so you might as well get the information directly rather than having it buffer through my measly mind. gains are better than SS MAF, throttle response also a bit more crisp as NOTHING is hindering airflow. system can be installed alone, or with $ ~1200ish dollar completely badass semi-waste of money carbon fiber airbox. saves a few pounds at best, optimizes airflow for topend power, sounds incredible at WOT, and looks trick. like a few others on this board, i plan on getting the system setup without airbox first. and probably getting that oh so sweet cf airbox later, maybe at the same time as a 48mm throttle body unit. as most of the gains come from the alpha N system, this is most cost effective in my eyes. I prioritize a built head, aggressive cams, TMS j-stock suspension over the fucking dope-ass cf airbox. get most of the gains from the alpha N, look forward to the dopeness.... sounds good to me.

                      heh......

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                      • #12
                        In summary Alhpa-N is DOPE :p

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                        • #13
                          Originally posted by Reelizmpro
                          What is the pipe diameter of the VSR cat system???
                          2.25" or 2.5" OD I think? I cant remember off-hand.
                          Chris L.

                          Spray paint and tire shine doesn't equate to a "restoration!"

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                          • #14
                            yea what i was thinking of was finding the high flow cat/cats itself and then incorporating (with flanges) it into a custom center section...idunno if its possible or the $ it will take cuz i didnt see anything like this in the search i did.

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                            • #15
                              hm for 600-850-1200

                              id be better off installing a haltech engine management .... ive used those in 3 cars ive owned already..... they incorporate new sensors and a new map sensor to measure air..... which means, no more AFM or MAF in the intake tube, but a map sensor on the firewall that reads air from the manifold prssure by vac line

                              around 900 for it...and its a fully customizable fuel and ignition computer

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