Loss of low-end with free-flowing exhaust and related questions
08-29-2007, 06:27 PM
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Join Date: May 2005
Location: Jersey
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Loss of low-end with free-flowing exhaust and related questions
By getting the piping bent and installed Tuesday, I finally finished my exhaust system for my 1995 240sx:
Obx 4-2-1 Header
Resonator test-pipe
2.5" exhaust piping from resonator --> flowmaster muffler.
It sounds great; really deep and grumbly if a bit loud. (okay, more than a bit), but now having driven it for a day, I've discovered a noticeable loss of low-end torque. My manager (I work at pep boys) says it's too open, and the loss of backpressure has hurt the engine's rev speed at low RPMs.
What might a cost-effective solution to this be? I really don't want to have to replace the exhaust I just invested in. :\
Would getting a stock catalytic converter and swapping that in for the resonator be a good compromise between high-flow power and enough backpressure for low end torque?
A J30 LSD is in the mail, and once that gets installed the next step is to put on a lightweight underdrive pulley and get it tuned (as soon as I find some cheap fuel management). Would it be better just to wait and deal with this low end power loss via the tune? Is that even feasible?
Also, I have a small exhaust leak at the manifold mount: when putting in the header I snapped the frontmost stud of those holding on the exhaust manifold to the engine, and cracked the EGR tube. I sealed and wrapped the EGR tube, but couldn't do much about the front of the manifold. I asked the exhaust shop who bent and fitted the 2.5" piping to check it out for me, but apparently they didn't do anything about it (despite charging me :[). I know I need to get this taken care of. Do I need to get the stud drilled and replaced? Can I just use gasketmaterial to fill the edges around the front of the manifold? Could this be a large contributor to the loss of torque?
I apologize for the litany of questions, but any and all help is appreciated!
I'm too in love with my 240 to slow down my tinkering, haha.
Obx 4-2-1 Header
Resonator test-pipe
2.5" exhaust piping from resonator --> flowmaster muffler.
It sounds great; really deep and grumbly if a bit loud. (okay, more than a bit), but now having driven it for a day, I've discovered a noticeable loss of low-end torque. My manager (I work at pep boys) says it's too open, and the loss of backpressure has hurt the engine's rev speed at low RPMs.
What might a cost-effective solution to this be? I really don't want to have to replace the exhaust I just invested in. :\
Would getting a stock catalytic converter and swapping that in for the resonator be a good compromise between high-flow power and enough backpressure for low end torque?
A J30 LSD is in the mail, and once that gets installed the next step is to put on a lightweight underdrive pulley and get it tuned (as soon as I find some cheap fuel management). Would it be better just to wait and deal with this low end power loss via the tune? Is that even feasible?
Also, I have a small exhaust leak at the manifold mount: when putting in the header I snapped the frontmost stud of those holding on the exhaust manifold to the engine, and cracked the EGR tube. I sealed and wrapped the EGR tube, but couldn't do much about the front of the manifold. I asked the exhaust shop who bent and fitted the 2.5" piping to check it out for me, but apparently they didn't do anything about it (despite charging me :[). I know I need to get this taken care of. Do I need to get the stud drilled and replaced? Can I just use gasketmaterial to fill the edges around the front of the manifold? Could this be a large contributor to the loss of torque?
I apologize for the litany of questions, but any and all help is appreciated!
I'm too in love with my 240 to slow down my tinkering, haha.
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