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Exhaust back pressure

2Bad

By 2Bad,
in General Automotive Discussion

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2Bad Newbie

2Bad

Posted
Posted

I took a stock R33 GTST for a test drive and the guy said it was "quicker" than a lot of them with 3" exhausts, how I took him to mean it was that it was more responsive and had more low down torque, therefore seeming "quicker" if you don't rev the crap out of it. Does the 3" reduce back pressure so much that it affects low down torque? Would a 2.5" be a more suitable choice for a near stocker? I can't seem to find any exhaust FAQs in the search forum, does anyone know where to find some good posts if this topic has been already covered?

At what point of modification does it make the 3" worthwhile (a certain kw, psi, or level of mod?) I want a daily driver that is still responsive down low.

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sewid Grand Master

sewid

Posted
Posted

The stock exhaust is 2.5".

A 3" or larger exhaust is usually the first step in any modification process. The mantra "get the air out before you get the air in" should be followed.

I drove my stock exhaust R33 GTST around for months. I then changed the dump pipe, front pipe and cat convertor to 3" high flow items. I noticed an increase in low down torque immediately but nothing really up high.

I drove that for months.

A week ago I completed the exhaust with a custom 3" system to a 3" inlet muffler with twin 2" outlets.

I noticed no real increase in low torque but a definate increase in top end.

In short. It's very worthwhile.

Plus the exhaust note makes the car such a pleasure to drive now and its also a lot smoother to drive when coming off throttle now. A very marked improvement.

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