i heard that without the backpressure, a NA 4 cylinder car will lose out on torque
has anyone experienced this?

 

I have. Its noticeable, but I think the slight increase in hp is worth it. Either way, torque and hp have their own benefits.

 

No you shouldn't loose torque just due to more effecient air/exhuast flow.... if that theory were correct then I could partially block my exhaust pipe and get more torque? The only thing about headers is if you notice there is 4-2-1 or 4-1 setups and one style is better for mid range and actually increases torque and one helps out on the top end a little better....

 

well, im talking about low end torque
even in the game Gran Turismo 3, when you get an exhaust system that is too freeflowing on a small 4 cylinder engine, you will lose out on bottom end torque, but you will gain more horsepower

 

which header is better suited for low end torque? 4-2-1 or 4-1?
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In many cases 4-1 headers are designed for racing applications where the vehicle is being driven at or near redline. The 4-1 design maximizes top end power, whereas the 4-2-1 evenly distributes it throughout the power band. There are cases where a 4-1 header works better than a 4-2-1 and creates more power in the mid or higher RPM ranges, but a 4-2-1 header will undoubtedly boost the horsepower of your car.


anyone here with a 2.5 inch catback exhaust pipe?
i think that a 2.5 inch should be good for a 4 cylinder, right?
its not too big, but it also allows the gases to pass through well

 

I got the 2.5 inch catback. If it's working well for me without restricting my engine, then it should work well for just about any street legal application

 

In most cases you want to go with an exhaust thats 2.25 max for a N/A car. One with a turbo you'll need 2.5 and bigger.

 

the catback that im planning to get is from megan racing and its 2.5 piping, but its for NA cars
i guess its good?

 

I would say 2.5 is really maxing it out. Im sure its fine, but I like my 2.25.