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N/A engines require back pressure to maintain low down torque and throttle response. you may not have issues seeing you are retaining the stock engine pipe and cat but it is a possibillity.

we actually reduced my exhaust down from 3" to 2,1/2" back to 3" behind the collectors to create back pressure.

how would i loose power??

Volumetric Efficiency. A 3" Catback will make more top-end power. A 2.5" catback will be the best balance between the low end and top end, and provide good driveability on the street.

Think of a straw. If the straws too small it won't take much to get the drink through the straw, but you'll be limiting the flow. Too big a straw and it takes more effort to fill the straw and get the drink through.

In the end it's going to come down to whether you want outright top end power, or more useable power.

I'm not sure what diameter the R33 GTSt exhaust is from factory, but remember that it's not going to be a high flow mandrel bend system with a straight through muffler. So you may well get a good balance of low-end and top-end with a GTSt exhaust. I myself really don't know though.

thanks for your help guys

but before i go and buy this exhaust i wanna see if it will bolt on first

its a apexi exhaust from the cat back

its from a series 2 r33 gtst and i want to put it on my series 1 gts n/a

any one done this before??

thanks

Oh so not a GTSt Stock Exhaust then... more than likely a 3" Mandrel Bend catback system. So unless you like revving it right out each gear, don't expect more performance in the bottom end, rather a loss of performance and an increase in top end. Too large an exhaust on an N/A will have a tendency to be quite loud as well.

Oh so not a GTSt Stock Exhaust then... more than likely a 3" Mandrel Bend catback system. So unless you like revving it right out each gear, don't expect more performance in the bottom end, rather a loss of performance and an increase in top end. Too large an exhaust on an N/A will have a tendency to be quite loud as well.

yeh i relised that

but it will fit onto my n/a r33?

yes it will be a direct bolt on undoubtedly. Apexi make there exhaust system to be a direct bolt on and from the picture out of the mechanics book they are all the same fittings as r33 GTS's so no problems there.

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