GS-R Header Question

[anthonyb5s4]

I plan on upgrading my exhaust setup in my gsr soon right now I have dc sports 4-2-1 headers everything else is stock

I found a decent exhaust system 60mm (2.36") that I plan on getting I also have a first gen skunk2 intake manifold port matched to a 65mm throttle body I will be installing along with a set of 2001 ITR cams and valve Springs I'm also running on a Obd2a p73 itr ecu to keep my car emissions compliant so plan on getting a high flow cat as well

My main issue is all the 4-1 headers I find have a 2.5" collector will that cause bottle necking in the exhaust since it's 2.36" or will it be fine also would i get a hi flow cat that matches the collector or exhaust diameter

[anthonyb5s4]

Not looking to make a crazy amount of power obviously just want something a Lil more power in the high end

I also plan on getting a hondata s300 and getting a decent Street tune on 93 octane since it's my daily that I plan on bringing to auto Cross events from time to time

[shooktd]

I plan on upgrading my exhaust setup in my gsr soon right now I have dc sports 4-2-1 headers everything else is stock

I found a decent exhaust system 60mm (2.36") that I plan on getting I also have a first gen skunk2 intake manifold port matched to a 65mm throttle body I will be installing along with a set of 2001 ITR cams and valve Springs I'm also running on a Obd2a p73 itr ecu to keep my car emissions compliant so plan on getting a high flow cat as well

My main issue is all the 4-1 headers I find have a 2.5" collector will that cause bottle necking in the exhaust since it's 2.36" or will it be fine also would i get a hi flow cat that matches the collector or exhaust diameter

The restriction starts at the collector, anything smaller than the collector will cause restriction. That much of a difference in size between the collector and exhaust on a stock gsr/type r wouldn't be anything noticeable power or torque wise, unless you plan on getting a tune. I ran a jdm itr heading 4-1 with a 2.5 inch collector and went to a 2-1/4 hks hi power. The car ran great, made 167whp and 113 trq un-tuned with skunk2 68mm intake manifold, 70mm sk2 throttle body and Aem SR intake. 3 inch will always make the best power. Even on a stock motor, as long as its tuned.

[anthonyb5s4]

The restriction starts at the collector, anything smaller than the collector will cause restriction. That much of a difference in size between the collector and exhaust on a stock gsr/type r wouldn't be anything noticeable power or torque wise, unless you plan on getting a tune. I ran a jdm itr heading 4-1 with a 2.5 inch collector and went to a 2-1/4 hks hi power. The car ran great, made 167whp and 113 trq un-tuned with skunk2 68mm intake manifold, 70mm sk2 throttle body and Aem SR intake. 3 inch will always make the best power. Even on a stock motor, as long as its tuned.

I do plan on getting a tune but nothing extreme just a basic setup I'm trying to break 170whp also should I run a 2.5" 2.36" hi flow cat

[lowcruzinteg4]

I do plan on getting a tune but nothing extreme just a basic setup I'm trying to break 170whp also should I run a 2.5" 2.36" hi flow cat

my buddy did a little over 170whp with no tune, stock bottom end, he did flat face valves shaved the head upgraded springs and stock cams,skunk 2 intake mani and stock tb with a short ram intake, 4 2 1 try y headers adjustable fpr bumped up the pressure a bit and a 2.75 exhaust