The Full Bolt on SR20 Engine, Part One, The Basics

The inlet flange is thick stainless tig welded to the cast body.  Look at the nice high-volume smooth transition.  The is going to flow much better than stock and the aftermarket housing that came on the car.

The housing transitions to a big 3″ exit, also with a thick warp and leak-resisting flange.  Like the exhaust manifold, the welds are hand-finished internally for less flow restriction.

The cast main body has these clearance channels to make room for fasteners and tools.  It is good that ISR thought this part out well!  If you have messed with T25 O2 sensor housings you know how it can be a bitch to tighten these nuts and how the studs can get hung up.

We were also very impressed with the quality of ISR’s downpipe.  It is constructed of tig welded stainless steel, all built in one piece out of a single mandrel bend.

Like everything else, the ISR downpipe has thick flanges.  The downpipe smoothly necks up in one piece from 3″ to 80mm for more flow just past the flange.


    1. What we wanted was inexpensive, simple and the ability to combine with any lash up of OEM and aftermarket parts to make this a pure bolt on with no fabrication needed. We know about Artec stuff, it just doesnt meet any of those criteria.

  1. Hey Mike!

    Great information!

    Question. If you were to choose between the GEN 2 GTX, 2860r or 2867r for this build, what is your pic?

    Thanks! D

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