Project Lexus IS-F Part 2: We test the PTS – Joe Z Series Exhaust

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The siamesed X pipe is one of the PTS/Joe Z exhaust’s biggest secrets, helping it produce a wide powerband.  The siamesed X pipe helps low end torque and droning, and actually somewhat helps top end as well.  The siamesed merge has a lot less restriction than a X cross merge.  We have had really good luck with this sort of merge on previous project cars over the traditional H pipe.

Joe Z is a dedicated Lexus owner who noticed the lack of parts for the brand and set out on a mission to design and bring to market several parts for various Lexus models, one of them being the IS-F.  We discovered Joe Z on a frustrating search to find a performance exhaust for our car.  We had been stumped, none of the usual players in the exhaust market made anything to our liking and we were about to design and build our own exhaust system which probably would not have done MotoIQ readers much good.

The PTS – Joe Z exhaust has lots of small features indicating good workmanship.  The flanges are hand match ported.

While scanning Lexus forums, we found posts about the PTS – Joe Z Series exhaust and when viewing pictures in the threads, we noted that the exhaust was much like something we would design ourselves.  So we tracked Joe Z down and obtained a sample exhaust to test.  The exhaust came with Joe Z himself who made himself available to observe our test, help us with our install and answer any questions.

0.250″ Thick laser cut stainless flanges enssure a warp and leak free service life with no corrosion.

To get ready for the exhaust install and to answer questions that IS-F forum members had about our prior K&N intake test we once again went to our partner shop Techosquare and once again strapped Project IS-F to their Superflow chassis dyno.  As we stated before, the Superflow is much more conservative that the typical Dynoject dyno so our numbers are lower that what is commonly reported for the IS-F.  The important thing is to not look at the numbers but the change in power that the parts add.

Nice tig welding done by hand is also a sign of good craftsmanship.

The K&N cold air intake has a reputation on the IS-F forums for “dialing back the power” after some miles have been put on it.  Some have reported a good gain only to have the car supposedly return to stock power levels after some driving.  We drove our car for more than 500 miles and several tanks of fuel before redynoing the intake.  500 miles is more than enough to trip any short or long term trim changes in the ECU.  So the first part of the test was to check to see if our car had lost power.

To see our original test of the K&N intake click here!