Sikky Lexus ISF Headers – 1 7/8″ 304 Stainless Steel

Our previous header made great power and was no slouch but we knew there was more to be had.  This desire to make the best header lead us through an exhausting year and a half of R&D.  With the aid of our modern design and testing equipment we started from scratch.  After a couple prototypes and several hundred dyno runs we started to close in on our final design.  This process is exhausting but a must in order to achieve our goals.  After loads of testing and tweaks with different configurations, we determined that the 1 ¾” primaries we and the other header manufacturers were using for the ISF and RCF were in fact too small.  1 7/8” was the magic number for tube diameter.  As a result of  increasing primary diameter we expected to see the gains up top and thought maybe we would lose some low end.   To our surprise we found gains across the entire rpm range including low end with the most notable at high and mid rpms.   Even more power was unlocked by changing the length of our primaries, as well as collector size and configuration.  To ensure we had it right we completed back to back to back runs with these different prototypes and even with competitors headers.   A stats comparison to our original headers as well as our competitor’s headers made it very clear we had reached our first goal.   Obtaining the highest power gain for any header tested on the ISF and RCF.

Next, focusing on perfect fitment that would eliminate any rubbing or contact with the chassis or other components.  Using a CNC pipe bender, we were able to design and build the header to utilize all single piece tubes except for one runner.  Improving strength and reliability and ensuring maximum air flow through the tubes.

Making this header is the best it could be required spending the extra time on the little details.   This header will stand the test of time because we constructed it entirely from stainless steel components and tig welded for strength.  Little details like our cnc machined groove in the collector flange ensure the gasket and leaks will not be a problem.  Smooth and flat head flanges mate perfectly with the cylinder head utilizing the OEM gasket.  The way they look you could display on your mantle but we would prefer they get used as intended turning your ISF or RCF into a beast.

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Header Installation