Originally Posted by Ketchmi

Greg, I love ya' man but you are pretty far lost in your X-pipe generalization. The factory cats are indeed restrictive but all my dyno testing involved the best set of cats I tested out of about 10 sets. (not the worst like some places do). The gains I posted are verified by hundreds of customers, not just my bragging. You must know at least a little bit about fluid dynamics, I have seen a lot of your work that demonstrates that. A true scavenging crossover with proper inlet and outlet angles and opening dimension really does provide the horsepower that I advertise. By simply moving the opening 1 inch closer to the ports I lost 10hp. My crossover is optimized for power from every aspect, the 2D mandrel bends included.

The catalytic converters I had made for us are 100cpi and are not intended to last 20 years like the factory part. If they were, they would be considerably more expensive along the lines of factory replacment cats. They are dyno proven to lose less than 5hp and usually show 1.5 to 2 horsepower loss. I specified a higher quantity of "wash" on the metallic substrate than the usual cheaper/readily available aftermarket cats. They are not California legal, what is anymore?

All of my advertised results are from same day/dame dyno testing. Usually not even removing the car from the dyno to swap components. Further tuning will certainly improve my stated figures but that is not what I was trying to demonstrate. My gains are from bolt on and go without any hassle.

Every test I advertised was showing the stock output of the cars beforehand with the stock cats and the 85-86' cars all started at approx 245-250 rwhp and the S4's were 265-270 range which is what I have seen hundreds of times with properly running cars, not with wasted/plugged cats or other problems that could be unknowingly repaired by swapping in the crossover. Big's GTS went from 270 to over 300rwhp WITH CATS!

Greg, your opinion is highly valued but please do not disparage other's achievements without firsthand experience. There is a reason most 928 people don't put headers on their cars, the output levels between headers and my crossover is so small that it's not worth the extra hassle.

BTW, many years ago I gutted the cats on one of mine and ran them. It was horribly noisy and lost power. I don't know why and I no longer care but it was firsthand experience, not guessing.

I have a set of Ken's chips and intend to see what they will do with my latest personal driver. If they work well it will save me from sharktuning it until I supercharge it and are well worth the price if they do.

This dyno sheet shows stock cats vs. Louie's X w/cats vs. mine with cats. Both Louie's and mine used the same high flow cats.

Originally Posted by danglerb

Calif can be very fussy on the visual inspection, or not. Fussy regarding cats means they want the CARB EO# and date off the cats and it needs to match the state smog book. The catch right now is the book says up 90 single cat, with 90 first year of dual cats.

For no problems I would keep a factory cat handy.

Originally Posted by PorKen

Of the myriad of programming changes in my S4 chips, the most advanced is new individual cylinder mapping for full throttle which customizes itself (using knock feedback) for each installation. These custom maps, with ~75 RPM divisions, are saved in semi-permanent memory. On top of this, there is adaptation to the highest permissible overall igntion advance level depending on conditions.