At 28" the 100 cell cat maxed out at 512cfm at 28” in the flow path on the cat. The cat has a 3” opening turbo side and a 2.5” muffler side. Reversed, the cat flows more but can not be used that way. The Bypass pipe hit 784cfm but it is for a 76/70 system, not my 63mm system. A 2.50” straight pipe flows 514cfm at 28”.

For reference at 28" my stock ZO6 cat maxed at 482cfm. A BMW M5 secondary cat maxed at 542cfm...BMW M5 primary cat flowed 524cfm at 28”. The Zo6 and M5 have 3” pipes on the cats, inlet and exit. The 100cell HJS will exceed those numbers with the same pipe size. The 2.5” pipe limits the overall flow.

Will test my stock TTS cat in April. If anyone has one laying around, I would pay shipping both ways to test it now.

Thanks

Tom d.

Good stuff o fire and it’s great chatting. Excited to see factory.

I can with the bypass pipe if you want to see the numbers. The cat is so restrictive, it would be the Control Orifice and the numbers would mirror with the muffler.

I really appreciate all of your helpful suggestions. Your expertise is invaluable.

If someone has a factory cat I can flow it now. If not, I’ll have one in April.

If you can increase velocity without increased pressure, yes. Cats create back pressure. On other platform tests they generally cause 5psi of back pressure. What makes this platform very cat sensitive is they are bolted directly to the turbine housing. Mass exhaust flow is trying to move along with tremendous heat expansion. Tough situation.

Disregard the bypass pipe data. Wrong pipe for my 2.50” system is in the box. Measures 3” at the big end and 2.7” at the little end. Will not bolt up to my muffler. Will send it back to Kline , since it is brand new, and reflow the smaller bypass. Apparently the bypass pipe is for the 76/70 Kline , so the flow numbers will be valid for that system. Mine is the 63 or 2.50” Kline. Also noted that the cats are one way flow only. So I edited the first post for accuracy after I went back to the bench again.