Test pipe = 5whp vs. MIL.SPEC 100 cell high flow cat

I have no idea where the PERRIN core is sourced from, so I can't comment on that. I will say that I have seen Chinese sourced cores blow out. Certain companies mysteriously discontinued their use of metal core cats after awhile...

Also, raw fuel in the exhaust will ruin catalysts...regardless if it's a ceramic or metallic core. So, if you were REALLY rich that could be the problem.

While nothing is bulletproof 100% of the time, I will say I have seen the MIL.SPEC 100 cell cats stand up to on-track abuse at Redline Time Attack and other places.

And yes, our cores are 100% made in

For a closer view of a 100 cell compared to a 300 cell unit here ya go (significantly less restriction with the 100 cell):



BTW, I have OVER 30,000 miles on my MIL.SPEC cat and last time I took the 100 cell off my car the core looked brand new.

26k miles running the perrin HFC, no issues.

Erik can you explain the diameter difference?

Those just happen to be different housings on each core. The housings we use are different than both of the ones pictured. IIRC, the one on the left is a 2.5" opening and the one on the right is a 2.5" cut open to around a 3". The core pictured on the left is the same one we use, and the one pictured in Roberto's exhaust earlier in this thread.

Let me know if all that made sense

Just tracked my car yesterday after I installed my Mil.Spec 100 cell and Trust TI-R cat-back. Not trying to sound like a know it all but I highly recommend a 100 cell if your going to get a HFC. I improved my 1/4 mile time by 3/10 of a second and trapped 5 mph higher.

Or you can do what Homer Simpson does just put a piece of electrical tape over the SES light, works like a charm.

Pure awesomeness

If you're ever caught at a light behind an evo running rich and without a cat, you'll notice how strong the poisonous gas is. I was stuck at a light behind two cars without a cat and i almost died..


Anyways I've had my Perrin for about 20K now without any issues either.

haha yeah your bad man test pipe or bust

I have the Perrin HFC threw a cataylst effiency code the first like 80 miles, cleared it came back on. So I contacted them and they sent me a CEL fix where it pushes the o2 sensor out but guess what came back? Then i tried contacting them and they said they would replace it but guess what he never talked to me again. I tried phone, e-mail, and AIM and no response. I will end up getting the Mil.spec

ya i j have the perrin hfc to ond threw a cel right away, i have just learned to live with it

What happens if you throw a different code, and don't know it due to the SES light being on already?

The mil.spec should pass inspection correct? Is it much louder than the stock cat? Any other recommendations for a HFC?

I bought my car with a perrin tbe , and It was throwing a SES light so I ended up doing the non-fouler mod, and I was reading this and I took out the cat, and it looked like a major restriction. I could barely see light threw it. Took alittle more work than I thought it was gonna. Ended up using a combo of drill, hammer, socket extensions and flipped socket(worked beautifully), and my favorite a crowbar. It is now a test pipe

I could feel a difference on the butt dyno, and it's just slightly louder.