100 cell high flow cats

bcfromfl

I'm still shopping for a car to put this all in, but I thought I'd buttoned up my parts list for mods. Based upon some of the discussion in this thread: Cats with Superchargers I thought the general consensus was that HFCs properly broken in...or at the upper end of the spectrum, mil spec cats, would stand up to FI. I don't want a lot of noise from under the car...no drone...and no stink.

But now this:
OK, so what do those of us who don't want to make our ears bleed or annoy the neighbors do?

redondoaveb

From what I was told, you want to keep them downstream from the factory location so they aren't subjected to the extreme heat exiting the header pipe under boost. Fast Intentions places them right before the x pipe on their lead pipes. A lot of people run theirs with forced induction. Notice the Z1's are in the factory location.

Jayhovah

And are also much cheaper cats. There are plenty of FI cars out there running cats... I think you are on the right track welding in the milspec's.

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redondoaveb

Yeah, I think so too. I understand Mil Spec and GESI are both good cats.

JSur

I had AAM HFC on for over 20k miles at 500+whp and they held up. I switched to resonated downpipes and looking to unload them if interested


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redondoaveb

I've got the mil spec cats on order otherwise I probably would take you up on your offer.

bcfromfl

Could someone point me to a diagram or something that describes this modified placement a little better? I'm having a little trouble visualizing it.

redondoaveb

Here's what the fast intentions lead pipes look like with the mil spec cats. Custom mod would look the same.

WTT Fast Intentions Lead Pipes SoCal

bcfromfl

Thanks for the link -- it helps a bit. I was thinking it would be necessary to find a custom shop with a mandrel machine, and big $$$$. But Fast Intentions sells the components to make this work with fitting a pair of HFCs further downstream? Any issues with bumping against the undercarriage?

I'm shopping for a late-model Nismo. Would this be compatible with the stock muffler in terms of fitment and/or reliability?

redondoaveb

Fast Intentions sells the lead pipes with cats but I believe they will only sell that section to customers that have already installed their cbe. They don't sell individual components as far as I know. I doubt there is any clearance issues. I'm not sure about compatibility, someone else may have a better idea. I already have a fast intentions cbe system. All that I need to do is cut off a section of the lead pipes and have the new cats welded in. Pretty simple.

bcfromfl

This is where I stumble a bit. The times I used to have to go to muffler shops years and years ago when I lived in upstate NY (because of all the salt on the roads), plus the times I changed my own exhaust parts (or trying to diagnose leaks) inching around on a garage floor on my back, taught me that this is an area of the car: 1) that I don't want to deal with, and, 2) requires exact-fitting parts. I once ordered a cbe for a car I owned from a company that insisted it was designed for my car, and lived with it banging against the frame for a couple of years in one spot, and the muffler hanging much too low in another...only to find out that they had sent me the wrong part.

When you say, cut off a section of lead pipe and weld in new cats, I wonder, what happens to the flanges that are supposed to mate together...precisely? I see on various websites that these Z-specific parts are often tig-welded, which is far beyond what is done in muffler shops -- they just use oxy-acetylene torches. If parts are welded instead of mated/bolted...especially if it's in a location not supported by hangars...you run the risk of cracking said weld down the road.

Jayhovah

I think you're overthinking it. The 100cel cats are small.. the shop will just cut out a section of pipe and tack the cat in place while the exhaust is still on the car, then take out the pipe for finish welding. It should fit fine when they are done... they literally do stuff like this every day.

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2013 Gun Metallic Sport - Gamma V3 Twin Turbogized
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bcfromfl

Thanks for that. The other thing I'm wondering, is if you move the cat back, it won't be able to reach operating temps, no? Florida isn't one of those states that tests, but this would be a major headache for those states that do. Plus, even with the 100-cel cats, you'd probably have stink to tolerate if they don't get hot enough.

You're right...I'm overthinking...

Chuck33079

The reason to move them back is to get them out of the way of the much higher temps that the cats would see in a FI application. Moving them downstream will still be hot enough for them to light off. These work very well. This isn't something to have an issue over.

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