I blew my warranty and all I got... by random84

6 minute(s) of a 15 minute read

Factory exhaust with cat delete sounds horrible. As others have noted, it makes a tinny, "ping" sound and there are bad harmonics in the 2k range. 

It makes headers and resonators an easy decision (the 15 psi helps). I am thinking ahead to this summer and heat management.

2-23-2015

I said I wouldn't do it - but I ordered ARH 1 7/8 headers today... with catalytic

converters! The metallic pinging, resonance and gurgling was enough after 2 days... lol. It might be premature but I am already getting wiffs of sulfur in the cabin; summer will only be worse so I talked myself into the cats. ARH says they're good for 1000 HP however I know there have been other experiences here; with my DD style I have my fingers crossed. 

I wanted to use SwainTech coating but after the receptionist said "we're trying to get things through within 3.5 weeks..." I didn't want to wait that long to pay twice as much and then wind up having issues w/ getting them installed in the middle of busy season. I opted for Calico instead although I know it's a less effective thermal barrier (at half the cost). 

And... 22" magnaflow

resonators should help turn this into a TriTexan-worthy build. 

It will be interesting to see how much I get from the exhaust change now that I'm sticking w/ hi-flow cats... Hopefully 15-20 WHP but we'll see!

2-23-2015

All of these (calico, jet hot, etc) are imho pretty much the same. It's more or less the same stuff I put on my firearms but I'm paying for the labor... Youll notice there is virtually no comparative data on the major brands to help you outside of straight advertising (Swaintech being the exception). 

ALL have isolated cases of failure or cracking - including swaintech. Expansion and contraction and oil coated (used) headers are common issues. All will help, Swaintech probably helps the most. 

There will inevitably be differences in prep, but the only "legit" thermal coating is likely Swaintech. Even it has durability issues and can/will crack. As I mentioned, it would take a month or more for then and they were not interested in my business when I called (they're busy) - so I opted for a lesser performing product at less cost with a faster turn-around. 

I looked at my application and my goals, and made a judgment call on what was the most important for me. YMMV.

I did not want to sacrifice low end TQ for little to no gain in top end HP. there appears to be no real benefit to 2" primaries on our cars (nor do the factory mufflers seem to be a restriction). 

The rule of thumb is they are not ideal until ~800+ HP

depending on who you talk to.

2-24-2015

I'm going to cross-post this here, as it's good info and makes me more confident about my choice:

I called American Racing

and the technician told me their hi-flow converter (200 cell) was actually changed/improved last year, and is rated for 2800 degrees (!), or ~800 RWHP. He stated "15-20psi" as an appropriate boost range, obviously relating to the 2800* EGT figure. Appropriately, he heavily emphasized the importance of a good tune to avoid dumping excess fuel into the exhaust - as we know a sure-fire way to kill converters. ARH basically told me if there was every an issue, they will take care of it, and that although they used to have several issues with some Ford products (ha), he's had only 2-3 with the CTSV line. Again, HP loss was estimated to be negligible, or in the 2-3 RWHP range.

I also called Kooks, the technician mentioned that both their hi-flow AND the "Green" cats are 300 cell units, although they recommend the Green on anyone running more than 10psi (the standard cat is not rated for more than 10psi). Interestingly, the tech/salesman did not know why this was, as both variants are stainless steel, 300 cell, etc but the Green Cat has more precious metals in it (obviously for higher emissions efficiency, which was the point of that product line); he basically implied that their recommendation was based solely on empirical evidence of "some guys" having problems with the regular hi-flow unit. The tech did not say specifically, but TriTexan was told less than 7-8 RWHP for Green Cats by another rep as he mentioned in his Exhaust thread.

From my perspective, the ARH technician was more confident in discussing the details of his product, but I'll just say it's possible you'll get slightly different answers if you happen to speak to a different rep from either company - I didn't get the impression there are hard and fast rules here (outside of the 2800* EGTs for ARH and the 10psi limit for Kooks).

So yeah, there are a few differences between brands and the "hi-flow" cats are definitely NOT the same. It sounds like ARH's updated product is more similar in "rating" to the Kook's Green Cat, and power loss is likely negligible in both cases relative to running no cats at all. After all, there was a 5 RWHP difference between my baseline pulls 30 seconds apart!

I read thought a lot of "headers" threads here and elsewhere, and IIRC RubberDuck also posted a ton of math mentioning it. I won't ever argue with a great shop like Vengence, but sometimes people just have their own preference and that's it. Heck, my tuner wouldn't even use the plugs I provided (which everyone here loves) for whatever reason.

ETA: 

The Duck generally recommends 1 7/8":

But Matt likes 2" headers and did some dyno comparisons:

575-625 RWHP?!

But Matt also notes:

LS7 heads with V blower, adaptor question...paging Duck?

So it looks like it boils back down to six of one or a half-dozen of the other! Given I'm not racing, and on the street, I "rounded down" and the 1 7/8" should have no real loss, outside of a few peak HP.