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Catts or no catts on supercharger power upgrade, & other opinions needed please
My 2004 ZO6 has a procharger. I am installing a BTR blower cam, springs, pushrods, smaller blower pulley, around a 3.4 as procharger recommended.which should put me at around 10 to 12.5 PSI, Boost a pump, And 60 or 80# injectors. I have had several people say GET RID OF THE CATTS. That they rob HP, and the supercharger does not like the restriction. Any help from, you blower guys would be great. Also not sure about, what size, 60 or 80# injectors.
Any input would be great.
Last edited by bada; 10-30-2018 at 08:21 PM.
Reason: .
In all honesty if it's a pair of 3" high flow metallic cats, the effects are probably minimal on power. If it's a lower end / not performance oriented cat, then I could see some issues from all the excessive heat, unburned fuel thru the exhaust (cam), all of which could lead to early cat failure, so you might as well just not run them. You see some extreme dynos on this, but those cars usually are making huge power where the cats are a significant restriction or the cats were plugged up and something else was going on.
For many it's a weekend fun or track car, so the choice of removing the cats makes sense, one less thing to worry about and I am in that boat as well. If I was driving the car a lot or the smell really bothered me, then I would consider installing high quality cats and running them. Also I think the statement of "superchargers dont like the restriction" really applies more to turbos- where no cats is pretty much always better in all ways.
As for the fuel stuff.... Are you running the stock fuel pump and a BAP or do you have some sort of external pump also? If so, is it a boost referenced FPR, and what are your power goals or expected power after these mods?
My 2004 ZO6 has a procharger. I am installing a BTR blower cam, springs, pushrods, smaller blower pulley, around a 3.4 as procharger recommended.which should put me at around 10 to 12.5 PSI, Boost a pump, And 60 or 80# injectors. I have had several people say GET RID OF THE CATTS. That they rob HP, and the supercharger does not like the restriction. Any help from, you blower guys would be great. Also not sure about, what size, 60 or 80# injectors.
Any input would be great.
I have AR long tubes with Cats along with a Novi 2000. Believe my injectors are 60, and at 6psi, we are just shy of 600 to the wheels. The tuner said cats, not me so obviously he wasn't worried about hp loss. I also have an 04Z
Last edited by Dave concrete; 10-31-2018 at 07:30 PM.
In all honesty if it's a pair of 3" high flow metallic cats, the effects are probably minimal on power. If it's a lower end / not performance oriented cat, then I could see some issues from all the excessive heat, unburned fuel thru the exhaust (cam), all of which could lead to early cat failure, so you might as well just not run them. You see some extreme dynos on this, but those cars usually are making huge power where the cats are a significant restriction or the cats were plugged up and something else was going on.
For many it's a weekend fun or track car, so the choice of removing the cats makes sense, one less thing to worry about and I am in that boat as well. If I was driving the car a lot or the smell really bothered me, then I would consider installing high quality cats and running them. Also I think the statement of "superchargers dont like the restriction" really applies more to turbos- where no cats is pretty much always better in all ways.
As for the fuel stuff.... Are you running the stock fuel pump and a BAP or do you have some sort of external pump also? If so, is it a boost referenced FPR, and what are your power goals or expected power after these mods?
We are getting ready to do bigger injectors and a boost a pump. The shop is going to do all the work. And they have not said anything about the external pump as of now. But that may change. Super tuner. He has done my three previous vettes, and my LS7 truck. As far as the FPR, I do not know what his plans are. I would like to get around 600 to 650 RWHP, with meth if possible. The headers are kooks long tubes. So I would think, the catts are kooks as well. The guy I bought the car from did all the work up till now. So I am stepping it up some.
I have a late 03Z so we have the same C6 style fuel system. 650whp I think you'll be pushing the limits of the stock pump with a BAP and meth... kind of depends on how much methanol you're running too. With our cars you have to drop the tanks, so swapping pumps is a of labor, but a walbro 450 will go in pretty easy.
Sounds like your fuel pressure regulator won't be boost referenced.... I would get the 80 lbers to be safe, 60 might work but you'll be right at the limit. I would definitely ask your tuner on this one as he may have his own thoughts or preferences.
I have a goal of ~650 and I put in a walbro 450, will have a BAP just in case, and will be running 80 lb injectors. My tuner said no driveability issues or big tradeoff vs 60s, so getting the 80s was a no brainer to me.
Ditch the cats, they will eventually clog, remember, with FI , the afr needs to be kept on the rich
side, most tuners do this to protect and keep the engine cooler , I removed mine as they clogged
in less than 2 seasons, so I drilled them out, if you have no emissions test we’re you live, that’s
what I’d be doing ...
Last edited by LedfootLarry; 11-01-2018 at 12:31 PM.
I like cats. I know I could make more power without them (especially with turbos) but my car is a daily driver and I won't put up with the smell of catless exhaust.
I am a little wary of putting metallic cats on FI cars, though. Seems that the high temperature and high flow can damage the thin metal substrate and cause it to slide down the pipe and/or start folding over. Here are some pictures from other threads on this forum from people who had that exact thing happen to them:
If it's just a weekend/fun car, I would get rid of the cats as long as the smell doesn't bother you too much. Otherwise, I would run the biggest ceramic cats that will fit. They are not sexy, but they will knock down the nasty smells and they seem to be the most durable choice.
Interesting note on the metallic cats. I have used magnaflow high flow metallic cats on multiple high boost/high EGT turbo cars and never had an issue and they always looked great when removed. Magnaflow markets the metallic as the highest temp product vs the ceramic... unless something has changed since I last looked.
I don't have any first-hand knowledge about the cars these came off, or the brand/mileage/etc. but I could look up the threads that the pictures came from; I just had them handy because I'd sent them to a friend recently who was debating metallic vs. ceramic for his car. I don't mean to come off as fear-mongering; this is second-hand, anecdotal evidence, but it appears that in addition to the heat, the exhaust velocity from high-HP cars causes more problems. If any of the cells are not perfectly straight or the core is not solidly attached to the case, the thin metal edges can start to fold over, then the force on the substrate increases, and seems to result in a chain reaction that quickly clogs the cat.
I have seen melted and cracked ceramic substrates too, but those failures usually seem to be the result of a bad tune or some kind of impact respectively.
Ditch the cats, they will eventually clog, remember, with FI , the afr needs to be kept on the rich
side, most tuners do this to protect and keep the engine cooler , I removed mine as they clogged
in less than 2 seasons, so I drilled them out, if you have no emissions test we’re you live, that’s
what I’d be doing ...
Then any reason the same extremely popular tuner who installed my blower as well installed the AR long tubes WITH cats did so. In fact did so knowing my state doesn't sniff. I asked, he said whatever one you want, I would do cats, the power loss is peanuts, but the risk could be great. Cats will be 11 years old this coming summer.
Last edited by Dave concrete; 11-01-2018 at 06:26 PM.
Well that’s great news Dave,and all anyone can really comment here is on there own personal experience with these .
I installed C6 Z 3” American racing cats, x- pipe , and mufflers on my car , and they clogged in just over 1 year, go figure !
Well that’s great news Dave,and all anyone can really comment here is on there own personal experience with these .
I installed C6 Z 3” American racing cats, x- pipe , and mufflers on my car , and they clogged in just over 1 year, go figure !
just as easy to install dummy cats to pass a visual
I was thinking about just gutting the cats. Do you guys think, that would be as good as running the off road pipe? All they would be at that point. Is just cosmetic for the emissions people. I really think, that would be as fast, as the off road pipe.
As far as tuning goes, the only time the car needs to be tuned slightly richer is under full throttle, where most drivers don't spend most of their time driving.
Under part throttle and cruise, the car should be tuned on the leaner side and run close to stock AFR's, which should make the cats last quite a bit longer.
My car was getting 29 mpg on the highway at cruise speeds with bigger injectors, turbos, etc.
I think you would be fine with a high flow cat on the car, and they WILL keep your clothes (and car) smelling much nicer.
Last edited by vrybad; 11-03-2018 at 10:07 AM.
Reason: Clarification.
10-30-2018, 06:52 PM
Catts or no catts on supercharger power upgrade, & other opinions needed please
