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high flow cat

5K views 13 replies 9 participants last post by  Aalto 
#1 ·
i went to a performance shop yesterday and talked to them about a high flow cat for my 08 canyon and they gave me a good price for it(120 bux). then i called my dealership about warranty and they said that if theres any problems caused by the aftermarket cat that it wont be covered at all. is this a risk worth taking? is there a real increase in horsepower at all? i appreciate the advice
 
#2 ·
The stock cat flows very well - it is not a restriction point.

Not worth changing in my opinion.
 
#3 ·
the dealership has to PROVE the cat caused the problem.

if they can't, they are obligated to fix the problem.
 
#4 ·
thats true. alot of people have told me that removing the cat or getting a high flow one will help the air flow and also have a nice sound
 
#5 ·
That's the cat in the header - not the one under the truck.
 
#6 ·
I put a highflow cat in (2nd cat) i didnt see much of a differnce if any in hp gaines,low end,torque, or top end. The only reason i put one in was because my oem 2nd cat blew apart and all the pieces were rattling and what not. But i say dont even worry about putting a highflow cat on put the 120 towards something else the stock one will be fine
 
#8 ·
thanx for the help guys i appreciate it. if you guys got any more ideas on some performance mods then let me know. thnx
 
#9 ·
well.....in xhrcustoms exhaust the highflow cat is well worth it...he has a dyno proven 10hp exhaust...its a 3" exhaust w/ magnflow highflow cat and a magnflow muffler...there is only one highflow cat that makes a difference!
 
#10 ·
i have a magnaflow exhaust and 3" piping right from the muffler and the high flow cat i was looking at is a magnaflow cat. so would u think its work it
 
#11 ·
MagnaFlow HF Metallic Spun Converter C/C 3" - 59959 , if your piping is mandrel bent and done right you should notice a difference!!!
 
#13 ·
tatman said:
i have a magnaflow exhaust and 3" piping right from the muffler and the high flow cat i was looking at is a magnaflow cat. so would u think its work it
Only if you drive the truck over 4500 rpm most of the time. Going to a 3" exhaust is going to cause you to lose low end torque. But most of the exhaust mods don't really do a thing for you, till you get up in revs.

The one thing that compounds the issue of just bolting/welding on, what should be a 'better' exhaust system, is the fact our trucks have variable valve timing.... on the exhaust valves only. So the VVT is more than likely negating a whole bunch of assumed gains from a "performance" exhaust system. I doubt that HPTuners or PCM for less, touch the settings for the VVT.
 
#14 ·
Im seeing if anyone will help me out with a question. I can't seem to find a straight answer anywhere. Anyways I picked up a 05 canyon with a 3.5L engine from my grandpa after my deployment. After the new tires and lift I moved onto the exhaust. Which coming from the north I would just straight piped it, but where I'm stationed now I have to make trips into Cali often. And I'm not trying to get screwed over. So I ended up getting MBRP cat back but it ended up being just alittle louder than the stock. So my question is would a new high flow cat like the (flowmaster 223 series) give me that rumble I'm missing or did I just waste money and should of just did a muffler delete from the start?
 
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