Personally, I like cats. Those little furry things r fun to play with. I got one but when I play with him too much he claws my hand bad. He's fun though and meows a lot. I think u should get some cats. Cats over no cats ftw!
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quote:
ORIGINAL: basketballord
http://www.superchevy.com/technical/engines_drivetrain/exhaust/0505phr_exh/ Scroll down to "Headers -- Primary Pipe Diameters" "Big pipes flow more, so is bigger better? Answer: absolutely not." Same goes for the cats/no cats argument I would think - there is an optimal level of exhaust flow...too much flow = no scavenging, too little = too much back pressure and decreased performance. Taking the cats off would be too much flow for a non - f/i V6, at least that's how I see it.
http://www.superchevy.com/technical/engines_drivetrain/exhaust/0505phr_exh/ Scroll down to "Headers -- Primary Pipe Diameters" "Big pipes flow more, so is bigger better? Answer: absolutely not." Same goes for the cats/no cats argument I would think - there is an optimal level of exhaust flow...too much flow = no scavenging, too little = too much back pressure and decreased performance. Taking the cats off would be too much flow for a non - f/i V6, at least that's how I see it.
exactly.....thats been basically my whole point.
I'm confused then Sancho. I thought you were saying backpressure was all bad, but I was saying that you need some backpressure for exhaust scavenging.
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thats right.....backpressure is bad but some will exist nonetheless. i'm agreeeing about the point that there is an optimal level of exhaust flow: close to zero backpressure and maximum exit exhaust velocity. how does backpressure create scavenging when its bringing exhaust gas back to the cylinder? only good thing that could do is bring fresh air/fuel back into the cylinder during the valve overalap but that would also bring exhuast gases back in and contaminate. i'm sure all these negative things will happen at some degree but keeping them to a minimum will result in better effeciency.
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haha....yeah, i'm done with it. anybody can research it and figure it out like i have. makes sense one you understand the whole backpressure concept. i see that pypes sells some high flow cats. anybody have em?
Yea my friend got pulled over a month back and the cop was a complete jerk.. gave him a speeding ticket... bent over and looked under the car (no cats). wrote him a huge ticket. not worth it IMO.
Am I the only one on here that questions this police officers qualifications to look under the car for the converters? The converters are best seen from looking under the hood. They are not located in the conventional location, as a single, big, flat muffler looking part located somewhere between the duals coming from the engine and the pipes coming out the back. Not everyone knows what they are looking at. I'm throwing the BS flag on that one!
I have long tubes and no cats. My car runs 14.13. Long tubes make power, taking the cats off make it sound like crap between 2500 and 3000RPM. Unless you are coming after me, don't do it.
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quote:
ORIGINAL: boss 244
I have long tubes and no cats. My car runs 14.13. Long tubes make power, taking the cats off make it sound like crap between 2500 and 3000RPM. Unless you are coming after me, don't do it.
so the long tubes compensate for the adsence of cats?
how does backpressure create scavenging when its bringing exhaust gas back to the cylinder?
Backpressure will not push exhaust back into the cylinder. That has been my point all along. Your timing would have to be out of whack to do that. When the piston is on the downstroke pulling in the air fuel mixture the exhaust valves are CLOSED.
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quote:
ORIGINAL: Wickerbill
quote:
how does backpressure create scavenging when its bringing exhaust gas back to the cylinder?
Backpressure will not push exhaust back into the cylinder. That has been my point all along. Your timing would have to be out of whack to do that. When the piston is on the downstroke pulling in the air fuel mixture the exhaust valves are CLOSED.
so there is ZERO overlap between the two valves? just wondering.
so there is ZERO overlap between the two valves? just wondering.
Pretty much correct, there is split overlap, but that is the point where the piston is at top and the engine will turn ever so slightly before that piston starts a downstroke. Even on split overlap the valves, both intake and exhaust, will be closed. The vaccum im talking about is created by the exhaust leaving the manifold. It doesnt pull exhaust into the cylinder as that cannot happen. The exhaust leaving the pipes will acutally help pull the exhuast through the porting of the head out the manifold. The exhaust valve opens and the piston comes up to push out the used gases then closes the exhaust valve, then the piston stalls for just a milli second(split overlap both valves closed) b4 coming on the downstroke with the intake valve open to pull in air/fuel mixture.
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" I'm so sick of all this talk about money....money, money,money......all I want to do is play the game, drink pepsi, and wear Reebok."
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Joined: 10/11/2005 From: Southern California Status: offline
quote:
ORIGINAL: Wickerbill
quote:
so there is ZERO overlap between the two valves? just wondering.
Pretty much correct, there is split overlap, but that is the point where the piston is at top and the engine will turn ever so slightly before that piston starts a downstroke. Even on split overlap the valves, both intake and exhaust, will be closed. The vaccum im talking about is created by the exhaust leaving the manifold. It doesnt pull exhaust into the cylinder as that cannot happen. The exhaust leaving the pipes will acutally help pull the exhuast through the porting of the head out the manifold. The exhaust valve opens and the piston comes up to push out the used gases then closes the exhaust valve, then the piston stalls for just a milli second(split overlap both valves closed) b4 coming on the downstroke with the intake valve open to pull in air/fuel mixture.
does this go for every new engine out there? our 4.0 for example?
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RE: CATS or NO CATS? - 
