getting my mandrel exhaust done next week and wondering if a resonator acts as backpressure at all along with making the tone quieter because im nervous about getting 2.5 catback and losing power because my dynamax muffler is only like 12" long i got so if the resonator will help with backpressure i might get a 12 or 18" one. thanks.
you wont lose any power by adding a resonator, you worry WAY too much about miniscule things. a 2.5" exhaust is plenty big and there isnt too much you can do to really restrict it enough to notice a big difference if any at all.
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** Flat Broke Racing Inc.**
im worried about losing power because 2.5 may be too big, wondering would a resonator make me have more backpressure so i can keep/gain some power. thanks again.
backpressure:exhaust velocity :: centrifugal:centripetal
(for the people going
)
Backpressure is to exhaust velocity as centrifugal is to centripetal (centrifugal is fictitious --
it doesn't exist)
Mainly your question is "how do I increase exhaust velocity"
If your exhaust system is properly sized for the amount of exhaust gases being expelled, the resonator won't really change the exhaust velocity.
There was a thread discussing
"is it backpressure or exhaust velocity"
well i know when i got the 2.25 put on like 2 years ago i took it for a spin in the parking lot with no muffler and the thing had no go.
Here's what I've noticed since I put the 2.25 on
Lower RPM - butt dyno says power loss up to 2500 rpm
Above RPM - butt dyno notices gain on my N/A engine
BOOSTED wrote:im worried about losing power because 2.5 may be too big, wondering would a resonator make me have more backpressure so i can keep/gain some power. thanks again.
you wont have any problems with a 2.5" exhaust, its on the big side unless you have some pretty decent mods done but its great for top end power...
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** Flat Broke Racing Inc.**
I know this will get argued but im almost postive that backpressure on any motor is a bad thing.
ugh, boosted i know what you mean.it seems that on these cars that if you just cut the cat off that you'll loose power because.... ding ding ding you have less backpressure to help promote the scavaging effect. Backpressure on a N/A motor is actually pretty good cause it helps with things like this. Some cars don't like backpressure as much as ours do. Like the new hemi trucks, I know that they don't like backpressure much at all, so cutting off the cats helps them more than it's going to help us on our 4cy cars. It's just the nature of the motor. So instead of pulling the next exhaust pulse out of the cyl.(scavaging) you just kinda dump it into the exhaust and let it float on its way.
Are you doing this for a boosted application? If not go out and buy a high flow cat. It'll make the car sound great and help you not loose much powerin your low end. 2.5 is kinda big for n/a thats why i'm thinking your going with boost. if you are just do what you were going to do, if not, just get a high flow, or get 2.25, or just get a res. or you'll prob be a little raspy with such a large diameter exhaust piping.
I just woke up and threw this together so there are many points that someone could pick at and argue with that I didn't feel like filling out cause this is already kinda long.
By his sig, he is boosted. Meaning 2.5 should be ideal.
tampaGT wrote:ugh, boosted i know what you mean.it seems that on these cars that if you just cut the cat off that you'll loose power because.... ding ding ding you have less backpressure to help promote the scavaging effect. Backpressure on a N/A motor is actually pretty good cause it helps with things like this. Some cars don't like backpressure as much as ours do. Like the new hemi trucks, I know that they don't like backpressure much at all, so cutting off the cats helps them more than it's going to help us on our 4cy cars. It's just the nature of the motor. So instead of pulling the next exhaust pulse out of the cyl.(scavaging) you just kinda dump it into the exhaust and let it float on its way.
Are you doing this for a boosted application? If not go out and buy a high flow cat. It'll make the car sound great and help you not loose much powerin your low end. 2.5 is kinda big for n/a thats why i'm thinking your going with boost. if you are just do what you were going to do, if not, just get a high flow, or get 2.25, or just get a res. or you'll prob be a little raspy with such a large diameter exhaust piping.
I just woke up and threw this together so there are many points that someone could pick at and argue with that I didn't feel like filling out cause this is already kinda long.
please stop making jbody folks look like a bunch of retards, you in all honesty should really go back to reading instead of posting and throwing in your
do you honestly have any proof that " on these cars they love backpressure "? because i would sure love to see it... maybe the drinking water is alittle different down where you are or something because around these parts there is proof of some noticable gain from uncapping the exhaust.
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** Flat Broke Racing Inc.**
my car has the po420 (low catalyst efficiency) code. I was considering replacing the cat, should i get one of those high flow cats as well ? are they near the same price as a factory one? I'm not worried about emmisions or anything, i'm also considering an aftermarket header pipe. can you guys advise me on what to get ? thanks.
2001 2 door five speed 122k.
custom steering linkage pop
2000 s10 (THE WORKS)
thanks guys,what exactly is the deal with some people using both 2.25 and 2.5 in their setups? im looking for the best setup i can do with keeping all around power at the same time, ill be going with a hollow cat and a 12" dynamax muffler. I might be getting my downpipe redone as well, i think the pacesetter one is 2.25", so any recommendations on the downpipe size going with the catback will help as well. Also would there be ANY power loss from running duals as oppose to just a single exhaust? thanks again.
we dont loose power when you cut the cat off because of backpressure but rather because your completely @!#$ w/ your AFR's which makes the car run pig rich, which makes the car run limp, which makes it seem slower.
USJDM.....GOT YA B!TCH! wrote:we dont loose power when you cut the cat off because of backpressure but rather because your completely @!#$ w/ your AFR's which makes the car run pig rich, which makes the car run limp, which makes it seem slower.
mines just gutted, so just the shells there
USJDM.....GOT YA B!TCH! wrote:we dont loose power when you cut the cat off because of backpressure but rather because your completely @!#$ w/ your AFR's which makes the car run pig rich, which makes the car run limp, which makes it seem slower.
actually i havent seen one go into "limp" mode yet when removing the cat. and as for the deal with some people using 2.25" and 2.5" exhaust in they're systems imo is thats just what they want, an exhaust system can only flow as good as the restrictions it has. I wouldnt remove the cat. converter completely unless you have HP tuners to disable the codes. as i said the cats dont restrict flow too much unless they're clogged.
Guys your really dragging this thread on about nothing, all of this information is fairly basic and can be found around the org VERY easy.
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** Flat Broke Racing Inc.**
you guys think single 2.25" mandrel bent catback, gutted cat (have on now) with 18" overall length dynomax muffler would gain me some since its not crushed like my current? im leaning more towards this setup after reading posts.
I'd go 2.5" with a header. But that's just what me and my shop would recommend for a supercharger. And even tho it's illegal to even have it hollowed out, I would highly recommend getting your hollowed out cat and having a shop weld a pipe in it. That cat just hollowed out will be the end of your high EGV...it ruins the scaveging effect.
A resonator will not make backpressure but will take out thise ugly high pitched engine sounds. For the most part even a turbo muffler at the end of the pipe make a negligable difference in performance.
A couple of questions you should consider tho. When does the charger begin to make boost? Do you have a performance cam with an intake/exhaust overlap? And finally do you have a header?
The reason I ask is because if you make boost down low(1800rpm or so) then that's your torque the scavenging effect would make a disgustingly low increase. If you have a performance cam with an overlap the supercharger will force some exhaust out when the intake opens so again your scavaging effect is useless. If you have a stock manifold it doesn't really have the best properties for scavenging. That's why headers always yeild an increase.
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'96 Cavalier Good ol' Pushrod 2.2
-24X,000 miles on factory build
-Some oil loss between changes, me thinks it be rings.
i had a custom 2.5" on my N/A engine with headers, stock cat, no resonator, and fartcan. i didnt felt lost of pressure more like backfire i had and ricey sound
.
But all that change
pacesetter w/ 2.25" magnaflow all the way to the back + resonator
do you guys ever find that your tire hits the muffler?
2001 2 door five speed 122k.
custom steering linkage pop
2000 s10 (THE WORKS)
