poppy exhaust
ok so i was wondering, would not having a middle muffler/cat cause popping exhaust when you decelerate?
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thats always there, not having those just makes it more appearant
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yes its possible and the larger the pipe ad less back pressure the more apparent and the louder it will be.
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and thats why i think stock hondas with 3" exhaust sound like fart cans because the have to much exhaust with no need this loss of back pressure will cause a loss in torque which the already have a lack of. haha
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i was just wondering if it helped because todays the first day i drove the car with the windows down and its kinda poppy, not backfiring though, and the middle/cat is gone.
glasspack yay or ney on the helping? i'm not going glasspack alone |
you should get a real exhaust made up. 2.5 inch with your choice of muffler. and if you need to pass emmiions some type of CAT
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^^^^ do what he said but get mandrel bent be careful bc alot of shops do crush.
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i was lucky enough that a local TUFFY beleive it or not had a mandrel bender and an amazing welder they borrow from the city. he's a bit pompous but did good work. and it only cost me 150 bucks for teh exhaust to be made and 20 for the muffler a shop special.... basically, i made out like a fiend!!! i just wish it was a more oval muffler and less canister style.
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ya deff. go with 2.5 mandrel bent at the largest, unless u have a turbo car cause then in that case u dont really need back pressure.. no matter what try to get madrel bends. what i did was got a performance cat the is flow through and the catalist is on the outer edge of the inside of the cat. but if you go to big you will lose to much back pressure and by doing tht you will lose some torque
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2.5 is decent with turbo, or atleast any ammount of turboing i may do in the future, its already 2.5, the previous owner did open up the exhaust and lickily its over 20 years old so i dont have to pass emmissions.
i was thinkin of getting a decent muffler, like a tanabe medallion G ("93db" performance muffler) but something to get the old chogy poppy sound out and have a nice humm |
At least you don't backfire with mean flames like I do ;)
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ive backfired with a flame about 2 times now... on my turbo car though. lol.
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haha, unburnt fuel......i had that happen:)
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i hate my current exhaust and i lose alot of low end, its 3.5 inch o2 elbow back and it sounds like ass.
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Originally Posted by teenbmxer
But if you go to big you will lose to much back pressure and by doing tht you will lose some torque.
And thats why i think stock hondas with 3" exhaust sound like fart cans because the have to much exhaust with no need this loss of back pressure will cause a loss in torque which the already have a lack of. haha First off, backpressure is bad and every measure should be taken to reduce it. I think that you are confusing backpressure with exhaust velocity. The goal of a performance exhaust system is to achieve the highest possible exhaust velocity and reducing as much backpressure as possible. I have posted some links that go into more detail. Enjoy. Destroying a myth Backpressure: The Myth and Why It’s Wrong The Mighty Backpressure Myth |
Originally Posted by Z33Driver
Oh, the dreaded backpressure myth. I don't think this myth will ever die. My fellow Z friends lend me your…eyes as I try to show you the light.
First off, backpressure is bad and every measure should be taken to reduce it. I think that you are confusing backpressure with exhaust velocity. The goal of a performance exhaust system is to achieve the highest possible exhaust velocity and reducing as much backpressure as possible. I have posted some links that go into more detail. Enjoy. Destroying a myth Backpressure: The Myth and Why It’s Wrong The Mighty Backpressure Myth |
Snwbrderphat540 did you read through any of the links?
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well, none of them do good explanations, the first one is vague and covers nothing but saying a lean mixture burns valves, its crap. the next two are honda forums so i just automatically skipped them. im finding mine.
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theres a reason running open heads will kill power, but please lets not go into header designs and header tuning.
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Just because they were on Honda forums doesn't mean they are worthless. You should at least read them before dismissing the information.
I understand why you say, "to little you DO loose low end torque". For example, you install a 3 inch exhaust on an N/A car, have a dyno done before and after and notice that you lost some low end power. You know that bigger piping will reduce backpressure, so you make the conclusion that reduced backpressure will decrease low end power. (reasonable argument) But that's not the whole story. If you re-examine that dyno you will notice that although your low end power suffered you will have more power up top. The reason for this is exhaust velocity. The larger piping will allow a higher exhaust velocity in the upper RMPs leading to more peak power. However, the larger piping is too large to maintain exhaust velocity in the lower RPMs. This is why smaller piping provides more power in the lower RPMs. Backpressure defined from Dictionary.com Backpressure:A resistant pressure exerted by liquid or gas against the forward motion or flow of an exhaust or pipe system. Residual pressure opposing the free flow of a gas or liquid, as in a pipe or an exhaust system. |
i mixed facts with other facts to create new "facts" from the thread i was thinking of. sorry.... but in essence i was right, in how i delivered it, i was wrong.
https://www.zdriver.com/forums/showt...t=backpressure also, i have a problem with this velocity term, because velocity will yield a back pressure reading the faster it is because that shows it has the pressure behind it to create it. and yet they complain about not having velocity. and that last thread is to ****ing long. im not reading that crap |
Originally Posted by snwbrderphat540
i mixed facts with other facts to create new "facts" from the thread i was thinking of. sorry.... but in essence i was right, in how i delivered it, i was wrong.
Originally Posted by snwbrderphat540
also, i have a problem with this velocity term, because velocity will yield a back pressure reading the faster it is because that shows it has the pressure behind it to create it.
Originally Posted by snwbrderphat540
and that last thread is to ****ing long. im not reading that crap
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Headers Explained - Part 1
Here's another explanation of backpressure from a different thread on this forum
Originally Posted by lww
Much controversy (and apparent confusion) surround the issue of exhaust "back-pressure". Many performance-minded people who are otherwise well-enlightened still cling tenaciously to the old cliché.... "You need some back-pressure for best performance."
For virtually all high performance purposes, backpressure in an exhaust system increases engine-pumping losses and decreases available engine power. It is true that some engines are mechanically tuned to "X" amount of backpressure and can show a loss of low-end torque when that backpressure is reduced. It is also true that the same engine that lost low-end torque with reduced back-pressure can be mechanically re-tuned to show an increase of low-end torque with the same reduction of back-pressure. More importantly, maximum mid-to-high RPM power will be achieved with the lowest possible backpressure. Period! |
"maximum mid-to-high RPM power will be achieved with the lowest possible backpressure. Period!"
now i dont know about you, but i like my power down low. considering that most z motors make peak power at 6kRPM but also look at a bikes exhaust system, they have a flapper that controls back pressure, what does that tell you? |
The flapper that you are referring to is an attempt to maintain the highest amount of exhaust velocity as possible, not to increase backpressure. Making an exhaust is difficult because you usually have to sacrifice low end power or top end power. Using a flapper or some kind of vavle can help to achieve both low and high end power. The goal is exhaust velocity, not backpressure.
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