Celica Forums Install Guides and Technical Articles Information and Articles Exhaust Facts And Misunderstandings

Since I'm really starting to get sick of all these damn exhaust threads asking the same thing and getting the same answers that in most case's are wrong i figured i would make this

1. Back pressure is BS most stock exhaust systems don't even have 1 psi of pressure in them.

2. If you would like to go for a dual exhaust go for it the only way it will hurt performance is weight and if you made it a dual exhaust from the header back (2 cats 2 pipes all the way back) and only reason that hurts performance is because heat.

3. "A 2.5 inch exhaust is bad and can hurt the engine." Wrong. You could go to a damn 5 inch exhaust but there will be a performance decrease because the exhaust gas's flow better when they're hot (cold air is more dense). On non-aspirated, 2.5 inch is perfectly fine.

4. "Mufflers make HP." Wrong. Mufflers don't "make" HP. For pure gains, the best muffler is no muffler.

5. "Turbo exhaust is hotter.". Wrong again. Exhaust temperature is raised/lowered by timing air/fuel ratio and spark. The turbo hanging off the header doesn't make a difference on exhaust temperature.

if you have a celica, there's no reason for a dual exhaust, whether it's a Y pipe with two tips, or a "true" dual system. BTW, there is no WAY you can put a true dual system on a celica.
a) It's a 4 cylender car. it doesn't need it.
b) there's no room under the car to run two pipes anyway. the best you could do is run one pipe in the stock location and run a Y pipe from the axle back. Even then, it's pointless for the motor.It won't help power gains at all. The only way I'd put dual tips on my celica is for show only.

just my two cents.

for anyone that knows about a celica dual exhaust is pointless and harmful to performance due to the weight of the extra piping

i said header not headers which would indicate a y pipe and what i said apparently wasn't clear enough for you
i said dual after the header (with a y) would hurt performance.
now as for axle back there will be a performance gain cause its still letting the gas flow smoother

i never said it needed it i said if you want to do it go for it as long as its axle back there will be some performance boost (over the stock system)

if someone wanted to run a duel setup after the header they would find away the TRD super doesn't fit the GTS but people found a way to mount it

i will be willing to walk down take the stock exhaust back of my car and weigh it then compare it to the weight of a 3 feet of pipe or hell even my tshm compared to a couple feet of pipe

2 feet of 2.5 inch piping from my old ramcharger weighs around 4 pounds so lets say you need 4 feet thats 8 pounds anyone who has handeld an exhaust knows that no aftermarket exhaust weighs less then that

except of course the titainum one which is like 7 pounds

my tshm is a hair over 20 on same scale

i think its listed as 21

tshm on same scale was a hair over 20 ( listed as 21 i belive)

ok. dual system after the header is not possible on the celica. it would involve ridiculous amounts of money to change the underside of the car to be able to handle that much piping. if you look under the car, ther is room for a 3" pipe (more or less) after the cat. if you wanted to put a Y pipe around the axle area, there's room for that, and i'm sure that's been done before. but neither will help performance.
the best exhaust for the celica n/a is probably a 2 1/2" system with a high flow cat and a decent muffler.

Best muffler is no muffler - agreed. but, not street legal.

There is no reason for dual exhaust on a Celica - also agreed. Dual exhaust on a 4-banger is gay, IMHO. But, it does fit the "looks fast" image that freakin' Toyota gave to the poor Celica. (Those idiots at the ad agency that came up with the slogan need to be shot.)

so that means its impossable ? no like i said it may take a lot of money but if someone wanted to do it they could

nothing is imposasble with the right anoutn of money

(ultimate celica 500hp awd ? thought that was impossable)

and what about the kazuma exhaust it has the higest gains of any exhaust and has no muffler (well a resonter but thats the size of a coke can)

so perhapse having a turbo on the end of your header and nothing attached to it and no tuning done to your car would not create higher exhaust temperatures. but since a turbo changes air fuel ratio and usually spark as well when you tune it correctly wouldn't having a turbo hooked up to your car and actually doing what it's supposed to do cause a change in exhaust temperature? I suppose a supercharger would do the same thing so it wouldn't be limited to turbos.

btw has anyone ever heard of those turbos you can mount to your tailpipe? I saw them put on on a camaro instead of going right on the end of the header it goes closer to where the muffler is and then pipes inlet air ducts up to the front it also acts as a muffler and completely replaces it so you don't need one anymore. don't remember who made them, but wonder if this method would be easier in making a custom turbo setup since you don't need turbo headers and you don't really need to figure out how to fit it all under the hood since it'll be sitting where the muffler is. The only difficulty I see is running the air inlet pipe back up to the engine.

for most turbo kits they keep the a/f ratio pretty rich so the temp shouldn't change much but on higher hp applications when your trying to squeeze the last drop of power out they will lean the a/f ratio out a lil more so the exhaust gets hotter so that it flows better (hot air is less dense)


as for the turbo some place other then the header yes i have seen them (my friend is getting one for his camaro ss) they don't go all the way back to the exhaust but they will mount them down usally right before where the cats are cause the engine compartments are so tight it makes it hard to mount a single turbo in a "normal location" cause all the pipeing that would have to be done to get headers to fit in there

the turbo pretty much goes where the downpipe would be on a normal turbo car

like this?

http://www.imagestation.com/album/?id=2683195093

For 4-cylinder cars you have to have some form of backpressure from the exhaust to make torque. Torque is what will get you moving from a stop. Getting rid of mufflers and going big pipes, will always result in net HP gains, but you'll lose the all valuable torque. For a streetable car, you need both HP & Torque, so its very important that you build something that give you a good balance of both.

with the celica this isnt exactly true. I run no muffler at all and I gained hp and torque. I actually put down more torque then just about anyone else N/A. right now I'm at 136wtq and thats including people with the same mods and more mods.

turbo exhaust is hotter... especially if you've been driving hard...

go look at EGT from a turbo car and an NA car...

^^ it was my understanding that turbo exhaust is hotter as well. don't feel like arguing it because i dont know the specifics of it...thats just the way i learned it.

yes turbo exhausts are hotter but its becuase of the tuning of them find a dybo shet that shows the a/f ratio along with the egt and you will see that when the ratio leans the egt will raise

thats why they have a egt usally cause its a good sign that something is going wrong in the fuel system

taken from www.overboost.com [overboost.com]
"A lot of the time, you'll hear someone talking about how much hotter the exhaust system on a turbo car gets than a naturally aspirated car. Well, if you are catching my drift so far, you'll know that this is a bunch of BS. The temperature of exhaust gas is controlled by air/fuel mixture, spark, and cam timing. Not the turbo hanging off the exhaust manifold.

When designing an exhaust system, turbocharged engines follow the same rules as naturally aspirated engines. About the only difference is that the turbo engine will require quite a bit less silencing. "

^^ well really, but the thing is...when you force a lot mor air into a previously n/a car with a turbo and obviously get fuel management to force more fuel into the increased air supply..the result is more burning.

kind of hard to have a turbo system that doesnt do that. no one's saying "it's only the turbo that makes all the heat"..its the result of having a properly working turbo

i could go out side now tune the pfc to run extreme lean and get higher egt temps then msot street turbos and the raito is still the same doesn't matter if its stock na with one pound of air and one pound of gas or a 2 bar turbo with 30 pounds of air and 30 pounds of gas

I hear what your saying, but what about this... isn't the power band then totally different? If you dyno'd your car with no exhaust, compared to a bone stock car, don't you have a huge dip in torque from idle to like say 4500rpm? But then maybe you get more peak torque and/or stronger band after 4500rpm? So then for a streetable daily driver, your car would be a total slouch in city traffic? That is why I think you need to have a respectable/usable power band for a daily driver/streetable car. Race cars, don't really care about low-end, so that's why they run with open exhausts, as they want maximum power/torque at the high rpms. So then choosing the right exhaust, does become a factor right?Because some people don't want to lose all there low-end completely. Correct me if I'm wrong there.

i wont mind since i want my car to be a 1/4 mile car then in high rpms it will be a beast

is having a straight pipe better than just taking off your muffler assembly at the axle? Figure if you want to have a daily driver and go to the track once in a while you can just unbolt the muffler at the track.




PS You can't have HP without torque since horsepower is a mathematlical product of torque. torque * RPM/5300 = HP.

i unbolt at the axel and it works for me jsut don't idel too long with out moving fumes ge to be a pain


and its LOUD

i'm getting to old for this, but ignorance is contagious!
1) back preasure is is really bs delta preasure or delta flow is everything
specify which one you are refering to dude. the more back preasure you have the less hp you make you can go to a bigger exhaust to lose the back preasure but too big messes with delta flow.

2)dual exhaust is not only heavy but because the crosssectional area of the two pipes combined gives a bigger overal pipe diameter it also messes with delta flow/preasure hurts performance. you can through that 5" exhaust out the door.!
and heat in the exhaust hurts performance? i wonder why i spent a whole lot of money buying 1/8th by 2.5" wide exhaust wrap to wrap my headers and kazuma? its to retain the heat in the exhaust we go back to delta flow/preasure
(i think you should look up delta preasure/flow)
3)you said it right down here, exhaust gases do flow better when they are hot. the 5" pipe would allow the gases to expand to quickly thus reducing delta flow.

4)mufflers do make hp and torque. it depends on the rpm band if the gases are allowed to exit into the atmosphere too quickly the scavenging effect is reduced. remember some vehicles are exceptions egs turbo charged vehicles cause the exhaust comes after the turbo.
5)i wonder if you ever seen the manifold or a turbo charger itself glow red hot! do you have a egt? well, i used to be into drag racing big time and egts were standard cause sometimes the exhaust would be soo loud if the motor detonated you would not hear it.but! you can see the egt sky rocket and as you back off to save the motor you would see it drop back. having seen countless egt( while sitting in the drivers seat dude) i can tell you that forced induction esp turbo charged vehicles run a much higher exuast temp. esp when its being milked for every drop of hp!

tell me what you think is the normal temp range for 95 rx7 twin turbo stock booost and a 95 supra stock boost. you would be surprised at the diffrence and they are both turbocharged. take the manifolds from a na car and put them on a rx7 and they would melt or crack in no time.
any way dont fuss,do some more research on exhausts.
later.

98% of the delta flow is formed at the header thats why we hace preformacce headeres and whys theres such a diffrence in power compared to 4 to 1 and 4 2 1
axel back duel does not weigh more i jsut weighd the pipe if you read the other post its lighter and as i said before 98% of delta is thorugh headers
i think you should go back and read my post and see that i said heat is nesscary for flow because dense air is harder to move

so far half of your post is useless cause you didn't read
thats not the exhaust making power it doesnt make power it will give you a lil more power due to flow but it doesn't make power like f/i would

yes i have seen them glow i have also seen n/a headers glow my bike headers will glow if i run it hard cause it was jetted lean and you say in there how you milk every last drop out read some of my posts i say in this it specifcaly says "for most turbo kits they keep the a/f ratio pretty rich so the temp shouldn't change much but on higher hp applications when your trying to squeeze the last drop of power out they will lean the a/f ratio out a lil more so the exhaust gets hotter so that it flows better (hot air is less dense)"
and what happens on a open atmospere bov when you let off the gas ? the maf still thinks theres 20 pounds of boost coming in so it runs really rich would prove my point again


maybe you should do some research and learn how to read the replys in a post casue 4 of 5 questions were already anwnsered

You know as far as dual exhausts hurting performance so do 18" wheels but people like the look. Im all for some dual exhaust setups cause i like the way they look.

except dual exhausts on a car that doesn't NEED it or has no BENEFIT from it is very pointless
doesn't look great at all.

good thread, people do need to learn about exhaust setups.
next we need a thread all about the available exhausts on the market that are good, as well as intakes
cause there is a thread bout them everyday. then the thread would have reviews in it only.

thats not the exhaust making power it doesnt make power it will give you a lil more power due to flow but it doesn't make power like f/i would


i think you are missing the point of my comments: its very important when you make statements about performance that you be as specific as possible.

a lot of guys on these sites dont have a lot of track experience esp. when it comes to the performance and tuning of motors.

you said that an exhaust dont make power i can say that a turbo charger dont make power either! it doesnt matter the amt of air that you have if it doesnt have the FUEL no more power will be made as far as combustion is concerned.

you said you have a bike, i used to race bikes as well (another life ago)and i know the importance and performance advantages of a good exhaust on bikes. all i'm saying if you are giving advice try to be more factually specific because the recipien of such might take it, "set it in stone and run with it"
peace

Does anyone know how the inside of a stock Celica exhaust look like?

To make 2 dual exhaust (left - right) it maybe a idea to connect the second pipe directly to the Muffler instead to use a Y connection.

Andres

does the extra 5lbs of weight from a dual exhaust really matter? NO it doesnt, so that shouldn't be a factor

??

so wat would be the best exhaust setup for a celi? im talkin to a shop and im thinkin of goin with a catback str8 2.5" pipe (mandrel bends)magnaflow resonator and not sure of the muffler yet, how good would that be? wat would be better performance wise?

my only question is a n00b one:

i say the only thing the resonator on a kazuma (or any other exhaust for that matter) is strictly for sound purposed, right?

someone said it's also for performance. is this so? if so, can someone explain it to me? i don't see the point of it. i want kazuma but i also want to cut off the dumb resonator because i think it sounds dumb.

its jsut there for sound doesn't really effect the sound too much make sit kinda higher pitch usally (with out it)

im just worried about db limits around here..i don't feel like getting pulled over for my exhaust even though my celica isn't a daily driver..so i can keep it off the roads for the most part.

the thing is..the kazuma exhaust is louder than a stock exhaust unbolted before the muffler. without the muffler, the car is pretty loud, but it's still under or right at db limits. kazuma puts it well over the db limits so i want to take the resonator out of kazuma and hopefully have the car sound something like stock without the muffler...probably a futile attempt since the intake/header i already have should push the sound up..but i could use any help i can get i guess

with out putting some type of muffler in the kazuma it will never be legal the resonater it does haveis soo small its pretty much useless taking it out will prolly increase sound by 1 db


do what i do
have a muffler shop cut out the stock resonater on the celi thats before the muffler then buy an exhaust (i have a tshm which i smodified to remover the muffler only thing on it is the tip) so when i want to be loud and have crazy lift i jsut bolt on that exhaust but if i wanna be able to actually drive around with my ear drums intact i can put the stock back on takes 20 minutes in driveway don't even need to jack up the car well i don't


cause belive me when i had the muffler off and didn't have the resonater in it was loud like too damn loud

i was hoping that cutting the resonator out would lower db...i don't want it to be screaming every time i drive..but i do want a true cat-back exhaust. apexi does make some nice ho-flow mufflers..might have to check them out but i was hoping to do without a muffler all together and still be right at or just under db limits

dual exhaust setup on a celica doesnt look that good in my opinion

well, since this is the all inclusive exhaust thread, i'll ask my question here. i've heard that a turbo car (i'm gonna turbo my car come summer) that isn't pushing more than 250-300 or so hp can work reliably with only a 2.5" exhaust. does that mean that i can get an aftermarket cat-back now and have no problems come summer?

its not a question of reliabilty

2.5 inch will be fine of course 3 inch is better but on low boost 2.5 inch is fine

since there is no true catback exhaust other then the kazuma you will ahve to do some moding like i did with mine which was jsut have the exhaust replaced after the cat
but with a exhaust you should be fine

so i can get, say, a TPR or Greddy EVO 2 and run it now, then come turbo just replace the bit of pipe between the aftermarket exhaust and the cat?

Thats what I'm wonderin. Will a "hi-flo" cat help if you have EVOII catback?Anyone?

on a n/a car a highflow cat won't really add much like 1 hp tops .. now if your cat before was all clogged up and you put a high flow on then it might feel like more but it really isn't

yea, a high-flow isnt gonna gain you much. but still..for about $40 shipped for 1 whp, thats not bad..not including installation

someone suggested i copy & paste this:



there was a post by somebody that acted like they knew what they were talking about. he said that an exhuast doesn't provide more horsepower. most exhuast makers show that there's not much gain. you don't really get an exhuast for horsepower. you really just get it for sound, unless you have forced induction. if you have forced induction it will help b/c you get your exhaust out quicker. you may gain a few if you get the headers all the way back.








Member: 21109 - Registered: 02/24/05 - Posts: 79 - From: Corner, Al



forums^ topics^ page top^
Speed4TheNeed
Caleb

= Online! =
Re: EXHAUST question
Posted: 03/20/05 08:22 AM Edit Reply Quote Q-Reply


^^ that statement is false.

what is true is that exhausts really don't 'make' horsepower. the engine obviously makes ALL the power. but there are a lot of things (like exhausts) that take away horsepower. that's why the difference between bhp (the factory rating of the engine at the flywheel) and whp (the horsepower you are actually putting out) is usually at least 13% loss in a manual. (my gts is rated at 180 bhp from the factory, but i only actually have around 160 whp--actual horsepower...which is a loss of around 20 horsepower).

yada yada yada..the purpose of the exhaust system is to remove waste gasses from the engine. the engine produces these waste exhaust gases in 'pulses' (it's not one continuous stream..think of a heartbeat where your blood is 'pulsed' with every beat of your heart. same with the engine.) to get these exhaust pulses out with MINIMAL gain, they need to be flowing consistently right behind each other...which in effect the previous exhaust pulse 'pulls' the next exhaust pulse along and so on and so forth. when running at a low rpm, your engine pushes out small pulses and produces them relativly slow. at mid rpms, your engine increases the size of the pulses (more air entering the intake means more air exiting through the exhaust) and produces them faster. at high rpm's the trend stays the same..the exhaust pulses are even bigger and produced even faster.

this is where the exhaust piping diameter plays a role. toyota realizes that MOST people use their celica as 'daily drivers'. what this means is that most people who buy our cars usually stay in the low-to-mid rpm range while driving. SO, toyota made their exhaust to realize this fact..which means the exhaust piping diameter is rather small to compensate for the relatively small exhaust pulses that aren't produced very fast.

however, if you're a daily driver you probably aren't on this site OR interested in daily driving much. most tuners or motorheads do their driving in the mid-to-high rpm range. because of this higher rpm range, the exhaust pulses are bigger and produced faster...so the small exhaust piping diameter of the stock exhaust becomes restrictive. so what most aftermarket performance manufacturer's do is INCREASE the exhaust piping diameter so the bigger (and faster) exhaust pulses won't be restricted. for our celicas, the best piping diameter size for 'enthusiast driving' happens to be around 2.3" - 2.4"..which is what almost all our aftermarket exhausts are.

for those of you who are interested in high rpm driving (drag, pro-street), you should get an even bigger exhaust than the 'enthusiast driving' exhausts i just mentioned. an exhaust diameter of about 2.5" - 2.6" would give you maxium gains in the high rpm driving range, but you will lose some down low.

why would you lose some down low? because like i was saying earlier at lower rpm's the exhaust pulses are smaller and produced more slowly. what this means is that when you use a big exhaust pipe diameter (such as 2.5"+), these smaller pulses do not 'fill up' the pipe completely and instead 'bounce' around. this creates backpressure because the exhaust pulses are not 'pulling' each other out as they should. and while i'm on backpressure, just let me state:

contrary to popular beleif, BACKPRESSURE IS NOT GOOD ANY WAY YOU SPLICE IT. IT'S NOT GOOD FOR TORQUE, IT'S NOT GOOD FOR HORSEPOWER. IT'S ONLY GOOD FOR MAKING YOU LOSE POWER. .

the myth of backpressure was created by people who bolted on a regular 2.3" enthusiast exhaust and saw gains. then they bolted on a 3" exhaust and saw a loss of power. "well, the 3" exhasut obviously has less backpressure than a 2.3" exhaust so the loss in power must mean some backpressure is good". NOT. the reason they lost power is becasue the exhaust pulses were bouncing around in the 3" exhaust CREATING backpressure instead of flowing along smoothly.

so in conclusion: realize what driving style you do mostly and pick the appropriate exhaust. for most of the people on this site that would be 'enthusiast driving' so get an exhaust around 2.3" - 2.4" in that case. if, however you decide all you really want is to go from point A to point B, then just leave the stock exhaust on. add a resonator/muffler if all you want is a sound difference. if you occasionally take your car to a drag strip, then i would suggest just unbolting your exhaust from the axle-back instead of buyinger a bigger diameter exhaust system.

sorry for the long post, but this was needed to educate a lot of the people here. this probably should be stickied cause i dont wanna have to keep saying this, but anyway

i was about to say " i basically said all that" but then i noticed it was an old post jsut added on so its all good

yea, i guess it's 'old' --i tyed it up yesterday or somethin

but yea, that was basically said already, just went a little bit more in depth

Very interesting and informative long post there Speed4TheNeed.