Standard corolla exhaust piping size

[Cougs]

I havent had time to go to the exhaust shop to get this checked out, but some riceboy told me he got an aftermarket muffler fitted only, because the 1ZZ-FE corolla had 2.25" piping (he wasn't specific)

Is that true? I thought cars like Type R's come with 2", and standard corollas would come with 1.5"-1.75" piping

Can anyone provide me with some insight? thanks :)

[trd_141]

Cougs i can help you out bro

I have a mate at an exhaust place in box hill

good price and doesnt bu**s*T around

he is the real deal

if you want i can go down with you and we can chat with him

[grimlock]

yeah the piping is smaller than 2inch for sure.

Hey buy my exhaust please? are you in sydney

The stock, system doesn't even have a high flow cat, and the bending is press, so you have lots of restriction.

The sportivo on the other hand is mandrel bent.

[trd_141]

the standard rolla doesnt have enough power output for justify a high flow cat

[grimlock]

yeah it does, stick a CAI, the rolla should have at least 80KWs at the wheel.

Pretty good.

[shaohaok]

like most mods for NA, a high-flow cat prolly doesn't give a significant gain on its own. but if u have done other mods to it, that might complement it and actually compound the gains of the next mod. bearing in mind that the effects of backpressure and scavangeing should be balanced for a good power/torque delivery.

[DANZZT231]

I too have a full exhaust system in plan. According to XtigerX who used to have Levin, he installed Hurricane headers and Lukey cat back, power was about 85kw at the wheel.

So Cougs, wanna look together?

[Cougs]

I too have a full exhaust system in plan. According to XtigerX who used to have Levin, he installed Hurricane headers and Lukey cat back, power was about 85kw at the wheel.

So Cougs, wanna look together?

thanks for the replies guys... so no one knows if it's stock 2.25"? I seriously doubt it anywayz

thanks for the offer TRD_141, might take you up on that

and Danz... yer let's go to box hill exhaust? I'm a bit busy atm... but see how we go :P

btw Danz is your plates SAU xxx? (sorry am I allowed to post that?)

If that was you, I drove behind you down Burke Road yesterday (friday night), but I turned off into the Monash Freeway

[DANZZT231]

To cougs

I knew it was someone from this forum when i saw that exclusive logo. Yes it was me, man how bad was the traffic?!!!

[DANZZT231]

And yeah i remember the 1zz piping is 1.75, very tiny. Grimlock. sounds like 1zz respond well to exhaust tuning. Right now I only got free flowing type muffler, do u think if i increase the size to 2.25 and stick in header would guarantee a leap in power while still using this free flow type muffler?

For hi flow cat, according to this shop i went to, there is no need for it. I will check again.

[kcorro]

for reference the corolla sportivo muffler size is

inlet 2 inches

outlet tip 3 1/4 inches

barrel width 300 mm

barrel length 350 mm

[DANZZT231]

OK, here's what this exhaust shop told me. Being an N/A u still need some back pressure, if the exhaust system is too big, then it will overkill. Old stuff.

So I ask what happen if i still want to use my free-flow muffler? is 2.25' too big? He said I will better off with 2' if i still want to keep my free-flowing muffler. If I want 2.25 the muffler gotta go and swap into reverse type. No need for hi flow cat too, this is what the other exh shop told me aswell.

As for headers, well that is damn hard to find but on Monday, hopefully, the exh shop can find me Hurricane headers.

Another thing the exhaust shop told me, mandrel bent is not needed if you're only getting 2' to 2.25'. For turbo, you will want to opt for mandrel bent.

Another idea I had in mind is to copy Sportivo exh system size. But I knew 2.25' is a bit too big for 1.8 engine.

[shaohaok]

Grab a drink, this is a biggie..

During the combustion process, when the exhaust valve is open, all of the compressed (and depeleted) air-fuel mixture spills out from the cylinders as fast as it can, through your exhaust manifold, into your catalytic converter(s), the muffler, and finally out the tail pipe. The problem with this is, just before your exhaust valve is about to close again, your intake valve opens up, allowing the fresh air-fuel mixture to rush into the cylinders. This is called overlap, and one of the things you take into consideration when choosing a cam, because it can be used to your advantage.

If there was no valve overlap, it would be 100% impossible to completely irradicate all of the spent gases from the cylinder. This has a two-fold effect on power output, depending on what RPM the motor is running at. At low RPM, this effect actually increases torque, because the least amount of compression is lost during the intake stroke, and the ratio of intake to exhaust gases is high. Unfortunately, as the RPMs increase, there is increasingly less time to evacuate the exhaust gases during the exhaust stroke, and more and more depleted air-fuel remains in the cylinders when the exhaust valve closes. The motor becomes incredibly inefficient near its readline. A motor designed for high-torque applications, such as towing, tends to exhibit less valve overlap then normal. The type of cam used in this application is often called an "RV" cam, because a recreational vehicle doesn't need horsepower as much as it needs low-end torque to get it moving.

Your car would also run terribly if there was too much valve overlap as well. When exhaust gases rush out of the cylinder, they create a low pressure area in the cylinder and the exhaust system, sucking the intake charge right into the cylinder, and right back out into the exhaust system. This is called scavenging. When that air spills out, so does the fuel it was carrying, so the O2 sensor reports a rich condition to the computer, often causing further decreases in the amount of fuel the computer injects. At low RPMs, this effect is most pronounced as there is sufficient time to suck out a significant portion of the intake charge, reducing torque. As the RPMs increase, however, the extra velocity imparted to the intake charge increases the amount that squeezes into the cylinder after the exhaust valve closes, as the valve closes so quickly at high RPMs that barely any intake charge escapes through the exhaust system.

No doubt you see the dilemna posed to designers when they choose a cam for the motor - the right combination of power must be achieved at the intended RPM range of the vehicle - if this is a tiny four cylinder, which must spin high RPM to make any power at all, you have to design in a higher amount of overlap. If the vehicle is mostly intended for low speed towing, you design in a smaller amount of overlap for more low-end grunt.

You can't control your overlap without changing the cams, but the effects caused by changing the back pressure are the same. When you reduce back pressure, it is equivalent to increasing valve overlap, and when you increase back pressure, it is the same as decreasing the amount of valve overlap. That's why some people will say, "you need a muffler for torque", or, "you'll have more high-end, but less torque, if you run straight exhaust". They are right, but a muffler's purpose is to reduce sound output, not horsepower! By reducing back pressure in an exhaust system, you increase high-end horsepower at the cost of low-end torque.

You can compensate for this by increasing the velocity of the intake charge. Increasing the intake velocity has the added side effect of increasing back pressure, because there is more air to be evacuated during the exhaust stroke. Note that if you increase intake velocity past the limits of the exhaust system, the gains you achieve are diminished to the point of being non-existent. That power will be there when you do upgrade the exhaust system, which is why something as simple as upgrading the exhaust system can result in huge horsepower gains.

You can decrease back pressure by increasing the size of your exhaust manifolds, or using separate tubes for each cylinder (called headers). Increasing the size of the exhaust pipe and decreasing its length also helps, as well as installing high-flow catalytic converters and mufflers.

[ZEEROLLA]

I hope you didn't type these out yourself Shaohaok :P

I heard of a guy with a 99 White Celica 2ZZGE that had a wild bodykit and dumped and he had a 2.5" system on but later swapped to a 2.25" which he said was far better. His car was LOUD though.

[CHA54]

well the last time I had a look under MAP81's levin the piping was much larger than 2", I was very suprised. Instead of speculating, why doesn't someone get dirty and actually have a look at one of your cars??? It only takes 20 seconds.

The noise level of the exhaust and the backpressure is determined by the type of muffler used. FWIW, the stock exhaust size on a 1.6L AE111 20V 4age is 2.25"

[MAP81]

After the headers and into the CAT is deffinately larger than 2" (looks more like 3") After the CAT it is 2" pressbent all the way, I actually measured it this morning after reading this post but hadn't gotten around to posting it up yet......

[DANZZT231]

I did look at the piping size of my car and they don't look 2'. Anyway, I'll just source the headers 1st then work out what size the cat back piping really is. If its 2' then maybe 2.25 is the way to go.

[DANZZT231]

Wait a second, Grimlock is selling his cat back system, and its 2'. Why would he change his exh system to 2' if the std is 2'?

[DANZZT231]

NEW INFO

According to this dude over in US, 1ZZ-FE exhaust goes like this.

The stock exhaust piping is 2.25" from manifold to resonator. Everything after the resonator tapers down to 1.75", including the stock muffler. But everything from axle-back (a.k.a. resonator-back) is already bolt-on (1.75"). That means that if you cut out the stock resonator, you would have to weld 2.25" piping from the catalytic converter and then weld that to the 1.75" stock flange. Then you could bolt-on the TRD Sport Muffler or other bolt-on muffler. So basically all you're saying is you want to eliminate the resonator. Other than that, nothing, not even the exhaust piping sizes changes.

Nonetheless, even with this resonator-less setup, you'll still only make a few extra hp and get a blaring car cuz you no longer have the resonator. The only way to make real power gains (I got about 10-13 whp with my exhaust setup) is not to choke the exhaust from 2.25" to 1.75", but to enlarge it to 2.25" all the way, or enlarge it 2.25" to 2.5" like I did. The sacrifice is slightly less power in the lower rev band, but much stronger performance in the mid-to-high band.

Source www.2003corolla.org

[grimlock]

Yeah i should have changed it to 2.25 for my setup, but i didn't want to have a weak low end.

I have a resonator on it, to reduce noise even further.

WHen i didn't have my SC on, the exhaust would just scream after 4.5rpm. Cause of the sports muffler,

[CHA54]

and remember the US exhaust is different to the australian in order to meet the US regulations which are tougher than the Aus reg's.

[DANZZT231]

I think if I keep my free flow muffler I would get good mid to top end, so I wanna give that a go.