by induction1, April 28, 2004
is there a general rule or a formula to detemine the best perf muffler for a car? i want to squeeze every bit of power and economy out of the new corolla, but do not want to sacrafice one for the other. i read some other posts on the topic, but can anyone recommend an exhaust which increases torque, hp and mpg? any 04 corolla owners with other upgrades, tips, tricks, etc which have given results? anything helps. thanks
Because the engine on the Corolla is already so efficient - it is vary difficult to get more performance out of it without trading it one aspect for another.
To increase Torque, HP, and MPG - an exhaust upgrade is not the way to go. But you can increase the HP and Torque with the TRD exhaust and just lose a few MPG and stay legal with the noise (some states, areas have limits on how loud an exhaust can be).
To increase HP, Torque, and MPG - need to make changes at the engine level, which would automatically void the new car warranty.
Can't get around that - no such thing as a free lunch. Good Luck.
Actually the TRD performance exhaust can be installed while keeping your warranty. the only true cat-back exhaust so far for the 03-04 is made by magnaflow, all others are axle-back
Dai_Shan
Polo: nice ride, you do all those installs yourself? I just got a similar model(2005 'S') but mine is auto haha :-/
Can improvement in HP be seen with just a muffler alone(no headerchange)?
What kinda cost would be involved for a decent/good muffler?
(btw: Polo-does that intake help significantly...price? (~130?)) is that AEM better then say the K&N intake system?)
induction you like your ride so far? Any quirks you noticed? Hi/Low points of the car?
peace
mine is still too new to notice anything. i'm waiting to hit the 1000 mile mark before i can start "driving it". i WILL be changing the oil at 1000 mi just to play it safe. the wind deflector on the moonroof makes driving noise louder (as opposed to when i hold it down) but i guess it reduces wind resistence, right?
induction1,
The wind deflector built into the moonroof helps with reducing wind buffeting the cabin. Partly, it will reduce some wind resistence because it extends the body further from the opening, but it won't improve your cd any.
Dai_Shan,
You can probably pick up some sport mufflers starting at around $150. TRD makes a really nice one for the Corolla - but cost some $$$$$. The one for the 8th generation Corollas (1998-2002) run about $350 - the 2003+ models are little more expensive. Same goes for the intake - TRD, Injen, and AEM were proven on the dyno to make more power (read - actually works). But with these mods - you only see power gains at higher RPMs and close to WOT. Everywhere else is just more noise or at low RPMs, an actual loss of power. If you go the S/C route - intake and exhaust are good starting points to upgrade with the blower.
Good Luck.
Keep in mind...most people don't realize this. Any aftermarket exhaust (possiblt he TRD included) will cause a loss in bottom end as a trade for soem top end power. You really need ot do some ECU reprogramming and minor eninge mods ot see some significant improvements. THe TRD should be a good compormise of sound, performance and economy.
IMO - all performance mufflers on large, long stroke, low reving (less than 8000 RPM) sound like A**. But that's just my opinion.
induction1:
It seems that the best muffler for you would have been the one that comes with a REAL sports car like a Celica GT/GTS. Why did you buy a Corolla if you want to drive fast? A Corolla is a daily driver commuting appliance, not an "enthusiast" car. I can't figure you "boy racers" out.
larry-
i'm only looking for info; i'm by no means a 'boy racer' (whatever that is) and my driving habits are quite tame believe it or not. i never gun the engine and for that matter, i always accelerate very gently from a stop and let her coast to a stop so as not to ride the brakes. i even drive the speed limit! based upon my varied array of exorbitant questions it's easy to assume the worst for my car, but surely you'll agree that it is not wise to judge someone by some offhand knowledge. my interest in this forum is to gain information on a wide area of auto knowhow not to be understood nor criticized, but thanks for the input larry 
It seems that the best muffler for you would have been the one that comes with a REAL sports car like a Celica GT/GTS. Why did you buy a Corolla if you want to drive fast? A Corolla is a daily driver commuting appliance, not an "enthusiast" car. I can't figure you "boy racers" out.
Larry some food for thought.
1.If these are not "enthusiast" cars why are there forums? oh thats right.
2.There are all kinds of cars and all types of people.
3. Corollas can be good performers while remaining economical.
4. If your not into modifying YOUR "grocery getter", why are you browsing the performance forums?.......... Oh thats right.
SIERRASTRIKE
any muffler will not violate warrentyActually the TRD performance exhaust can be installed while keeping your warranty. the only true cat-back exhaust so far for the 03-04 is made by magnaflow, all others are axle-back
why is everyone so mis informed when it comes to the warrenty,
sure the manufacture may dis-honestly try to screw you on a warenty saying a mod or after market part did the damage etc, but the dealer acually likes to do warrenty work, it suplements their walk in work...
Federal Law states you can do just about anything street leagal and not void warrenty
Federal Law says you can use aftermarket parts...
you can not go out of normal bounds, put 21 inch rims on a Corolla and ask the dealer to fix the fender wells...
you can add a TRD superchager and do it your self and not void the warrenty , you do not have to have the dealer do it,
Headers can over heat, headers can be blamed for heat damage and can be used to violate engine damage due to heat warrentys, but the Tranny is still covered...
so think in reason and you will be fine,
TRD CAI is fine on the warrenty, installed by me, my local mechanic or Toyots, no matter
cat back exahust fine on the warrenty, in front of the CAT well this could be debated by the warrenty,
This is a myth that just won't die. There is no evidence anywhere to back up the claim that exhaust back pressure somehow creates torque.Any aftermarket exhaust (possiblt he TRD included) will cause a loss in bottom end as a trade for soem top end power.
You are right about one thing, though... an upgraded exhaust won't add any power until about 5500 rpms, and even then you're only talking 1 or 2 hp. Economically, it's a terrible upgrade, and should be considered an appearance mod.
Engine upgrades all work in concert. If you allow more air to flow through the engine by getting an aftermarket intake and exhaust, your hp won't really change because the engine can't use more air. In a similar vein, if you throw on a supercharger or a really wild set of cams, but then don't upgrade the intake and exhaust, the engine will struggle to breath at high RPMs.
You're both right. Back-pressure and loss of torque with aftermarket exhausts are wildly mis-understood.
I think the problem lies in people's interpretation of the terminology involved here. For a physics standpoint - it is about flow velocity, scavenging, volumetic efficiency and interference.
In a stock exhaust system, the pipes are smaller and the velocity of the gases in the exhaust pipe is high. As the engine pumps the exhaust gases into the pipe at low RPM - a wave or pulse of pressurized gas travels down the pipe at a high velocity. After the exhaust pulse starts to travel down the exhaust pipes, a low pressure area forms behind it. This draws even more exhaust from the cylinder, leaving a partial vacuum in the cylinder as the exhaust valve closes. This is the so called scavenging effect.
The partial vacuum remains in the cylinder as the intake valve opens. The air/fuel charge, in turn, becomes "packed" into the cylinder - creating a denser air/fuel charge than without the partial vacuum. This increase in volumetric efficiency will in turn result in more power and torque.
The problem with larger diameter exhaust pipe is it has lower flow velocity, thus a lower scavenging effect.
The term backpressure - comes from the fact that as a pulse goes down the exhaust pipe, it will cool and slow down. The subsequent exhaust pulse will actually reflect off this slowed pulse and head back up to through the exhaust manifold to the exhaust valve.
What does all this mean - for most people (ie. non-forced induction) - a smaller pipe actually has LESS backpressure (reflected pulse) than a larger one. The idea that a larger pipe will flow more, is true, in the right conditions.
At lower RPMs - A more "restrictive" exhaust (smaller diameter pipe) will generally produce better torque numbers than a "freer flowing" exhaust (larger diameter pipe). This is probably where people get the idea that back-pressure is essential to the development of torque.
At higer RPMs - the opposite will be true. Since the larger diameter pipe has a greater cross-sectional area compared to the smaller pipes - the closely spaced pulses tend to "back-up" more in the smaller pipe.
A caveat: This is all complicated with the different types of aftermarket parts. Some headers have ceramic coatings inside and out - that help with controlling the speed of the pulses (hold in heat). Some use venturi designs to do the same thing (necking down, or different sized pipes). Engine valvetrain technology like variable valve timing and variable camshafts (ie. VTEC, VVT/VVTL, Vanos, etc.) also change the approach to making power.
If you are on a budget, Magnaflow makes a cat-back exhaust for the Rolla that nets a nice gain.
If you have money to spare, you could use the Borla axle-back exhaust, coupled with the midpipe from JP Performance to get a nice gain in power.
Both of these options could be combined with the JP Performance header.
If you are really worried about warranty issues, the Borla/JP solution is 100% bolt-on, using the factory mounts, so you could easily go back to stock, although some dealers aren't fond of people doing that. The factory warranty stops at the 2nd cat, though, so you wouldn't have to worry about any warranty problems with the Magnaflow cat-back.
I posted this same reply elsewhere:
Gentlemen,
I highly recommend you take a look at:
http://www.aero-turbine.com/index.html
I am considering getting one in a couple months, when finances are better. First of all, I've never seen any exhaust advertising increased mileage. Secondly, the testimonials are very convincing. Thirdly, the price is perfectly comparable to any other muffler out there, and if you think about it, people spend way more on additionals like performance cats and headers. I think Aero is the way to go. You could easily have it installed by any muffler shop for a minimal fee, since it's a relatively simple job.
Looks very impressive - nice graphics and web site is very convincing. Too bad the physics involved don't work out like they say. Just a lot of techno babble to make it sound like technically novel idea.I posted this same reply elsewhere:Gentlemen,
I highly recommend you take a look at:
http://www.aero-turbine.com/index.html
I am considering getting one in a couple months, when finances are better. First of all, I've never seen any exhaust advertising increased mileage. Secondly, the testimonials are very convincing. Thirdly, the price is perfectly comparable to any other muffler out there, and if you think about it, people spend way more on additionals like performance cats and headers. I think Aero is the way to go. You could easily have it installed by any muffler shop for a minimal fee, since it's a relatively simple job.
For a larger displacement engine - better exhaust will definitely increase performance. Just doesn't work well with smaller displacement motors- unless they are heavily modified.
Looks cool though.
Love your ride Polo. Where did you find the Toyota emblem? I'm looking for a lighted one.
Corollace,
If I had to guess, I'd say that the last 4 posts you've made have been advertisements for that damn muffler, stfu already.
