Exhaust question.

[BigDScion]

Has anyone had a chance to hear or see what kind of numbers the Tsudo N1 Extreme Cat-Back Exhaust System produce? I'm thinking about getting it for my TC but I'm not sure yet. Any suggestions?

[claytongozoom]

nope, sorry man. your best bet is to go to youtube.com or dailymotion.com and see if you can find a clip. just google around a bit, you'll find something i'm sure, even if it's on a different car you'll still get a rough idea of what it sounds like. as for on the tC, look for a company that has tested and dynoed and see if you can't find yourself a graph showing the performance increase.

[ForBiddeN]

my frined has a tsudo on his celica i dought they would sound the same beacse he has a 1.8 and we have a 2.4 but its real quiet and its kinda ricey i didnt like it but yah waht clay said see if they have a sound clip of it on 1 of thoes sites.

[BigDScion]

I was wondering would it be worth a chance to get something like eBay Motors: 04 05 06 07 TOYOTA SCION TC CATBACK EXHAUST MUFFLER (item 180119297590 end time May-25-07 12:37:19 PDT) Just as a starter axle back. Or would it be better to spend the extra little bit of money to go with a tsudo axle back all I want is sound out of it.

[navylife59]

tsudo or the TRD are your best bets

[orangesuburban]

i got the magnaflow, dont know what it does for numbers, but its real quiet until you get on it, then it sounds pretty mean, no rice...

[hotrice]

i've got the greddy on the way to my place right now. i listened to it on you tube and it sounds the deepest

[ForBiddeN]

Originally Posted by navylife59

tsudo or the TRD are your best bets

ive herd the tsudo and it sounds like rice with the headers!!!!!!!

[navylife59]

They ALL will sound like that when you replace the OEM headers. You will have to add a large resonator to curb that.

The OEM header has the pre-cat. You take that out and the back pressure drops way more that just replacing the s-pipe. Alot of people (me included) run the DC Spors header. It is a 4-1 design with a rather small collector. This is a major rice maker. My HKS Power with custom 2.5" exhaust was so loud with one 12" resonator, I had to have Jotech add another just to make it bearable on the highway. BTW I have no pre-cat, cat, or OE resonator.

[ForBiddeN]

do u have your pipeing curved a certen way to make back pressure? seems to me like u barly have any lol.

[TeknoMaeg]

Originally Posted by ForBiddeN

do u have your pipeing curved a certen way to make back pressure? seems to me like u barly have any lol.

Back pressure to ANY degree is detrimental...

Some say that "an engine needs backpressure to work correctly." Is this true?

No. It would be more correct to say, "a perfectly stock engine that cannot adjust its fuel delivery needs backpressure to work correctly." This idea is a myth. As with all myths, however, there is a hint of fact with this one. Particularly, some people equate backpressure with torque, and others fear that too little backpressure will lead to valve burning.

The first reason why people say "backpressure is good" is because they believe that increased backpressure by itself will increase torque, particularly with a stock exhaust manifold. Granted, some stock manifolds act somewhat like performance headers at low RPM, but these manifolds will exhibit poor performance at higher RPM. This, however does not automatically lead to the conclusion that backpressure produces more torque. The increase in torque is not due to backpressure, but to the effects of changes in fuel/air mixture, which will be described in more detail below.

The other reason why people say "backpressure is good" is because they hear that cars (or motorcycles) that have had performance exhaust work done to them would then go on to burn exhaust valves. Now, it is true that such valve burning has occurred as a result of the exhaust mods, but it isn't due merely to a lack of backpressure.

The internal combustion engine is a complex, dynamic collection of different systems working together to convert the stored power in gasoline into mechanical energy to push a car down the road. Anytime one of these systems are modified, that mod will also indirectly affect the other systems, as well.

Now, valve burning occurs as a result of a very lean-burning engine. In order to achieve a theoretical optimal combustion, an engine needs 14.7 parts of oxygen by mass to 1 part of gasoline (again, by mass). This is referred to as a stoichiometric (chemically correct) mixture, and is commonly referred to as a 14.7:1 mix. If an engine burns with less oxygen present (13:1, 12:1, etc...), it is said to run rich. Conversely, if the engine runs with more oxygen present (16:1, 17:1, etc...), it is said to run lean. Today's engines are designed to run at 14.7:1 for normally cruising, with rich mixtures on acceleration or warm-up, and lean mixtures while decelerating.

Getting back to the discussion, the reason that exhaust valves burn is because the engine is burning lean. Normal engines will tolerate lean burning for a little bit, but not for sustained periods of time. The reason why the engine is burning lean to begin with is that the reduction in backpressure is causing more air to be drawn into the combustion chamber than before. Earlier cars (and motorcycles) with carburation often could not adjust because of the way that backpressure caused air to flow backwards through the carburetor after the air already got loaded down with fuel, and caused the air to receive a second load of fuel. While a bad design, it was nonetheless used in a lot of vehicles. Once these vehicles received performance mods that reduced backpressure, they no longer had that double-loading effect, and then tended to burn valves because of the resulting over-lean condition. This, incidentally, also provides a basis for the "torque increase" seen if backpressure is maintained. As the fuel/air mixture becomes leaner, the resultant combustion will produce progressively less and less of the force needed to produce torque.

Sorry to go off topic... As far as the Tsudo exhaust goes... it's a personal choice but every time I have heard a Tsudo it has sounded like extreme CRAP.

[navylife59]

I guess I am the exception. I have heard of one Tsudo before it sounded rather well. It was not on a tC though. As for the backpressure debate, it is more about exhaust tuning and exhaust pulse timing. It is easier to hit the "sweet spot" for exhaust scavaging than with a more open exhaust. Yes, it is true that your low-end torque curve will be flat till the exhaust tuning catches up on a big pipe. Easy test.....take your car and completely remove the exhaust and tell me how it runs. Even with some mods and tuning, it still won't have the low-end till you atleast put a header on.

[TeknoMaeg]

Originally Posted by navylife59

I guess I am the exception. I have heard of one Tsudo before it sounded rather well. It was not on a tC though. As for the backpressure debate, it is more about exhaust tuning and exhaust pulse timing. It is easier to hit the "sweet spot" for exhaust scavaging than with a more open exhaust. Yes, it is true that your low-end torque curve will be flat till the exhaust tuning catches up on a big pipe. Easy test.....take your car and completely remove the exhaust and tell me how it runs. Even with some mods and tuning, it still won't have the low-end till you atleast put a header on.

It may be a good sounding exhaust on a properly tuned exhaust with the right size resonator and what not...

As far as exhaust tuning goes... you are right. It's all about pulses and tubing length. Not so much about size.

[navylife59]

That is why I think some of the headers out there aren't really designed with any scientific forethought. Unequal length tubes, improperly placed and sized collectors; that just makes for poor gains. Worse yet, it could hender performance.

[TeknoMaeg]

Originally Posted by navylife59

That is why I think some of the headers out there aren't really designed with any scientific forethought. Unequal length tubes, improperly placed and sized collectors; that just makes for poor gains. Worse yet, it could hender performance.

Some do... I wish I had a mandrel bender at my disposal... my exhaust would be flawless...

[JRW-910]

Be careful... many times headers and even exhaust systems will not only cost you money... but will also cost you performance... hp and tq. Of course, the only real way to know is to get a baseline on the dyno, install the system, and then redyno the car. Any done this?

-JRW

[ForBiddeN]

there are some dyno readings posed on the froum of what headers to use and not to use but as for full exhost u got me.

[navylife59]

Just by looking at their designs will clue you in on any major mistakes they may have made. If their design is implemented well, then it is all about quality and aesthetics. The same goes for turbo manifolds. Of course, with turbo manifolds it is all about short and equal length for turbine efficiency. N/A and S/C will benefit from properly timed exhaust pulses.