No-cat or cat-back new exhaust? diameter?
05-11-2006, 08:39 PM
#1
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Join Date: May 2005
Location: Concepción, Chile
Posts: 8
No-cat or cat-back new exhaust? diameter?
Hi guys, first of all, i'm NichO from Chile, and a proud owner of a Toyota Yaris (echo) hatchback 1.3 liters 86hp 2NZ-FE 2004... :D
Sorry my english if i make some mistakes
I'm planning on installing a new exhaust..
My idea is: 4-1 header, no-cat, resonator and my RS*R muffler that i already have.
I'm looking for power gains but of course without sacrificing torque.
Also i already have a k&n typhoon kit by the way.
but after reading some threads:
i would like to know if is there any real power gains by removing the catalytic converter?
I've heard that this is true, considering that cats are restrictive... but of course i guess i would have to compensate this with an o2 simulator, because my CEL would light on right?
something like this would work?
Or is it really not worthy?
Would it be the best to make it a cat-back exhaust, with a new resonator or should i keep the stock one?
Also, what would be the best diameter for this setup?
I've read some threads where 2.5" is too much, and remember that my ride is only 1.3cc (2nz-fe) so maybe a smaller setup would be better.
I've heard that 1.8" exhaust has given good results, just like the exhaust designed for 2NZ-FE by OMP racing (italy) that i want to emulate
No cat, 1.8" diameter, 5" Resonator diameter.
ps. i'm prety sure that we have different ECU's by the way, 32 bit i guess, if it makes any difference.
Thanks a lot for your help!
Sorry my english if i make some mistakes
I'm planning on installing a new exhaust..
My idea is: 4-1 header, no-cat, resonator and my RS*R muffler that i already have.
I'm looking for power gains but of course without sacrificing torque.
Also i already have a k&n typhoon kit by the way.
but after reading some threads:
i would like to know if is there any real power gains by removing the catalytic converter?
I've heard that this is true, considering that cats are restrictive... but of course i guess i would have to compensate this with an o2 simulator, because my CEL would light on right?
something like this would work?
Or is it really not worthy?
Would it be the best to make it a cat-back exhaust, with a new resonator or should i keep the stock one?
Also, what would be the best diameter for this setup?
I've read some threads where 2.5" is too much, and remember that my ride is only 1.3cc (2nz-fe) so maybe a smaller setup would be better.
I've heard that 1.8" exhaust has given good results, just like the exhaust designed for 2NZ-FE by OMP racing (italy) that i want to emulate
No cat, 1.8" diameter, 5" Resonator diameter.
ps. i'm prety sure that we have different ECU's by the way, 32 bit i guess, if it makes any difference.
Thanks a lot for your help!
05-11-2006, 09:04 PM
#2
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Join Date: Dec 2005
Location: Lost in Tranquility
Posts: 3,270
Are you planning on staying N/A or are you one day going to go F/I? I have heard it is better to keep the cat, becuase you lose some HP with it off and you get the dreaded CEL light. Why not go with a high flow cat, a new resinator and maybe 2" or 2.25" piping. Thats what i did and used 2.25" piping, but i m going F/I, but i love the power i get from the car with the new exhaust on it now. hope this helps a little, im sure some other's will chime in with some good info to.
05-11-2006, 09:31 PM
#3
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Join Date: May 2005
Location: Concepción, Chile
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Originally Posted by ProshopXB
Are you planning on staying N/A or are you one day going to go F/I?
I'll think about the high flow cat... but i can't understand why would i lose HP removing a restrictive element?
at least no gain.. but losing?
Actually i saw your topic when you installed your exhaust line, congrats! .. looks
awesome, great job. Didn't you lose any low end power?
Thanks!
05-11-2006, 09:39 PM
#4
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Location: Lost in Tranquility
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Really cant tell if i lost low end power, may have lost a little, but nothing worth mentioning. I'll see if i can find the thread that stated about losing HP with out the cat and get back to you.
05-11-2006, 09:52 PM
#5
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Not sure if you have read these already but here is a few statments about removing the cat and the threads they came from.
https://www.scionlife.com/forums/vie...t=removing+cat
https://www.scionlife.com/forums/vie...t=removing+cat
Originally Posted by suspended
http://www.02simulator.com
now partially i do have to agree with rton20's, the only time removing a cat is going to help is with turbo cars where backpressure isn't really needed, for an n/a motor without high compression and full rebuild, removing the cat will just make your exhaust loud, and make you lose back pressure.....less back pressure=less torque...i've seen automatics stall out at part without cats b/c there wasn't enough comperssion to keep up the backpressure of a straight pipe.
now partially i do have to agree with rton20's, the only time removing a cat is going to help is with turbo cars where backpressure isn't really needed, for an n/a motor without high compression and full rebuild, removing the cat will just make your exhaust loud, and make you lose back pressure.....less back pressure=less torque...i've seen automatics stall out at part without cats b/c there wasn't enough comperssion to keep up the backpressure of a straight pipe.
Originally Posted by RTon20s
What most people today don't understand is that modern catalytic converters do very little to actually limit performance. The gains seen by removing a catalytic converter in a modern vehicle are minimal if existent at all. And in some cases removing the catalytic converter can cause you to loose power.
In some cases replacing the stock catalytic converter with an aftermarket high flow unit can make a slight difference. But from what I have read on here, there is only one aftermarket converter that is even worth consideration.
At least this is the way it has been explained to me by the exhaust shops I have dealt with. I know there are exhaust pros in here (Stylis), so if anything I have said is incorrect, let me know.
In some cases replacing the stock catalytic converter with an aftermarket high flow unit can make a slight difference. But from what I have read on here, there is only one aftermarket converter that is even worth consideration.
At least this is the way it has been explained to me by the exhaust shops I have dealt with. I know there are exhaust pros in here (Stylis), so if anything I have said is incorrect, let me know.
Originally Posted by Stylis
Removing the catalytic converter will cause the check engine light to come on. This has been proven and will cause your gas milage to go down in the crapper. Your motor will dump fuel into exhaust system and your idle will be wierd in some cases. We have VVT-I, so the motor will try to correct it self if the readings are not there from the 02 sensors. Eric M. was the very first scion guy to do this, I know because I built him the system 2.5 years ago. (Man I'm old) :D Anyway, I hope this info will help you in your decision.
05-11-2006, 10:10 PM
#6
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Join Date: May 2005
Location: Concepción, Chile
Posts: 8
Great info dude!
I think i read the 2 firsts ones.. but still i have a clear picture of it.
thanks a lot..
now... considering to keep the stock cat and saving all the trouble of the o2 sensors, how would a 1.8"/2" cat-back with a new resonator perform?
4-1 headers, cat-back exhaust, new resonator, rs*r muffler
sounds good to make a power difference right?
thanks again!
I think i read the 2 firsts ones.. but still i have a clear picture of it.
thanks a lot..
now... considering to keep the stock cat and saving all the trouble of the o2 sensors, how would a 1.8"/2" cat-back with a new resonator perform?
4-1 headers, cat-back exhaust, new resonator, rs*r muffler
sounds good to make a power difference right?
thanks again!
05-11-2006, 10:21 PM
#8
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Location: Austin, TX
Posts: 2,122
This is offtopic but....
You're in Concepción, Chile eh?
I was in Chile for 2 months, from October to December last year.
I went through Puerto Montt, Puerto Varas, Chaiten, and Hornopiren.
I went mountain climbing on Villarica, and Quetrupillan.
You're in Concepción, Chile eh?
I was in Chile for 2 months, from October to December last year.
I went through Puerto Montt, Puerto Varas, Chaiten, and Hornopiren.
I went mountain climbing on Villarica, and Quetrupillan.
05-11-2006, 10:30 PM
#9
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Join Date: May 2005
Location: Concepción, Chile
Posts: 8
Originally Posted by hayalex6
This is offtopic but....
You're in Concepción, Chile eh?
I was in Chile for 2 months, from October to December last year.
I went through Puerto Montt, Puerto Varas, Chaiten, and Hornopiren.
I went mountain climbing on Villarica, and Quetrupillan.
You're in Concepción, Chile eh?
I was in Chile for 2 months, from October to December last year.
I went through Puerto Montt, Puerto Varas, Chaiten, and Hornopiren.
I went mountain climbing on Villarica, and Quetrupillan.
Actually i go every summer to Villarica and Pucon to spend my vacations.. amazing place, about 4 hours driving from Concepcion. Nice to know some people who have been in my beautiful country dude
sorry the off-topic everybody
05-11-2006, 11:09 PM
#11
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Join Date: Oct 2005
Posts: 2,066
Well here I was all ready to post up and Proshop goes and steals my thunder. Oh well, at least he quoted some good sources. 
As far as the diameter I would think with the 1.3 a full 2" exhaust would be more than sufficient for any naturally aspirated application. You might see a slight increase in torque by using the 1.8" exhaust, but the difference could be so slight you would never notice.
And if you ever do go to f/i the 2" exhaust would work just fine without being too restrictive until you could upgrade to 2.25".
Hope that helps, and keep us updated with your progress.
As far as the diameter I would think with the 1.3 a full 2" exhaust would be more than sufficient for any naturally aspirated application. You might see a slight increase in torque by using the 1.8" exhaust, but the difference could be so slight you would never notice.
And if you ever do go to f/i the 2" exhaust would work just fine without being too restrictive until you could upgrade to 2.25".
Hope that helps, and keep us updated with your progress.
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