New question about sikky headers & oem exhaust
10-01-14, 11:36 AM
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New question about sikky headers & oem exhaust
Hi all ~
I'm thinking of going sikky headers.
Here's the brief reason why I want to go with stock exhaust.
If I go headers with catback exhaust, the sound would be crazy for me, plus emittimg non-environmental exhaust gas, cause there are no cats. So I have to set up new cats in this case. But I don't want to spend money for all those headers, aftermarket catback exhaust and additional cats. It's a way too much for my situation.
By far, it's not something new story to you guys.
Anyway, in this case ( headers & oe exhaust only )
I want to hear from you guys about technical aspect of this setting.
I'm not quiet interested in the difference of power gain between headers & stock exhaust and headers & aftermarket catback exhaust.
I know the stock exhaust has some back pressure at some point for fuel efficiency and sufficient torque at low rpm. But honestly I don't know how much restrictive the oe exhaust is. I have not seen any date about oe exhaust pressure ( when it comes to bmw 1m, oe catback exhaust pressure is 8.7kpa, 0.5 ~ 1.2kpa for oe axle back. Usually kpa for normal sedan is about 25, less than 10kpa for high performance car. )
And you might know the fact that when the back flow of the exhaust gas start going back into the engine, it could harm the engine badly.
So here's my questions.
1) headers & restrictive oe exhaust system could lead to the result of getting exhaust gas flow back into the engine by any chance ?
2) I know few member go with this setting. Could anyone tell me if there is any engine overheating problem ?
3) Do you guys have any data about where the most restrictive parts of oe exhaust?
Some says it's the crushed Y pipe.
Some says they are the cats.
Some says they are sub muffler and main mufflers that affects entire car's exhaust pressure ( this opinion is quite reliable because he makes oe exhausts for some brands. )
I'm thinking of going sikky headers.
Here's the brief reason why I want to go with stock exhaust.
If I go headers with catback exhaust, the sound would be crazy for me, plus emittimg non-environmental exhaust gas, cause there are no cats. So I have to set up new cats in this case. But I don't want to spend money for all those headers, aftermarket catback exhaust and additional cats. It's a way too much for my situation.
By far, it's not something new story to you guys.
Anyway, in this case ( headers & oe exhaust only )
I want to hear from you guys about technical aspect of this setting.
I'm not quiet interested in the difference of power gain between headers & stock exhaust and headers & aftermarket catback exhaust.
I know the stock exhaust has some back pressure at some point for fuel efficiency and sufficient torque at low rpm. But honestly I don't know how much restrictive the oe exhaust is. I have not seen any date about oe exhaust pressure ( when it comes to bmw 1m, oe catback exhaust pressure is 8.7kpa, 0.5 ~ 1.2kpa for oe axle back. Usually kpa for normal sedan is about 25, less than 10kpa for high performance car. )
And you might know the fact that when the back flow of the exhaust gas start going back into the engine, it could harm the engine badly.
So here's my questions.
1) headers & restrictive oe exhaust system could lead to the result of getting exhaust gas flow back into the engine by any chance ?
2) I know few member go with this setting. Could anyone tell me if there is any engine overheating problem ?
3) Do you guys have any data about where the most restrictive parts of oe exhaust?
Some says it's the crushed Y pipe.
Some says they are the cats.
Some says they are sub muffler and main mufflers that affects entire car's exhaust pressure ( this opinion is quite reliable because he makes oe exhausts for some brands. )
Last edited by bdkim88; 10-01-14 at 11:39 AM.
10-02-14, 06:45 AM
#3
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bdkim88 I've had my PPE headers installed with oe exhaust for nearly a year now.
So far it's been hassle free but reading your post it's made me think because the more I drive the car the more I feel that the oe exhaust is causing more restrictions.
over the past few months I've noticed that when driving (usually 3rd gear or 4th) and I let go of the gas slightly, to let the car cruise on it's own momentum I feel a slight restriction, similar to running bad gas or letting go of the gas pedal completely.
It only happens for a sec or two but it is noticeable to me, which is why I'm now thinking this could be from the oe exhaust gases going back up the headers since I'm letting go of the gas and there isn't enough pressure to drive the exhaust gasses out (due to oe exhaust restriction).
You've given me some food for thought. sorry I can't comment on your questions above much more but this is what I'm experiencing and hopefully sooner rather than later I will be installing my exhaust.
In addition to the above I feel that I'm getting way more engine noise than exhaust at the moment, especially when I'm parked. It is not annoying or too noticeable but it makes me think that I'm restricting the engine and emissions more than what it should be.
So far it's been hassle free but reading your post it's made me think because the more I drive the car the more I feel that the oe exhaust is causing more restrictions.
over the past few months I've noticed that when driving (usually 3rd gear or 4th) and I let go of the gas slightly, to let the car cruise on it's own momentum I feel a slight restriction, similar to running bad gas or letting go of the gas pedal completely.
It only happens for a sec or two but it is noticeable to me, which is why I'm now thinking this could be from the oe exhaust gases going back up the headers since I'm letting go of the gas and there isn't enough pressure to drive the exhaust gasses out (due to oe exhaust restriction).
You've given me some food for thought. sorry I can't comment on your questions above much more but this is what I'm experiencing and hopefully sooner rather than later I will be installing my exhaust.
In addition to the above I feel that I'm getting way more engine noise than exhaust at the moment, especially when I'm parked. It is not annoying or too noticeable but it makes me think that I'm restricting the engine and emissions more than what it should be.
10-02-14, 09:01 AM
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Thanks for reply
Yes, that might be the one of the best combo so far.
But I can not stand the loud sound and the exhaust gas if I go with catback exhaust
So maybe I have to install additional cats..
As you know, some of high flow cats are around 2~3K
Therefore I want to know if there is any issue with headers only
10-02-14, 09:18 AM
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Thanks for reply
bdkim88 I've had my PPE headers installed with oe exhaust for nearly a year now.
So far it's been hassle free but reading your post it's made me think because the more I drive the car the more I feel that the oe exhaust is causing more restrictions.
over the past few months I've noticed that when driving (usually 3rd gear or 4th) and I let go of the gas slightly, to let the car cruise on it's own momentum I feel a slight restriction, similar to running bad gas or letting go of the gas pedal completely.
It only happens for a sec or two but it is noticeable to me, which is why I'm now thinking this could be from the oe exhaust gases going back up the headers since I'm letting go of the gas and there isn't enough pressure to drive the exhaust gasses out (due to oe exhaust restriction).
You've given me some food for thought. sorry I can't comment on your questions above much more but this is what I'm experiencing and hopefully sooner rather than later I will be installing my exhaust.
In addition to the above I feel that I'm getting way more engine noise than exhaust at the moment, especially when I'm parked. It is not annoying or too noticeable but it makes me think that I'm restricting the engine and emissions more than what it should be.
So far it's been hassle free but reading your post it's made me think because the more I drive the car the more I feel that the oe exhaust is causing more restrictions.
over the past few months I've noticed that when driving (usually 3rd gear or 4th) and I let go of the gas slightly, to let the car cruise on it's own momentum I feel a slight restriction, similar to running bad gas or letting go of the gas pedal completely.
It only happens for a sec or two but it is noticeable to me, which is why I'm now thinking this could be from the oe exhaust gases going back up the headers since I'm letting go of the gas and there isn't enough pressure to drive the exhaust gasses out (due to oe exhaust restriction).
You've given me some food for thought. sorry I can't comment on your questions above much more but this is what I'm experiencing and hopefully sooner rather than later I will be installing my exhaust.
In addition to the above I feel that I'm getting way more engine noise than exhaust at the moment, especially when I'm parked. It is not annoying or too noticeable but it makes me think that I'm restricting the engine and emissions more than what it should be.
Your experience tells me a lot, I really appreciate it.
I think it's very sophiscated subject..
So, at first I need to know the exhaust pressure of each section of the oe exhaust system
Maybe it could help understanding isf more deeply
I'm thinking of checking at the end of this year ( now I'm quiet busy
)
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10-02-14, 09:27 AM
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Thanks for reply
The oem 2nd cats are little more expensive than I thought. About 1.5~2K each?
So I want to use something equal price range with oe cats or more than that
It's my taste though
10-02-14, 09:35 AM
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Thanks for your advice
Unfortunately, in Korea, there are just 3 ISF which installed headers
Because there are maybe only 60 ISF in Korea
And not like you guys, I have to spend almost 3K for perchasing, importing the headers and installation
All of you members in US, you are the perfect guys for owning ISF
In my case, I have to spend nearly 3K for install JoeZ exhaust
So, cheer me up
ps. Maybe I might go California next year. I'll look forward to hope to hear some sounds when I get there
Last edited by bdkim88; 10-02-14 at 09:40 AM.
10-02-14, 09:40 AM
#10
I will have to look at my stock manifolds I have in the garage cause I thought adding aftermarket headers makes it impossible to have cats unless aftermarket cats are welded in. So Sikky headers with the stock exhaust rstains the factory cats?
10-02-14, 09:43 AM
#11
^^^^The stock ISF comes with 2 pairs of Catalytic Converters. The Primary Set is located just behind the factory exhaust manifolds, and each manifold and cat are one assembly. The Secondary cats are located in the stock exhaust system. So, if you install headers and keep the stock exhaust, you retain the Secondary Set of cats.
Lou
Lou
10-02-14, 09:45 AM
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As I understand
So, when you replace into with just sikky headers or ppe, only 1st cats will be removed.
10-02-14, 11:09 AM
#14
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iTrader: (2)
Not without finding someone who will ignore the visual. There's always a way to pass. Not all of them follow the letter of the law, and a pass won't save you from a roadside inspection by CHP. Just one of the myriad reasons I left California after 24 years of living there.
10-02-14, 12:13 PM
#15
Not without finding someone who will ignore the visual. There's always a way to pass. Not all of them follow the letter of the law, and a pass won't save you from a roadside inspection by CHP. Just one of the myriad reasons I left California after 24 years of living there.
Just interested to know what the smog check numbers looked like to see the effectiveness of the secondary cats.