HFCs and test pipes question
Thread Starter
Registered User
Joined: Mar 2011
Posts: 13
Likes: 0
From: houston tx
HFCs and test pipes question
I just recently got into cars because of my 08 Z, so I am not very familiar with certain things. And my question is, I currently have a Greddy Se exhaust on my car and I'm thinking of getting test pipes and HFCs for some performance gain. Is that redundant? Since the greddy se is an axle back or it doesn't matter I can still get some gain out of it?
From what I've researched it's better to run the cat back exhaust instead of an axle back. But I already bought the greddy se, so I don't want to have to buy another one. So will the hfc and test pipe help for this greddy se exhaust?
From what I've researched it's better to run the cat back exhaust instead of an axle back. But I already bought the greddy se, so I don't want to have to buy another one. So will the hfc and test pipe help for this greddy se exhaust?
I just recently got into cars because of my 08 Z, so I am not very familiar with certain things. And my question is, I currently have a Greddy Se exhaust on my car and I'm thinking of getting test pipes and HFCs for some performance gain. Is that redundant? Since the greddy se is an axle back or it doesn't matter I can still get some gain out of it?
From what I've researched it's better to run the cat back exhaust instead of an axle back. But I already bought the greddy se, so I don't want to have to buy another one. So will the hfc and test pipe help for this greddy se exhaust?
From what I've researched it's better to run the cat back exhaust instead of an axle back. But I already bought the greddy se, so I don't want to have to buy another one. So will the hfc and test pipe help for this greddy se exhaust?
But to answer your question in a nutshell, HFC and test pipes are the same part so to speak just one is a smaller catalyst which makes more flow (hince the saying High Flow Cat, HFC) now test pipes have NO catalyst in the pipe that may throw a check engine light but has the best flow since there are no guts in the pipe. so you much choose HFC or Test pipes, not both. and you will get gains from either no matter the exhaust but yes cat backs/true duals typically offer more gains but axle back is fine since you already bought it. hope i could help.
Thread Starter
Registered User
Joined: Mar 2011
Posts: 13
Likes: 0
From: houston tx
Ok thanks guys. Especially z_enthusiast's comment was very helpful.
The greddy is louder than the stock exhuast, but it is quite quiet comparing to the catbacks or dual, it has a mellow rev. And I like it
The greddy is louder than the stock exhuast, but it is quite quiet comparing to the catbacks or dual, it has a mellow rev. And I like it
So are you saying that you have an axle back exhaust? I'm not familiar with the "Greddy SE" exhaust.
Basically, here's exhaust in a nutshell. You have headers which come right off the engine. We have two rows of cylinders (V6) so we have 2 headers (an inline 4 like a Honda Civic has one header). Then the cats bolt to the headers and come next in the exhaust flow. After the cats is a Y-Pipe or X-Pipe (y-pipe stock). After that would be a mid-pipe. And finally the axle back (typically referred to as the "muffler" section).
If you have an axle back you probably just have what is essentially a new muffler. It will give you a little sound but honestly doesn't give you any power really. A cat-back exhaust is just what it sounds like.. a full new exhaust system which starts after the cats.. so it would include y-pipe or x-pipe, mid-pipe, and muffler. This will give you up to about 10 whp on our cars.
So then if you want still more power, you can get HFC's or test pipes which replace the stock cats. This will give you at least another 8 whp for HFC's or 10+ whp for test pipes because the cats are by far the most restrictive part of the exhaust system. Obviously a HFC still has a cat in it which is still more restrictive than just an open tube (a test pipe) so it yields less power gains.
Then if you still want more power after this you can go with intakes and finally a tune. A tune is a great idea once you have intake and full exhaust because it will allow you to really utilize all of the new extra air flow capabilities.
Replacing the headers on our car isn't really worth-while because our headers from the factory are already equal length tubing and perform very well.. plus they're an absolute pain in the butt to install!
These are pretty much the only power adding cars you can do to our HR 350Z's unless you decide to go FI (forced induction.. like turbo or supercharger). Some will say that these mods aren't worth it but I totally believe they are. I love my mods and I can definitely tell a nice difference and bump in power!
BTW, whp = wheel horse power, and to make it simple 10 whp is about 12 crank hp which is what your car has when it says 307 hp.
And oh yeah, one more thing. If you have emissions testing where you live, replacing the cats is the only thing you have to worry about. If you replace them there's a chance you will get a CEL (check engine light) which is telling you that your cats aren't performing right (they aren't making your car environmentally friendly). Well obviously lol.. they aren't there anymore! The CEL doesn't mean that your car is hurting though or anything like that.. and is ok to ignore (in this particular case), but it will cause you to not pass emissions testing. If you get a tune though, it can get rid of the CEL for you. There are also other ways of fixing it, search around here and you can find more info on the topic.
Hope this helps and enjoy your Z!
Basically, here's exhaust in a nutshell. You have headers which come right off the engine. We have two rows of cylinders (V6) so we have 2 headers (an inline 4 like a Honda Civic has one header). Then the cats bolt to the headers and come next in the exhaust flow. After the cats is a Y-Pipe or X-Pipe (y-pipe stock). After that would be a mid-pipe. And finally the axle back (typically referred to as the "muffler" section).
If you have an axle back you probably just have what is essentially a new muffler. It will give you a little sound but honestly doesn't give you any power really. A cat-back exhaust is just what it sounds like.. a full new exhaust system which starts after the cats.. so it would include y-pipe or x-pipe, mid-pipe, and muffler. This will give you up to about 10 whp on our cars.
So then if you want still more power, you can get HFC's or test pipes which replace the stock cats. This will give you at least another 8 whp for HFC's or 10+ whp for test pipes because the cats are by far the most restrictive part of the exhaust system. Obviously a HFC still has a cat in it which is still more restrictive than just an open tube (a test pipe) so it yields less power gains.
Then if you still want more power after this you can go with intakes and finally a tune. A tune is a great idea once you have intake and full exhaust because it will allow you to really utilize all of the new extra air flow capabilities.
Replacing the headers on our car isn't really worth-while because our headers from the factory are already equal length tubing and perform very well.. plus they're an absolute pain in the butt to install!
These are pretty much the only power adding cars you can do to our HR 350Z's unless you decide to go FI (forced induction.. like turbo or supercharger). Some will say that these mods aren't worth it but I totally believe they are. I love my mods and I can definitely tell a nice difference and bump in power!
BTW, whp = wheel horse power, and to make it simple 10 whp is about 12 crank hp which is what your car has when it says 307 hp.
And oh yeah, one more thing. If you have emissions testing where you live, replacing the cats is the only thing you have to worry about. If you replace them there's a chance you will get a CEL (check engine light) which is telling you that your cats aren't performing right (they aren't making your car environmentally friendly). Well obviously lol.. they aren't there anymore! The CEL doesn't mean that your car is hurting though or anything like that.. and is ok to ignore (in this particular case), but it will cause you to not pass emissions testing. If you get a tune though, it can get rid of the CEL for you. There are also other ways of fixing it, search around here and you can find more info on the topic.
Hope this helps and enjoy your Z!
Last edited by AadosX; Apr 13, 2011 at 11:12 AM.
Trending Topics
Thread Starter
Registered User
Joined: Mar 2011
Posts: 13
Likes: 0
From: houston tx
Wow that was very thorough AadosX, felt like I just passed exhaust 101.
Thanks a lot dude, you basically answered all of the questions that I have in mind.
Thank you guys, your info was very helpful. I've learned quite a handful.
Thanks a lot dude, you basically answered all of the questions that I have in mind.
Thank you guys, your info was very helpful. I've learned quite a handful.
No problem, I do what I can hehe. Nothing annoys me more than people that can answer questions easily and have the knowledge to do so but choose not to because they're lazy. Learning and then helping people out is what forums like this are all about IMO.
So are you saying that you have an axle back exhaust? I'm not familiar with the "Greddy SE" exhaust.
Basically, here's exhaust in a nutshell. You have headers which come right off the engine. We have two rows of cylinders (V6) so we have 2 headers (an inline 4 like a Honda Civic has one header). Then the cats bolt to the headers and come next in the exhaust flow. After the cats is a Y-Pipe or X-Pipe (y-pipe stock). After that would be a mid-pipe. And finally the axle back (typically referred to as the "muffler" section).
If you have an axle back you probably just have what is essentially a new muffler. It will give you a little sound but honestly doesn't give you any power really. A cat-back exhaust is just what it sounds like.. a full new exhaust system which starts after the cats.. so it would include y-pipe or x-pipe, mid-pipe, and muffler. This will give you up to about 10 whp on our cars.
So then if you want still more power, you can get HFC's or test pipes which replace the stock cats. This will give you at least another 8 whp for HFC's or 10+ whp for test pipes because the cats are by far the most restrictive part of the exhaust system. Obviously a HFC still has a cat in it which is still more restrictive than just an open tube (a test pipe) so it yields less power gains.
Then if you still want more power after this you can go with intakes and finally a tune. A tune is a great idea once you have intake and full exhaust because it will allow you to really utilize all of the new extra air flow capabilities.
Replacing the headers on our car isn't really worth-while because our headers from the factory are already equal length tubing and perform very well.. plus they're an absolute pain in the butt to install!
These are pretty much the only power adding cars you can do to our HR 350Z's unless you decide to go FI (forced induction.. like turbo or supercharger). Some will say that these mods aren't worth it but I totally believe they are. I love my mods and I can definitely tell a nice difference and bump in power!
BTW, whp = wheel horse power, and to make it simple 10 whp is about 12 crank hp which is what your car has when it says 307 hp.
And oh yeah, one more thing. If you have emissions testing where you live, replacing the cats is the only thing you have to worry about. If you replace them there's a chance you will get a CEL (check engine light) which is telling you that your cats aren't performing right (they aren't making your car environmentally friendly). Well obviously lol.. they aren't there anymore! The CEL doesn't mean that your car is hurting though or anything like that.. and is ok to ignore (in this particular case), but it will cause you to not pass emissions testing. If you get a tune though, it can get rid of the CEL for you. There are also other ways of fixing it, search around here and you can find more info on the topic.
Hope this helps and enjoy your Z!
Basically, here's exhaust in a nutshell. You have headers which come right off the engine. We have two rows of cylinders (V6) so we have 2 headers (an inline 4 like a Honda Civic has one header). Then the cats bolt to the headers and come next in the exhaust flow. After the cats is a Y-Pipe or X-Pipe (y-pipe stock). After that would be a mid-pipe. And finally the axle back (typically referred to as the "muffler" section).
If you have an axle back you probably just have what is essentially a new muffler. It will give you a little sound but honestly doesn't give you any power really. A cat-back exhaust is just what it sounds like.. a full new exhaust system which starts after the cats.. so it would include y-pipe or x-pipe, mid-pipe, and muffler. This will give you up to about 10 whp on our cars.
So then if you want still more power, you can get HFC's or test pipes which replace the stock cats. This will give you at least another 8 whp for HFC's or 10+ whp for test pipes because the cats are by far the most restrictive part of the exhaust system. Obviously a HFC still has a cat in it which is still more restrictive than just an open tube (a test pipe) so it yields less power gains.
Then if you still want more power after this you can go with intakes and finally a tune. A tune is a great idea once you have intake and full exhaust because it will allow you to really utilize all of the new extra air flow capabilities.
Replacing the headers on our car isn't really worth-while because our headers from the factory are already equal length tubing and perform very well.. plus they're an absolute pain in the butt to install!
These are pretty much the only power adding cars you can do to our HR 350Z's unless you decide to go FI (forced induction.. like turbo or supercharger). Some will say that these mods aren't worth it but I totally believe they are. I love my mods and I can definitely tell a nice difference and bump in power!
BTW, whp = wheel horse power, and to make it simple 10 whp is about 12 crank hp which is what your car has when it says 307 hp.
And oh yeah, one more thing. If you have emissions testing where you live, replacing the cats is the only thing you have to worry about. If you replace them there's a chance you will get a CEL (check engine light) which is telling you that your cats aren't performing right (they aren't making your car environmentally friendly). Well obviously lol.. they aren't there anymore! The CEL doesn't mean that your car is hurting though or anything like that.. and is ok to ignore (in this particular case), but it will cause you to not pass emissions testing. If you get a tune though, it can get rid of the CEL for you. There are also other ways of fixing it, search around here and you can find more info on the topic.
Hope this helps and enjoy your Z!
Great post
Thread
Thread Starter
Forum
Replies
Last Post
