Intake & Exhaust Questions and info regarding various aftermatket exhaust systems for the G35 (Headers,Y-Pipes, and Cat-Back Systems)

Catback and Plenum Spacer

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Old Apr 16, 2014 | 12:01 AM
  #31  
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Just Google Motordyne or look in the marketplace.
 
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Old Aug 19, 2014 | 02:30 AM
  #32  
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I have read a few different things in regards to the spacer or kinetix v+ upper plenum. I have an 05 coupe 6MT with the K&N drop in with stock everything and was wondering if I added either of those mods if I would have to get an exhaust or a tune. I have always heard that if your exhaust is restrictive then an intake does no good. Can somebody clear that up?
 
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Old Aug 19, 2014 | 03:51 AM
  #33  
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Originally Posted by Exodus5656
I have read a few different things in regards to the spacer or kinetix v+ upper plenum. I have an 05 coupe 6MT with the K&N drop in with stock everything and was wondering if I added either of those mods if I would have to get an exhaust or a tune. I have always heard that if your exhaust is restrictive then an intake does no good. Can somebody clear that up?
An engine is a very fancy air pump. Getting as much air in and out as efficiently as possible is the key to making HP thru air mods. Any time you can get rid of chambers that cause turbulence (I.e. resonators, baffles [g-tube], mufflers) or parts that are restrictive that keep the engine from breathing in or expelling sufficient air (i.e. cats, pipes that are too small, restrictive filters, imperfect plenum designs, mufflers), you are improving the efficiency of the motor and that is always good.

We also have very smart cars that are tuned to run a certain way and require an air/fuel ratio that is considered "optimal". Any time you change a part that improves flow, the computer tries to adjust the air/fuel to run as close to stock as possible. This isn't always possible, however, so when you change too many parts that improve flow you get air fuel mixtures that are less than optimal which means you need a tune to rewrite the computers objectives.

So yes, intake without exhaust will show improved airflow, but not as much as it would when paired with an exhaust, and neither of them do a whole lot without a proper tune. Some are noticeable without a tune and some aren't. The most noticeable are the plenum spacer and a good exhaust.
 

Last edited by ScraggleRock; Aug 19, 2014 at 02:45 PM.
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Old Aug 19, 2014 | 11:24 AM
  #34  
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Originally Posted by Gdirtyfive55
An engine is a very fancy air pump. Getting as much air in and out as efficiently as possible is the key to making HP thru air mods. Any time you can get rid of chambers that cause turbulence (I.e. resonators, baffles [g-tube], mufflers) or parts that are restrictive that keep the engine from breathing in or expelling sufficient air (i.e. cats, pipes that are too small, restrive filters, imperfect plenum designs, mufflers), you are improving the efficiency of the motor and that is always good.

We also have very smart cars that are tuned to run a certain way and require an air/fuel ratio that is considered "optimal". Any time you change a part that improves flow, the computer tries to adjust the air/fuel to run as close to stock as possible. This isn't always possible, however, so when you change too many parts that improve flow you get air fuel mixtures that are less than optimal which means you need a tune to rewrite the computers objectives.

So yes, intake without exhaust will show improved airflow, but not as much as it would when paired with an exhaust, and neither of them do a whole lot without a proper tune. Some are noticeable without a tune and some aren't. The most noticeable are the plenum spacer and a good exhaust.
And to add on to his fancy explanation, HFCs/TPs also does wonders since the cats are pretty restrictive.
 
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Old Oct 22, 2014 | 06:56 PM
  #35  
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I got High Flow Cats from that, but what is the TP? Is that stand for test pipe?

I ask these noon questions because I don't have a lot of money I am willing to spend without good solid proof and bang for my buck. I over research stuff. I'm also not quite sure which direction I want to go either. Fi w/ TT or just a single, n/a, L's swap... Idk what I want right now. I do know that I'm currently in maintenance/repair phase until I fix the issues it has now. After everything is good and TLC is over idk which direction I want. I might just optimize what I have and save to build a separate motor and tranny to swap back and fourth when I have issues. Or I am bored.
 
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Old Oct 22, 2014 | 09:49 PM
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Originally Posted by Exodus5656
I got High Flow Cats from that, but what is the TP? Is that stand for test pipe?
Yes, TP stands for test pipe which is just another name for a straight pipe.
 
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Old Oct 23, 2014 | 12:24 AM
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Had any of you bothered to read the stickys they explain what mods to make first! Like one member posted gas engines are nothing more than air pumps! The faster you get air in and out the more WHP you'll make! Intakes have never made any WHP that's a fact! However if you combine an intake with a spacer which corrects Nissans design flaw and HFCs plus a high flow exhaust that's when you'll need a tune because you'll be running lean. Only then will everything you've bolted on add up to power/torque and put a smile on your face! None of these mods alone will make you run lean, it takes everything listed!
Gary
 
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Old Oct 23, 2014 | 12:47 AM
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Thanks Gary! So referring to what was said earlier about test pipes, how easy is it to do a car delete and how reliable is the motor after?
 
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Old Oct 23, 2014 | 01:03 AM
  #39  
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Originally Posted by Exodus5656
Thanks Gary! So referring to what was said earlier about test pipes, how easy is it to do a car delete and how reliable is the motor after?
if u delete the car, I don't see the motor being very reliable at all
 
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Old Oct 23, 2014 | 01:30 AM
  #40  
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Originally Posted by SwtLaotiaNix7
if u delete the car, I don't see the motor being very reliable at all
My bad.. Lol I was aiming for the t, guess I hit the r. So a cat delete.. I know it would allow a lot more air flow, but what potential hang ups would I have without cats just going headers, resonators, muffler, and tips? I understand the cat burns off emissions, but if I either place the o2 sensor elsewhere or remove it all together is the question after a cat delete.
 
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Old Oct 23, 2014 | 01:39 AM
  #41  
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You can use non-fowlers for the rear O2 sensors which will prevent any codes from popping up. TP's really aren't going to affect the engine's reliability. Also, why are you going with headers? Without cam work the only thing they're going to do is make the car louder.
 
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Old Oct 23, 2014 | 04:17 AM
  #42  
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Just bringing up scenarios. I probably won't get into headers, cams, or pistons until I have a clear vision of my power plant. Idk if I want fi or an or go all out with a LSX swap. Just collecting knowledge to spend my money as wisely as I can without wasting money on something that is sub par for the price. I have researched plenums, cats, spacers, exhaust, header,..... Basically every part I can swap for a performance boost. All that trying to make sure I get exactly what I want.
 
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Old Oct 23, 2014 | 11:25 AM
  #43  
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You shouldn't do cat delete, go with HFCs the environment will thank you! Freeing up the exhaust will not damage your engine! If you do go with HFCs using any part of the OE exhaust system will cause rasp and other noises you won't enjoy listening to.
Gary
 
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Old Oct 23, 2014 | 02:04 PM
  #44  
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Does brand matter much? If I mix and match HFC and a cat back kit? Honestly I was thinking of having a shop make me a cat back system instead of spending a large chunk for the same thing.
 
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Old Oct 23, 2014 | 08:10 PM
  #45  
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Originally Posted by Exodus5656
Does brand matter much? If I mix and match HFC and a cat back kit? Honestly I was thinking of having a shop make me a cat back system instead of spending a large chunk for the same thing.
spend a small chunk for a used one.
Brand matters usually in terms of quality and rasp/drone issues.
The lower priced setups have shitty welds, discolor over time and drone and rasp a ton
 
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