Anybody running this setup?
Senior Member
Joined: 09-17-06
Posts: 551
Likes: 0
From: Earth
Originally Posted by NJHK
I understand what you're saying actually but it still comes down to that yes, they need a bigger exhaust system but there is a such thing as too big of an exhaust system. If this wasn't true, people wouldn't be experiencing loss of power at one part of their powerband than the other when going with a very big exhaust system.
I'll give you an example...I have a 4g eclipse, 3.8L V6 SOHC w/MIVEC. Stock I come with a 2 1/2" exhaust system already. Know what most people change on the exhaust system? Just the muffler cause the exhaust is mendrel bent and 2.5"s, which is perfect for that size engine. Some people thought about going 3" and did it. What happened? Sounded nice but a good amount of power lost.
Now I know what you said, there is a difference but an N/A car and F/I car but you still used the theory of comparing a 2.0L S/C w/14 PSI to an 4.0L N/A engine.
I'll give you an example...I have a 4g eclipse, 3.8L V6 SOHC w/MIVEC. Stock I come with a 2 1/2" exhaust system already. Know what most people change on the exhaust system? Just the muffler cause the exhaust is mendrel bent and 2.5"s, which is perfect for that size engine. Some people thought about going 3" and did it. What happened? Sounded nice but a good amount of power lost.
Now I know what you said, there is a difference but an N/A car and F/I car but you still used the theory of comparing a 2.0L S/C w/14 PSI to an 4.0L N/A engine.
My theoretical use of a 2.0L to a 4.0L was only used to compare the amount of exhaust produced. The torque and HP curves of each engine, based on one being a V6 and one being a FI/I4 would be far too different to use as a direct comparison. Even if we could use a 2.0L I4 compared to a 4.0L I4, the bore-to-stroke ratios, rod length, rotating mass, etc. would skew the results too much to get a direct comparison either.
Theoretical analogies are just that; Theoretical.
Senior Member
Joined: 09-17-06
Posts: 551
Likes: 0
From: Earth
Originally Posted by hatrickstu
^^^ that happens when the majority of the participants are not complete friggin idiot e-tools
I like to keep an open mind when it comes to this stuff because IMO, nobody is right until proven so, including myself. I've read up on exhaust theories quite a bit because it's actually a newly explored territory. Nobody really gave it much thought until the average HP on production cars (thanks to FI and EFI) has gone up a lot within the last 10 years.
The hardest part is understanding that no two engines are the same so not one statement about exhaust applies to every engine. It's all based on what the engine is built for, how it's tuned, the bore, stroke, usable RPM range, etc., etc.
By no means am I saying that a single 3" diameter pipe is better for our cars than a 2.5", or a 2.25". A true dyno testing of each size available, as well as different mufflers, along with proper tuning (fuel map, timing curve, etc.) would have to be done in order to find the most productive size.
And even then, while a 3" might provide the most HP at a given RPM, would it produce the most MPG? Or would the difference justify the trouble of using a 3" pipe?
If the dyno testing was done, we may find out that 3" provides no more power than the 2.5", and may, in fact, cause a loss in low RPM torque due to some other unknown variable that was either missed or overlooked. Granted, the loss should not be as high as a N/A engine would be, but there may still be some loss, regardless of what "rule" we (specifically "me") think applies.
Senior Member
Joined: 01-05-06
Posts: 10,877
Likes: 2
From: East Brunswick, NJ
Originally Posted by aj_92rs
Uhhh..... Thanks?
I like to keep an open mind when it comes to this stuff because IMO, nobody is right until proven so, including myself. I've read up on exhaust theories quite a bit because it's actually a newly explored territory. Nobody really gave it much thought until the average HP on production cars (thanks to FI and EFI) has gone up a lot within the last 10 years.
The hardest part is understanding that no two engines are the same so not one statement about exhaust applies to every engine. It's all based on what the engine is built for, how it's tuned, the bore, stroke, usable RPM range, etc., etc.
By no means am I saying that a single 3" diameter pipe is better for our cars than a 2.5", or a 2.25". A true dyno testing of each size available, as well as different mufflers, along with proper tuning (fuel map, timing curve, etc.) would have to be done in order to find the most productive size.
And even then, while a 3" might provide the most HP at a given RPM, would it produce the most MPG? Or would the difference justify the trouble of using a 3" pipe?
If the dyno testing was done, we may find out that 3" provides no more power than the 2.5", and may, in fact, cause a loss in low RPM torque due to some other unknown variable that was either missed or overlooked. Granted, the loss should not be as high as a N/A engine would be, but there may still be some loss, regardless of what "rule" we (specifically "me") think applies.
I like to keep an open mind when it comes to this stuff because IMO, nobody is right until proven so, including myself. I've read up on exhaust theories quite a bit because it's actually a newly explored territory. Nobody really gave it much thought until the average HP on production cars (thanks to FI and EFI) has gone up a lot within the last 10 years.
The hardest part is understanding that no two engines are the same so not one statement about exhaust applies to every engine. It's all based on what the engine is built for, how it's tuned, the bore, stroke, usable RPM range, etc., etc.
By no means am I saying that a single 3" diameter pipe is better for our cars than a 2.5", or a 2.25". A true dyno testing of each size available, as well as different mufflers, along with proper tuning (fuel map, timing curve, etc.) would have to be done in order to find the most productive size.
And even then, while a 3" might provide the most HP at a given RPM, would it produce the most MPG? Or would the difference justify the trouble of using a 3" pipe?
If the dyno testing was done, we may find out that 3" provides no more power than the 2.5", and may, in fact, cause a loss in low RPM torque due to some other unknown variable that was either missed or overlooked. Granted, the loss should not be as high as a N/A engine would be, but there may still be some loss, regardless of what "rule" we (specifically "me") think applies.
Yeah, I like discussing things cause like you said, no body is perfect and always right, including myself. If someone like yourself can show me a theory that makes more sense than the one I know of, I'd be willing to take that into consideration.
And yes, I like the intellectual conversation as well.
Thread
Thread Starter
Forum
Replies
Last Post
ThoR294
Wanted - What to buy - All categories
4
Oct 4, 2015 08:44 PM