Quick Exhaust Question....

TDUB

TDUB

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Ok I'm about to replace my cats with 2.5 magnaflows and 2.5" pipe to my catback system. I currently have the 2.25" magnaflow LS exhaust system. Would there be any benefit to going with a custom 2.5" system all the way back other than sound?
 
I don't know for sure but I think that might actually hurt you or at lease take away some torque because the LS needs alot of backpressure
 
I've heard that but I believe its bs on these cars unless someone has proof to the contrary. There are several people that have run 2.5 cat backs without a loss of power including Quik. I'm just wondering if there's any noticeable gains by switching out my system or if it would be worthless.
 
mine has the magnaflow catback but I'm unsure the difference in gain or loss as well if it's deleted...I want my cats deleted if I get those custom headers sully is trying to get together :/
 
I plan to go fi eventually, but I plan on building up a motor first and then swapping it in so there is as little down time as possible. I hardly ever drive the LS, it's no longer my dd so if I lost a little now to gain later it wouldn't be that big of a deal. However, if you read older threads Quik had the 2.5 before he went with the supercharger and he's not the only one who has done so but I couldn't find any dyno results either way.
 
What 2.5" pipe will do is change your power curve. You'll lose some low-end torque, but your top end power will be increased.
 
That's what I've been reading and kind of figured. Little bit of loss on the low end and more a gain in the middle-high end. But exactly how much and do the costs outweigh the benefits? Another thing, I already have the 2.5" cats so if I went ahead and had the mid pipes done in 2.5" back to my 2.25" cat back what effect is that going to have performance wise?
 
Nothing. Your exhaust will only flow as well as it's most restrictive component.
 
I wouldn't think so. On my stock pipes on my 2000 V8, the pipe from the resonators back looked smaller than the pipe between the cats and resonators.
 
In an older thread someone said they thought that the mid pipes were 2.5 but then someone else said it was 2.25 all the way back. It's like with the magnaflow, it's advertised as a 2.5 on most sites which is one of the reasons I bought it but in reality it's only a 2.25.
 
pektel said:
Nothing. Your exhaust will only flow as well as it's most restrictive component.
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close, but technically incorrect. Exhaust is moving air which behaves the same as a fluid flowing through a closed system (think water through a hose). Everything that flows into one end comes out the other, so we are talking pressure loss (Head in hydraulic terms). The pressure loss through the system is the sum of all minor losses (friction, bends, contractions, etc). In this case the pressure loss is commonly referred to as "backpressure" Open exhaust ports would have no pressure loss and therefore no backpressure.

Changing the size of the line is like adding a larger hose, reducing the backpressure as we all know. The same flow comes through the pipe but the velocity is less so less loss. Of course the values can be calculated or measured but that is overly complicated for the end user.

As with any "performance" mod there is a risk of actually losing performance when changing something the car was designed around. In a FI application Quik is pushing more flow through the exhaust and in fact needed the greater diameter to maintain approximately the same backpressure as stock. I would recommend keeping the same size exhaust if you intend to do a full system.... for performance reasons. If you are changing the pipes for sound then do what you will.
 
TDUB said:
I've heard that but I believe its bs on these cars unless someone has proof to the contrary. There are several people that have run 2.5 cat backs without a loss of power including Quik. I'm just wondering if there's any noticeable gains by switching out my system or if it would be worthless.
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You could do everyone a favor and get it dyno'ed before and after. Then we could all know for sure how it affects our cars and if it is worth the change.
 
FALECF4 said:
You could do everyone a favor and get it dyno'ed before and after. Then we could all know for sure how it affects our cars and if it is worth the change.
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I would but there's only a few shops around here with dynos and I'm pretty sure they charge more than the cost of the exhaust would be.
 
Frogman said:
Modular Madness. Wouldn't trust those morons to tune your car, but they do have a dyno that's reasonably priced. They are on State and... IIRc, a little south of 9000 S... or thereabouts.
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Yeah I know about them. However, I'm still wondering if it's worth it to go with a 2.5" set up
 
join a mustang club

those guys do dyno days all the time. They get some smoking prices for it too
 
Shops all around here will setup your car and do just a dyno pull for $75...now tuning the car once you have the data is another story..that's where it can get expensive
 
SPSully said:
join a mustang club

those guys do dyno days all the time. They get some smoking prices for it too
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I've thought about it. I just don't like my 5.0 enough and I can't exactly drive my Mach 1 yet lol. Is there anyone else on here that has a 2.5" exhaust? What kind of gains/losses did you see?
 
I have a 2.5" exhaust. Why? Because that's what my friend had at his shop. Gains or losses? No idea. Don't really care either. :D
 
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