Exhaust-what size?
11-30-2007, 07:12 AM
#21
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but yeah, i could only see a 3VZE or the 5VZE setting off alarms with just headers, and nothing else...
11-30-2007, 08:47 AM
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I have a 22re, pace setter header, 2.5" a$$, cheapo turbo muff, bore 40 over, k/n intake, no cat(at the time).....
I would set off about 3/4 of the alarms I past
If you like a little exhaust gurgle, go with 2.5, but 2.25 will help keep a solid low end torque for the 3.slow...
choose wisely young grasshopper
I would set off about 3/4 of the alarms I past
If you like a little exhaust gurgle, go with 2.5, but 2.25 will help keep a solid low end torque for the 3.slow...
choose wisely young grasshopper
11-30-2007, 09:57 AM
#24
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I've seen .25" increases drop low range horsepower by almost 8whp on natually aspirated engines especially ones that don't have much torque to begin with.
The kid about cried that his $600 catback actually was slowing him down but looks and sound rule what people put on their cars/trucks sometimes.
2.5" on a 3.0 is hurting it down low and if you put it on a dyno you'd see since you're fooling yourself if you feel an increase in power.
2.25" is as big as you'd want to go even on a NA 3.4 3rd gen motor.
The kid about cried that his $600 catback actually was slowing him down but looks and sound rule what people put on their cars/trucks sometimes.
2.5" on a 3.0 is hurting it down low and if you put it on a dyno you'd see since you're fooling yourself if you feel an increase in power.
2.25" is as big as you'd want to go even on a NA 3.4 3rd gen motor.
08-27-2008, 10:18 PM
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05-22-2011, 06:20 PM
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Heres how it works.
As the guy before me stated, diameter size affects flow.
Smaller diameter exhaust pipes increases exhaust velocity which = increased scavenging which = increased lower end torque and decreases high end torque + decreased gas mileage.
Larger diameter pipes decreases exhaust velocity which = higher exhaust volume flow but decreases scavenging. This in turn will decrease your low end torque but increase your high end torque + increase fuel mileage due to increased volume.
The only real way to optimize your torque output throughout the powerband is to use stepped headers and custom collectors. Stepped headers are just that, stepped diameter main runners. Start small, and increase the runner length 2 more times before the collector. Various diamater and collector lengths will affect your exhaust flow. The problem with finding the right tune is it requires endless hours of fabrication and dyno testing. Most of which the common person and/or shop doesnt have the ability to do. NASCAR engine builders and tuners spend endless hours in the fab shop and on the dyno to tune their exhaust.
In short there is no way to find the perfect combo for headers and exhaust when buying from aftermarket manufacturers. You will never tune your exhuast to its full potential unless you have thousands of dollars to pay a race shop to build a complete custom exhaust for you.
Heres another fun fact for exhaust flow. NASCAR cup engines are producing anywhere from 750 to 900 HP and Torque. Did you know that with that much power the main runner on the header is only about 1 7/8" and only steps up around 1/8" with each step? Did you also know that the defacto exhaust pipe diameter is 2.25"? Just remember that these cup engines are far far more efficient than any production made engine. Cup engines normally run at 110 to 120% volumetric efficiency as opposed to the average 75 to 85% of production cars. So do you really think that the little low powered 3vze needs 3" exhaust? You'd be out of your mind to use 3", you will kill any power you have and decrease your mileage due to highly decreased scavenging. It is possible to go too big.
As for backpressure, again NASCAR is different, they run 0psi in the exhaust. On road cars you want anywhere from 1 but no more than 3psi. This really doesnt have much affect on fuel mileage, more so on driveability and smoothness of the ride.
From what I've learned recently at school, and from what I see on the forums here, I'd say upgrade the headers, leave the downpipe the stock size, add a highflow cat, and add no more than 2.25" catback with a highflow performance muffler (if you want a muffler). Personally I prefer Magnaflow, they seem to be the best buy in my opinion. Plus my instructors also recommend Magnaflow and they are retired NASCAR engine builders. If you are curious about my education in these matters. I recently graduated from NASCAR Technical Institute located in Mooresville NC A.K.A. Race City USA, a branch campus of Universal Technical Institute.
Just remember these simple rules and you will know what you are about to do to with ANY engine, race or street.
Small pipe = low end torque increase = high end torque decrease = decreased fuel mileage.
Large pipe = low end torque decrease = high end torque increase = increased fuel mileage.
There is much much more I could go into detail with trying to increase efficiency but it will take a while. If anyone is interested I could go further into detail.
Tip of the Day: After an exhuast upgrade, just because its louder doesnt mean its more powerfull!
As the guy before me stated, diameter size affects flow.
Smaller diameter exhaust pipes increases exhaust velocity which = increased scavenging which = increased lower end torque and decreases high end torque + decreased gas mileage.
Larger diameter pipes decreases exhaust velocity which = higher exhaust volume flow but decreases scavenging. This in turn will decrease your low end torque but increase your high end torque + increase fuel mileage due to increased volume.
The only real way to optimize your torque output throughout the powerband is to use stepped headers and custom collectors. Stepped headers are just that, stepped diameter main runners. Start small, and increase the runner length 2 more times before the collector. Various diamater and collector lengths will affect your exhaust flow. The problem with finding the right tune is it requires endless hours of fabrication and dyno testing. Most of which the common person and/or shop doesnt have the ability to do. NASCAR engine builders and tuners spend endless hours in the fab shop and on the dyno to tune their exhaust.
In short there is no way to find the perfect combo for headers and exhaust when buying from aftermarket manufacturers. You will never tune your exhuast to its full potential unless you have thousands of dollars to pay a race shop to build a complete custom exhaust for you.
Heres another fun fact for exhaust flow. NASCAR cup engines are producing anywhere from 750 to 900 HP and Torque. Did you know that with that much power the main runner on the header is only about 1 7/8" and only steps up around 1/8" with each step? Did you also know that the defacto exhaust pipe diameter is 2.25"? Just remember that these cup engines are far far more efficient than any production made engine. Cup engines normally run at 110 to 120% volumetric efficiency as opposed to the average 75 to 85% of production cars. So do you really think that the little low powered 3vze needs 3" exhaust? You'd be out of your mind to use 3", you will kill any power you have and decrease your mileage due to highly decreased scavenging. It is possible to go too big.
As for backpressure, again NASCAR is different, they run 0psi in the exhaust. On road cars you want anywhere from 1 but no more than 3psi. This really doesnt have much affect on fuel mileage, more so on driveability and smoothness of the ride.
From what I've learned recently at school, and from what I see on the forums here, I'd say upgrade the headers, leave the downpipe the stock size, add a highflow cat, and add no more than 2.25" catback with a highflow performance muffler (if you want a muffler). Personally I prefer Magnaflow, they seem to be the best buy in my opinion. Plus my instructors also recommend Magnaflow and they are retired NASCAR engine builders. If you are curious about my education in these matters. I recently graduated from NASCAR Technical Institute located in Mooresville NC A.K.A. Race City USA, a branch campus of Universal Technical Institute.
Just remember these simple rules and you will know what you are about to do to with ANY engine, race or street.
Small pipe = low end torque increase = high end torque decrease = decreased fuel mileage.
Large pipe = low end torque decrease = high end torque increase = increased fuel mileage.
There is much much more I could go into detail with trying to increase efficiency but it will take a while. If anyone is interested I could go further into detail.
Tip of the Day: After an exhuast upgrade, just because its louder doesnt mean its more powerfull!
09-08-2011, 09:58 AM
#27
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Flowmaster 40
I've got 2.5'' from the manifold. No Cat. Single in dual out 2.5'' flowmaster 40. Best exhaust ive heard on the 22re. I would suggest that to anybody.
P.S. -If you're looking for quiet exhaust, this is not for you.
P.S. -If you're looking for quiet exhaust, this is not for you.
09-08-2011, 10:26 AM
#28
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Just so I can establish the mentality on this site, I've got a question for everyone.
How many people believe that, cut and dry, smaller pipe=more backpressure=more torque, larger pipe=less backpressure=lower torque?
Smaller pipe= Faster escape for exhaust (it moves faster and is hotter) better pulsation and flow is what you are looking for.
STRAIGHT IS GOOD!!! Shoot for a straight exhaust path rather than a big fat exhaust. easier to get it straighter with a smaller exhaust usually.
Larger exhaust will move slower and lose heat, thus moving slower.... The larger and longer the worse you will be... You want the smallest pipe possible without RESTRICTING flow.
Same concept for forced induction. a 3" intercooler pipe on a 500hp car is worthless waste of money and hurts performance. you should be running a 2.5" pipe. But most people choose go big or go home... And not real logic. It sounds cool to have 2.5" pipe. who the hell wants 2.25"? psh.... the bigger it is the more more HP.... not.
How many people believe that backpressure is what creates torque?
How many of you, say "in order to have torque, you have to have backpressure"?
How many people believe that, cut and dry, smaller pipe=more backpressure=more torque, larger pipe=less backpressure=lower torque?
Smaller pipe= Faster escape for exhaust (it moves faster and is hotter) better pulsation and flow is what you are looking for.
STRAIGHT IS GOOD!!! Shoot for a straight exhaust path rather than a big fat exhaust. easier to get it straighter with a smaller exhaust usually.
Larger exhaust will move slower and lose heat, thus moving slower.... The larger and longer the worse you will be... You want the smallest pipe possible without RESTRICTING flow.
Same concept for forced induction. a 3" intercooler pipe on a 500hp car is worthless waste of money and hurts performance. you should be running a 2.5" pipe. But most people choose go big or go home... And not real logic. It sounds cool to have 2.5" pipe. who the hell wants 2.25"? psh.... the bigger it is the more more HP.... not.
How many people believe that backpressure is what creates torque?
How many of you, say "in order to have torque, you have to have backpressure"?
Has nothing to do with that.
IMPORTANT PART. engineering and design for specific use to vary the power curve slightly and performance.. exhaust size is COMPLETELY relative to the size and output of the motor.
Last edited by 4x4climber; 09-08-2011 at 10:28 AM.
11-25-2011, 06:56 AM
#29
wow..........
now i'm REALLY confused...........
Running a 4x4 87 P/U automatic 22RE w/Supra AFM upgrade. When I add a header should I use a 2.25 or 2.5 exhaust? dont care about "cool exhaust noise" or setting off car alarms (sorry I'm not 15) but would like a bit more power & torque from the old girl. not unhappy now, just would like a bit more.
now i'm REALLY confused...........
Running a 4x4 87 P/U automatic 22RE w/Supra AFM upgrade. When I add a header should I use a 2.25 or 2.5 exhaust? dont care about "cool exhaust noise" or setting off car alarms (sorry I'm not 15) but would like a bit more power & torque from the old girl. not unhappy now, just would like a bit more.
11-25-2011, 01:57 PM
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I got a question to, I got a 22RE and was thinkin bout cuttin the exhaust right in front of the converter and then runnin 2 1/4 back and come out in front of the rear tire. Would there be enough back pressure or not and right now the exhaust ends right after the converter
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