drifty325i
New Member
Thats it i had to be practical and for it to be possible would help lol.
1UZFE exhaust experts
- Thread starter drifty325i
- Start date
The 1UZFE EGR Delete Kit is available for sale here.
This is an example of WHY it is very hard to make any specific recommendations. The vast majority of other examples would loose low end with no noticable high end gain and be louder when going to the larger pipe.
So, what is the explanation?
It is probable that your specific combination effectively creates a tuned effect where the larger pipe is seen basically by the engine at LOW RPM as the end of the tailpipe.
Sound is just like any wind instrument such as a clarinet, tuba or slide trombone where the end sound is a result of the ENTIRE system. Sound waves can either cancel each other or add to each other depending on the specifics for a particular system.
Peak power is another thing. The butt-o-meter dyno is no indication of actual gains or loss. It is possible that you do not notice much of a low end loss when in fact there is one (not saying this is the case just a possibility). Now, with less low end the top end will "FEEL" stronger by contrast.
So, without test results it is not as easy to determine what, how and why things are as they are.
The bottom line IN YOUR CASE you like the pipe size.
That said unless you are exceeding 350hp the 2.5" pipe SIZE is not a restriction.
Please remind us of your current system.
God that sounds cool! i honestly cant wait for the v8 sound, i think im looking forward to that THE MOST
drifty325i
New Member
drifty325i
New Member
This is what im using, 1 3inch rosonator, 1 3inch inlet muffler with twin outlets. All 2.5 inch pipes
drifty325i
New Member
How on earth would it be quieter? Unless the 2.5 was a poor design there should be no real performance gain over a 2.5 of the same quality
1UZFE Matt
Member
Drifty325i I run 2 into 2 extractors then twin 2.25" to about the back of the gearbox then single 2.5" with a straight through resonator and a straight through magnaflow muffler. Sounds awsome and has given me 210kw (Flywheel) with stock crown motor/management and K&N filter. Have a listen here.
http://www.youtube.com/watch?v=LucLEaqwTCo
or
http://www.youtube.com/watch?v=Fdde5BcKYq8
Cheers.
Matt.
http://www.youtube.com/watch?v=LucLEaqwTCo
or
http://www.youtube.com/watch?v=Fdde5BcKYq8
Cheers.
Matt.
This is an example of WHY it is very hard to make any specific recommendations. The vast majority of other examples would loose low end with no noticable high end gain and be louder when going to the larger pipe.
So, what is the explanation?
It is probable that your specific combination effectively creates a tuned effect where the larger pipe is seen basically by the engine at LOW RPM as the end of the tailpipe.
Sound is just like any wind instrument such as a clarinet, tuba or slide trombone where the end sound is a result of the ENTIRE system. Sound waves can either cancel each other or add to each other depending on the specifics for a particular system.
Peak power is another thing. The butt-o-meter dyno is no indication of actual gains or loss. It is possible that you do not notice much of a low end loss when in fact there is one (not saying this is the case just a possibility). Now, with less low end the top end will "FEEL" stronger by contrast.
So, without test results it is not as easy to determine what, how and why things are as they are.
The bottom line IN YOUR CASE you like the pipe size.
That said unless you are exceeding 350hp the 2.5" pipe SIZE is not a restriction.
Please remind us of your current system.
drifty325i
New Member
Man this thread is good, cheers guys
drifty325i
New Member
God that sounds cool! i honestly cant wait for the v8 sound, i think im looking forward to that THE MOST
Something that most people do not grasp is there is a BIG difference between flow capacity and flow dynamics.
Here is a way to help visualize the flow concern.
For our example we will use a theoretical engine with a flat torque curve of 300ft/lbs. From this we can easily calc power at any RPM. Here are the horsepower calcs for even RPM ranges:
57hp @ 1000rpm
114hp @ 2000rpm
171hp @ 3000rpm
228hp @ 4000rpm
285hp @ 5000rpm
342hp @ 6000rpm
Horsepower is a very good indication of exhaust flow (also intake flow).
When we choose an exhaust pipe, say 2.5", at some point that pipe size will restrict flow enough to reduce power measurably.
I state that it will support at least 350hp before this happens.
Now, ask yourself, if it can support 350hp how much is it restricting at 300hp?
How about at 200hp?
Obviously any power and flow number lower than its capacity means there is no restriction.
Now, it is BEST to have a high velocity in the pipe. High velocity acts to power the flow away from the engine. There is nearly ZERO flow reversion when velocity is high. The way to get velocity is use the SMALLEST pipe size needed. So, for 200hp you need a smaller pipe for best power than for 300hp.
So, when you install a pipe to support max flow it is TOO BIG for all other RPM/power levels.
This is why a bigger pipe almost always hurts low RPM power.
SOMETIMES (rarely but on occasion) an engine will make more low RPM power with a bigger pipe. This is USUALLY the result of the DYNAMICS of the entire SYSTEM.
There are many variables but ONE consideration is how the engine SEEs the bigger pipe. It may see it as NO PIPE AT ALL at low RPM. In this case the engine THINKS the system is only as long as the smaller pipes before the increase. IF and this is a BIG IF... the short pipes are accidentially the correct size, shape, length and position for making good low RPM power then this would make for an increase in low RPM power.
Now, if you have the time, money, patience and ability to test various combinations you may come up with the above OR GET LUCKY.
Now, lets assume you do the above. What happens at middle and high RPM?
Again, unless you test and measure you do not know. If the engine thinks it has short pipes at low RPM at some point that will change. This creates a change in the power curve and is usually LESS power or a dip in the dyno curve. If you are lucky and improved low RPM power but have a dip at transition you will then FEEL like it is pulling harder at higher RPM if you did not loose any high RPM power with the system. In fact you could loose some high RPM power and still FEEL stronger because of the contrast between the dip in mid power and increase in top end.
Here is a way to help visualize the flow concern.
For our example we will use a theoretical engine with a flat torque curve of 300ft/lbs. From this we can easily calc power at any RPM. Here are the horsepower calcs for even RPM ranges:
57hp @ 1000rpm
114hp @ 2000rpm
171hp @ 3000rpm
228hp @ 4000rpm
285hp @ 5000rpm
342hp @ 6000rpm
Horsepower is a very good indication of exhaust flow (also intake flow).
When we choose an exhaust pipe, say 2.5", at some point that pipe size will restrict flow enough to reduce power measurably.
I state that it will support at least 350hp before this happens.
Now, ask yourself, if it can support 350hp how much is it restricting at 300hp?
How about at 200hp?
Obviously any power and flow number lower than its capacity means there is no restriction.
Now, it is BEST to have a high velocity in the pipe. High velocity acts to power the flow away from the engine. There is nearly ZERO flow reversion when velocity is high. The way to get velocity is use the SMALLEST pipe size needed. So, for 200hp you need a smaller pipe for best power than for 300hp.
So, when you install a pipe to support max flow it is TOO BIG for all other RPM/power levels.
This is why a bigger pipe almost always hurts low RPM power.
SOMETIMES (rarely but on occasion) an engine will make more low RPM power with a bigger pipe. This is USUALLY the result of the DYNAMICS of the entire SYSTEM.
There are many variables but ONE consideration is how the engine SEEs the bigger pipe. It may see it as NO PIPE AT ALL at low RPM. In this case the engine THINKS the system is only as long as the smaller pipes before the increase. IF and this is a BIG IF... the short pipes are accidentially the correct size, shape, length and position for making good low RPM power then this would make for an increase in low RPM power.
Now, if you have the time, money, patience and ability to test various combinations you may come up with the above OR GET LUCKY.
Now, lets assume you do the above. What happens at middle and high RPM?
Again, unless you test and measure you do not know. If the engine thinks it has short pipes at low RPM at some point that will change. This creates a change in the power curve and is usually LESS power or a dip in the dyno curve. If you are lucky and improved low RPM power but have a dip at transition you will then FEEL like it is pulling harder at higher RPM if you did not loose any high RPM power with the system. In fact you could loose some high RPM power and still FEEL stronger because of the contrast between the dip in mid power and increase in top end.
Well said.....
Yep, the bigger the pipes you do lose the lowend power but at high rpms you are wide open and flowing...It's almost a give and a take...
Smaller pipes gives you much better lowend power but squeezes the topend and high rpm power...
The key is to find a happy medium which is probably 2.25 mandrel piping thru out on a N/A 1uz-fe exhaust system...
I would still like to think that with some huge mandrel piping that you can almost roll a tennis ball down your headers on out thru the mufflers would be your best bet if you can somehow retain your lowend torque and not bog... Back pressure in the exhaust plays a key roll....
Yep, the bigger the pipes you do lose the lowend power but at high rpms you are wide open and flowing...It's almost a give and a take...
Smaller pipes gives you much better lowend power but squeezes the topend and high rpm power...
The key is to find a happy medium which is probably 2.25 mandrel piping thru out on a N/A 1uz-fe exhaust system...
I would still like to think that with some huge mandrel piping that you can almost roll a tennis ball down your headers on out thru the mufflers would be your best bet if you can somehow retain your lowend torque and not bog... Back pressure in the exhaust plays a key roll....
Kiwi.in.aus
New Member
Mr Brady is on the money , I used to build pipes for VFR400R's , a 400cc 360 degree V4 , the first underseat system I built was exactly right !!
More fluke than anything , the primary headers where 20" long then the pipe diameter stepped up about 20 % this step up was for the mandrel bends I could get off the shelf , the secondary length was about 18" , again correct just by chance then the pipe pipe diameter stepped up about 20 % again to go into the twin mufflers which where 50mm straight through the guts , this fooled the engine into thinking the gases had gone to open air , this worked from 5800 RPM all the way to 14,000 RPM , unknownly we had got it spot on .
When we did the same to a mates VFR750 we got it completely WRONG !!
Being a 750 his engine worked from about 4500 RPM to 9500 RPM and redline was 11000 RPM , after we fitted the new underseat system it had a Huuuuge hole through to 9000 RPM and then it went mental !!
Up the top it had 10 more HP than the standard specs , but what a hole , this is when we went and talked to a guy who builds race headers for all kinds of things after he's done all the calculations , he asked for cam timing , duration , the redline and port sizes and the capacity and what area of the rev range we needed the engine to work and of course being a bike we said mid-range .
This is when we learnt about primary header size and length , secondary size and length and how to " fool " the engine into thinking something different had happened to the systen due to the size of the pipe .
And the number one god VELOCITY !!
As I can't buy a semi decent set of Tri-Y's for my Celsior I will make my own and low down and mid-range will be the target , primary header size will not be bigger than 1.5" [ 38mm ] and might even be the next size down 35.8 mm , gotta keep that velocity up !!
People tend to think that bigger is better and this is not the case .
More fluke than anything , the primary headers where 20" long then the pipe diameter stepped up about 20 % this step up was for the mandrel bends I could get off the shelf , the secondary length was about 18" , again correct just by chance then the pipe pipe diameter stepped up about 20 % again to go into the twin mufflers which where 50mm straight through the guts , this fooled the engine into thinking the gases had gone to open air , this worked from 5800 RPM all the way to 14,000 RPM , unknownly we had got it spot on .
When we did the same to a mates VFR750 we got it completely WRONG !!
Being a 750 his engine worked from about 4500 RPM to 9500 RPM and redline was 11000 RPM , after we fitted the new underseat system it had a Huuuuge hole through to 9000 RPM and then it went mental !!
Up the top it had 10 more HP than the standard specs , but what a hole , this is when we went and talked to a guy who builds race headers for all kinds of things after he's done all the calculations , he asked for cam timing , duration , the redline and port sizes and the capacity and what area of the rev range we needed the engine to work and of course being a bike we said mid-range .
This is when we learnt about primary header size and length , secondary size and length and how to " fool " the engine into thinking something different had happened to the systen due to the size of the pipe .
And the number one god VELOCITY !!
As I can't buy a semi decent set of Tri-Y's for my Celsior I will make my own and low down and mid-range will be the target , primary header size will not be bigger than 1.5" [ 38mm ] and might even be the next size down 35.8 mm , gotta keep that velocity up !!
People tend to think that bigger is better and this is not the case .
stevechumo
Active Member
Jbrady,
No one can beat you on the exhaust so far. Very well said. I'd like to add a little detail is that when the engine sees the exhaust gas or no exhaust gas, that means the flow has the effect on the backpressure that has the effects on the exhaust valves....etc. And this has effect on the engine performance over all.
No one can beat you on the exhaust so far. Very well said. I'd like to add a little detail is that when the engine sees the exhaust gas or no exhaust gas, that means the flow has the effect on the backpressure that has the effects on the exhaust valves....etc. And this has effect on the engine performance over all.
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