** New ** PTS Full True Dual Exhaust – Joe Z series for IS250 & IS350
06-11-08, 07:26 AM
#64
06-11-08, 07:40 AM
#65
06-11-08, 09:56 AM
#67
In a well researched system like this one you will have gains across the band but the race opens up the exhaust more than the street so it gives up low end for more top end, with regards to the street version
06-11-08, 10:05 AM
#68
This is generally true when openning up exhaust. the more you open it up the more you can potentially lose low end. that is why people who get custom exhausts often lose hp but their wallet and audio dynos tell them otherwise.
In a well researched system like this one you will have gains across the band but the race opens up the exhaust more than the street so it gives up low end for more top end, with regards to the street version
In a well researched system like this one you will have gains across the band but the race opens up the exhaust more than the street so it gives up low end for more top end, with regards to the street version
06-11-08, 02:30 PM
#69
Tech Info Resource
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Back pressure will reduce power at any RPM. The reason why some people think back pressure helps low end is because they don't understand all the different things that can cause back pressure. In many cases "opening up" an exhaust actually increases back pressure at low RPMs because of the harmonic characteristics of the exhaust at low RPMs. This shouldn't be the case for removing a catalytic converter.
Joe - you didn't total the weights. Adding them in my head quickly it appears your exhaust in street trim weighs one pound more than stock and in race trim weighs two pounds less than stock. Is that true?
06-11-08, 02:41 PM
#70
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Here Lance...
I have now requoted my own post with the weight totals...
I used my head too..
Coincidentally, the Street trim weighs the same as stock..
The race trim weighs 3lbs less than stock..
OEM Exhaust Weight = 68 Total pounds
Front-Mid Section = 28lbs
Rear Axle Section = 40lbs
Street Performance Weight = 68 Total pounds
Front Section w/CATS = 16 lbs
Mid Section w/Resonators = 20lbs
Dual Rear Sections w/Mufflers & Tips = 32 lbs
Race Performance Weight = 65 Total pounds
Front Section NO CATS = 13 lbs
Mid Section w/Resonators = 20lbs
Dual Rear Sections w/Mufflers & Tips = 32 lbs
I have now requoted my own post with the weight totals...
I used my head too..
Coincidentally, the Street trim weighs the same as stock..
The race trim weighs 3lbs less than stock..
OEM Exhaust Weight = 68 Total pounds
Front-Mid Section = 28lbs
Rear Axle Section = 40lbs
Street Performance Weight = 68 Total pounds
Front Section w/CATS = 16 lbs
Mid Section w/Resonators = 20lbs
Dual Rear Sections w/Mufflers & Tips = 32 lbs
Race Performance Weight = 65 Total pounds
Front Section NO CATS = 13 lbs
Mid Section w/Resonators = 20lbs
Dual Rear Sections w/Mufflers & Tips = 32 lbs
06-11-08, 02:45 PM
#71
Tech Info Resource
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Thanks Joe! I really do have a lot of respect for your willingness to provide fair information and build quality products. I also know it can be really hard to beat stock, believe me I've tried many times and come up short.
06-11-08, 04:22 PM
#72
Actually the "backpressure" increases because the pipe is bigger. More atmospheric pressure to over come. Yes, I'm keenly aware that atmospheric pressure doesn't change because the pipe's diameter changes, but the absolute pressure in pounds (without the per square inch parts) goes up as diameter goes up, so the exhaust needs more energy to maintain the same velocity with a larger diameter pipe. That's where you lose low end power. It's not because you took "backpressure" away, it's because you increased absolute pressure on the exhaust port.
Joe - you didn't total the weights. Adding them in my head quickly it appears your exhaust in street trim weighs one pound more than stock and in race trim weighs two pounds less than stock. Is that true?
Joe - you didn't total the weights. Adding them in my head quickly it appears your exhaust in street trim weighs one pound more than stock and in race trim weighs two pounds less than stock. Is that true?
06-11-08, 06:17 PM
#73
This is generally true when openning up exhaust. the more you open it up the more you can potentially lose low end. that is why people who get custom exhausts often lose hp but their wallet and audio dynos tell them otherwise.
In a well researched system like this one you will have gains across the band but the race opens up the exhaust more than the street so it gives up low end for more top end, with regards to the street version
In a well researched system like this one you will have gains across the band but the race opens up the exhaust more than the street so it gives up low end for more top end, with regards to the street version
06-12-08, 09:44 AM
#75
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Join Date: Nov 2004
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"iSuxeL"
^^ All you gotta do is re-look at the DYNO graph and ignore any info below 5K rpms.
Clearly, at 5k rpms you can see the difference begin between the Street & Race versions & where the lines cross... and never cross again..
Anything under 5k rpms is where the Tech is starting the dyno & shifting through the gears... Up until 4th gear is reached and than WOT (wide open throttle) occurs.!
Hope this clears things up for you..
******************************************
As promised last night we shot a really quick video...
The quality was great up until I loaded onto youtube.
Either way you can hear it prefectly in my opinion.
Enjoy and grab some popcorn...!!!
Click on still photo..
Joe Z
^^ All you gotta do is re-look at the DYNO graph and ignore any info below 5K rpms.
Clearly, at 5k rpms you can see the difference begin between the Street & Race versions & where the lines cross... and never cross again..
Anything under 5k rpms is where the Tech is starting the dyno & shifting through the gears... Up until 4th gear is reached and than WOT (wide open throttle) occurs.!
Hope this clears things up for you..
******************************************
As promised last night we shot a really quick video...
The quality was great up until I loaded onto youtube.
Either way you can hear it prefectly in my opinion.
Enjoy and grab some popcorn...!!!
Click on still photo..
Joe Z
Last edited by Joe Z; 07-25-09 at 08:08 AM.