[Rennmeister]

Equal vs. Unequal Length Headers Info


The sound recording part at the bottom is interesting. Essentially it's a plot of pressure measured off the rear bumper between an OEM header and a EL Killer B header. You can see the difference in sound waves pretty clearly.

EL

https://www.youtube.com/watch?v=hoEoVyy4PW4

UEL

https://www.youtube.com/watch?v=5sjbuqCkz24

 

[zax]

I always enjoy your content.

Thank you for posting!

 

[XJman]

Anyone without the equal length headers are missing out. Man it sounds so smooth and clean.

 

[EJ257]

Anyone without the equal length headers are missing out. Man it sounds so smooth and clean.

I have no regrets having gone EL


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[ProZach626]

Anyone without the equal length headers are missing out. Man it sounds so smooth and clean.

The boxer "rumble" might be what I love most about my car. (I know the term is cheesy, but it's familiar to most people) My car has much more emotional and overall experience value for me than it does performance value. I rarely drive hard. I don't even want to get a down pipe, because it changes the pitch of the exhaust note. However, if I were concerned with performance I would go ELH all the way. I understand the performance benefits. I also understand the reliability benefits, but with my car reliability can't get much worse.

 

[4EverMetal]

With a twin scroll turbo with unequal heads would defeat the bennifets of the twin scroll design. I love the twin scroll in my WRX and if the next STI has one gone will be the UEL headers.

 

[zax]

if the next STI has one gone will be the UEL headers.

I would certainly hope this to be the case.

Looking at the way Subaru judged the American market in 2003, it's easy to see why UEL headers were incorporated... and it has little to do with the sound.

in 2001, Subaru was criticized for a cripplingly high boost threshold in the WRX by several American automotive journalists. Subaru came to the conclusion Americans wanted torque and they wanted it now. The EJ257 was designed to incorporate AVCS for improved turbo dynamics, smaller and higher-velocity ports for low-rpm cylinder filling, greater displacement, and that UEL header to spool the turbo just a touch quicker. I still say that the way in which Subaru was beaten at its own game is almost poetic. Before the USDM STI, turbo cars had a high strung and peaky character. The EJ257 was designed to break that mold by offering a turbo mill with greater mid range. Current 2L mills can produce the power of an EJ257 with even greater midrange thanks to DI, high CR, and "headerfold" designs to minimize heat loss. If Subaru had brought over the EJ207 to USDM, it would be somehow special today in the sea of high-torque turbo mills. But alas, the EJ257 is everything the other turbo mills are, but worse. :shakehead:

 

[Rennmeister]

I would certainly hope this to be the case.

Looking at the way Subaru judged the American market in 2003, it's easy to see why UEL headers were incorporated... and it has little to do with the sound.

in 2001, Subaru was criticized for a cripplingly high boost threshold in the WRX by several American automotive journalists. Subaru came to the conclusion Americans wanted torque and they wanted it now. The EJ257 was designed to incorporate AVCS for improved turbo dynamics, smaller and higher-velocity ports for low-rpm cylinder filling, greater displacement, and that UEL header to spool the turbo just a touch quicker. I still say that the way in which Subaru was beaten at its own game is almost poetic. Before the USDM STI, turbo cars had a high strung and peaky character. The EJ257 was designed to break that mold by offering a turbo mill with greater mid range. Current 2L mills can produce the power of an EJ257 with even greater midrange thanks to DI, high CR, and "headerfold" designs to minimize heat loss. If Subaru had brought over the EJ207 to USDM, it would be somehow special today in the sea of high-torque turbo mills. But alas, the EJ257 is everything the other turbo mills are, but worse. :shakehead:

A lot of it also has to do with emissions limits being tied to engine displacement.

Remember that Europe also got the EJ255 / EJ257 motors.

I'm sure markets also wanted to see a clear "upsell" to the STI. Just having another 50 - 70 HP wasn't enough, it needed a "bigger motor."

 

[zax]

I would certainly hope this to be the case.

Looking at the way Subaru judged the American market in 2003, it's easy to see why UEL headers were incorporated... and it has little to do with the sound.

in 2001, Subaru was criticized for a cripplingly high boost threshold in the WRX by several American automotive journalists. Subaru came to the conclusion Americans wanted torque and they wanted it now. The EJ257 was designed to incorporate AVCS for improved turbo dynamics, smaller and higher-velocity ports for low-rpm cylinder filling, greater displacement, and that UEL header to spool the turbo just a touch quicker. I still say that the way in which Subaru was beaten at its own game is almost poetic. Before the USDM STI, turbo cars had a high strung and peaky character. The EJ257 was designed to break that mold by offering a turbo mill with greater mid range. Current 2L mills can produce the power of an EJ257 with even greater midrange thanks to DI, high CR, and "headerfold" designs to minimize heat loss. If Subaru had brought over the EJ207 to USDM, it would be somehow special today in the sea of high-torque turbo mills. But alas, the EJ257 is everything the other turbo mills are, but worse.

A lot of it also has to do with emissions limits being tied to engine displacement.

Remember that Europe also got the EJ255 / EJ257 motors.

I'm sure markets also wanted to see a clear "upsell" to the STI. Just having another 50 - 70 HP wasn't enough, it needed a "bigger motor."

Oh yes, I'm aware that the EJ207 could not have easily conformed to USA emissions. Still, Subaru could have engineered a solution provided they were willing to allocate the funds.