Weapon R header...

[tooter]

The header just arrived today, and it looks like a piece of jewelery...











This is a view looking into the exit pipe. You can see the split Y nature of the header.



I'll post more pics during the installation effort. It also came with a new donut gasket, but not an engine gasket. I don't think that will be an issue since the engine has less than 200 miles on it.

[1.5]

ooooooooo so shiny

[Golddeenoh]

^ what he said but more excited and louder.

[WeeYari]

Installed yet??? No!! Why not???

Come on, come on, hurry it up!!!

[goliath1812]

:) let's see it installed and tested!! :)

[marcus]

subscribed

[tooter]

Well, it only took 2 hours to get the old header off!

The car needs to be jacked up so that you can get underneath to loosen the 2 spring bolts holding the downpipe to the header. All the header bolts were easy compared to the one lower bolt that holds the bottom flange of the header to a support bracket. That one was an absolute b*****rd to get off.

Here's comparative pics of the headers. At 5 pounds 12 ounces, the Weapon R header is 6 ounces heavier than the stock header because it has a really thick flange.



The stock tubes are 28mm diameter, while the Weapon R tubes are 36mm in diameter. This is an increase of 30%.



I'll begin to install the new header today just to see if it fits, but won't be able to complete it because I need to get some new bolts. The bottom exit tubing needs to be ground down as it's about 3/8 inch too long. This isn't a problem that a grinder can't fix.

[CrankyOldMan]

I'm curious about how the change in diameter affects flow velocity and scavenging efficiency. There has been lots of discussions centered around those mechanics for intakes, exhaust headers, mid-pipes, axle-backs and even short downpipes.

Also, are you going to heat-wrap it? I've seen a few people do that to reduce engine bay temps--but I think they have a CAI as well.

[tooter]

Originally Posted by CrankyOldMan

I'm curious about how the change in diameter affects flow velocity and scavenging efficiency. There has been lots of discussions centered around those mechanics for intakes, exhaust headers, mid-pipes, axle-backs and even short downpipes.

Also, are you going to heat-wrap it? I've seen a few people do that to reduce engine bay temps--but I think they have a CAI as well.

I have no idea. I'm just going to install it and drive it and see how it works. Tri Y headers are a very old tried and true exhaust design based on sound physical principles, so I trust in the manufacturer's R & D that it will work just fine.

Discovered that the stock donut gasket won't fit the new header because the stock exit tube is 45mm in diameter while the Weapon R is 47mm for an increase of 4.5%. Thankfully it came with its own oversized donut.

Ground off the excess tubing to fit the donut...



Next comes the installation...

[cali yaris]

Can you post a few more pictures of the new stock header? Looks different than previous years.

[tooter]

Originally Posted by cali yaris

Can you post a few more pictures of the new stock header? Looks different than previous years.

Yes, it's very different.
I'll post detailed pics tommorrow when there's good daylight. It's a really strange combination of tubing with a falafal like shell molded over them with a welded seam all around the edges. It must work pretty well overall, because the factory has the luxury to test its designs to see what works best over the widest range of driving conditions.

Bottom line: I'm totally pleased with the low end torque of this Tri Y header. It outperformed my expectations.

[vten]

its the same design witht the one I have since a couple years ago .

it's a good buy

[tooter]

Originally Posted by cali yaris

Can you post a few more pictures of the new stock header? Looks different than previous years.

Hey Cali,

Here's some pics of the 2012 OEM header. Note the horizontal bulges connecting the outer two tubes...



...and on the other side horizontal bulges connecting the inner tubes. Toyota configured their OEM header a semi-tri y design although none of the tubes are discretely separated from each other like the WR header.



The inside is all one open smooth undulating chamber.





What had appeared to be tubes welded inside the engine flange are actually the two halves of the formed metal header shell. Each side makes up 180 degrees of the tubes.



It reminds me of those hot pressed sandwich makers that seal the sandwich all around the edges, except in this case the sandwich is welded. Side view shows the full length weld.

[auxmike]

Any trouble getting the airflow sensor out of the OEM manifold?

[tooter]

Ta da...





As Ace Ventura would say... "Like a glove..."


Idles nice and quiet and smooth and did not trigger the Check Engine Light. Gonna take it for a test ride, then I'll disconnect the battery to let everything reset to allow for the new parameters.

[tooter]

Originally Posted by auxmike

Any trouble getting the airflow sensor out of the OEM manifold?

No, it came off very easily.
I took the old manifold out first... and then removed the sensor by slipping a 19mm box end wrench over the sensor plug to get to the nut. I had plenty of leverage with it out on the ground and there was no way for the wrench to slip off.

Took the car for a test run to town to gas it up and calculate the mileage. The benchmark pre header mileage is 36.5 for the first 207 miles. Next fillup I'll have a pretty good idea of how much the mileage improves with the header.

I do know this... the header works great!


It has a bottom end sweet spot from 2,000 to 3,000 rpm which is right where I drive the most. There's a really steep hill going up to the house, and the car used to bog down in 2nd gear so you had to press more on the gas to get it to go. Now, that's completely gone! You just press like normal and it goes right up the hill with no bogging down.

I really didn't expect a whole lot of difference seeing as the rest of the exhaust is totally stock, pumpkin muffler and all, but this marked improvement in low end torque is far beyond my expectations.

The installation took me a total of 6 hours including an hour of grinding the excess tubing off the header. Everything was done by the "Braille method" because there was no way to directly view what I was doing. I was able to use all of the original bolts including the OEM spring bolts whiwh attach the header to the downpipe. Later I'm going to get some longer engine bolts because the thickness of the flange, but there was still plenty ot threads on the stock ones, and the torque on them was light because they came off without any hesitation even from the awkward working conditions.

[1.5]

Looks great what does the butt dyno say?

[malibuguy]

that reminda me of a 5th gen terseo manifold.

prior to installing my weapon r header i ported the lower weld joints to smooth them out. i did not have the longer bits to go further in.

mine did not come with a new donut gasket...i just ordered a replacement from advanced auto...fit perfectly on.