Effect of DC headers on torque curve?

[Captain Slow]

The one thing I really love about my Yaris is the great low-end torque (especially for a 1.5L), does anyone have an anecdotal evidence or dyno data to show how the DC header effects low-end torque? Thanks.

[tooter]

I only have anecdotal for a Weapon R header, but it's a slightly different design (4-2-1) from the DC (4-1).

http://i17.photobucket.com/albums/b90/compost_bin/car/bth_IMG_5897.jpg

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSS40GOzsoE3vspIifTTUsbJAqRXock4 Sv7AI2gf6LnYEFVeZZC



It was the very first mod I did, so everything else was bone stock. I climb the same steep hill to return to my home, and with the header alone and no other changes, the car climbed the hill noticeably easier at between 2K-3K rpm. And with the stock muffler, the difference in sound is zero.

[4/20 NEVER FORGET]

I have a DC header. I installed it on the car when the only other mod was a K&N Typhoon intake. The change in the car was noticeable after the DC header, unlike other mods which haven't made a noticeable overall difference. In my opinion, the car had a more linear power output through the rev range after the header was installed. Before installing, I felt the power was all down low and the car really "ran out of breath" as the revs climbed. After install, the car showed power nearly all the way to redline, which I like. I don't feel it lost low-end torque, some people have complained about that but I did not notice it.

Now my mods are K&N Typhoon intake, DC header, 2.25" obx exhaust resonator-back, MI crank pulley and NGK iridium plugs. The car is very torque-y down low, I regularly find myself shifting to 5th gear at 40-45 mph around town. I don't have a tachometer installed yet, but the car feels like it's pretty low in the rev range but still has good power. It climbs hills on the highway with 3 people in the car in 5th gear easily as well.

I've said it in other threads and I stand behind my statement, I think the DC header is great.

[Kaotic Lazagna]

iirc, 4-2-1 headers provide better low to mid range gains with little gains or even a decrease in the high end, and 4-1 headers provide gains in the high end with little or even a decrease in the low to mid range. If I ever get a header, I think I'll get the Weapon R 4-2-1 header.

[Captain Slow]

I'm all about 0-60 times and don't really care about top speed so a 4-2-1 might be a good choice for me.

I never really go faster than 80mph, but I love slamming someone into the passenger seat when I take off.

[Captain Slow]

odd, seems the weapon-r is only available for 07-08 years.

[Kaotic Lazagna]

I think it should fit any 1NZ Yaris, someone correct me if I'm wrong. lol

[BEEF]

Well, tooter's is a 2012 so I know it fits that.

I also have a weapon-R.

I was told that the 4-2-1 and 4-1 are as described but we have shorty headers and the effect talked about has a lot less to do with the gains than the sheer size difference. there are a few guys that are playing with long tube headers and are seeing gains.

I was told that I would basically see the same thing from any of the aftermarket headers and the DC one is quite a bit more expensive.

My car is rather peppy with an AFE intake, Weapon-R header, and resonator back (mandrel bent) 2" custom exhaust. I do have the light weight crank pulley but it is still in the box....

[tooter]

odd, seems the weapon-r is only available for 07-08 years.

It's now '07-'12... and likely '13 too.

The place I got mine from had their listing as '07-'11, so I took the risk to find out if a Weapon R would fit a '12. When you think of it, the odds were heavily in my favor as Toyota is pretty good at making good use of the same parts for years. It fit like a glove. :thumbsup: I contacted the seller and let them know so that they could update their website listing.

Beef is right. The space between the exhaust ports on the head and the headpipe is really short so headers can't make a whole lot of difference. But they do help. But even being as short as they are, I was pleased with the slight bottom end improvement of the 4-2-1 design on an otherwise completely stock car.

Garm has them for about $200 if I recall, which is a great price.

[DJYojimbo]

with the weapon r it's just bolt on right?

[Captain Slow]

I'd love to know where they are available for much cheaper than the DC Sports model. I see Garm has the DC Sports for $289, but I don't see the Weapon R on his site. Every place I've seen the Weapon R it's very close in price to the DC Sports.

[TPA5]

I'm all about 0-60 times and don't really care about top speed so a 4-2-1 might be a good choice for me.

I never really go faster than 80mph, but I love slamming someone into the passenger seat when I take off.


Then you probably should have bought a different car.



:wink:

[DJYojimbo]

here's weapon r link on Garm's Website http://shop.microimageonline.com/Weapon-R-Stainless-Header-953-116-108.htm

[Captain Slow]

Then you probably should have bought a different car.



:wink:

I traded in a BMW 325i for the Yaris, I like smaller nimble little underpowered cars, my point was that if I'm going to build power I'd rather it be in the "seat of the pants" department than in the top speed/top-end area.

The Yaris, even bone stock has the most torque at launch I've ever seen out of a naturally aspirated 1.5L motor, and I really like that. That's why I had several Miatas too, torquey little motors. I like torque more than horsepower....I seldom drive about 55mph so I'd rather FEEL like I have lots of power than have it all up-top and be able to pull on people on the interstate.

:thumbup:

[tooter]

with the weapon r it's just bolt on right?

I did need to do a little filing on where the metal exit protruded beyond the donut. This is after filing...

http://i17.photobucket.com/albums/b90/compost_bin/car/bth_IMG_5903.jpg

...just to make sure there would be no metal to metal contact to keep the donut from sealing.

But other than this minor issue, it's bolt on and drive. :thumbsup:

http://i17.photobucket.com/albums/b90/compost_bin/car/bth_IMG_5910.jpg

[xnamerxx]

It doesn't really matter what header you buy that replaces the stock one, they will all produce similar results +/- 10%. You really get much volume/length given the space that's available.

Most of the conceptions of 4-2-1 and 4-1 only really matter when they're optimally designed but seeing as nothing replacing the stock piece will be optimally designed so they'll all perform similarly.

Now with 4-1 you can get lots of low end and a 4-2-1 can give lots of top end, so you shouldn't pick something depending on what it can conceptually give.

[Foot]

Captain Slow, I kind of like my 1400 ninja on the take off better than any car I have ever been in.

[DJYojimbo]

I want low end I thought weapon r is low end

[tk-421]

I have basically the same setup as BEEF, plus the lightweight pulleys and 1zz tb. I did not feel a torque loss after installing both the header and exhaust, and there was a significant improvement performance-wise. Climbing steep hills is no longer such a big issue in my case.

BTW, I agree that there's probably 90% chance that the difference between 4-1 and 4-2-1 is negligible in our case.

[tooter]

I want low end I thought weapon r is low end

As I understand it, 4-2-1 tri Y headers are generally for more low end torque.

http://image.circletrack.com/f/9716091/ctrp_0806_18_z+the_header_test+a_vs_d.jpg

[4/20 NEVER FORGET]

Is that a map for a yaris? Or just in general?

[DJYojimbo]

I think i'm just going to get the DC headers! Seems like everyone who has them are happy no install issues

[Captain Slow]

probably the #1 reason the DC generally gets better reviews than the others is because it is ceramic coated, meaning not only does it look better but it also holds the heat in better. this translates to lower under-hood temps and hotter exhaust gasses that rush out of your tailpipe faster.

i'm going to go with the DC just for that reason. sure there's header wrap, but that stuff can shorten the life of your pipes and can also soak up oil if there's a spill and cause a fire.

i've got the MI lightweight crank pulley and a TRD air filter so I shouldn't notice any low-end torque losses (hopefully). whenever I eventually get one and install it I'll report back to this thread with my results.

[tooter]

Is that a map for a yaris? Or just in general?

It's definitely not a Yaris! :laugh:
I was just looking for any definitive back to back comparative graph between a 4-2-1 and a 4-1 that showed that the 4-2-1 enhances low end torque. Whatever that graph was for, the headers had to have been way longer to make that much difference. On the Yaris, it comes down to a coin toss because no matter what you put on, it's too short to make much of a difference betwen the two designs. One reason I chose the Weapon R is because I think that stainless steel headers look really neato even if you can hardly see them. :wink: