?equal length or unequal length headers?
 

SO as the header reads equal length headers or unequal length headers.

what are the benefits between the two.

I know putting them on will gain some power but does one type add more trq than the other?

:search:

Equal length is more efficient, the only reason anyone is making UEL ones is because most Subarus come that way stock and people like the burble the exhaust makes.

You can still get an increase in power from a good UEL header, but it won't be as good as a good EL header.

The difference in 400+ WHP cars is between 10-20 WHP, (This means that for lower HP cars, the difference will be less) EL making more power than the UEL. It depends on your likes and goals. I went UEL because I loved the sound, and was willing to compromise the around 10 WHP.

Borla dyno'd UEL vs EL..

UEL produced more Power. Not much more.....but more nonetheless

Biggest difference is the sound. EL is more like a race car UEL is like the traditional Subaru sound. The changes to power and torque vary. UEL can flow better than stock. EL can flow better and be tuned length. The tuning determines where the torque occurs in the rev range. The P&L and the FA20Club are tuned to improve the torque dip. Ones like the JDL and Super Sprint are more top end tuned. But this is a general overview. Do some googling and you'll see there is a ton of things that go into header design.

Any proof of this?



Simmons

I think you will see proof in higher HP FI builds with equal length over unequal. I doubt you'll be able to tell with the ~350 hp and under builds. No one really has tested it either for full proof.

Whole reason I like the Nameless/FA20 club designs is they are convertible from NA to FI.

But only if you are aiming for a Turbo. I guess you benefit from still being able to do both, huh?

Basically. I've yet to see anyone attempt a longtube UEL but with the design of the longer runners on one side, I don't think it can be done. You'd have to cut the longer side short to wrap it up front which makes it an equal length again.

I would go UEL unless you have a planned FI build down the road. Even then, AVO turbo kits use a UEL and push a really good amount of horsepower so don't let anyone tell you that UEL is bad for turbo. It really depends on what your goals are.

I don't know the science well enough to try to explain it with numbers and proof, but the runner length (and length between steps if it's stepped) is very important for flow, scavenging and eventually power output. Look at how long the runners are on the longtube EL designs and how they perform.

Every platform in the world makes more power on long tube headers over short tube headers, and it's all down to the long tubes being the proper length for the flow characteristics of the engine.

IMO, running UEL header is like running a V8 with a long tube on one bank and short tube on the other. Sure it'll make power over stock, but it could make more.

I haven't seen any long tube headers make a better tq curve then my JDL UEL Header?

I am not saying that it is not possible, just wanted some dyno results to prove it.

Simmons

I don't think you're going to find any until people run wide open exhausts. Long tube equal length headers will make more power on any engine with open exhausts. Add in mufflers, cats and bends to accommodate things and most of the advantage goes away. It's an old debate before subarus it was equal length vs. shorty headers. It would be really interesting to see a direct comparison between the JDL UEL and the P&L EL header on the same car.

The only one I have seen is the Nameless header, but it was on pump gas. Was your dyno on e85?