Project: RAMROD (wrx TDO4L Port and Polish) !Dialup!WARNING!

[beataru]

We checked the waste gate, its not the problem, there is definately an exhaust leak somewhere, I just need to get some cash together, pull the engine out, and build me a header.

[calebz]

Why not just acquire another stock header for now?

[beataru]

I have thought about this, I know of a few junkyards that actually have my engine, I dont know if they have exhaust though. I have absolutly no cash right now, and I am truly on my last half tank of gas this car will see, unless I can get some Dough in my pocket.

 

I dont like the bends of the stock header, if my bro in law and I took out the engine, and made a template of the crossmember and everything under there, we could put together a fairly decent header that flows nice, what do you guys think the pipe diameter should be? Bear in mind this is a turboed car so I want to keep the velocity up.

[4WDFrenzy]

I don't think that I would go bigger than 2 to maybe 2-1/4" ID piping. I know that it sounds small, but it should be big enough to lose some of the restrictiveness of the factory manifold, but still small enough to keep the exhaust velocities at a decent level.

[beataru]

Actually thats far too big for this engine to spool my turbo.

[discopotato03]

Your call but generally the size of an engines exhaust port is a good size to think about .

 

I think we need to remember that we are feeding two pots through each side and they are 450 odd cc pots at that . You need to have the system large enough that the exhaust "shot" (which is going to have the most pressure/velocity behind it when the exhaust valves first crack open) has minimum restriction on its way to the turbine .

 

One of the fellas here in Australia recently removed all the heat shielding and thermal wrap from a std EA82 header and let me tell you they are really pathetic . The up pipe is smaller than the crossover pipe and the joiner at the turbo side head points slightly the wrong way (ie worse than a 90 deg "T") .

As I said at the AU Subaru site they were obviously looking for high manifold pressure (EGR) and probably low torque because high torque FWD turbos are dangerous in the hands of idiots .

Someone here made one up out of stainless and it basically had the two engine pipes joining in a collector at least facing the up pipe - which was larger in diametre than the engine pipes . That person claimed that a basically stock engine (better catback) was much better down low (more torque) and made almost wastegated boost from ~ 2000-2100 rpm .

 

One thing I hear whispers about is that the Vortex EA82 header is supposedly a little larger at the turbo flange ie 41mm vs 36mm than the L series EA82T one . Can anyone confirm this ?

 

Std headers are rubbish , cheers A .

[Gloyale]

 

One thing I hear whispers about is that the Vortex EA82 header is supposedly a little larger at the turbo flange ie 41mm vs 36mm than the L series EA82T one . Can anyone confirm this ?

 

I don't have any literature to support it, but I did notice recently that the 2 crossover pieces I have in the back are different sized. About excactly the amount you describe. I thought perhaps a year model change. But now that you mention it, the bigger one is from an XT and the smaller pipe from a Wagon.

[beataru]

XT hunting we go now..... heh I doubt theres one down here, or one that isnt on its way to the smasher In a turbo charged system you want, and it will always be this way, the turbo to be the largest restriction. I could, and probably will, step the header size up after the merge collector. Idk its a long road ahead.

[PoorManzImpreza]

Here's a link to back yard boys in aussieland for a custom header a forum member is working on:

http://www.ausubaru.com/forum/showthread.php?t=3644&page=13

 

looks interesting and also similar to the TWE header..

 

Exhaust port matching with our engines would equate to a 2" header to mirge pipe..way too big to keep exhaust gas velocity up, and it is exhaust gas velocity that spools a turbo, keeping exhaust gas temperatures high also increases gas velocity and helps spool the turbo..as always everything has a balancing act to follow; too much egt means you are running lean and on the virge of creating a boat anchor, too narrow a header pipe diameter means loss of topend...

 

IMHO the best bet would be keeping the ports split for another 2 to 4 inches or so and during this split narrow the pipe from 2" port diameter down to 1 1/2" or 1 3/4" (1 3/4" would be my choice) then mirging left and right head in a smooth 'Y' junction (keeping this transition long also ensures smooth flow and velocity) to a single 1 3/4" then at 2" or less away from the turbo, flare out to port match the turbine housing inlet...ceramic coating and wrapping the header also promote heat retention and high gas velocity..

 

The key here is continuing the port split while the pipe cones down from port size to header pipe size this will allow the exhaust gas to maintain velocity as it transitions to the 1 3/4 in pipe smoothly and since we are port matched all the way no turbulance would be generated by abrupt size transitions..

I have a few ideas on how one would keep the siamesed ports split outside the head for that 2 to 4 inches, but haven't tested them out as yet..

 

just my 2 cents

Kaz

[4WDFrenzy]

Actually thats far too big for this engine to spool my turbo.

 

I have to agree, the 2-1/4" pipe is probably far too big. I figured that the 2" would be adequate though. Then again, I have never built a header before either. I think that I got myself confused with the WRX header that I used to have. The runners from each exhaust port were 2" diameter. Considering that the EA82T has shared ports, I was figuring that my 2" calculation would've fit the bill. One thing to think about though is that the biggest problem with the stock manifold is that "Tee" where the passenger side exhaust bolts up. If the exhaust gasses were flowing more smoothly toward the turbocharger, one would think that 2" pipe would be able to be used for the whole header, including the uppipe. This is more than likely going to be the size that I use when I get my manifold made. Oh well, like discopotato03 said, it's your call.

[beataru]

Hey I appreciate all of the support and ideas. When (if ever ) I get this thing made, If it is decent design I will have it ceramic coated, assuming I have the money of course, and I might get header wrap for it and possibly a turbo blanket.

 

I washed the beast today.. Its so nice to have a clean car, although my inside needs to be clean, Im mad at my self for letting it get this dirty . If I do ever get this turbo spooling again, and redo my intercooler setup after that, all in all it should be a quick wagon. Im not asking for much, just a 12 second car :-p

[subyrally]

when i mande the custom header for my rx, i got 1 7/8" id mandrel bent piping for hte cross over and then for the collector, since no one makes the right size for a 2 into 1, i actually got an exhaust tip from advance auto. i had to cut off the mounting end of it where its flaired out to slide over the muffler tip, then i cut off the two angle tips at the other end of it. the only prblem was that the two pipes they use for the tips come together like a clam shell inside of the tip, so it needs to be trimmed with a dremmel. but for $8 you get a 2, 1 7/8" into 1, 2" collector. then from there i used a 2" pipe upe to the turbo. my first attempt wasnt pretty and leaked (bad welder) but the second version came out nice since i had a shop build it for me. made a notaceable difference in lag as well as top end power. then again, i was running the td04 and 3" exhaust from the turbo back. man, i miss my rx.