best headers?

[evoWiPeR]

i was looking at headers for my car and i was wondering if i should just get

i was looking at the cusco headers but i was wondering if i should get the grupp-s one with the helix up pipe?

[ScreaminFast]

Unless you want to spend 800-1500 on headers.....get the GTspec V2 ones....come with an uppipe for 500


saves money....

[TB RACING]

Middle of next month we should have a new 4-2-1 design that replaces the uppipe as well. I'm very excited about it as it should be very competitively priced and most out there right now are only 4-1 design.

[ScreaminFast]

there are downsides to teh 4-2-1 design as well, though...

[TB RACING]

there are downsides to teh 4-2-1 design as well, though...

what would you say those downsides are?

[ScreaminFast]

4-2-1 is usually more torque than a 4-1, but the 4-1 will always make more topend power....so I guess its up to brian with what he'd want for his car....i've been nothing but happy with mine, and they are swaintech coated

[TB RACING]

4-2-1 is usually more torque than a 4-1, but the 4-1 will always make more topend power....so I guess its up to brian with what he'd want for his car....i've been nothing but happy with mine, and they are swaintech coated

I think you have the concept down, but a generic statement like that is leaving out some key points.

It all comes down to the design of the pipes.

Generally a 4-2-1 will make more down low usable torque, and a 4-1 will make more high end HP.

But what you have to look at is where in the powerband it creates the gains.

A 4-1 might be severely limited in some designs becuase it might only create its additional power at 6500rpm on. And up until then it may have a decrease in torque. Thus making a higher peak hp car, but less usable power throughout the powerband.

Likewise a 4-2-1 might have a large enough torque increase up thru the mid range to create gobs of extra usable power, but not really top the charts in the PEAK hp.

It's all how it compliments the rest of the car.

I'd personally rather have more average gains than losses. Increasing the peakiness (not really a word) of the car is great for numbers or drag racing but I've seen some headers that only make power gains at the very top of the powerband.

So basically you can't really compare just 4-2-1 to a 4-1 other than with the generic statement.

But you can compare dyno charts. Before picking out a manifold you should try to get some comparision charts to look at from the manufacturer and see where it creates the gains and even possibly losses.
Then compare the pros and cons.

Also getting advise from people running them helps. Screaminfast seems to like his.


Another interesting thing I found and have yet to figure out. Is the EasyStreet WRX that runs somewher in the 9's still appears to be running stock headers. Perhaps they know something we don't.

[ScreaminFast]

yea to tell you the god's honest truth, i didn't buy mine for the power numbers...i mean supposedly the gtspec ones were dynoed for 20whp or something silly like that....but they save a crapload of weight...

[Photofixer]

 I'm just thinking Brian you should probely not even consider that for quite some time. The stock headers were designed to handle extreme degrees of heat, I think most or more of the WRX "Project cars in Mags". Have all for the most part kept the existing Headers, Plus, Don't you lose? Some Low End Torque, or is it the other way around?  

[Oppie1]

i was looking at headers for my car and i was wondering if i should just get

i was looking at the cusco headers but i was wondering if i should get the grupp-s one with the helix up pipe?

I have GT Spec gen II headers sitting in my garage still in box w/ uppipe. I don't know if I want to put them on because of CEL problems from other St-i owners.
I'll let you have them for $450. I would suggest sending them out to Jet Hot. My quote was $160 to have them coated.

[byroll01]

what check engine lights are people getting?


BTW. Headers are one of the last things you need for an engine buildup.  Brian could be alot more things that would improve HP before he need headers.  Oppie what do you have done?  Have you down Turboback exhaust yet? Yeah this would mean you have to port your turbo but you would get alot bigger gains that with a header.
I'll be at judgment day sunday if you wabt to talk power mods...the STi ECU doean't like them and you may end up LOSING power.  B4 tuning my car made 10hp more than stock and it ran like dogcrap.

[evoWiPeR]

ohh ay very last thing will be headers,

first ecu then fmic, then bigger turbo so i'll then get headers, but that won't be for a while so im good try to sell them off i don't want them yet

[Oppie1]

what check engine lights are people getting?

Oppie what do you have done?  Have you down Turboback exhaust yet? Yeah this would mean you have to port your turbo but you would get alot bigger gains that with a header.
I'll be at judgment day sunday if you wabt to talk power mods...the STi ECU doean't like them and you may end up LOSING power.  B4 tuning my car made 10hp more than stock and it ran like dogcrap.

Byron, I bought the headers for future use. I was planning on eventually getting the vf34 ported/coated with a TBE and the headers. I will be entered in JD, so I will talk to you then.

[ImprezaRSX]

what check engine lights are people getting?


.

Headers frequently cause a "Catalytic System INefficiency" code because they bleed off the exhaust heat to the atmosphere and don't deposit the heat in the catalytic converters. A cold cat doesn't work. I could see how someone who hasn't made modifications to cure a CEL due to cats would get this CEL from headers.  


As far as header selection is concerned:
4-2-1 is a great discussion.
However, more importantly than how many merges is the size of the pipe. A primary that is smaller will maintain a high exhaust gas velocity and therefore AID in scavenging the other cylinders due to the low pressure region created at the merge by the rapid exhaust flow. This is good for low end torque and reducing turbo lag. Regardless of 4-1 or 4-2-1.   The small primary however, causes more flow restriction at higher rpm and therefore hurts top end performance.
A large primary will have low exhaust gas velocity and will not provide adequate scavenging until the high rpm range. How high? Depends on the size of the pipe. Bigger the pipe, higher the rpm range, more turbo lag.  This obviously kills low end torque.

another aspect is the materials ability to retain heat. If you hold more heat IN the exhaust then the exhaust gas will have a higher specific volume (the inverse of density) and therefore a higher velocity. In turn resulting in less turbo lag and better scavenging.

So, what you have to ask yourself when picking a header is what the hell do you want?
Do you want max peak power with crappy driveability? Do you want low end grunt with a dead top end? Do you want the mid range to scream up into the top end?

I think the answer for any daily driven or track car is:
"Whatever gives the most area 'UNDER THE CURVE'"
in other words, when looking at a dyno sheet, which setup gives me the most area under my HP/Torque curves in the RPM range that I do the most accellerating/racing.  Which is affected by your gear ratios.  If you have 19 gears and your RPM only drops 800RPM while shifting, then 600HP from 6200-7000RPM is prime- even if it's only 15hp everywhere else.

Well, now that that is clear as mud I have one more question:

TBRacing, Did you ever get those headers in?
In feb you said "middle of next month".  
If you got'em, could you post a picture so we could see them?

[Timdog1650]

As far as fitment goes and generally nifty power gains, Borla are good headers and they're cheap. I don't have them, this is hearsay from Rich at Precision tuning who says they're the only manifold he recommends due to the fact that they go on great, they have butt-dyno tested power gains (on wrx's albeit) and dont' mess anything important up in the ECU/engine relationship.