[Kunz]

Hi Friends

 

Some of you might have seen the new race Header with wider runners on the RSbarn Homepage.

http://www.rsbarn.com/catalog/index.php?...cts_id=139

 

I tried to contact Pete twice to get more Information, but somehow that didn't work.

 

Now does anybody here has some experiance with this header, especially in combination with 100-cell cat and 3" exhaust?

Dynos before vs after would be interesting as well.

 

What interests me most is how it changes the torque and power curve over the revs, how much the expected gain would be about... what can you expect from that part?

 

Thanks for your shared experiance

Andi

Partial Post: Please Login or Register to read the full post.

[JWahlsten]

I have Pete's header on my car, but am not running a 3" cat back.  Conventional wisdom puts the 3" on the 968 as too large unless you're planning on racing and only looking for power up top.  You'll lose torque in the mid range where most of us spend time driving on the street.

 

I have the header in addition to his stage 2 chip, and the airbox mod.  It adds a nice bump in power.  I don't have dyno charts.

 

Search the exhaust section of the site.  We've discussed exhaust options here in depth.

Partial Post: Please Login or Register to read the full post.

[Kunz]

Hi and thanks, Wahlsten!

Do you use the regular header?


Well in the thread just below this one (preparing to built a 3" exhaust) i wrote about the setup i have right now:

Rsbarn header (the old and ceramic coated one), 100 cell cat with 2.5 in and 3" out and then all the way back in 3".

Together with the other mods, the 3" exhaust was a gain all over the revs im my case.


I wonder now if using the new inox-header with wider runners could be an advantage the the regular one...

Partial Post: Please Login or Register to read the full post.

[Rap]

I have a rebuilt header, Pete's cam package, and he has put several cat backs on. Dyno has been done three times this year and we ended up with 222 at the wheel. That is opposed to 247 at the wheel with the sc. This dyno was on the old engine without any of these mods

Partial Post: Please Login or Register to read the full post.

[flash]

yeah, but what was the torque curve like?

Partial Post: Please Login or Register to read the full post.

[ds968]

No way, no how, will any of those mods get anywhere near the torque curve of an SC'd car. Top end HP, sure it may be within 10-15% , but that's almost irrelevant in tne day and night acceleration difference between the two " mod " set ups .

Partial Post: Please Login or Register to read the full post.

[flash]

i don't think anybody would try to compare those.  the original poster asked about the torque curve, due to the very common result of low and mid range torque loss when opening up the exhaust.  i was asking the same question.  too often peak horsepower numbers are tossed around for purposes of comparison, and what really matters is torque numbers, and the torque curve.  horsepower is ok for 1/4 mile stuff, and that is where the craze of focus on that began, because all you do is run flat out.  but for road racing, it's not about horsepower.  it's about torque.  you need the flexibility of a wide torque band.

Partial Post: Please Login or Register to read the full post.

[Rap]

I dearly miss the torque from the sc. It did make me lazy and slowed my learning curve. Yet without it momentum becomes the drill and that's a good thing. Torque was the same or close. I would have to pull it out.

Partial Post: Please Login or Register to read the full post.

[flash]

no chance torque is anywhere near the SC.  the SC makes 240 lb/ft at the wheels at peak, and starts making over 200 from 2500 up.  i'm willing to bet peak torque with the header is about 200 lb/ft at the wheels, and over a narrow band.

 

but that's not the point of this thread.  however, if you have a chart, it would be helpful to the original poster

 

something to realize though is that the header will be extremely dependent on the cams in order to make the power it does.  cam timing and valve overlap is incredibly crucial on normally aspirated engines.

Partial Post: Please Login or Register to read the full post.

[williamoss]

I am confused with all the discussions of HP. I thought that the normal engine, i.e. stock developed 240 HP. So why all this talk that the SC produces 240. I would of thought the SC would be higher.


 

And how many HP would a stock engine, with an RS Barn 1st stage chip, and the RS Barn cat back exhaust produce?

Partial Post: Please Login or Register to read the full post.

[ds968]

The SC is 240 hp at the rear wheels - 300 hp at the flywheel. ( vs 240 at the flywheel for the N/A engine ) .

Partial Post: Please Login or Register to read the full post.

[williamoss]

_{thanks for the clarification}

Partial Post: Please Login or Register to read the full post.

[flash]

actually, my tests showed 271 at the wheels for the stage 3.

   

 

stock is about 198 at the wheels.  rs barn stage 1 chip and air box mod would add almost 20, depending on the condition of the motor.  cat-back does nothing.

 

again though, not a fair test, and not what this thread is about.

 

i would expect a larger tube 4 to 1 header, with a collector that worked, and a larger primary exit tube, would push the torque band to the right, where horsepower gains would start at about 4k and peak at about 5500.  it would have a corresponding torque loss from about 3500 down.  that's what i saw on the original header, when tested by itself.  a larger tube header would allow more flow, but at this displacement, unless you manipulate the cams, increase compression, and really tune the heck out of it, things would only get worse.  it would require some form of anti-reversionary pulse control though, and i'm not sure you can do enough of it in cam timing.  if you do all of that though, you could gain a few ponies.  in racing, that can be the difference between winning and losing, and if you want to stay in class, that may be all you can do.  for a DE car, i would choose the broadest flattest torque curve possible.  perhaps not as exhilarating as revving the piss out of a motor, but faster, assuming you know how to drive that setup.

Partial Post: Please Login or Register to read the full post.

[williamoss]

Thanks flash for the information. I forgot to mention that my car had the air box modification. I am surprised some do not do it as it is a home project and costs under $15 and so easy to do

Partial Post: Please Login or Register to read the full post.

[flash]

well...not quite that cheap.  the K&N filter alone is $50, and is responsible for about half of the gain the airbox mod makes.  but yes, it really is a no brainer.

Partial Post: Please Login or Register to read the full post.

[Kunz]

Thanks a lot for all the inputs and discussions!

What i've read seems to make sense to me, even though obviously no one here tested the racing header with wider runners themselfs.

Partial Post: Please Login or Register to read the full post.

[flash]

while certainly the collector and the cam timing have proven to be challenging on this car, it seems to react like pretty much any other car as to header size, tailpipe size, and all that.  i would expect no different result on this engine as on any other in terms of flow, velocity, and such. fluid dynamics are fluid dynamics.

 

did that help?

Partial Post: Please Login or Register to read the full post.

[Ernie]

So the stage 3 SC results in a 53 hp gain at the wheels? Pretty impressive!

Partial Post: Please Login or Register to read the full post.

[flash]

??? - somebody needs to put new batteries in the calculator.   no - it results in a 74hp increase at the wheels.  stock is 197.  stage 3 is 271.  at least, that's what i got on the car i tested on.

Partial Post: Please Login or Register to read the full post.

[ds968]

Search for flash's post called " drivetrain loss explained " - comprehensive article on essentially how one gets to rwp numbers.


P.S. guys with tiptronic cars ( myself included ) probably won't like what they read ; but at least it's an explanation for one of the reasons my automatic is slower than my six speed , in spite of having the exact set up . Well, that and more weight .


So the RS Barn headers , as any other mod , including SC can be expected to produce less of a result in a tip vs a six speed, right ?

Partial Post: Please Login or Register to read the full post.