This is why I love this forum... Great guys, great cars, I do learn a bunch, Thank you all.

 

I have EVOMS headers. The turbo spool is faster and the sound is raspier. I would do it just for that alone. As far as power gains or being faster? It's hard to tell 15hp gains with the butt dyno on a 600hp car.

 

Pretty sweet.

 

Headers can really decrease lag on a turbo car, but you really have to be careful about configuration and quailty. Exhaust leaks and reliability are problems. I would go with a European source and opt for a higher quality (=$$) product. I don't why you are asking about intake temperature, as they located are at the other end of the engine.

 

Someone mentioned reduction of back pressure with header. As pressure in the header is the driving force for the turbine wheel, is this necessarily a good thing?

I found some good discussion of header on wikipedia . As expected each solution has pluses and minuses and there doesn't seem to be a one size fit all solution. The stuff on exhaust scavenging is also interesting.
There are also some info on Garrett web site that's fun to read, and a thread on rennlist about guys who port and polish the headers. I'll dig it up later.

>>>>>>>>>>>>>>>>>>>
http://en.wikipedia.org/wiki/Manifol...e_engineering)
Great care must be used when selecting the length and diameter of the primary tubes. Tubes that are too large will cause the exhaust gas to expand and slow down, decreasing the scavenging effect. Tubes that are too small will create backpressure against which the engine must work to expel the exhaust gas from the chamber, reducing power and leaving exhaust in the chamber to dilute the incoming intake charge. Since engines produce more exhaust gas at higher speeds, the header(s) are tuned to a particular engine speed range according to the intended application. Typically, wide primary tubes offer the best gains in power and torque at higher engine speeds, while narrow tubes offer the best gains at lower speeds.

 

Because the air circulates in and out and it passes by the "Headers" so depending on the flow and materials used to make the headers it can affect temp, in my opinion. So i am asking you folks...

 

In my car headers (Fabspeed) did make a significant improvement in spool up time...But my car has 570AWHP so it needed a pair of improved headers as the (really good)stock ones were over their limits...Headers improve spool up time and let the turbos spin more free at high RPM...I combined them with LWFW and the difference(in spool up) is great...We have two exact same cars the one with headers and LWFW and other without...Driving them side by side shows the differences...However keep in mind that OEM headers do not fail...while aftermarket might fail...if they do not cooled up properly...

 

I would challenge you to find headers developed and welded overseas that are superior in quality than what American tuners can offer.

Just as an example, look at the welds on these AWE manifolds...they are a work of art.

 

i thought headers just eliminated exhaust manifold's back pressure? how does it affect temp? lol

but yeah it makes it sound much raspier and it's a pretty cheap upgrade depending on who you buy it from.

 

While you are LOL'ing there, I have always been a Corvette guy before the TT, headers on there DO raise the temp and make issues if they are not the right one for your application and work well with your tune... but thank you for the feedback, I am learning this process that's why i asked.

 

Impressive designed, what are they made of?

 

Are you registered on rennlist? There is an excellent thread there...a little old, but some pretty good pics about "quality"

http://forums.rennlist.com/rennforum...t-headers.html

 

I am not trying to endorse one vender over another, but I have to give AWE credit for excellent craftsmanship...here's a comparison of the collectors. Notice the "quality" welds from the European tuner (RS Tuning) versus the US tuner who has taken the time to hand grind the internal welds.

 

As an engineer i can tell you that outside welding of the photos of these headers is just good...But not a state of the art...weldings are too thick...if the steel of the header has a thickness of e.g. 2mm the maximum thickness of the welding should be 2mm+10%x2mm=2,2mm if the thichness is more than that,the steel will brake right next to the welding point,where the steel becames less strong...in these photos fat weldings are clearly shown...any mechanical engineer can comment on that...
P.S. My comment has nothing to do with US or European headers...i just comment on the photo...(I also have Fabspeed headers that are US made with a good price...)

 

Cannaga,

Great info. That is exactly why our header's were developed to offer the best case scenario. FVD headers reduce exhaust back pressure and temperature without sacrificing velocity to ensure optimal turbocharger boost. Our headers feature a 42 mm primary tube that empties into a 50 mm (id) collector. Too large a diameter on the primary will effectively reduce back pressure and exhaust temperature, but consequently lower the exhaust gas velocity and reduce performance. Bigger is not always better! FVD headers provide maximum flow, optimal cooling and maximize your performance. All FVD headers are mandrel bent with a pyramid style merge collector that extends to the flange for smooth, laminar exhaust flow and are manufactured from the highest quality T-316 stainless steel and produce dyno proven horsepower and torque!

Here's a link...http://shop.fvd.de/us/en/Porsche-0/9...aders-set.html