Turbo headers.

[tauruck]

How critical are equal length header pipes in a turbo application?. Thanks.

[kiwi belly tank]

It's really not. Pulse timing is unusable due to drive pressure.
  Sid.

[tauruck]

Ah, that's why the Duttweiler motor in the Speed Demon has unequal pipes.

[SPARKY]

I bought into the belief that one gives up very little with good Log manifolds 

[tauruck]

Should I just build them so they fit the chassis?.

[sabat]

I think the only consideration is if you have a divided turbine housing, and then you might see less lag by directing primaries according to firing order. But this is LSR, who cares about lag.    Dean

[Sumner]

I think the only consideration is if you have a divided turbine housing, and then you might see less lag by directing primaries according to firing order. But this is LSR, who cares about lag.    Dean

You are right.  The borg warner  turbos we are using...

http://purplesagetradingpost.com/sumner/Hooley%202013/13%20-%20hooley-construction-2013-1-a.html

.... have the divided housing and I looked into dividing the pipes up by the firing order as you mentioned but borg warner told me that for our application they...



...recommended not dividing the input to the turbine.  If you do divide the input then you probably need waste gates on each side.  We are running 4 wastegates not for that reason but only in that they were cheaper than one large one which would be our choice down the road.

After SW I was able to find springs that would fit our wastegates that should open with about 2 lbs of boost and then from there on up we can control the boost with the e-boost 2 controller.  The 8 lbs stock springs where just too much boost too quick.

After some prodding, he didn't think he could, Hooley fabricated some...



...nice headers for the Stude.  His first attempt at headers like this.  I think he did good and I think the effort will pay off.....

http://purplesagetradingpost.com/sumner/Hooley%202013/13%20-%20hooley-construction-2013-8.html

On the headers I believe that the better you can make...



...the exhaust side the more efficient the motor will be and the less boost you will have to run for the same HP level which also means less heat that has to be taken out of inlet air by the intercoolers.  It is comparable to making equal HP with less boost using good flowing heads vs. having to run higher boost to overcome bad flowing heads.

Steve Morris Engines....

http://www.stevemorrisengines.com/engines

...has 2000+ HP engines and they seem to ...



... make the headers as good as possible.

As far as log headers are concerned the car and available room can play a factor.  On the Speed Demon they have packaged very nice headers inside the car.  With a streamline/lakester if you have to make the frontal area larger to package individual tube headers in the car the HP needed to overcome the increased frontal area might be more than the gain from better headers vs. log style headers.   No clear-cut answers,

Sum

[Peter Jack]

A smooth flowing design is the most important consideration. If you were using a log design it would be important that the pipes enter the log such that they were encouraging the flow toward the exit as much as possible. Individual pipes going into an efficient collector are probably a better solution.

Pete

[SPARKY]

PJ  I agree

 I made my entery at 45 deg. and kept stepping up the ID as I went along the log

[redhotracing]

We use OEM manifolds turned backwards and have no issues building a ton of boost and power...
I've seen lots of cars with $2,000 custom headers that look prettier, but if shorties make the HP
you want, save the cash for something else... like O-rings to keep your heads from pushing h2o 

[Tman]

Buy Corky Bells Turbo book. Well worth the time. There are some shots of the log I started in my build thread as well.

[Captthundarr]

Keep up all this turbo talk and I might just have to stab a couple in Amy's camaro.

[Peter Jack]

Go for it Frank! 

Pete

[Crackerman]

It's really not. Pulse timing is unusable due to drive pressure.
  Sid.

Pulse timing might not be as critical, but it still can be very effective to light a slow spooling turbo.  Drive pressure is nothing more than a compressed gas, pulses still travel, at sometimes a greater speed than the <1psi in a typical scavenging header system. Although temp has a larger role in that velocity.
That being said, doing everything you can to reduce flow restrictions between exhaust manifold and turbine wheel (including the wheel itsself) you will be able to make more power, due to lower drive pressure.
A good comparison would be (in a diesel application) a stock ported cummins 24 valve exhaust manifold compared to a steed speed competition exhaust manifold.
Fleece performance saw almost 60 hp gained at peak,with a faster spool time, due to better flow, not necessarily higher veloctiy of exhaust gasses. Also a large gain in torque due to more airflow down low and a diesels innate ability to generate torque at low rpms.  And more power up top without restricted high rpm flow.
Keep the exhaust hot and flowing well to get the best performance and highest turbine efficiency.

[Richard 2]

don't forget the slip joints