i am building my own turbo manifold for my GSR swapped civic coupe . a friend of mine tells me that all the tubes must be equal length. any truth or reason for this???
Say what?! Mine are all curvy and shit… must be a turd huh
i was originally going to go with a ram horn style witch equal length wouldn’t be a problem. but then ive been thinking about stuffing the turbo in the fount bumper. witch is a bit more complex and more difficult to keep equal lengh.
It does not have to be equal length and pretty much none out there are.
It needs to get the exhaust from the ports to the turbine. That’s literally all that is required. The shape in the middle is determined by your space constraints, how much time and effort you want to put into this, and what your goals are.
Just build a log mani, or if you are feeling ambitious a mini-ram.
Not sure I really agree with that. Log manifolds can be really restrictive and inefficient depending on how they are constructed. A good individual runner manifold that delivers a straight shot into the collector will normally do just fine.
Its your fuel map, its got a nast hole, thats why you’re unloading in third
- rep.
are you talking cast oem log manifolds or two 90’s, 2 T’s and a turbo&wg flange stainless hand made manifold?
There is alot of science behind a proper header that takes in consideration the bore, stroke, port sizes & lengths, cam angles, timing, tubing size, length, etc… Its all about maximizing the savaging effect on combustion chamber by timing the exhaust pulses at the merger point and the length, and volume of each runner to the valves. I am not an engineer and far from a turbo expert, but how is this any different than a header? Each runner converges into a collector, instead of the rest of the exhaust installed past that point as it would be on an NA engine, there is a turbo. Think of the turbo as a cat. Its just another restriction in the flow of exhaust gasses out of the exhaust.
Now, I think this is where the point of all that science on a turbo header is thrown mostly away… Most NA engines and cam specs put a peak power band at such a point that the primary lengths are rather long. Where as turbo builds are usually higher rpm ranges and tq isnt much of a concern off boost. Trying to maximize the savaging effect to make extra tq and power is a waste of time, because its a lot easier to turn up the boost for more power, or change the turbo characteristics so it spools earlier and ramps in such a way to make more early on tq.
More or less my assumptions would be keep it simple. Header volume to turbo inlet should be at least 1.5 X Engine displacement. So your not stuffing a bus into a key hole, yet its not so large that velocity is slowed down dramatically. Look at a log VS long tubular turbo manifold. Logs tend to spool turbos a bit earlier let lack the upper rpm power. Log = smaller volume and shorter path to the turbine = quicker spool, more tq down low, starving the upper rpm though. Tubular = more volume, lower velocity but more gasses stuffed in there to do the grunt work of spooling the turbo and less restriction for the upper rpm range.