View Full Version : what are your thoughts 20b turbo manifold
03-06-2011, 08:01 AM
so BOB and I are building a turbo manifold for my 20b and was wondering to get some opinions on why long tube and equal length runners ?
For the turbo manifold? Or are you talking about the intake manifold?
03-16-2011, 07:51 AM
well thinking about a log style turbo manifold for my 80mm turbo on my 20b!
There's benefits and drawbacks to both manifold designs. Log style manifolds (if constructed correctly) will hold more heat which translates into more consistent temperature differentials across the turbo resulting in faster spool up times. This comes at the price of horrible exhaust flow which will limit the amount of horse power and torque when not under pressure.
Mandrel bent type manifolds flow much better but do not retain as much heat as the log style. This means, in short, that you will have slightly longer spool up times but less back pressure on the engine when not in pressure.
There are ways of getting the best of both worlds however. Taking the flow characteristics of the mandrel type manifold with a heavy steel wall for the runners and combining it with either ceramic or heat wrap causes the temperature to be retained within the manifold resulting in more uniform exhaust gas temperatures while not impeding flow.
Additionally with mandrel bent type manifolds you can adjust the various runner lengths for a specific pulse pattern to better effect the turbo--but that might be outside the scope of your build.
03-18-2011, 08:50 AM
thanks VEX ! this is what I have far. have to build for the waste gate. which it will come right off the neck!
That's a nice design. I can't tell however at what angle the middle rotor is exhausting into the manifold. If it's angled it will flow much better than if it were intersecting the main runner at a right angle.
03-18-2011, 10:37 PM
second rotor is flowed and have it flowing forward .I will post better pics.
05-04-2011, 08:50 PM
nice design ...
05-08-2011, 02:57 AM
Looks good! Stick welded?
Here's the one I made for my RX4....
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