True Twin Scroll Turbo & Manifold Design Discussion

[scotty nm35]

Not a bad job, at least the angle promotes good flow, but damn its tiny. I would have gone for a much larger gate.

What is it with everyone running 38mm/40mm gates, no love for the 50's and 60's? There is power to be made there...

Here is an exhaust I worked on recently, Not an easy job but it got the results. 0.82 split GT3076. Aircon lines remain intact.

[Mitcho_7]

That looks so nice Scotty. Was it expensive? Looks like there would be a fair bit of work in it.

Is there much performance loss with running a single gate off a split pulse manifold with a twin scroll turbo?

Obviously it won't be as good as a twin gate setup, but do you loose much response, power or torque anywhere?

[scotty nm35]

Not really, it cost him around 2 grand for the full system, plus he had intake and cooler piping made.

I would think if you can get the gate to seal the two halves a single wastegate would work just as well, as long as it was big enough and had good flow.

[bigmikespec]

It is funny how people scoff as using a single wastegate on a twin scroll manifold and turbine housing without fully understanding what difference it would make. Who ever started the rumours that you needed two "or else" must be laughing and selling a lot of wastegates!

Anyway, dividing the wastegate flows right up until the wastegate (such as the photo in the link) would be much better than just merging the two flows before the gate (like on a Greddy or HKS manifold).

Yes it is in a great spot before the turn on the turbine housing to control boost very well.

[The Dan]

Gating off the housing doesn't negatively effect the twin scroll design.

It works better than 2 gates

[GTR_JOEY]

Better then 2 gates?? Can you explain that Dan

[Mitcho_7]

6boost do a split pulse single gate manifold don't they? Has anyone tried one out?

If you are going to the trouble of buying a twin scroll turbo, I would have thought you would get a decent manifold to get the most from it rather than putting the gate off the turbine housing? I was always under the impression people only did the gate off the turbine when wanting to run external gate on the stock manifold

Edited July 26, 2012 by Mitcho_7

[scotty nm35]

As the highest pressure point it makes sense to me to run the gate off the housing which is why I talked Artz into it. The idea for my setup, (if I ever get around to making it) is to get the flow straight through the turbo, cutting out the back of the scroll and making the wastegate the priority when it is open. With twin scroll just run the splitter up to the gate and the same will apply.

Too many setups I see favour the turbo at the expense of the wastegate flow which would mean too much power is lost up top imo.

[R31Nismoid]

It is funny how people scoff as using a single wastegate on a twin scroll manifold and turbine housing without fully understanding what difference it would make. Who ever started the rumours that you needed two "or else" must be laughing and selling a lot of wastegates!

Anyway, dividing the wastegate flows right up until the wastegate (such as the photo in the link) would be much better than just merging the two flows before the gate (like on a Greddy or HKS manifold).

Yes it is in a great spot before the turn on the turbine housing to control boost very well.

The whole point of twin scroll is to work in the firing order 'pulse'.

Would make sense...

Manifold is divided

Turbine housing is divided

... that the wastegate would follow a similar premise.

Be good to see some actual information/testing/data with single vs dual with a true T/S setup to dispel - I'm assuming you have some?

[bigmikespec]

I am assuming you do thinking it is undoubtably better.

You can't have evidence for everything (I see you honking that horn a lot be-littling people) sometimes it is just not feasible. You should understand that there is more "best practice" using engineering principles in industry that have been established over a long time by some very smart people.

[R31Nismoid]

You honked it just as hard. You said i wouldn't understand the difference - proof me up, so i can (and everyone else for that matter)

[GTR_JOEY]

The whole point of twin scroll is to work in the firing order 'pulse'.

Would make sense...

Manifold is divided

Turbine housing is divided

... that the wastegate would follow a similar premise.

Be good to see some actual information/testing/data with single vs dual with a true T/S setup to dispel - I'm assuming you have some?

This was my understanding

[SimonR32]

6boost do a split pulse single gate manifold don't they? Has anyone tried one out?

If you are going to the trouble of buying a twin scroll turbo, I would have thought you would get a decent manifold to get the most from it rather than putting the gate off the turbine housing? I was always under the impression people only did the gate off the turbine when wanting to run external gate on the stock manifold

I had a twin scroll 6boost with single Tial 44mm and twin scroll T04z.

Worked mint... I also don't see the huge need for twin gates

[bigmikespec]

^^^ must be a WA thing... lol

[mico]

^^ massive warrior with absolutely no proof to ever back up your statements, lol.

[BMYHOE]

well i have a "true" twin scroll setup on a RB2530 with twin gates, GTX35 with 6boost

I also have a Twin scoll setup for a RB2630 with single HKS 60mm on a 6boost - i havnt picked a turbo yet for this motor.

the RB2530 i should have some results within a month or so.

the RB2630 i wont have any results for at least 9months

[mico]

i thought the whole purpose of having a merge collected single pulse mani was so u dont need a split pulse ??

[bigmikespec]

PM me "mico" if you need an explanation. SimonR32 has just given his opinion based on his experiences. From what I remember he has his R32 GTR well sorted.

[Lithium]

Mico - Whoever said that? If they have, they're being pretty bold about pulling the wool over your eyes - the whole point to split pulse is you are splitting the pulses and reducing exhaust collisions etc. If you have 6 pulses feeding into one collector, no amount of design is going to change the fact that you'll have twice as many high pressure pulses pushing for the same space in the same time.

[mico]

cant remember but i heard that a few times. with a merge collected mani like a 6boost, the exhaust is not clashing tho is it ? coz its merge collected ?