twin scroll v8 experts needed.

[-ghost-]

Going back to twin turbo and getting rid of the log style manifold but with 2 .td05 twinscroll turbos so everything has turned up ready i got to start making them to which an argument started with a friend about which cylinders should be put together for each scroll. It's never going to be perfect as I'm only doing each bank of 4 cylinders rather than the 8 together but one way it will be better than the other.

The firing order is 1-8-4-3-6-5-7-2,*right front 2-4-6-8, left front 1-3-5-7.

Now I've always thought it was the 2 pistons near tdc so 1- 5,3 -7 left hand and 2-6, 4-8 but my friend thinks it should be left 1-3, 5-7 and right 2-4, 6-8.

So now that I'm fed up of it I'm now going to ask? Which way should it be?

[munkul]

you're trying to separate the next exhaust pulse from the previous one. So draw it out on paper (i just did, lol) with the cylinders in order and the firing order for each one.

1-5, and 3-7 for the right bank are correct. That's connecting firing order 1,6, and 4,7.

2-6, 4-8 for the left bank is incorrect. That's connecting firing order 5,8, and 2,3 (you dont want two pulses next to each other).

So the correct answer for the left bank is 2-4, 6-8. That's connecting firing order 3,8 and 2,5.

[piman2k]

Way beyond my understanding. I didn't know you could get twin scroll housings for TD05s.

[-ghost-]

Cheers munkul it all got very confusing and with no internet at the time. I had my spare engine with a head off so was trying to guess it off the position of the pistons . Then confusing the life of each other.


Piman I'm surprised i thought you was all into the twin scroll stuff.

[piman2k]

Yeah for sure I am, but I don't follow TD range turbos dude so was surprised you could get a twin scroll housing on such an old design.

[-ghost-]

They are basically evo 8-9 turbos Mitsubishi have been doing twin scroll for a very long time. I'm just praying they are slower boosting that the .gt28s as it's like getting hit by a train the way the power comes in. So I'm hoping it will be less of a jolt on the gearbox.

I was a little disappointed by the Borg warner s366 single turbo hence back to twins.

I didn't mean the turbo i ment the physics of twin scroll.

[piman2k]

Yeah I know. MR2 was twin scroll as well I think.

[zeppelin101]

What GT28s? The 16g TD05s are only slightly bigger on the turbine side (~2mm). Compressors are a lot bigger but you'll be driving it more efficiently with a twin scroll manifold so I wouldn't bet on it being less of a hit on the box necessarily.

Maybe you could look into a pair of Eaton TVS1900 chargers instead if you want serious progressive power Internal bypass too so less than 1/2hp drive loss at cruise...

[-ghost-]

I'm not changing it again

I've got a bigger Z33 box this time and going with a different management which should be able to control the boost better. It's also got switchable maps. I think it should be ok under 500 whp.

Me and charges don't go.

[zeppelin101]

Well great if you're only after 500whp then you only need one of them

[-ghost-]

Well I've got to have something more to aim for 700whp next target. just the costs 3-4 grand for gearbox then a full cage to tie in with new custom subframe/diff, another prop and drive shafts. I have enjoyed doing and learning all the fab work.

All i need now is the tardiss effect to happen in my engine bay to fit it all in

[skyshack]

It depends on if you have a x-plane crank or a flat plane crank.

Flat plane crank looks like an inline 4 crank and has uneven firing. Light crank, fast reving, uneven firing almost exclusive to racing.
0, 45, 180, 215, 360, 405, 540, 585 degrees. Connect turbo just as you would for inline engine. Front-rear into one scroll, middle pair into other scroll.

Cross plane crank? Best of luck, it's not called a bundle/nest snakes for nothing. On each bank there is a cylinder that fires 90° after another, this has to be taken over to other bank. To get pulse 360° separation on 1-8-4-3-6-5-7-2,*right front 2-4-6-8, left front 1-3-5-7. You need
1-6, 8-5, 4-7 and 3-2.
To have 180° separation on each scroll pair.
Turbo 1 scroll 1, 1-6, scroll 2, 4-7.
Turbo 2 scroll 1, 8-5, scroll 2, 3-2.
None of those pairs are on the same bank. Nest of snakes or a veritable Can of worms?

[skyshack]

As cam is usually less than 270° you can have uneven pulse and not get reversion.
1-3 both bank 1
2-6 both bank 2
4-7 x-over
5-8 x-over
Getting even spacing on the scrolls of each turbo is not possible.

you're trying to separate the next exhaust pulse from the previous one. So draw it out on paper (i just did, lol) with the cylinders in order and the firing order for each one.

1-5, and 3-7 for the right bank are correct. That's connecting firing order 1,6, and 4,7.

2-6, 4-8 for the left bank is incorrect. That's connecting firing order 5,8, and 2,3 (you dont want two pulses next to each other).

So the correct answer for the left bank is 2-4, 6-8. That's connecting firing order 3,8 and 2,5.

1-8-4-3-6-5-7-2-
1-----3---5-7---
--8-4---6-----2-

Munkul - no cross over much simpler to make.
1---------5-----
------3-----7---
--8-----6-------
----4---------2-

Mine - cross over - forget it.
1-----3---------
--------6-----2-
----4-------7---
--8-------5-----

Can of worms
1-------6------- turbo 1 scroll 1
----4-------7--- turbo 1 scroll 2
--8-------5----- turbo 2 scroll 1
------3-------2- turbo 2 scroll 2

[-ghost-]

Its done now and im never doing it again I wish I had just stuck with the log manifolds its such a tight space to have 2 manifolds with 2 wastegates and 2 exhuasts along with the turbos

[dukey]

That sounds like loads to pack in along with steering too. Haha. Would love to see it in great detail

[-ghost-]

its swings and roundabout with the steering as the turbos are in front to the sides of the engine so the its easier to miss the steering then headers would be.

But the passenger side wasn't too bad as there is a bit more room on that side but the drivers its so so so tight.

Ill upload some photos in the morning.

[dukey]

that would be good.
yeah I suppose you only need a 2.5 inch going past the steering where as I have a stupid starter motor and 4 1.75 inch pipes there haha. makes me want to go turbo.

[-ghost-]

no there was no space on the steering column side so the drivers side exhaust runs in front of the engine and then down the passenger side its not ideal but I didn't want to start cutting more of the body but yeah I opted for the 2.5 rather than the 3 inch i used before. 2.5 inch each bank sounds better too.

[ANDY black s13]

I really want to see the can of worms manifolds
just think of the room it would take up tho ,and the heat it would generate

[zeppelin101]

that would be good.
yeah I suppose you only need a 2.5 inch going past the steering where as I have a stupid starter motor and 4 1.75 inch pipes there haha. makes me want to go turbo.

You would have been better off with 1.5", 1.75" is massive overkill unless you've got serious gas flow. It's all about gas velocity with NA engines.