Twin Scroll T04z On A 25/30

[Lukas 33]

Hey guys

I am just sitting here at work browsing sau and started to ponder about what it would be like having a twin scroll t04z on my car. I dont plan on doing it right now or anything so its nothing urgent. Was just wondering if anyone could share some advice.

If I wanted to see about 420rwkw with a twin scroll t04z at about 20 - 22psi would I need the .84 or 1.00 twin scroll rear? Also I was looking into twin wastegates aswell. How would you go about chosing wastegates? I am fine with chosing one for when you are using only one wastegate but is it any different?

If you wanted a minimum of 16psi would you get two wastegates of 45 - 50mm and have eqaul spring pressures of 16psi or would you get each wastegate a spring of 8psi. And would you need two 45-50mm wastegates or because you have two of them would twin 38mm ones be fine?

Sorry to be a pain but I would just like to know and my search of the forum didnt unveil too much

Cheers

Lukas

[JonnoHR31]

if you want a base of 16psi you need 16psi springs, regardless of how many gates you have. not sure how important it is but probably best to make sure both gates get their pressure from the exact same source, as any difference in pressure could see one gate open more than the other.

[Lukas 33]

if you want a base of 16psi you need 16psi springs, regardless of how many gates you have. not sure how important it is but probably best to make sure both gates get their pressure from the exact same source, as any difference in pressure could see one gate open more than the other.

O ok I thought there was a wastegate for the front three cylinders and another for the back three. I dont know though haha thats why Im asking

[saliya]

Hey guys

I am just sitting here at work browsing sau and started to ponder about what it would be like having a twin scroll t04z on my car. I dont plan on doing it right now or anything so its nothing urgent. Was just wondering if anyone could share some advice.

If I wanted to see about 420rwkw with a twin scroll t04z at about 20 - 22psi would I need the .84 or 1.00 twin scroll rear? Also I was looking into twin wastegates aswell. How would you go about chosing wastegates? I am fine with chosing one for when you are using only one wastegate but is it any different?

For 420-450 you would probably want the .84. With a 3.0 you could _probably_ run 1.00 and aim higher.

I have the TS .84 Garrett housing on a 2.6.

420kw is not a given; at these kinds of power levels and with this turbo you are talking more about tuner than raw hardware. Plus, if you have low compression, bad flow, or other mechanical problems there are guys struggling to make 380+.

The TS essentially turns the single large into twins on the exhaust side - in that you get the benefits from the valve openings/pressure waves directly. On the inlet side it's just a harder-driven compressor.

If you wanted a minimum of 16psi would you get two wastegates of 45 - 50mm and have eqaul spring pressures of 16psi or would you get each wastegate a spring of 8psi. And would you need two 45-50mm wastegates or because you have two of them would twin 38mm ones be fine?

Spring pressure should be viewed as 'release pressure' - that is, you want two 16psi springs (without EBC).

Gate size is actually about how much gas you want to throw away, not what the minimum boost level is. I have an ancient 50mm HKS gate that has no problems holding boost down to 17psi on my setup (plumb-back gate).

The lower the boost you wish to run, the larger the gate size for dispersal required; the higher the boost, the smaller gate needed.

If you were going to do a TS properly with twin blocked-to-port gates, I'd be _very_ surprised if you needed anything bigger than 38mm for down to 7-8psi boost. That is, pretty much the smallest gate (x2) you can buy _should_ be fine.

Cheers,

Saliya

Edited December 14, 2009 by saliya

[JonnoHR31]

O ok I thought there was a wastegate for the front three cylinders and another for the back three. I dont know though haha thats why Im asking

yer there is but each of them still sees the full pressure from your boost source (usually intake manifold), so if you ran a 8psi spring in both gates then you'd only need to make 8psi boost at the manifold to crack the gates. if you put 2 8psi springs in 1 gate then it wont crack until 16psi as the springs are doubled up. would be best to use springs slightly lower than your target boost and use a boost controller to reach the boost you want

[Shiraz200SX]

twin gates are a total waste of time and money.

why would you buy two gates, when a turbosmart pro gate 60 is ample to actuate even the largest of the garrett turbos??

call turbosmart and speak to either Michael or Matt. Very helpful.

(i dont work for them, and i gain nothing from pointing you towards them, simply experience)

[R31Nismoid]

Pretty easy to see why on face value.

Unless you are running the gate to merge pre flange/turbine housing, you need two gates for twin scroll as the channels are separate.

Merging seems to not occur on anything bigger than SR/2ltr manifolds for whatever reason. Most i look for RB's and 2JZ's are all dual gate.

There must be a reason for it, what that might be, one can only assume the best boost control due to runner pulses and so on.

Wastegate doesn't do a lot more than that afterall

Lukas - if you can make 380rwkw on -5 turbos with a mild head tidy up, stock cams etc etc... you'll make 400rwkw with a T04Z with ease. Same motors with a t04Z would make probably 420rwkw on around 20-22psi give/take with the varying setups/port jobs out there and builders beliefs on what works vs the $$

All you need to worry about is the bottom end put together, so it stays together

If you want 450rwkw+ then you need a bit more work and cash behind it all.

[Lukas 33]

yer there is but each of them still sees the full pressure from your boost source (usually intake manifold), so if you ran a 8psi spring in both gates then you'd only need to make 8psi boost at the manifold to crack the gates. if you put 2 8psi springs in 1 gate then it wont crack until 16psi as the springs are doubled up. would be best to use springs slightly lower than your target boost and use a boost controller to reach the boost you want

Yeh ok I see what you mean now. I thought you meant something else at first :S Well 16 would be the lowest boost setting and I would just use my EBC to get me up to about 22 psi

twin gates are a total waste of time and money.

why would you buy two gates, when a turbosmart pro gate 60 is ample to actuate even the largest of the garrett turbos??

call turbosmart and speak to either Michael or Matt. Very helpful.

(i dont work for them, and i gain nothing from pointing you towards them, simply experience)

O ok righto I thought twin gates was the shit? Well like I said this is me just pondering for now I havent completely made up my mind

For 420-450 you would probably want the .84. With a 3.0 you could _probably_ run 1.00 and aim higher.

I have the TS .84 Garrett housing on a 2.6.

420kw is not a given; at these kinds of power levels and with this turbo you are talking more about tuner than raw hardware. Plus, if you have low compression, bad flow, or other mechanical problems there are guys struggling to make 380+.

The TS essentially turns the single large into twins on the exhaust side - in that you get the benefits from the valve openings/pressure waves directly. On the inlet side it's just a harder-driven compressor.

Spring pressure should be viewed as 'release pressure' - that is, you want two 16psi springs (without EBC).

Gate size is actually about how much gas you want to throw away, not what the minimum boost level is. I have an ancient 50mm HKS gate that has no problems holding boost down to 17psi on my setup (plumb-back gate).

The lower the boost you wish to run, the larger the gate size for dispersal required; the higher the boost, the smaller gate needed.

If you were going to do a TS properly with twin blocked-to-port gates, I'd be _very_ surprised if you needed anything bigger than 38mm for down to 7-8psi boost. That is, pretty much the smallest gate (x2) you can buy _should_ be fine.

Cheers,

Saliya

Sweet yeh ok that makes a bit more sense now. I wouldnt want to go much more than about 420rwkw anyways as I dont want to push everything too far. I was told by something that the 0.84 would be too restrictive haha clearly they are clowns.

I dont think I would want to aim for the 1.00 TS housing as it would be just that little bit more laggy. How easily do you think the 0.84 TS would spool in comparison to a GT35R with a 1.06? Just that my choices would be go the 0.84 TS or get the GT35 1.06. I know this has been covered a couple of times but I was just wondering if you yourself have used the both?

So you think twin tial 38mm gates would be fine? Would it be better to play it safe and go a little bigger than 38?

Pretty easy to see why on face value.

Unless you are running the gate to merge pre flange/turbine housing, you need two gates for twin scroll as the channels are separate.

Merging seems to not occur on anything bigger than SR/2ltr manifolds for whatever reason. Most i look for RB's and 2JZ's are all dual gate.

There must be a reason for it, what that might be, one can only assume the best boost control due to runner pulses and so on.

Wastegate doesn't do a lot more than that afterall

If you want 450rwkw+ then you need a bit more work and cash behind it all.

Ok firstly that is one FCUKING HOT exhaust manifold. OMG I love it!!!

And back on track...Yeh I wouldn't really want to go beyond 450rwkw or anything silly like that. I also wouldn't want to rev past 7000. Would the 0.84 be responsive enough that I wouldnt have to rev the shit out of to get somewhere?

How much power can the TS 0.84 t04z actually make? I wouldnt want to be struggling to make the 420 thats all. Alright I better head off and do some work Cheers

[TiTAN]

your power band is going to start around 3500-4000rpm, if its built and balanced properly why not go to 8000 the turbo isnt going to have any issues with the revs.

[saliya]

O ok righto I thought twin gates was the shit? Well like I said this is me just pondering for now I havent completely made up my mind

The idea behind the twin gates is to keep both halves completely separate right up to the turbo.

If you have a single gate you need the division between the two parts to go right up to the gate face itself -

this usually means a flange up the middle that extends beyond the end of your pipework like this:

(image from http://forums.evolutionm.net/evo-engine-tu...gas-both-4.html, reposted here so it doesn't go missing)

If you don't have the flange and/or it doesn't go right to the gate face you start losing some of the benefits of twin scroll because there's now a way for exhaust pulses to go into the "other side" of the manifold.

Sweet yeh ok that makes a bit more sense now. I wouldnt want to go much more than about 420rwkw anyways as I dont want to push everything too far. I was told by something that the 0.84 would be too restrictive haha clearly they are clowns.

Check the dyno thread...

I dont think I would want to aim for the 1.00 TS housing as it would be just that little bit more laggy. How easily do you think the 0.84 TS would spool in comparison to a GT35R with a 1.06? Just that my choices would be go the 0.84 TS or get the GT35 1.06. I know this has been covered a couple of times but I was just wondering if you yourself have used the both?

No, I haven't used both. Nor have I used the 1.00 housing on the T04Z; and at the time I chose my turbo (awhile ago) nobody was using the 35s.

If I were doing it again now I would probably go for a 35 (this is because at the output level of the T04Z virtually everything else on a stock GTR comes up short and needs to be changed).

You probably really need to take a look at some of the US Mitsubishi/Subaru forums because they seem to be willing to chop and change turbos/headers far more often than we do over here

and the GT35 seems to be a very popular choice atm.

When I made my choice my method was to figure out a desired output figure (for me, it was 400 kW); work out the airflow required to suit that;

then choose the smallest turbo that I thought would make that airflow fairly efficiently (for me, that was the T04Z split pulse).

So you think twin tial 38mm gates would be fine? Would it be better to play it safe and go a little bigger than 38?

Twin 38mm gates can probably bleed off about as much air as a single 55mm gate. It wasn't that long ago that a 55mm gate was the biggest you could readily get. Remember, the more air you're using to drive the turbo, the less air needs to go through the gate. So I can't see why they wouldn't be fine.

But the best way for you to find this out is to directly ask someone that's already done it/doing it - check out the 25/30 and 26/30 sections (there are a lot of posters).

Cheers,

Saliya

Edited December 14, 2009 by saliya

[Lukas 33]

your power band is going to start around 3500-4000rpm, if its built and balanced properly why not go to 8000 the turbo isnt going to have any issues with the revs.

I was more worried about the motor having issues with revs. Isn't revs what kills oils pumps etc? If the band is between 3500 and 4000 that seems to be about where he gt35 is with a 0.82.

Saliya - Cheers for all the info, very helpful. I had a browse through the rb30 dyno read outs and didnt see too much in regards to t he TS t04z. I will have another ponder around when I get some spare time

Cheers

Edited December 15, 2009 by Lukas 33

[PM-R33]

twin gates are a total waste of time and money.

why would you buy two gates, when a turbosmart pro gate 60 is ample to actuate even the largest of the garrett turbos??

call turbosmart and speak to either Michael or Matt. Very helpful.

(i dont work for them, and i gain nothing from pointing you towards them, simply experience)

I don't think you understand why you use twin gates on a twin scroll manifold, it has nothing to do with how big the turbo is and needing two gates due to it's size.

I think you are thinking of twin gates on a normal exhaust manifold, then yes, it is a waste of time and money and it would mean you are trying to run a very tiny amount of boost through a massive turbo.

Edited December 15, 2009 by PM-R33

[STATUS]

twin gates are a total waste of time and money.

why would you buy two gates, when a turbosmart pro gate 60 is ample to actuate even the largest of the garrett turbos??

call turbosmart and speak to either Michael or Matt. Very helpful.

(i dont work for them, and i gain nothing from pointing you towards them, simply experience)

um you would buy two as it works better especially if you run a true split style manifold which REQUIRES TWO.

[PM-R33]

Like i said, i think he is confusing himself thinking twin wastegates on a normal exhaust manifold.

[Lukas 33]

Twin wastegates isn't too pricey at the moment either. Two Tial 44mm Wastegates delivered to me for $850

[sneakey pete]

If you were going to spend the big bucks on a turbo like that with the power to match, why do such a shitty job on the internals that your afraid to rev past 7000?

[Lukas 33]

If you were going to spend the big bucks on a turbo like that with the power to match, why do such a shitty job on the internals that your afraid to rev past 7000?

You're right I should pull out the motor and rebuild it all again? Is it so bad that I don't want to rev the f**k out of the motor? It is all balanced etc I just don't really want to rev the f**k out of it. Ive never even seen the rev limit in my car EVER. I will see how the car goes rev wise with this tune. Maybe I will put the limit at 7500. I was just thinking 7000 as I don't want to have to wait so god damn long if I had to rebuild again. I just kind of wanted this motor to last longer than 4 weeks. A build takes quite a while being a pov ass uni student. Is the extra 500rpm that big of a difference? It only a street car. It has never seen a race track or a drag strip ever.

[TiTAN]

if it is never going to see a track does it even need 400kw?

[Lukas 33]

if it is never going to see a track does it even need 400kw?

I didn't say it won't see a track I just said it hasn't yet. No it probably doesn't need 400kw and I might not even do this depending on how the 0.82 gt35r goes with a better exhaust. I was just throwing around some thoughts and getting other peoples ideas if maybe they were considering it aswell.

Although if this is a "need" it thing they I guess I don't need more than 70kw to drive around town and I should buy myself an exel...........f**k THAT lol

I might go for the occasional run down the strip against a mate or just have a go around the little track we have here but this definately isnt a purpose built race car. Just thought it would be good to have street power on 16 and then strip power on 22 or something. I don't know any more.

What do you guys rev your rb25/30's out do? Just so I can ponder some more.

PS: Sorry if that post sounds grumpy, I just woke up.

[Duncan1]

I didn't say it won't see a track I just said it hasn't yet. No it probably doesn't need 400kw and I might not even do this depending on how the 0.82 gt35r goes with a better exhaust. I was just throwing around some thoughts and getting other peoples ideas if maybe they were considering it aswell.

Although if this is a "need" it thing they I guess I don't need more than 70kw to drive around town and I should buy myself an exel...........f**k THAT lol

I might go for the occasional run down the strip against a mate or just have a go around the little track we have here but this definately isnt a purpose built race car. Just thought it would be good to have street power on 16 and then strip power on 22 or something. I don't know any more.

What do you guys rev your rb25/30's out do? Just so I can ponder some more.

PS: Sorry if that post sounds grumpy, I just woke up.

I drive a built 32 gtr with a T04z on the circuit and i dont think the car will be any fun at all with a 7k redline. Honestly your power ban and redline will come together like cousins at a tasmanian family reunion!

You need to be able to rev it til at least 8000-8500 to really make it somewhat responsive!