2JZ on stock twin turbos Stupid idea or not?

[trd-drifting]

I have posted here as i didnt want to high jack the other thread

With all this talk about 1jzgte/2jzgte stock twin turbo power gains i have been thinking a lot. My car should be back on the road at this rate within 2-3 months. It’s just a stock 2JZGTE with the basics link etc in a mkiii...
Now I was thinking of making the pipes for the inlet myself, then thought why I’m at it why don’t I make a new manifold for it as the twin turbo ones shouldn’t be to tricky and I can get all the pipe etc.. for relatively cheap.

So what I was thinking removing the old log exhaust manifold making a twin turbo steam pipe manifold, and then 2 separate turbo dump pipes, and 2 separate inlets. Then I will Sort out the water and oil lines after. I have the time on my hands at the moment and it won’t cost me the earth.

Planning on going single soon so this will be only temporary, as I have just about finished my turbo manifold but won’t change to single for a while.

Stupid idea or should i do it in the coming few months?

[Girvs]

A lot of time, money and effort if you're going to upgrade in the near future. I'd save the money and time and prep something else for your upgrade.

[Looonie]

Very good plan, similar to what I'm going to try and do with the 1JZ (turning rear turbo around).

Much more efficiency gained from the turbos, allowing more boost, more power and longer life.

With regards to "money wasted" if you go single turbo in future, you can sell off this setup if done right to somebody else to make back your money.

[trd-drifting]

A lot of time, money and effort if you're going to upgrade in the near future. I'd save the money and time and prep something else for your upgrade.

Yes if you were to pay some one to do it will be very expencive. I dont mind as it a bit of practise i will learn somthing proberly, and im waiting on things so have nothing to do in the mean time. The manifold will cost me max $100 to make if that including a laser cut 2JZGTE flange and i will just have to buys some alloy pipe etc for the intake... so i picking max $350 if that and a day and a half work prob if that. The gaskets will be the most expensive part.

I think i will only do it if people think it is viable.

[Quint]

So you're making a manifold to change the orientation of the turbos? (eg. not back to back).

[trd-drifting]

So you're making a manifold to change the orientation of the turbos? (eg. not back to back).

Yea thinking of the idea at the moment seriously considering it. Have a little bit to much time on my hands for once. And then making two seperate intakes as if you have read the thread just below this one,
"1jzgte/2jzgte stock twin turbo power gains"

Just Getting peoples opinions as i do come up with a lot of stupid ideas from time to time

[2jayzgte]

I talked to the guys who will probably be doing this mod for me later on this year he reckons it will be quite an easy mod to do mind you he didn't sauy how much but he thought the process of doing it would be fairly simple.

[gmacrae]

Seen plenty of people waste lots of time and money trying to tweak those stock twins.

The turbos being back to back isnt the problem, nor the compressor side piping, nor the stock cast manifolds (turbines are very restrictive anyway, better manifolds aren't going to help). The real problem is the wastegate (or lack of). The tiny little single ~22mm wastegate on the front turbo cant do the job if you have a nice free dump/exhaust. People free up something in the system, wastegate cant keep up, car makes more boost, guy thinks the system is working better than before because its making more power (out of control boost will make more power - duh)

If you're going to do anything with the stock turbos, just weld up the stock wastegate (front turbo) and bypass valve (rear turbo, assuming you dont want sequential) and build an external wastegate into the joiner between the 2 manifolds. Then you could make up a new y-pipe (dump from each turbo into 1). You'll still be stuck at about 240-250 rwkw though - it'll just spool better and make less heat with a good free y-pipe and dump.

250rwkw aint nothin to sneeze at, but it'll be running those old ceramic turbos pretty hard, and if they shit themselves, it'll all have been pointless - a small single makes much more sense.

[Looonie]

Not really a completely logical argument there.

If he modifies his manifolds and intake piping to run the two factory turbos independently, then even if they do shit themselves buying another set for $100 to bolt straight on is a damn site cheaper than $3,000+ for a single turbo conversion.

[Quint]

If he modifies his manifolds and intake piping to run the two factory turbos independently, then even if they do shit themselves buying another set for $100 to bolt straight on.

That's the reason why i built a dump pipe for my twins, the turbos are consumable *shrug* litterally have half a dozen in my garage. Not a JZ, but same principle, the dump pipe definitely aids your spool time (dramaitically) and noticed about a ~2psi increase in boost.

Its a bit of a pauper way to go, but hey, sometimes sinking thousands into an old car isn't appropriate at the time and all you want is a little more joy.

[Girvs]

Yes if you were to pay some one to do it will be very expencive. I dont mind as it a bit of practise i will learn somthing proberly, and im waiting on things so have nothing to do in the mean time. The manifold will cost me max $100 to make if that including a laser cut 2JZGTE flange and i will just have to buys some alloy pipe etc for the intake... so i picking max $350 if that and a day and a half work prob if that. The gaskets will be the most expensive part.

I think i will only do it if people think it is viable.

If its going to be that cheap, then worth giving it a crack, esp if the engine won't be in yet. I just envisaged it'd take more than a half day of fabrication, esp to try to get everything lining up perfectly.

[trd-drifting]

If you're going to do anything with the stock turbos, just weld up the stock wastegate (front turbo) and bypass valve (rear turbo, assuming you dont want sequential) and build an external wastegate into the joiner between the 2 manifolds. Then you could make up a new y-pipe (dump from each turbo into 1). You'll still be stuck at about 240-250 rwkw though - it'll just spool better and make less heat with a good free y-pipe and dump.

Cheers for your opinion, don't completely agree with it but realisticly im only doing this for shits and giggles cause i can and have a bit of free time at the moment. Also the expense is not much. and the rear turbo rubs against the clutch master cylinder. I agree with the waste gates being to small and is the only concern i have but do not think will be a major issue, but on the other thread there is proof that seperate intakes to the turbo make about 15-20kw more.
240-250rwkw? well i could dig the dyno sheets out but my 1JZ made 255rwkw on a hub dyno at 0.9bar boost about 4-5 years ago and my 2jz was over heating to other issues and made 271rwkw. I know this is not much power but just wanting to see if it makes much of an improvement on stock twins.
The motor is out and getting balanced at the moment so wont take much to dos s the turbos are off. I would not bother if it was all in and running.

I just envisaged it'd take more than a half day of fabrication, esp to try to get everything lining up perfectly.

Haha half i day i would be a crazy man, add a day onto that im picking at least

Picking the pipe and bends up today so crossing my fingers car will be going in 2-3 months max as long as i don't loose my motiviation.