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Making twin turbo 240Z - need advice


AggieZ

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I am going to make a twin turbo for my 240Z.

I have considered all options for upgrading my engine/tranny and have rejected them. The reason is I feel that if the 2.4 liter engine is taken out, it is no longer a 240Z. I'm just ol' school. I fully understand this route will cost extra money. I'm not worried about that.

PLEASE ADVISE.

Did you consider Nitrous Oxide?

it is pretty much the only cheep way to be fast occasionally, and retain all of the characteristics of the car(when the switch is off).

Will

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To make up a twin turbo for the L24, you've have to make seperate intake and exhaust manifolds for the engine, and not to mention that you would lose power with a twin turbo setup on an inline. I've seen someone try this, and had nothing but bad luck with his inline. And I'd have to agree with red_dog007 about picking up the RB26DETT.

Justin

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Really? there is 1 fast z with a twin turbo setup (but his has a custom dual overhead cam setup and a 3.1l)

I think you can do a twin turbo setup if you use the right combination of parts.

he wants to keep the L24 engine, so dropping in the RB (while a nice fast engine) is out of the option.

it will be a lot of work, and you might not get as much power as you could with different setups, but i think it might be neat.

Not sure what you mean by losing power in the L6 with a twin turbo setup. the RB is a twin.

maybe you mean in the z engine? I think if the turbo's were sized properly you should be able to make the same power as a single setup.

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...

Not sure what you mean by losing power in the L6 with a twin turbo setup. the RB is a twin.

maybe you mean in the z engine? I think if the turbo's were sized properly you should be able to make the same power as a single setup.

The point of a twin turbo setup on an inline engine is to have two different sized turbos that are tuned to different positions on the engines power curve to broaden the area of added power. In a dual turbo application on an inline engine both turbos share the exhaust and the intake of all cylinders. This is not the same functionality of a dual turbo system on a banked engine like the RB, where each bank gets an identical turbo.

Turbos usually have a sweet spot in the engines rpm band where they function most efficiently. Adding a second turbo to an inline engine would be done to make additional power over a part of the powerband the first turbo did not address with a slight overlap. With a larger area of added power from properly adding a second turbo, gearing can be used through more of the powerband instead of the "bump" in power usually generated by a single turbo, meaning a larger area of effectiveness in the entire drive train, and more flexibility in the shifting of the car.

As I understand the physics of the design of an inline engine dual turbo system it functions like a 12db per octave crossover, tailoring the output curve of a smaller turbo to match the output curve of a larger one so that the areas of power overlap slightly, making a larger area of more power. Using two turbos the same size on an inline engine means both were two small to be effective in the first place, and added more weight and complexity than a single turbo system properly mapped for the engine(twice the tubing). Adding them such that they operate on cylinders excluded from each other says exactly the same thing as far I have read.

A dual turbo setup on an inline engine done to maximize performance takes lots of information about the engine, the turbos, the fuel curves, the plumbing before, between ,and, after, and the cooling system. It is not horribly difficult to just add a second turbo, but adding one to maximize performance adds complexity and weight to the complete engine system.

If you don't want to do the math, or get someone involved who will, I would choose another way of adding performance. The end result could be bragging rights that reveal a

great idea with a bad implementation.

Will

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I get what you saying Will for the most part but get lost, I'll reread your post but

before I lose my train of thought....

Out the block (figure of speach), It seems like forged mechanicals would be the way to go is it not?,

but would the block (engine) hold up and up to how much power with what kind of

gaskets and head studs strong enough to handle it?

EDIT ~~ OK Will, I reread it and get what your saying now.

interesting concept on using the different turbos, is the Z33 ('90-'98) the same?

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Only one person in this thread has some idea of what they are talking about, and that is HLS30. Please, if you do not know for 100%, don't spread wrong information.

To the original poster, if you truly want to TT your L24, you have a LOOOOOONG road ahead of you. Everything will be custom fabricated and you will need to do A LOT of reading and research. The fact that you are posting here HOW to do this indicates that you are no where close to being ready to undertake this project.

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I am going to make a twin turbo for my 240Z.

I have considered all options for upgrading my engine/tranny and have rejected them. The reason is I feel that if the 2.4 liter engine is taken out, it is no longer a 240Z. I'm just ol' school. I fully understand this route will cost extra money. I'm not worried about that.

PLEASE ADVISE.

Did you consider Nitrous Oxide?

it is pretty much the only cheep way to be fast occasionally, and retain all of the characteristics of the car(when the switch is off).

Will

If you are hung up on the 2.4 liter displacement thing, here is an option. There is a RB24SOHC engine that Nissan exported to the Philippine auto market. This motor uses a RB25 block with a RB20 crankshaft.

Just throwing this out because I like to be different. I agree with your sediments about the thought of it no longer being a "240Z". Sticking to the 2.4 liter displacement with newer technology would have a cool retro effect.

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interesting concept on using the different turbos, is the Z33 ('90-'98) the same?

Yes. Same with the TT Supra Mk IV of the same era. There's a reason they are both holding their value and considered "super cars" by many. Gobs and gobs of consistent power.

As for a TT build on an L6 not setup for it to begin with...monster job. Get an RB and you have Nissan power at least. I've even heard of some guys dropping a Supra 2JZ engine into for monster hp but if your not careful, the torque will pretzel the car.

Dig around on HybridZ. It's all there. Good luck.

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I think that he would be better off with a pimped out L24. Cam, diff, tranny, ect.

That is basically what my goal is as I want to keep the same L24 under my hood. Thought of a turbo, not worth it imo, when this thing can still be a monster N/A.

About the turbos, parallel twin-turbo both have their own exhaust manifold, and push the same boost. This setup basically takes the work on one turbo and splits it between two turbos evenly.

The BMW 335 uses this technologly and does it good. Extremely low pressure (only 6psi, so 3psi per turbo) No lag, tons of low end and midrange power and effectivly N/A up top.

Then there is seqential twin-turbo which share the exhaust manifold and there is one small turbo and then one large turbo.

Vertially all V shaped engines use parallel just to make plumbing easier, but inlines can go either way fairly easy without too much plumbing.

There is also another type of system that can be used, but it rarely seen at all.

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