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Discussion Starter #1 (Edited)
Hi everybody:)
I'm wondering why we don't see dual chamber/plenum intake manifolds on a 2jz so often?
it's very common here in Europe with them on the VAG platforms & they claim better results with this type of intake manifolds.

Pictures below is an example of the style of manifold I'm referring too.
(picture is for a vw vr6 engine)
249904
249905
 

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They're expensive for most applications. People wanting a drag car can just compound turbo. Dual plenum intake manifold is good for longevity applications like old school ralley racing. Audi probably did it best.
 

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Discussion Starter #3
The one above is around $800-1000,- a lot of intake manifolds for the 2jz are over that price.

but let's look aside from the cost, is it worth performance/drivability wise?
 

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It is very cheap. No pictures of the internals. Key is trumpets and leveraged angle of attack for the pressure v. flow for the angle of the first manifold.
If the EGTs are even, and it can withstand 40psi, then it will sell. Need to have a DBW option also.
As it stands, looks like some snake oil bullshit until they can post up some diagnostic tech specs, pressure before/after, individual exhaust temps, fuel trims, etc.
 

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Discussion Starter #5
The pictures is only for showing which type of manifold I'm referring too. (Not for a 2jz, it's for a vw vr6 engine)
 

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Discussion Starter #7
Isn't that the same with the ¨normal¨ type of intake manifolds?
I know a lot of power is being made with the ¨normal¨ types of manifolds. I'm just wondering if the normal type (2jz community) style is better than the other (vag community)
 

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Isn't that the same with the ¨normal¨ type of intake manifolds?
No. OEM manifolds are compromises and cylinder to cylinder flow is way off most of the time, resulting in each cylinder requiring a different amount of fuel. OEMs will tune their engines to the stressors of the weakest cylinder.
Aftermarket will tune the engine to near knock, or knock, and back off timing or add fuel, and, well, fuck it, it's tuned, customer got their HP number on a dyno. Problem is almost everyone only uses a single O2 sensor down stream of the merge collector and that doesn't take into individual cylinder tuning into account at all.
Even if they do take that into account, usually they are adjusting trim on the injectors to get EGTs balanced across the motor.
This creates different stresses on the rotating assembly and can cause harmonics issues even if all EGT are even when tuned with fuel trim edited because each cylinder has a different expansion force due to the difference of fuel and air.

These are designed to create an equal flow of air to each cylinder, so each cylinder is the same. It's like tuning for one cylinder, on a multi cylinder engine.
 

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I linked this in my original thread on K20, and it has more information past the time when I had originally posted it.
 

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Discussion Starter #10
No. OEM manifolds are compromises and cylinder to cylinder flow is way off most of the time, resulting in each cylinder requiring a different amount of fuel. OEMs will tune their engines to the stressors of the weakest cylinder.
Aftermarket will tune the engine to near knock, or knock, and back off timing or add fuel, and, well, fuck it, it's tuned, customer got their HP number on a dyno. Problem is almost everyone only uses a single O2 sensor down stream of the merge collector and that doesn't take into individual cylinder tuning into account at all.
Even if they do take that into account, usually they are adjusting trim on the injectors to get EGTs balanced across the motor.
This creates different stresses on the rotating assembly and can cause harmonics issues even if all EGT are even when tuned with fuel trim edited because each cylinder has a different expansion force due to the difference of fuel and air.

These are designed to create an equal flow of air to each cylinder, so each cylinder is the same. It's like tuning for one cylinder, on a multi cylinder engine.
Thanks for the explanation??
 

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I think it's because you need to do some calculations of the rail size etc. So you can make an error on the flow part if you do it wrong. My friend is running one on his Supra. You can buy the kit from our local fabricator, but obviously it's a custom job and requires some knowledge and welding skills:
 

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People have reported that adding either holes or slits between the two chambers helps keep the flow distribution much more even. Difficult to experiment with unless you can use some decent CFD software to model it all out. Pics are for a Datsun L engine modeled off of the HKS intake manifold.
 

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Discussion Starter #13
I think it's because you need to do some calculations of the rail size etc. So you can make an error on the flow part if you do it wrong. My friend is running one on his Supra. You can buy the kit from our local fabricator, but obviously it's a custom job and requires some knowledge and welding skills:
Thanks
Do you have pictures of it assembled/welded together?
 

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Discussion Starter #14
People have reported that adding either holes or slits between the two chambers helps keep the flow distribution much more even. Difficult to experiment with unless you can use some decent CFD software to model it all out. Pics are for a Datsun L engine modeled off of the HKS intake manifold.
looks good 👍
 
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