Strange Intake Manifold Sound
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Strange Intake Manifold Sound
While the car was on the dyno today, we have been trying to address some of the small problems that have surfaced. We've been able to figure out most but there is one that is baffling us.
There is a sound coming from the intake manifold when you give partial throttle, which sounds comparable to lifter tick in a typical piston motor (but obviously there are no lifters in a rotary).
Also under partial throttle the intake manifold actually expands and contracts, this is partial throttle blips revving to like 2000 if that.
There is a sound coming from the intake manifold when you give partial throttle, which sounds comparable to lifter tick in a typical piston motor (but obviously there are no lifters in a rotary).
Also under partial throttle the intake manifold actually expands and contracts, this is partial throttle blips revving to like 2000 if that.
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Originally posted by ranger4277
What do you mean it expands and contracts? Like it is swelling up and deflating again? Which part of the manifold is doing this?
What do you mean it expands and contracts? Like it is swelling up and deflating again? Which part of the manifold is doing this?
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That's because it is made from a composite. Paul Yaw was going to address that issue on his supercharged race car by building an aluminum upper manifold. He had this same concern.
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I know aluminum can handle a good amount of pressure with no issues but what about the new composite upper manifold? A few LS1 guys that have gone to forced induction have cracked the factory composite manifolds on those engines. These are made from basically the same stuff. I'm not saying that it necessarily will crack or break, but it isn't as strong as metal.
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Originally posted by rotarygod
I know aluminum can handle a good amount of pressure with no issues but what about the new composite upper manifold? A few LS1 guys that have gone to forced induction have cracked the factory composite manifolds on those engines. These are made from basically the same stuff. I'm not saying that it necessarily will crack or break, but it isn't as strong as metal.
I know aluminum can handle a good amount of pressure with no issues but what about the new composite upper manifold? A few LS1 guys that have gone to forced induction have cracked the factory composite manifolds on those engines. These are made from basically the same stuff. I'm not saying that it necessarily will crack or break, but it isn't as strong as metal.
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Originally posted by rotarygod
That's because it is made from a composite. Paul Yaw was going to address that issue on his supercharged race car by building an aluminum upper manifold. He had this same concern.
That's because it is made from a composite. Paul Yaw was going to address that issue on his supercharged race car by building an aluminum upper manifold. He had this same concern.
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Originally posted by Japan8
You know I wondered about that too. Can the manifold really take much pressure since it's composite. Based on SSR's findings... that answer is apparantly no. It is really surprising that it's flexing at 1500 rpm 25% throttle @ 5psi.
You know I wondered about that too. Can the manifold really take much pressure since it's composite. Based on SSR's findings... that answer is apparantly no. It is really surprising that it's flexing at 1500 rpm 25% throttle @ 5psi.
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SSR, it's time to set yourself up as a site vendor. Please PM me or get in touch with Ryan Scott at advertising@rxtuner.com . Thanks.
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I remember from some odd years ago there was an article in a car magazine about using composites for things like intake manifolds. At the time I had wondered about the heat resistance and strength of the composites... now I find myself wondering the same thing again. Maybe this is a mod that someone should look into... replacing the upper intake manifold with an aluminum one.
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Originally posted by Japan8
I remember from some odd years ago there was an article in a car magazine about using composites for things like intake manifolds. At the time I had wondered about the heat resistance and strength of the composites... now I find myself wondering the same thing again. Maybe this is a mod that someone should look into... replacing the upper intake manifold with an aluminum one.
I remember from some odd years ago there was an article in a car magazine about using composites for things like intake manifolds. At the time I had wondered about the heat resistance and strength of the composites... now I find myself wondering the same thing again. Maybe this is a mod that someone should look into... replacing the upper intake manifold with an aluminum one.
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Originally Posted by SSR Engineering
My mistake, that is when we are hearing the sound, but the manifold is flexing under revs with NO LOAD, there is no boost going through the manifold and it is flexing, this is 50-100% throttle in neutral.
#19
Originally Posted by rotarygod
That's because it is made from a composite. Paul Yaw was going to address that issue on his supercharged race car by building an aluminum upper manifold. He had this same concern.
https://www.rx8club.com/series-i-aftermarket-performance-modifications-23/turbo-intake-manifold-design-34440/
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I just called the shop in san diego producing this turbo system and they said it's available to the public right now. They have 2 kits. The one that is available does not come with a fuel management system. The other turbo kit that is expected (how many times have we heard that) to be done in the coming weeks will include fuel management for a few a higher price of course.....
He told me they were going to try and dyno the car sometime this week to get some #'s...
I'll call them back later and see how the progress is coming....
He told me they were going to try and dyno the car sometime this week to get some #'s...
I'll call them back later and see how the progress is coming....
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Originally Posted by SSR Engineering
My mistake, that is when we are hearing the sound, but the manifold is flexing under revs with NO LOAD, there is no boost going through the manifold and it is flexing, this is 50-100% throttle in neutral.
Having said that, I could certainly see concerns pressurizing a composite manifold that is optimized to work under a vacuum. Composites can be very strong, but they also can be more easily tailored to specific operating conditions than alloys. Moving from a vacuum to a pressurized system could easily put it outside it's "safety zone."
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