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I keep laughing at how you guys don't seem to get what Vlad is saying.
Engine vibrates. With rubber mounts, me no feel vibration. With solid mounts, me feel vibration.
it's like you guys think that solid mounts actually make the engine itself vibrate more. that doesn't make any sense. engine vibrates the same, no?
The same with or without dampening? No, it's going to lower the amplitude when you dampen it. That's what dampers do, they remove energy from they system. The frequency will stay the same, that depends on the RPM of the engine. The amplitude will decrease the more you dampen it. Very simple physics.
But the motor mounts only dampen and isolate vibration from the chassis, not dampening the vibration to the intake manifold. I don't see how isolating vibration from the rest of the chassis would also change the vibration experienced by something that's hard mounted to the engine.
But the motor mounts only dampen and isolate vibration from the chassis, not dampening the vibration to the intake manifold.
Not true. Example, someone replaces crap dampers on their motor mounts suspension. The user notes that the dampers changed the handling characteristics of the vehicle regarding the suspensions ability to keep the tire contacting the ground, and the ride comfort of the vehicle. The car is faster around a track (tire control changed), and yet also has changed the way the entire chassis feels. The reason it has an affect on both is because it's connected to both.
Originally Posted by turbofan
I don't see how isolating vibration from the rest of the chassis would also change the vibration experienced by something that's hard mounted to the engine.
Because the dampers are dampening vibration. It's what they do.
Most places that appear to be holes are not actually holes. They are where the tip was lifted when welding or a weld covers another one. It can create a small black spot that looks an awful lot like a hole but isn't. But, because people will perceive them as "holes" when they aren't - I am EXTREMELY OCD about the guys covering those up or fixing it. It saves comments or emails such as this. It is easy enough to test to see if it is a hole or not. Does light shine thru it? Will a small paperclip push into the hole? I have no idea how old this manifold is, but we would be happy to fix it.
As for the cause of failures, ya'll nailed it on the vibration. Now add in the G forces that engine is under at an increased rev limiter - and I'm not surprised there is a crack there. Say you create the perfect storm - solid motor mounts and you're about to shift at red line in boost, in a corner, and then hit a bump - vibration, G force, and pressure. IF something is going to give it will be the softest metal or the weakest link in this equation, and that is the aluminum in the intake manifold.
Like I said, we'd be happy to fix it. Just give me a call. Also talk to Corky about additional bracing to try and avoid future cracks. As long as solid motor mounts are used, though, I would expect that you will continue to fix cracks occasionally.
Stephanie
Most places that appear to be holes are not actually holes. They are where the tip was lifted when welding or a weld covers another one. It can create a small black spot that looks an awful lot like a hole but isn't. But, because people will perceive them as "holes" when they aren't - I am EXTREMELY OCD about the guys covering those up or fixing it. It saves comments or emails such as this. It is easy enough to test to see if it is a hole or not. Does light shine thru it? Will a small paperclip push into the hole? I have no idea how old this manifold is, but we would be happy to fix it.
As for the cause of failures, ya'll nailed it on the vibration. Now add in the G forces that engine is under at an increased rev limiter - and I'm not surprised there is a crack there. Say you create the perfect storm - solid motor mounts and you're about to shift at red line in boost, in a corner, and then hit a bump - vibration, G force, and pressure. IF something is going to give it will be the softest metal or the weakest link in this equation, and that is the aluminum in the intake manifold.
Like I said, we'd be happy to fix it. Just give me a call. Also talk to Corky about additional bracing to try and avoid future cracks. As long as solid motor mounts are used, though, I would expect that you will continue to fix cracks occasionally.
Stephanie
The pin holes are in fact that, I did a boost pressure test using soapy water and I sprayed down the manifold. If I continue to have problems I will contact you guys at BEGI I have another event on the 23, I will check the manifd again for boost leaks after I finish reinstalling it, and then again after I go to the event to see if I have more problems.
It's kind of crazy to me that solid mounts would be an acceptable reason as to why a manifold would crack, but I'm not an engineer. I will add some pictures of my current bracing and setup to give you a better picture.
The pin holes are in fact that, I did a boost pressure test using soapy water and I sprayed down the manifold. If I continue to have problems I will contact you guys at BEGI I have another event on the 23, I will check the manifd again for boost leaks after I finish reinstalling it, and then again after I go to the event to see if I have more problems.
It's kind of crazy to me that solid mounts would be an acceptable reason as to why a manifold would crack, but I'm not an engineer. I will add some pictures of my current bracing and setup to give you a better picture.
Thanks
Like, I said we'd be happy to fix it. Email me for a RMA form and send it in.
Bracing will help, but will not be the "be all, end all". Corky can help with those ideas. It is much like the Stainless S4 manifolds we use to sell. The weight of the turbo had to be supported as to not crack, however, it still had to be able to move because of thermal expansion. Regardless of what we did, the stainless was never strong enough and this manifold would crack at some point no matter what. And sometimes, the more you brace it the more it cracks - espcially if it heats up and moves.
Stephanie
I did a leak down test today and immediately heard leaks coming from the my intake manifold. I found two pinholes and a cracked weld. I am not the original buyer of the intake so I don't know all of its history. The pinholes are on the 1st and 2nd runner and the crack is on the first runner. I searched here to see if its a common issue and found this thread. The pinholes are near the injector and you can see where either fuel has been seeping out or gunk has been making its way into my engine. I have already sourced a local shop to strip the intake of the blue paint, repair the damage and pressure test the intake.
I did a leak down test today and immediately heard leaks coming from the my intake manifold. I found two pinholes and a cracked weld. I am not the original buyer of the intake so I don't know all of its history. The pinholes are on the 1st and 2nd runner and the crack is on the first runner. I searched here to see if its a common issue and found this thread. The pinholes are near the injector and you can see where either fuel has been seeping out or gunk has been making its way into my engine. I have already sourced a local shop to strip the intake of the blue paint, repair the damage and pressure test the intake.
I don't know if the pinhole leaks were from when BEGI built it, or from vibrations. I have heard of a good number of weld failures with honda IM conversions. The consensus I have seen seems to think it most the vibration of the engine that causes issues. I have also heard from various spec miata drivers that without the stock brace IM manifolds have been known to crack and break studs due to vibrations.
If it is cracking along a weld, that is a vibration. I see a small hole in the crack, but that does not look a welding issue. Do you have a better photo?
Thanks,
Stephanie
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