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how do BP's kill engines?

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Old Apr 7, 2002 | 08:46 PM
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how do BP's kill engines?

I know that bp's kill engines... but how exactly does this occur? is the barrier between the ports and something else too thin? please explain it for me.
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Old Apr 7, 2002 | 09:02 PM
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As I understand it, the bridge will eventually crack just from heat cycling (it's really thin there). Add the extra wear from more power on top of that, and you've got a 40,000 mile motor... full of big grins
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Old Apr 7, 2002 | 10:47 PM
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so could you reinforce it somehow? like maby a company could create some "sleeves" that would make it harder.
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Old Apr 7, 2002 | 10:53 PM
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It'd probably be difficult to make a sleeve that increased the life of the bridge. I'd imagine that the actual casting of the housing would have to be modified to help its longevity.
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Old Apr 7, 2002 | 10:58 PM
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we need to figure out how... does the renesis have room for a bp that will last?
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Old Apr 7, 2002 | 11:05 PM
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Now that's an interesting question Anybody know just how different the castings are on the Renesis motors?
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Old Apr 7, 2002 | 11:13 PM
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one of the rich FD guys needs to buy an 8 and remove the engine, take masses of pictures, and post them for all of us to study.

If my dad gets an 8 (its either that, an STI or a 350Z) I will get him to go out of town some time and all the midwest gearheads can come over here, take the engine apart in 1 day, study it for a day and reassemble in 1 day. that'll be an interesting weekend, hahahahahaha
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Old Apr 8, 2002 | 12:15 AM
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with a bridgeport, and pport, there is going to be more ware on the apex seals. i think that that is one of the main reasons that bp's donot last..
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Old Apr 8, 2002 | 02:23 AM
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everytime u increase the hp of a car ur puting more stress on the motor... so anything can go bye bye..
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Old Apr 9, 2002 | 09:49 PM
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I want to make a Bridgeport exhuast on the new renesis side plates since all the ports could in theory be bridgeports. OFcourse the bridge in the exhuast would likely last even less long due to the high temp exhuast exiting through that and the bridge it self would likely not get adaquate cooling and fail quickly.. ...thats just a guess, who knows?
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Old Apr 10, 2002 | 02:49 AM
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Why not just go periperhal port on the exhaust? You'd make even more power.

OH WAIT - WE ALREADY HAVE THAT.

Renesis makes more power because it has higher compression than any previous model, and the noise characteristics of the side-port exhaust allow Mazda to fit an exhaust that is less restrictive without it being too loud.
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Old Apr 10, 2002 | 04:38 AM
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bridge porting the intake and exhaust ports on a renisis could be interesting
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Old Apr 10, 2002 | 07:17 PM
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Why not just go periperhal port on the exhaust? You'd make even more power.
Like you said, we already have that. I want to see some funky engine out there. I'm sure a bridge will not last that long with exhuast exiting with no real cooling going through the bridge directly.

This is just a guess, but I bet Mazda engineers noted that the sideplates get more heat damage then perpheral exhuast because the exhuast gases are more in contact with the sideplates in it. I am talking closer to the exhuast port itself. But on the bright side, I'm sure the lastibility of the rotor housing has been improved some.
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Old Apr 10, 2002 | 07:29 PM
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On the sleeve idea, I think it could work, hear me out...

Instead of leaving the bridge, port/cut out the whole area and a little more. Have someone cast a partial replacement piece made out of a harder/more durable piece of metal that looks like a BP. That "sleeve" will go in the spot that has been cut out. Secure it in there somehow then lap the housings. The bridge will be more durable.

Critiquing (sp?) my idea though, due to the housing and the sleeve being to different materials, they'd have a different expand/contraction rate... right? That's the only problem that I could see with it at the moment.
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Old Apr 10, 2002 | 09:27 PM
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Instead of going to all that trouble, why not just spray-weld some more material along the sides of the dish on old-school rotors, so you can have higher compression AND the peripheral exhaust ports?

OOPS I'm giving too many of my plans away... Hey maybe someone will do it first and tell me how well it works. I don't have access to spray-welding... yet... and I wouldn't trust braze or MIG welding on cast iron.
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