84.5mm pistons for BP
#1
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Going to refresh my old 84mm bore BP block with a small overbore and some 84.5mm slugs. Looks like 84.5 isnt a common size and only wiseco and JE make an off the shelf piston in this size. I had 84mm wisecos in the car previously and would like to run them again. Wiseco 84.5 lists the compression as 8.5-8.8....so Im not sure if its 8.5 or 8.8. They both have the same part #. Does anyone run 84.5 wiseco that can confirm? Thanks.
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The 84.5 isnt any more expensive though, I could use the existing block out of my car but I already have the old block out and ready to take to get machined. I dont think itll cost any more to bore 84 - 84.5 vs 83 - 84 would it?
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I did read about that, I thought the general consensus was that 84.5 is ok but going to 85 with boost is too thin. I do have another block I could use instead if the walls end up being too thin. I can talk to my machine shop and have him measure the thickness to find out. My buddy years ago ran 85mm with 28psi on his drag miata, made over 450 at the wheels and it was perfect, but I would rather not take any chances.
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Only if he has the tools to sonic test it
https://www.miataturbo.net/engine-pe...g-boost-69187/
Seeing dozens of people get screwed by liar machine shops, I'd probably ask to see the machine they use instead of just having them tell you "yeah we tested it, it's ok" which usually means "we eyeballed it, nothing stood out, so pay us our money"
https://www.miataturbo.net/engine-pe...g-boost-69187/
Seeing dozens of people get screwed by liar machine shops, I'd probably ask to see the machine they use instead of just having them tell you "yeah we tested it, it's ok" which usually means "we eyeballed it, nothing stood out, so pay us our money"
#13
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Only if he has the tools to sonic test it
https://www.miataturbo.net/engine-pe...g-boost-69187/
Seeing dozens of people get screwed by liar machine shops, I'd probably ask to see the machine they use instead of just having them tell you "yeah we tested it, it's ok" which usually means "we eyeballed it, nothing stood out, so pay us our money"
https://www.miataturbo.net/engine-pe...g-boost-69187/
Seeing dozens of people get screwed by liar machine shops, I'd probably ask to see the machine they use instead of just having them tell you "yeah we tested it, it's ok" which usually means "we eyeballed it, nothing stood out, so pay us our money"
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