AirSpeed VW Community Forums
General Forums => Air Speed Lounge => Topic started by: Boost_Retard on December 22, 2005, 10:53:20 AM
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Ok, so i know a thick wall 92 is an odd ball (92 bore in 94OD cyl) BUT i think they would be great in turbo cars..street cars..and in my case...off road cars...
bigger bore than 90.5...thicker walls..and i would assume that they would run cooler than a 94...
altho i have never ran AA stuff..it looks like a good product
there had been talk about thick wall 92s on shoptalkforums, and Kona just sent me an e mail saying that he needs 200 orders to make a production run...there are quite a few ppl that want them over on shop talk..but i figured i would fill you guys in just incase you dont rear over on that forum..
i want a set..real bad :) and i cant have them unless more orders or interest is shown...
im sure air speed has room to stash `100 sets of thick wall 92s!
help a brother out!
Cale
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How much $$ will they go for? and would they fit a block bored to 94mm?
Emilio
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Well, i will give kona a call..
i assume they will be in the same price range as all the other AA stuff..
and yeah the plan was to make them as a drop in for 94mm bore..at least thats my understanding..
if i get a set..i plan to cut the the cyl (case end) down to 90.5/92mm bore.. so they will drop into 90.5 case..and use 94mm head.
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The more I think about it, the more I agree that you are right, that the hole in the case should be the 90.5 hole. More case material, and a wider seating surface on the cylinder.
If anyone thinks the cylinder being thin down there is bad, I once bought an engine that had NPR 90mm pistons. The case was bored to a dia of 91.5mm. You read that right, the cylinder wall thickness at the skirt was 0.75mm, or .030\". They would still be going but a broken crank took them out at 81,000 miles. If they were to fit a 90.5 case, the wall thickness would be 2.0mm, or 266% thicker than my example above. Oh well, it's a fairly easy machining operation to turn the skirts of the cylinders down.
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Talked to kona again today..
thick wall 92s are a go! sweet...
90 bucks for 4 bare thick wall 92mm cyls..
145 bucks for complete Hypersomethingorother cast slipper skirts and cyls..
True forged are in the works..
dont you air speed guys have a hookup with this dude? gonna be makin any orders anytime soon?
i wanna buy a set of bare cyls..better get 2 sets though..
Merry Holidays! haha
Cale
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How much $$ will they go for? and would they fit a block bored to 94mm?
Emilio
No answer. They are not that thick I gathered.
Emilio
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145 bucks for complete Hypersomethingorother cast slipper skirts and cyls..
True forged are in the works..
Just to set the record straight, the term is hypereutectic.
A brief explanation from Wikipedia as follows:
Hypereutectic pistons are cast pistons made from aluminum with over 16% silicon content for strength and durability. The term 'hypereutectic' comes from eutectic.
Special melting processes are necessary to
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thanks for the info!
by what your saying..it sounds like they should not be a problem in an NA motor..
what kinda books/school you reccomend to learn about metals and such? obviously you have invested some time on the subject.
now...these cimas that i and just about everyone else on the website, has run.. what are they made out of?
i know they say forged...but everyone knows they are not a true forged... are they also hypereutectic?
thanks
Cale
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thanks for the info!
by what your saying..it sounds like they should not be a problem in an NA motor..
what kinda books/school you reccomend to learn about metals and such? obviously you have invested some time on the subject.
Any entry level book on physical metallurgy is a good start if you are really interested in metals and materials. There are tons of case studies on the web on metal and material failures which make for very interesting reading, if you are so inclined, and if your searching skills are sharp. (fire up those bots!)
now...these cimas that i and just about everyone else on the website, has run.. what are they made out of? i know they say forged...but everyone knows they are not a true forged... are they also hypereutectic?
Alas, I don't know much about the current version of CIMA pistons, other than that they are made of an investment cast aluminum. I don't even know the grade! I suppose I should have some failed or throw away ones chopped up, micrographed to determine grain structure, and do a few physical tests to determine strength.
It all doesn't mean a hill of beans, though, unless you know what cylinder pressures, temperatures, unfactored stresses,etc. they are subjected to in order to make some kind of empirical judgement as to fitness for purpose.
The physical tests are really good for determining what contributing factors lead to a failure (after the fact).
As far as hypereutectics go, Keith Black makes a hypereutectic piston that many of the pro stock drag racers use, and these are not low compression engines. The only reason I can see for this is due to the predictable expansion characteristics (less) than forged pistons. Go figure.
Csaba