Welded vs Billet Crankshaft
02-24-2004, 02:19 PM
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Welded vs Billet Crankshaft
Allegedly, a billet crankshaft (scat, etc) can handle up to 2000hp, and a pulse welded crank is good up to about 600hp...
True? what about max RPM? any other drawbacks/limitations?
I remember an east coast shop touting welded crank strokers, and he was limiting rpm to about 6400 - but then he also tried comparing a 300Z to an older (pre GT)928....
as always, any input is greatly appreciated - thx again!
True? what about max RPM? any other drawbacks/limitations?
I remember an east coast shop touting welded crank strokers, and he was limiting rpm to about 6400 - but then he also tried comparing a 300Z to an older (pre GT)928....
as always, any input is greatly appreciated - thx again!
02-24-2004, 04:00 PM
#2
Devek tried Welded Cranks earlier I think. I'm not sure how they worked. Its cheaper - but at what cost. I think a nice way would be to slightly decrease the OD of the rod journal, thereby getting a few more MM of stroke out of a stock crank... If thats something you wanted. Thats seems safer to me then welding on more material. I don't think that new material would ever be as strong as the rest of the structure.
02-25-2004, 03:19 AM
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Rob,
I would tend to agree with Brendan - great advances have been made in welding and surface treatment, but I have yet to see any good science/real-world testing of a high (~500 HP) welded crank with longetivity.
Longetivity being one of the key words here. Sure, 1000 race miles are very hard on a car. But,just because they are 10 or 20 times harder does not meant that a part will last that much longer in 'everyday' high performance driving - or stop and go traffic, which is the REAL torture test.
Somebody may have a way to make it work, but I have yet to see even the suggestion that a welded crank is as good as a scratch crank, let alone data to prove it.
Cams are a differnet story, but even welded cams can have serious issues if not done 100% correctly.
Greg
I would tend to agree with Brendan - great advances have been made in welding and surface treatment, but I have yet to see any good science/real-world testing of a high (~500 HP) welded crank with longetivity.
Longetivity being one of the key words here. Sure, 1000 race miles are very hard on a car. But,just because they are 10 or 20 times harder does not meant that a part will last that much longer in 'everyday' high performance driving - or stop and go traffic, which is the REAL torture test.
Somebody may have a way to make it work, but I have yet to see even the suggestion that a welded crank is as good as a scratch crank, let alone data to prove it.
Cams are a differnet story, but even welded cams can have serious issues if not done 100% correctly.
Greg
02-25-2004, 04:22 AM
#4
Rennlist Member
I just happened to be reading through the Devek Vol. 3 catalog, link on their homepage earlier today.... somewhere in there it says they dropped the welded cams because while OK for racing applications, they found that the stress on the cam nose at idle caused them to chip.
D
D
02-25-2004, 02:31 PM
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as always - thx for the input!!
as I feared, it was too good to be true...it's finally starting to sink in - bottom line is: except for the mahle way(ie, devek & 928intl), we just don't have much data/testing on other internal mods - so anything else is a sophisticated experiment(some more than others)...reminiscent of the 60's when hotroders were finding unique ways to improve detroit iron, albeit w/more technology to overcome/use...ah, 928 mods-to boldly go where no gearhead has gone - these are the voyages of the modified shark....or maybe it's more like,"do ya feel lucky punk, do ya?...BANG!"
back to billet...thx again!!
as I feared, it was too good to be true...it's finally starting to sink in - bottom line is: except for the mahle way(ie, devek & 928intl), we just don't have much data/testing on other internal mods - so anything else is a sophisticated experiment(some more than others)...reminiscent of the 60's when hotroders were finding unique ways to improve detroit iron, albeit w/more technology to overcome/use...ah, 928 mods-to boldly go where no gearhead has gone - these are the voyages of the modified shark....or maybe it's more like,"do ya feel lucky punk, do ya?...BANG!"
back to billet...thx again!!
