Gotta love big revs on a YB - now with FFD goodness
06-05-2012, 11:01 PM
#81
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14-02-2013, 07:39 AM
#90
Too many posts.. I need a life!!
Out of interest and this is just aimed at sparking a debate and hearing tuners views
the 550-650bhp usually quoted as the limit for the rods, where does this come from?
Have tuners tested to destruction, I know its hard finding on different specs with reliability over a certain amount of miles.
or is it a threshold just over rs500 btcc power that is just assume to be near the limit.
Has anyone ever gone to 700 on standard rods reliably?
the 550-650bhp usually quoted as the limit for the rods, where does this come from?
Have tuners tested to destruction, I know its hard finding on different specs with reliability over a certain amount of miles.
or is it a threshold just over rs500 btcc power that is just assume to be near the limit.
Has anyone ever gone to 700 on standard rods reliably?
Engineers design parts to withstand a certain load amplitude (tensile and compression / or only tensile) over a number of cycles (ups and downs). When you exceed the load amplitude for a given component; that means more power, the number of cycles to failure decrease dramatically, which is shown when rods brake at high hp / rpm engines.
The reason why the rods in the cossie-engine withstand as much as they do is due to engineers didnt have finite element simulations when designing components in the 80s, they just designed them in a good manner (way overkill on 200hp).
The crank-design on the YB is actually great for high rpm as it has only 1 counterweight per cylinder. This lowers the natural frequency of the crankshaft aswell as lowering the crank inertia and bearing loads. However double counterweight cranks as most uprated ones are is actually better on lower rpms as they increase bearing loads (they got more inertia / heavier); but then again they are stiffer and more balanced.
You should take it to an experienced tuner to get some info on what to do with your engine.
Last edited by nixon_2wd; 14-02-2013 at 07:44 AM.
14-02-2013, 04:37 PM
#91
Atleast the Cossie rods are forged steel and look tough as f**k. Here's some pictures next to Saab (B204?) rods:
Atleast it looks like you need a 1000 lb bomb to break those but who knows.
Atleast it looks like you need a 1000 lb bomb to break those but who knows.
Last edited by Cossie92; 14-02-2013 at 04:38 PM.
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