SUPRASUZUKI Posted December 12, 2007 Share Posted December 12, 2007 Actually he's stuck here until 7:15 because he's on holiday as of Friday Sorry mate, I thought you'd have shot off by now. I'm off until Tuesday, convalesence and holiday. Got to work the remainder of next week though. Quote Link to comment Share on other sites More sharing options...
Ian C Posted December 12, 2007 Share Posted December 12, 2007 If you assume that the minimum factor of safety you would want to risk is 1.2, then that is a maximum inertia load of 66kN, which is what you would get at approx 10000RPM. Before someone comes in at this post and reads it in isolation and interprets it as "10000RPM is OK on stock rod bolts" I'll add the caveat that this totally ignores the effect of bearing crush loads, fatigue and anyting else that I may have forgotten. So would it be safe to say that the average rod bolt failure is because of fatigue instead of plain old instant tensile loading? -Ian Quote Link to comment Share on other sites More sharing options...
Guest KDW Posted December 12, 2007 Share Posted December 12, 2007 Just to end the bike thing, It is actually drivable, but not very good for the twisties. It has a 6" over stock swingarm, otherwise it would easily flip at 250km/t. But all in all, it's actually more usable than you'd expect, due to the higer rev range than on a car. It is very scary though, guaranteed to get your blood pumpin' Quote Link to comment Share on other sites More sharing options...
Digsy Posted December 12, 2007 Share Posted December 12, 2007 So would it be safe to say that the average rod bolt failure is because of fatigue instead of plain old instant tensile loading? -Ian Well, I just spent an hour or so typing a long reply to this, then went and had my dinner before posting it. Unfortunately, the website decided to log me out in the meantime and I lost the lot Provided that the rod bolt is the root cause of the failure then I would say that it would be down to fatigue. However, the bolt does not have to fail completely in order to cause an engine failure. For example, if the bolt lost its preload, either by overloading or plain old coming loose, then that could cause the bearing to spin and sieze. Up until now I had just been using Excel and a calc for piston acceleration from the Bosch book to work out the fatigue loading, but before I went home I made a quick and dirty model in some concept-level software. Not FEA, but stuff we use for a first look-see. What I found was that there are not one but three "safety factors" that need to be achieved for the software to call it a "safe" design. One is simple preload versus inertia load, and corresponds closely to my Excel stuff. The second is fatigue, and that looks at the maximum and minimum loading in the bolted joint. What the third is has slipped my mind for the time being I need to put a bit more detail into the model before I can get any sense out of it, and some of it will require more knowledge about the engine (bearing sizes and standouts, etc). However, I was a bit surprised to find that even with my best guesses at values for the stock engine I could not meet all the targets. I'll have another look during my lunch break tomorrow if I get time. I possible I'll post up a list of all the data that I would need to do it properly. Quote Link to comment Share on other sites More sharing options...
Carl_S Posted December 14, 2007 Share Posted December 14, 2007 Standard rev limit is 6800rpm, the rev counter usually over reads a little. You don't want to be going higher than this without a lot of internal modifications to the head and engine. My engine and head have had modifications done. And has a TOMS racing ECU. I was told I can keep rung the car with the needle right at the end of the rev range if I want. Is this becuase of the engine mods and the ECU, or just the engine mods? And does this sound unlikely? will give details of the mods to the engine if you like, don't really understand them becuase I'm a newb, perhaps you can explain what they do and if they help achieve a higher safe engine RPM. Quote Link to comment Share on other sites More sharing options...
Carl_S Posted December 14, 2007 Share Posted December 14, 2007 You probably will find another limiter circa 8000 revs, it's called a con rod bolt lol, is that what is known by some mechanics as "putting a leg out?" Quote Link to comment Share on other sites More sharing options...
CJ Posted December 14, 2007 Share Posted December 14, 2007 My engine and head have had modifications done. And has a TOMS racing ECU. I was told I can keep rung the car with the needle right at the end of the rev range if I want. Is this becuase of the engine mods and the ECU, or just the engine mods? And does this sound unlikely? will give details of the mods to the engine if you like, don't really understand them becuase I'm a newb, perhaps you can explain what they do and if they help achieve a higher safe engine RPM. I would like to know what mods the car has to allow the tuner to make that claim. Quote Link to comment Share on other sites More sharing options...
CJ Posted January 1, 2008 Share Posted January 1, 2008 Did anyone get to see the list of engine mods? Quote Link to comment Share on other sites More sharing options...
Wez Posted January 1, 2008 Share Posted January 1, 2008 Reminds me, I still need to lower my rev limit Quote Link to comment Share on other sites More sharing options...
CJ Posted January 9, 2008 Share Posted January 9, 2008 I would like to know what mods the car has to allow the tuner to make that claim. I guess we'll never know then Quote Link to comment Share on other sites More sharing options...
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