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reving to 7000 rpm


Guest P-Irish

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Well I believe the others are stainless, so the Ti ones would have approximately twice the unltimate tensile strength (ie less likely to snap) but approximately half the youngs modulus, so are more prone to bending.

 

That assumes the same profile / section as stock though, yes?

 

If they're different, this could be even better?

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The Crower Ti are very strong and light weight. They are H-beam items, they cost more than double the price of carillo's though. I used crower Titanium's in my turbo hayabusa running almost 600bhp, never missed a beat.

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600bhp/litre, isn't that almost old formula one turbo levels of power :innocent:

 

Digsy, did you say that the stock con rod bolts can hold almost 40kN? If you ran up to say 35kN load by increasing the revs, how much of a rev increase is that, and what's the theoretical maximum rpm giving 40kN?

 

-Ian

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600bhp/litre, isn't that almost old formula one turbo levels of power :innocent:

 

Digsy, did you say that the stock con rod bolts can hold almost 40kN? If you ran up to say 35kN load by increasing the revs, how much of a rev increase is that, and what's the theoretical maximum rpm giving 40kN?

 

-Ian

 

Ummmm... probably lots :) No time to analyise it properly right now, but I'll do it before I go home tonight.

 

The thing is that its not going to be as simple as all that. Increasing the revs up to the point where the inertia loads are, say, 95% of the bolt preload will tell you a safe rev limit for a single engine cycle. What it won't tell you is how many cycles you will get through before the bolts fail through fatigue.

 

That's possibly why there is a seemingly monster factor of safety built in to the stockers.

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600bhp/litre, isn't that almost old formula one turbo levels of power :innocent:

 

Digsy, did you say that the stock con rod bolts can hold almost 40kN? If you ran up to say 35kN load by increasing the revs, how much of a rev increase is that, and what's the theoretical maximum rpm giving 40kN?

 

-Ian

 

I thought the Busa was 1300cc ?? maybe not !

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Ummmm... probably lots :) No time to analyise it properly right now, but I'll do it before I go home tonight.

 

The thing is that its not going to be as simple as all that. Increasing the revs up to the point where the inertia loads are, say, 95% of the bolt preload will tell you a safe rev limit for a single engine cycle. What it won't tell you is how many cycles you will get through before the bolts fail through fatigue.

 

That's possibly why there is a seemingly monster factor of safety built in to the stockers.

 

Ah, fatigue failure. How does that work, is there a wavy line somewhere where a bolt will last "forever" and once you cross it you get into a finite lifespan that gets shorter and shorter the more of a kicking you give it?

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It's close Ian, the 'Busa is 1300cc though.

Still pretty good at about 210kg.

 

Performance bikes built one for an attempt at the UK bike speed record, they managed 720bhp.

 

For how long ;)

 

How, honestly, undriveable (er, rideable?) would a 600bhp bike be?

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The Crower Ti are very strong and light weight. They are H-beam items, they cost more than double the price of carillo's though. I used crower Titanium's in my turbo hayabusa running almost 600bhp, never missed a beat.

 

600bhp from 1.3! on a motorbike?!?! jesus christ, what was the lag like on that, or does the higher rpms that death traps have help with that?

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For how long ;)

 

How, honestly, undriveable (er, rideable?) would a 600bhp bike be?

 

How long? No idea, but not long flat out. Then again, how many highly tuned engines (cars or bikes) get used in real anger for long periods. Race engines of course, but these are regularly rebuilt.

 

I would class 600bhp in a bike as unusable on the roaad (but then mine's only 158bhp and I don't use that on the road!!), but how many of us use the full potential except on the track?

 

Throttle control is the key, like driving your car fast, in the wet, with no traction control. You can do it, but you can't take the

p1ss (otherwise, you're likely to 'hit Diesel');).

 

I'd love a go on it though!

 

The PB 'Busa stuck with the 11,000 redline I believe, but was bored to 1622cc.

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Right - here's what you get for making me rush things ;)

 

 

What I forgot is that talking about small end and pison mass alone is fine for rod shank strength, but wrong for rod bolts. The rod bolts see all of the inertia created by the piston, pin and the upper part of the rod: i.e. everything above the rod cap joint line. So by whacking up the total reciprocating mass to 0.313kg (piston) + 0.76kg (rod) and then knocking off about 0.1kg for the rod cap and bolts we get an inertia load of nearly 30kN, so with your 2x40kN bolts, that's your factor of safety down to 2.6 right there, ignoring all of the other factors :)

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What I forgot is that talking about small end and pison mass alone is fine for rod shank strength, but wrong for rod bolts. The rod bolts see all of the inertia created by the piston, pin and the upper part of the rod: i.e. everything above the rod cap joint line. So by whacking up the total reciprocating mass to 0.313kg (piston) + 0.76kg (rod) and then knocking off about 0.1kg for the rod cap and bolts we get an inertia load of nearly 30kN, so with your 2x40kN bolts, that's your factor of safety down to 2.6 right there, ignoring all of the other factors :)

 

What estimated max rpm does that translate into :innocent:

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What estimated max rpm does that translate into :innocent:

 

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.

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