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Discussion Starter #1
My coworker and I were talking about this...and at the risk of sounding like a complete noob, need some logic explained to me....:wacko:

It's common knowledge that a stock D can handle roughly 220whp or so at it's max. My question is what if you're at the 220whp already and been boosting great for a while with no problems, but want to add a vac-u-pan system to make it run more effecient (while also freeing up some power), will I risk throwing a rod because I took stress *OFF* of the block?

My obvious answer is yes, due to it maxing out the rods...but my logic isn't making sense of why? If it's less crankcase pressure causing it to run more effecient, would you detune it back to 220whp? Or could you have a (even more reliable) 250whp D?

**All these numbers are hypethetical, just for the sake of showing a point**

Bottome line: If an already maxed out D will pop because you made it run better, and as a side effect added a little more power?
 

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simple answer, if you're on the threshold of finding the weakest link then why worry about it anyways?

if you are making 220whp and add a cam (more efficient) is it going to blow?

i doubt the 220whp threshold, i think its closer to 260whp if not higher with the correct tune.
 

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Discussion Starter #3
This is all in theory here...

Say you're already at the threshold of it blowing, and you add something to make it more effecient but adds HP as a SIDE EFFECT, will it blow even though you made it more effecient (In this case, took pressure OUT OF the crankcase)
 

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Discussion Starter #5
Vaccuum pump in the example
 

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The HP limitation is just used to make it easy on n00bs. The reality behind those numbers is that they should be easily obtainable without a big risk of detonation. Well tuned setups can survive beyond 220 hp, while poorly tuned setups can blow up at 160 hp.

So no, the power free'ed from a vacuum pump will not make the engine blow up given that the rest of the setup stays the same and is well tuned.
 

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Discussion Starter #7
Ok, sorry this is my mistake, but the numbers and power adders are HYPETHETICAL. Doesn't even have to be a honda.

If your weakest link is, say, the rods....and the rods are maxed out (WHATEVER the hp is) and you do something to add effeciency (like add a vaccuum), which in turn puts out MORE HP, but less stress, it shouldn't matter...right?

Technically you could have 500hp rated rods running a reliable 700hp effecient motor, is that right?

Hopefully not too confusing
 

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Ok, sorry this is my mistake, but the numbers and power adders are HYPETHETICAL. Doesn't even have to be a honda.

If your weakest link is, say, the rods....and the rods are maxed out (WHATEVER the hp is) and you do something to add effeciency (like add a vaccuum), which in turn puts out MORE HP, but less stress, it shouldn't matter...right?

Technically you could have 500hp rated rods running a reliable 700hp effecient motor, is that right?

Hopefully not too confusing
Just to answer question no it wouldnt matter..HP is a by-product basically and if you can get everything working together and increase the by-product without adding stress then it wouldnt matter what hp you are at. Depending on the efficiency you could be at 250 300 or maybe even 400hp.
 

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Just to answer question no it wouldnt matter..HP is a by-product basically and if you can get everything working together and increase the by-product without adding stress then it wouldnt matter what hp you are at. Depending on the efficiency you could be at 250 300 or maybe even 400hp.
but adding efficiency is going to cause more stress on the rod no matter what you do unless you de-stroke the motor and lower the rpm limit your still going to be putting more stress on the rod than the maximum tensile strength of the metal. Were talking about hard parts getting too much pressure on them at the wrong angle so if you can somehow tune the motor to create alot of pressure (such as 400+ hp) and still have the majority of the combustion take place while the rod is relativity straight and still has a good r/s ratio you could probabilly run like that for a long time. but the second that burn goes awry and detonates or burns too long it will bend and snap the shit out of that rod. Hell, ive seen eagle h-beams snap because of detonation.
 

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The stress on the rods from moving the pistons throught the crankcase pressure will be reduced (gone?), so in theory there will be less stress on the rods, and you'll end up with more power to the wheels as a result.

No, the resultant extra power will not lead to more stress on the rods. In fact it will be less.
 

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The stress on the rods from moving the pistons throught the crankcase pressure will be reduced (gone?), so in theory there will be less stress on the rods, and you'll end up with more power to the wheels as a result.

No, the resultant extra power will not lead to more stress on the rods. In fact it will be less.
the efficiency from the reduced windage on the rods is minimal probibally not even measurable the main point of inducing a vac in the crankcase is to increase ring seal and by increasing ring seal you are adding the ammount of pressure that the rod will see and thus my point. the only thing that you can do that will help create efficiency and create more power at the same time is reducing rotating mass yet keeping the same strength and even then your only reducing the moment of inertia not increasing power output.
 
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