Made it to the dyno

[Guest 280ZForce]

I will be the one to test the rods, as it seems, no one is running stock rods in HIGH hp applications.

what do you consider high hp for our engines? I'll pull all the power I can outta this engine was I get it running and start w/ the tuning. I definitely should have the 500+ whp and tq in the bag with the new setup, should be a very feasible goal to start with atleast.

 

I'm using stock rods that have been race prepped from a Z knowledgeable machine shop that used to build Z race cars for endurance races and what not.

 

But you'll get to the point of finding their potential before I will cuz I'm still working on getting some loose ends tied up before I can fire it up and break it in even.

[1 fast z]

Oh, I am thinking in the 700 rwhp range.

[Guest 280ZForce]

Oh, I am thinking in the 700 rwhp range.

500 is my starting conservative goal, my build can handle the higher range just have to make sure tuning is on mark, obviously essential with any setup.

[1 fast z]

I hope to do mine on pump gas, with meth injection. SO I can have 700+ rwhp all the time. Should be around 28 PSI or so with my setup. Crossflow, and double the valves helps also, hehe.

[nbesheer]

I'm still working on getting some loose ends tied up before I can fire it up and break it in even.

 

And by loose ends you mean replacing every possible thing there is to replace

 

Actually `yield' is point at which the material stops deforming elastically, and starts deforming plastically.

 

And can someone explain this to me ?

[X64v]

Elastic deformation is like gently squeezing the sides of an aluminum can, the walls move back into shape when you let go.

 

Plastic deformation is like crushing the same can, it doesn't return to it's original shape, it stays crushed.

 

http://en.wikipedia.org/wiki/Deformation

[1 fast z]

A spring has one of the highest yeild points, a peice of anneled copper, has a LOW yeild point, like a solid copper head gasket.

Sample graph

 

Many metals follow Hooke’s Law until a certain level of stress has been applied, after which the material will distort more severely. The point at which straight line behaviour ceases is called the limit of proportionality: beyond this the material will not spring back to its original shape, and is said to exhibit some plastic behaviour. The stress at which the material starts to exhibit permanent deformation is called the elastic limit or yield point.

 

 

 

[thehelix112]

Not citing your references is called plagiarism.

 

http://www.ami.ac.uk/courses/topics/0123_mpm/index.html

 

Dave

[hughdogz]

nbesheer, Brian totally is right but I don't think that graph is indicative of a typical metal. If I remember correctly, after the yield point the curve goes horizontal (a definition of yielding is you get more strain without adding much, if not any more stress). It doesn't make sense to me that you could lower the stress, yet get more strain (elongation).

 

It's also interesting that once you're past the yield point and unload, it takes a different path back, but with the same slope. At this this point it is plastically deformed and the strain doesn't start at zero anymore and it is now considered "work hardened". You can add more stress then the first time before it starts to plastically deform again.

 

Getting back on topic, in reality I'd be surprised if a connecting rod stretches like the chart shows. The common mode of failure is fracture at the small end. The chart is correct only it happens at a localized area where a crack forms, grows and finally runs and you get fatigue failure. To help avoid fatigue failure, you should only cyclically load up to half the ultimate tensile strength IIRC. Another method is to shot peen the rods so that it adds a pre-compressive stress to overcome before you even get to a tensile load. Polishing is important too to help eliminate any stress risers (cracks or sharp inside corners) from forming.

 

BRAAP has a great example that shows failure due to buckling resulting from detonation...looks more like a pretzel than a connecting rod. Somehow the hyper-eutectic pistons came out still looking brand new!

[Tony D]

So 600 hp on stock rods is possible as long as it is not an endurance road race car being spun at 6-8k for hours on end. Perfect, as Bryans car is a street car.

 

No, I never said that. I said that with 100 passes down the track, you have maybe 10 laps at a reasonably sized track. I don't know where the failure point is, but given most of the races they had were less than 2 hours in length, extrapolation of 'time under full load' could be done. If they didn't trust them for a 2 hour event...

 

As for dragracing-vs-tranny failure. Torque. Bonneville is a nice place where people run stock trannies, and then find out stuff drag guys never find out....like the stock RX7 transmission has a flex in the countershaft that allows both 2nd and 5th gears to engage when passing through a turbocharged RX's torque peak at over 140mph... Made the car jump airborne, do a 360, blow the transmission out from under the car, and then do a series of flat spins... Depending on the torque you put it through, and how will determine when it fails, right off the line, or down the end where you're going much faster...

 

Also, I believe I mentioned SMALL end deformation or elasticity. The gudgeon pins scored the walls. I mentioned nothing about the big end and loss of oil pressure. This is a function of piston weight, true...and of rpms and the length of time at the rpms. I would say the small end indeed stretched and returned to normal size as when checked it was all round and to spec size---the only way the gudgeon pins will move to the walls is if the small end stretched and let them move!

 

Unless you are on a Mustang Dyno where you hold your peak HP rpms (under load) you will never replicate the conditions.

The inertia dynos just pass through the rpm ranges too quickly.

[1 fast z]

Tony, what was the mass of the pistons in the big boniville motor? You guys used press in pins, right? Double true arc's is what I uses to help against walk.

 

 

 

The helix, is contributing more useless info to a TECH thread, its sourced in the properties of the picture, DUH, dude you are TOTALLY a freaking nut case man. On a side note I see in your profile with a gigantic turbo, you only run high 12's, slower then lots of NA cars on this site. Thats impressive keep up the good work.

[RTz]

It stops right here guy's. Play nice or it will be shut down.

[1 fast z]

I vote for a shut down.

[RTz]

I vote for a shut down.

 

You got it.

 

Peace,

[COZY Z COLE]

The outcome of this thread is a classic example of where juvenile actions rule over adult based content...

 

 

LARRY