ZRAYGO:

I think its great what your plans are for your car but in the same time, if someone tunes your car bad it will blow up just as easy as mine with no internal work. my car is now going on 4k + miles at 8 psi with no problems. Only time I have open the hood was to do an oil change. How long it will last? Only thing I can say is that i will let everyone know when it does blow up, But I am sticking with the story that it is all about tuning.


On a side note I would really love to see a dyno of a PE kit.

 

Spaz...I couldnt agree more.

Let me put this into perspective for everyone.

With proper tuning, I think the stock pistons and rods/bolts can see 450whp and beyond with very good reliabilty. Think about it for a second.....

An internal combustion engine is really a remarkable machine. When tuning properly....even to very high HP levels, the crank, rods, and pistons are working in perfect unison and harmony, like a quality swiss watch. There are a lot of things going on the engine, but its still literally works like clock-work. If you increase cylinder pressure and HP, you...of course...put more stress on the motor....but in a very methodical and precise, and linear fashion.

Compare that to raising the rev limiter. The stress on the rods at 7000rpm is......read this....10 TIMES great than at 6000rpm (Corky Bell, "Maximum Boost") . So something as simple as raising the rev limit on a N/A engine puts exponentially more stress on the rods than simply increasing boost slightly. How about this example. During detonation, or pinging, the cylinder pressure and the force being exerted on the pistons can be 5-10 times the stress on the pistons when compared to normal uniform combustion.

The reason I am giving these examples, is that lots of 350Z's have their revs raised to 7100, and occasional pinging for a sec or two will not destroy a motor right away...despite the insane pressures and stress on the pistons, rings, rods, bolts, and bearings...this cars are emerging unscathed.

Based on this logic, a properly tuning F/I car should be able to easlly withstand signficantly more boost than most people think.

Tuning is everything! I will of course, be the first to concede that forged internals and LC pistons will certainly make tuning for high HP much easier, and the forged jobbies will hold up much better to detonation and high revs...but I think my point is still valid.

And I really wanna see one...just one....example of a PROPERLY tuned car that blew their motor with F/I. Every example I have seen was either a result of a lean condition, or too much timing advance.

If i was a betting man, I would think that at some point, even with proper tuning, I bet we'll blow a piston ring....and loose compression...rather than actually breaking a rod, or shattering a piston. The two "best" ways to break a motor are to blow a ring, or headgasket. In most cases, this results in almost no significant permanent damage to the block or head, and makes the repairs relatively straightforward. In the combustion chamber, the force of the explosion is looking for the path of lease resistance.....and when that point is reached...the path of least resistance is the rings. The ring lands also tend to take the MOST abuse.

Once I find my junkyard Maxima motor , and a place to keep it....I will really start to test the limits of this baby.

Hope this makes sense.

 

opps....one minor error. When you increase rpm from 6000-7200rpm, inertial loads on the pistons/rods increase by 150%....not 10 times like I thought. But you get my point....though.

Also, becuase of the magic of turbo charger, when you double the output of the motor, intertial loads do NOT double...thank GOD. It all has to do with the fact the maximum inertial load occurs only at TDC and BDC....the spot when the piston and rod reverses it's course of travel. And becuase only 20% of the AF mixture is burned in the first few degrees of revoltion.....you essentially get some get a little kick back from the F/I gods, and the load is signficantly reduced.....

I lifted this info right out of Cork Bell's book "Maximum Boost". I would consider it required reading for anyone interested in F/I. It's a very easy read too.

 

Just saw this. Here is my AF:

 

thanks for posting this. yeah, your car gets a little leaner after 5500rpm...just like mine. At 6psi, I redline at 11.5:1.

I deciede to just run 6psi until I get my FPR and return line connected. We need just a bit more pressure towards redline.

 

/agree

I am hoping that I may ask you a few questions once you are done with your fuel solution.