Dyno Carnage! ;)
Hahahaha. Sort of. Not often I get to blow shit up "on purpose".....
Had Nadine's and my Silvia on the dyno Friday at 3am lol. Quick back story.... We actually have good rods and good pistons on the shelf, but decided to use a stock motor instead, and see if we could break into the 8's after last years 9.4 half track pass with a stock motor (plus cams).
Anyway, last year, at ~580rwhp, the car ran a couple 9'7's at 147mph, and the last run was 650rwhp, and a 9.4x letting off just past the 1/8th after destroying the powerglide transmission.
Lots of myths and rumours about the famous 2jz, and I don't do myth, I wanted fact.
This years combo, 272 Crower custom grind cams, a stock intake whos pelnum I had enlarged, 70mm throttle body ford truck tbody, Turbonetics 75mm turbo, EBAY cast exhaust "log" manifold and wastegate. Garrett 4.5" thick intercooler. Bottom end is stock, except ring gaps opened up generously, and a hand hone of the cylinders (we were re-using rings from another motor)....
Within the third pull, it was making 700rwph through the auto. It was at this point I KNEW it would run 8's, so we decided to turn it up.
750, 790, 840... 902RWHP!
The 902 rwhp run was interesting. At about 35 psi, the motor came on wicked strong, and the power curve went to 902 by about 5800 rpm, then dropped about 100hp to around 800 at 6300. I rode out the run, and it hovered around 800 till 7500.
We stopped briefly checked plugs, scratched our heads, and then made another pull. And at the magic number of 666.4 rwhp during this run, the motor kicked a rod out the block and oil pan.
This was on race fuel, no attempt was made to cripple the tune with retarded timing etc. Just wanted to see what it was good for, timing was very close to MBT and monitoring calculated CA50, AF was proper.... etc
Anyway, after dissassembly, we made this little meme
You will notice 4 bent rods, a destroyed rod and piston. I am willing to bet, the point the motor dropped 100hp was when the rods bent, and the last run finished it off.
As the rods bent, the crank counterweight smacked the piston skirts (due to reduced clearance), and clearanced them lol, and I suspect the last one bent a bot more, and broke everything when it hit.
Bearings are MINT, and probably re usable.
The pistons ARE strong for a casting. Except for skirts where crnak hit, no damage, ringlands intact. They have a 8mm steel "cooling" coil cast within the piston top, they have lots of weight and material in the top. If you picture the valve relief edge, and the back of the top ring groove, they actually have more meat in that area than a CP piston I saw recently, and our current Probe's.
The rods are "ok". Here is a shot of the 2jz rods, next to the L33 rods from a junkyard 5.3l motor.
The Crank is nothing short of awesome.
Doing some math based on fuel flow, the power where the rods failed was somewhere around 1140 Crank HP, and at such a low rpm means LOTS of torque and cylinder pressure working on them at that point. Killing torque at this point with retarded timing could extend the power they are good to slightly.... but they would not last long anyway lol. In case you are curious, 1140 crank hp in a 2600 pound car is good for ~174mph quarter mile trap speeds. Insane actually.
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Originally Posted by killramos
