High Compression Pistons

[Lextreme II]

We are making a high compression N/A VVTi 1UZFE for a customer and we utilized the older 1UZFE rods. He will be running 98 octane and demanded a 11.75:1 compression. With moderate head porting with oversized valves and stage II cams we estimated to reach 400 bhp. Here are some pictures.

 

[XR8tt]

Tell the engine builder the pistons are in the wrong way.. Lol...Hahaha

 

[hi98gs]

Wow, That is gonna be interesting to tune. Is the RPM limit gonna be changed? I wonder how much more power you may get by letting this engine rev higher and with a good set of cams and exhaust, that motor will be great!

Is the owner gonna get the pistons coated?

 

[Lextreme II]

No.. just NA. We utilized the earlier rods for additional strength. We have done few like this type of setup before. I will tell my guy that the piston is going the wrong way...LOL

 

[ed_ma61]

400hp? at wheels?

you wont do that on 'stage2' (wtf) cams and those rods david. maybe 400hp at engine, but not at wheels

 

[Lextreme II]

400hp? at wheels?

you wont do that on 'stage2' (wtf) cams and those rods david. maybe 400hp at engine, but not at wheels

Ed,

Please re-read my initial post again.

 

[StiCk3]

400HP is an estimate and a big one at that.

I take it that the VVTI system is coming out for the cams?

 

[ed_ma61]

considering a stock 1uz vvti can put out around 260-270hp to the wheels with an aftermarket computer and a simple tuned exhaust (no intake changes, engine unopened), getting an extra 50hp to the wheels with basic cams and another 1500-2000rpm shouldnt be too bad

id still be VERY wary though of putting much faith in the earlier rods though if that is the plan. sure, theyre not as weak as the later vvti rods, but i wouldnt go hanging new pistons (they dont look the lightest either), cams, and heads around them, and expecting 8000rpm redline to be sustained. imho higher rpm NA use is more demanding on fatigue strength of components than lower rpm FI, so any experiences of folks saying how they made XYZ power on these rods without breaking is a bit of a false reassurance

just my 2c

 

[Zuffen]

Ed,

You're right.

The heavier the piston the more likely a rod will let go.

The problem is the most stress on the rod is at TDC on the exhaust stroke as the crank tries to pull the rod and piston back down.

The piston tries to pull itsef off the end of the rod.

Few rods break from compression. Most (perhaps 100%) fail through tension.

I'm certainly not trying to teach Ed how to suck eggs here as he knows this already!