1uz, 2uz, 3uz rods any different...

[mmmjesse]

The connecting rods that are attached to the crank carry the pistons which carry increased weight load as the rotating action increases (rpms)... That's basic physic's (gravity, weight and speed) and that makes perfect sense.. I do agree that rods should be rated for strength thru rpm action and force...

Higher rpms create more load on the rods...

Thats basically what i wanted to say but after a long hot day at work i couldn't put the thought together.

Jesse

 

[jibbby]

I almost popped a brain cell on that post...So don't sweat it Jesse....

 

[JustenGT8]

So what your saying Justin boost is more natural for the rods to handle stress rather then a high performance cam change that increases rpms?

I would have thought the power of the bang in the combustion chamber would have a instant jolting and thrusting motion on the rod itself...However, after looking at so many busted rods it uppers the breaks occure mostly on the upward motion where the pulling upward force would bust the nut or big ring bottom portion... If that's the case RPM's would be more probable for rod destruction rather then brute piston force..

Thanks guys I am getting a grip on this yet...

All i'm saying is that boost doesn't put anywhere near the same stress on the rod during a normal combustion cycle (which while fast is actually a gradual force NOT a big shock) than increased rpm.

Now, if you are suffering detonation then you do have an 'explosion' going on and the combustion pressures go thru the roof. This does create that 'shock' or instant jolt you describe and would not be good for rods at all...usually a piston or bearing goes 1st but a rod on the limit could conceivably let go too.

 

[4000GT]

My 2 cents, there are a few 1UZ turbo motors here running 650WHP on stock bottom end internals (race and performance street cars).

 

[jibbby]

Timing, and a proper fuel mix is key to not blowing a motor when pressing for HP's as you state Justin.... If the bang happens before the piston reaches top dead center then you have pre-detonation and that would ad major stress to the piston, rods, rod studs, crank...Totally going against the rotating action of the motor...That is a big, no no....

E-solver it is clear the early model 1uz-fe's are very stout. Infact, I can't find any early 1uz-fe blown motors, rods, cracked blocks, etc.. Later model 1uz, 2uz, and 3uz's are a different story..

E-solver -To me that's amazing because first off the 92-94 1uz-fe motors have been around much longer and have also experienced more common wear then all the other motors. Infact from what I understand there are more of the those motors out there in the world also... So 650WHP would not suprise me too much on the bottom end, but wow that is alot power on the stock rods, rod studs, and crank... I would assume when you say bottom end you mean the stock pistons have been changed out to forgies... Right? I don't think any xuz-fe stock pistons can handle a true 650whp, if so now that would be a suprise to me...

 

[cribbj]

My 2 cents, there are a few 1UZ turbo motors here running 650WHP on stock bottom end internals (race and performance street cars).

Sounds do-able, but only just. I'll bet those motors are right on the ragged edge of holing pistons. We've found the 2JZ-GTE can get away with 500whp on stock internals with good intercooling (FMIC) and VERY good fuel. So just by simple ratioing, 4.0/3.0 x 500 = 667 whp.

Not to say that 500 for the 2JZ or 667 for a turbo 1UZ is a "safe" figure at all - we've seen stock 2JZ's blow at lower outputs; it all depends on the conditions doesn't it?

 

[4000GT]

I have a mag article on one I will try find it and post. From memory the pistons were stcok, but was tuned on C16...

 

[4000GT]

Ok, found the article, it maxed out the dyno at just over 600WHP (torque obviously maxes it out but thats the HP it did it at).

Not quite as standard as I thought, but here is the list of mods to motor is:

o-ringed block, ARP rod bolts, mild porting, and aftermarket valve springs.

 

[jibbby]

E-solver, according to your last post the 1uz-fe was running stock pistons and rods, just stronger ARP studs and valve springs...WOW!!! Where did you see and read that article? That 600whp would be the most I have ever seen or read about...

I think that is all new high for the 1uz-fe motor if it's true.... Time to boost away without fear.......

 

[4000GT]

New Zealand Performance Car Magazine, RS 2005 Edition, Pages 56-60.

 

[4000GT]

Recall also it has an o-ringed block, which I am assuming is to run decent boost, not sure how much they run, but they do use twin T04E turbos.

 

[rms]

I am trying to work this out in my head... Why would higher rpms compromise the rods?

example -

1) One engine revs 7000 rpms and creates a peak HP rating of 500whp
2) Second engine revs 9000 rpms and creates a peak HP rating of 500whp

The following loads are not meant to be accurate and do not allow for the elliptical motion of the rod shank. They are based on a 560gm piston and 40% of a 660gm rod with std 1uz bore and stroke. They are only an indication of the loads involved.

1- To increase torque from 270lb/ft to 540lb/ft
270lb/ft = 213 lb/sq/in force on piston crown.
540lb/ft = 427 lb/sq/in force on piston crown.

2 - tensile load on rod from deceleration as piston approaches TDC on exhaust stroke
7000rpm = 2.5 ton
9000rpm = 4.19 ton

3- based on nominal Argo rod cross section the stress in the shank is
7000 = 21,000 lb/sq/in
9000 = 36,000 lb/sq/in
If the material and design has a fatigue limit of 30,000 psi, at 7000rpm it will last forever ??? but at 9000rpm it is only a matter of time.

 

[V8Datto]

They are based on a 560gm piston and 40% of a 660gm rod with std 1uz bore and stroke.

Thanks rms for that, Makes perfect sense.

Just wanted to know the exact weight of the standard 1uz piston
Where did you get your 560g from?

The reason I wanted to know is because I will be running Ross Forged pistons
and they only weigh 464grams and argo rods of 615grams (not including weight of piston rings or piston pin clips)

 

[rms]

560gm is std WRX Sti piston and pin, 660gm is std SBC 5.7" rod.
Have not weighed std UZ piston or Argo rods, weights should be ballpark for the example.

Anything you can do to reduce weight, while maintaining or preferably increasing rigidity, will give a performance benefit. That applies to the whole car.

 

[jibbby]

Yeah, thanks RMS...It appears according to your calculations for every additional 2500 rpms the actual force load doubles on the rod....

RPM's make a big difference to say the least...

 

[rms]

Yeah, thanks RMS...It appears according to your calculations for every additional 2500 rpms the actual force load doubles on the rod....

RPM's make a big difference to say the least...

The load increases at the square of the rpm increase.

2 x rpm = load x 4

20% x rpm = 80% x load

50% x rpm = 200% x load

 

[jibbby]

Gotcha....Thanks for correction RMS...

 

[V8Datto]

So does any one know the weight of a standard 1uzfe piston?

 

[XR8tt]

The nice thing with turbo's is there is "some" pressure on piston on the exhaust stroke... This IS where rods can fail...
Also as power increases especially on forced induction engines. The detonation threshold is reduced [esp with std compression].. Detonation will kill any good engine...

 

[Jake Breyck]

Seriously, the -only- reason a rod would fail on the very bottom of the big end is because the bolts failed. The only time there would be stress on the very bottom is when the rod is being slung upward. The most stress is where RMS stated, where the shank meets the big end.

This is very correct. here is a honda rod cap that had a bolt fail. even tho the cap bent it held togather.