i bent the rods with k24/18g's installed not the k16 and i 100% positive that it was not the tune that caused the pre-detonation it was my lack of using good fuel/along with ambient air temp and too much boost

tim

 

So basically, the lack of using good fuel/along with ambient air temp and too much boost, caused pre-detonation that bent the rods. Not as much the structural integrity of the rods themselves. Especially true considering the ring land cracked.

Again not trying to insult you, I'm just still waiting to hear of an actual case where the strength/structural integrity caused the rod to fail. After seeing the power Jamie Carter and David Kim/Switzer have made on the stock engines, it's apparent that the engine is plenty strong enough, when the proper tune-up/fuel is used. I'm starting to believe the limits might be much higher than most initially perceived (and I'm anxious to explore this quite a bit more in depth myself on our own car).

 

take a look here
http://www.pauter.com/billet_rods.htm

 

I think you may have missed my point. People often use your car as an example of what a "safe power" level is. You bent rods due to detonation, not power, not the boost.. Had you had a tune and injector in the car that was able to run 1.34 bar safely, you most likely would have never had issue.


My point about mentioning the k16 was, you can easily cause more stress on an engine with small turbo's and a bad tune then big turbo's and a good tune.

 

no insult taken i have stated many times here and in other post and PM's it was my fault and it was a combo of air temp/octane/to much boost... this combination hampered the strength/structural integrity and caused the rod's to fail

 

pre-detonation may have caused the rods to bend... you can run 1.34bar on a stock motor but you must have the right fuel(oct) and enough of it (injectors) and the right tune which you could supply at EPL or todd at Protomotive.

 

ive asked this questions in the past as well... do we know of any cases of blown engines that were running good gas, at acceptable boost levels, but just too much power, which would deem the rods to be the week link?

 

I've yet to see any myself although I'm sure they exist somewhere, there norm seems to be too much boost, too little fuel or quality fuel. In many cases it could also be a result of early experimentation in tunes. As now many tuners have made adjustment and figured thing out, the power levels have increased and may continue to increase.

 

^^^^^^^^^^^^^^^^^^^^^^^
AGREED!

CYLINDER PRESSURES INCREASE 5x W/DETONATION!

 

Agreed!!!!^^^

+2

 

another thing thing , theres more that can be damaged then rods , when going that high on power with a stock motor, lets not forget that..

let me quote Kevin from UMW

"Well half of you guys are in denial.. The other half call me when they hear the gremlins in there engine. Last year I shipped out 6 new crate engines for the un lucky souls.. Looking at the active users that are on right now, I see 2 of them with engines that have had there engines torn down for rods or intermediate shaft/crank damage.

Lets for a second forget about the rods... How does one address the intermediate shaft failures and vario cam modules stuffing the valve trains in these engines..

Anyone that pushes these engine over 700HP better realize that a new engine is over $25K You can buy a few used EVO's or Supra's for that price."

 

Sign me up for a few used supra's and evo's for 25k.

In all seriousness, please post documented cases of properly set up and tuned cars that have broken because of power... Im not sure I know one. Please post and prove me wrong.

 

I'm afraid the information is incorrect. I believe this was the first 996tt motor to bend a set of rods or any rods for that matter. I believe this ocured in 2003. All six rods were bent. The pistons had no signs of detonation.

The statement about 700+ hp being a ticking time bomb is also incorrect? Unless you are playing with wild boost levels. Our recent motor motor is 4.2L (80.1 mm crank, 105.7 mm pistons, no variable cams). The engine dyno'ed @ 1200+ hp @ 1.4 bar. The turbo's were not the ones being quoted in the title of this thread. There is not one single stock Porsche part in this motor. If I wanted to break the motor fast I would use a boost levels above 1.4, below that it is pretty much bullet proof. By that I mean 30 to 40 hours wide open usage. Just playing on the street will see a lot more time. The current motor was designed to run 2.0 bar and use top fuel and nitrous if so desired.

 

cjv so are you saying that a stock motor with 700 to the wheels running it hard as most people drive , is not a ticking time bomb?

 

So I am not taken out of contex, let's define some things.

1) Motor built right for the application.
2) Building the motor to produce 700+ hp without the use of boost above 1.3 bar.
3) A 700 hp @ 1.3 bar correctly build motor will yield 30 to 40 all out race hours. On the street 20 to 30 thousand miles would be a reasonable number.

An internal stock motor would be a ticking time bomb at anything above 600 rwhp driven hard all the time.