rosenbergendo

Just thinking this 4.0 motor has had lots of issues already. From the redline going from 9k to 8.8 to seemingly 8.6 it seems there is something going on in the valve train of the motor. Now with cars burning up in the first real weekend on the track and production being delayed it certainly has me wondering if it would be smart to get the car and use it for its intended purpose.

Ceepe

Punctuation. You no haz it.

karimgt3

There is a thread on this already..

Only one car got burnt not several, and the reason is unknown yet, but keep in mind that this particular car had been fiddled with at the dealer prior to the fire, and that the source wasn't the engine itself. No proof of any problems or "several issues" in the motor, nor in the valve train as u mention yet..

It was also said that with the redline at 8800, the RS has the same piston speed of the 991GT3s at 9000rpm.
The car shifts at 8600 in Sport Auto mode, its not the redline. You can make it go all the way to 8800 in manual mode.

llstuey

If i recall you had a meltdown when your car came with Dunlops and have told everyone that 2014 GT3s will crater in value... yes, you should probably avoid the 1st cycle of the RS if you are worried about these issues. Do you have an RS allocation?

ipse dixit

Maybe you can explain to me why the redline was changed from 9000 to 8800.

I understand the end result is the same (i.e., same piston speed at redline) but why the change? And yes, I am aware of the longer bore/stroke that was used to make this happen.

But why did Porsche change the redline?

Same ends, but different means to get there. Why?

911_RS

I'm guessing because of a bigger displacement? Bigger displacement engines are not safe on high rpm redline…

lumber

The only guys worried about the rs having issues, are not getting one.
How weird is that...

rosenbergendo

Gotta be a **** everywhere I guess. 2014's at my 2 South Florida dealers have been much much more difficult to move. Crater, no. More difficult to move-absolutely. I got over the Dunflops, you have a great memory.

karimgt3

Is it to make it safer? Is it because there is no need? Is it because of the higher capacity engine that would like to rev less? Increase engine life? We don't know.. But now that they lowered the rpm, and that it is supposedly safer, then why the worry?

But we are sure that porsche wouldnt have launched it if they weren't completely sure they solved it with the 991GT3 since it's almost the same engine..

karimgt3

Lol

WazRS

Speculative philosophy is the philosophy embodying beliefs insusceptible of proof and attempting to gain insight into the nature of the ultimate by intuitive or a priori means.

Wael

Jimmy-D

There is nothing wrong with the 991 GT3 engine. That was a l ready dealt with and corrected.

Also, the reason it does not have a 9000 red line is the higher displacement does not warrant it.

Now- I know everyone paranoid about the recent fire because of the GT3 but no one has a clue if even related t o engine

Petevb

Not sure if I'm understanding your question correctly...

Piston speed gives a good indication of the stress on the rods, pistons and crank due to acceleration. The GT3 is quite close to the practical limit of production materials. You can't simply add more material to the rods or pistons to make them stronger, because they would also get heavier and hence the stress would stay constant. Instead you need to use higher grades of light, strong materials like titanium and aluminum alloys if you want to increase stress and hence piston speed. However Porsche is using some of the best materials in the GT3 engine already. Hence the RS kept piston speed stress constant and dropped the revs.

The other option would have been to keep the stroke short and make the bore wider. This could have let them stick with 9k, but unless they changed the bore spacing the cylinder walls would have gotten very thin, leading to thermal issues. The combustion chamber would also have gotten uncomfortably large, leading to potential emissions and flame front issues.

arena-RTR

Ding ding ding! We have a winner!

To summarize what he said: There is nothing wrong with the engine: The reason the revs were lowered was because physics.

karimgt3

Thanks Petevb!