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Only selling as i live in the new forest and shes too quick for the forest roads i have had quattro turbos in the past s2s and they dont even come close in performance
Yet another rod discussion... pretty much like discussion religion...
Forum member "maRS2"'s ADU pushes 2.2bar and 620nm at 3300rpm with stock RS2 turbo and stock rods. In the winter months, this figure is closer to 700nm due to the colder charge air. No problems on stock rods as long as pre ignition is kept at bay. 4 cyl VW 16v turbos have pushed 500+ hp at the wheels (and survived) with stock rods. The compressive load per rod equals close to 750hp on an inline 5.
The peak buckling and bending loads on a rod happen at bottom dead center, and is caused by inertia of the piston that has to decelerate from high speed (approx 75m/s), stop, and accelerate again during a few milliseconds. The heavier the piston, the higher the rpm, the higher the buckling load. A bone stock S2 engine puts more buckling and bending loads on the rods at BDC at 6000rpm than an I5 tuned to 750nm does at peak torque. Torque drops to close to zero at BDC, so the buckling loads are not cumulative.
Then why do people observe bent rods with increased boost/torque: Increased boost/increased torque dramatically increase combustion chamber temp, and thus the likelihood of detonation and pre-ignition. This is what kills rods. Torque is just an indirect cause of the bent rods. Torque produced by boost is thus more likely to indirectly bend rods than torque produced by flow.
Detonation can lead to pre ignition, but detonation rarely causes bent rods by itself, even though the cylinder pressure and force during detonation is many times that of peak torque during clean combustion, in addition, the load from detonation is a shock load, which has the potential of much more damage due to the rapid loading and inertia.
Yet another rod discussion... pretty much like discussion religion...
Forum member "maRS2"'s ADU pushes 2.2bar and 620nm at 3300rpm with stock RS2 turbo and stock rods. In the winter months, this figure is closer to 700nm due to the colder charge air. No problems on stock rods as long as pre ignition is kept at bay. 4 cyl VW 16v turbos have pushed 500+ hp at the wheels (and survived) with stock rods. The compressive load per rod equals close to 750hp on an inline 5.
The peak buckling and bending loads on a rod happen at bottom dead center, and is caused by inertia of the piston that has to decelerate from high speed (approx 75m/s), stop, and accelerate again during a few milliseconds. The heavier the piston, the higher the rpm, the higher the buckling load. A bone stock S2 engine puts more buckling and bending loads on the rods at BDC at 6000rpm than an I5 tuned to 750nm does at peak torque. Torque drops to close to zero at BDC, so the buckling loads are not cumulative.
Then why do people observe bent rods with increased boost/torque: Increased boost/increased torque dramatically increase combustion chamber temp, and thus the likelihood of detonation and pre-ignition. This is what kills rods. Torque is just an indirect cause of the bent rods. Torque produced by boost is thus more likely to indirectly bend rods than torque produced by flow.
Detonation can lead to pre ignition, but detonation rarely causes bent rods by itself, even though the cylinder pressure and force during detonation is many times that of peak torque during clean combustion, in addition, the load from detonation is a shock load, which has the potential of much more damage due to the rapid loading and inertia.
Well put Espen.
I think the rod hysteria is coming from 3B's throwing rods out of the blocks due to the spark hop issue not because Audi made crap rods.
I believe that even if you put some Scat-rods or such in a 3B and the spark hop occurs it can still kill those rods, it just takes slightly more effort, the problem is still there.
Correct?
Many RS2's is running non stock setups pushing 400-450bhp and holding up just fine.
Since I have an ABY I will feel no worries throwing an RS2'ish setup on and fetch a nice 400bhp with my stock rods.
I believe there's a very informative thread on here somewhere where this is covered thoroughly, mainly by you Espen.
I'm with Espen on this one... Pre-Ignition on that single coil dissy setup is the root cause - I am sure. I had never really understood this problem until earlier this year, but the insight of Paschens Law had the light bulb go on for me.
The only ABY/AAN engine I can think of that suffered bent rods was Pembo's rally car - dunno if they got to root cause of that one - very odd as it runs K24 with 34mm restrictor and balanced / blueprinted engine to GpA spec.
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