Can a tune eliminate the need to avoid redlining a cold engine?

Question

As with any car, you'll want to be a little gentle right off the bat when driving a cold car. Not granny driving, but not hooligan either - to let the engine warm up at least to some degree.

My car in particular, an Audi A4 2011 model 2 litre diesel, states in the owners manual that you'll want to avoid full throttle application and redline while the coolant temperature needle is at the coldest.

When I apply full throttle, there's a few factors I assume come into play that I'm curious about. Mainly, the engine produces torque from the combustion of diesel. With stock engine mapping on my car, that's around 290 Nm of torque in the rev range 1500-2500 u/min.

I've had my car stage-1 tuned, so it reaches 290 Nm at 1200 u/min, and I figure that the car can also produce 290 Nm with way less throttle application than with the original mapping.

So how does this work out and how does it affect the engine? Consider the two scenarios:

• Original mapping, 290 Nm @ 100% throttle, undesired when cold
• Stage-1 mapping, 290 Nm @ 50% throttle (50 just to pick a number), not bad for the engine when cold (at least what I've heard).

What's the difference? The engine is producing the same amount of power, so how come one of them isn't favourable with a cold engine, while the other is?

Answer 1

The tune might reduce the severity of the problem, but it can't cheat physics.

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As explained in this answer, redlining while the engine is cold puts undue stresses on the engine that shortens its useful life.

Since this is a turbocharged vehicle, the tune is increasing torque output by increasing boost pressure, which increases operating temperatures:

▲ intake charge pressure → ▲ combustion chamber temperatures

The consequence of this is that at 1200 RPM the engine will warm up faster on the Stage 1 tune than the stock tune.

However, for reasons listed in the linked Q&A, this does not negate the manufacturer's recommendation; there will still be a temperature difference across the combustion chamber and engine block/head while the engine is warming up.