Turbo vs NA warmup and driving habits

[SteveSRT8]

I believe he is saying while the engine is cold then boost would be harder on it than a comparable N/A engine.

Once warmed up it becomes moot, but everyone knows that the more power produced per cubic inch the more likely you are to wear it out sooner. That doesn't mean turbo motors suddenly explode, just that an equivalent design N/A would likely last a little longer under the exact same duty cycle.

Many modern turbos do not allow full boost when cold, and modern engine controls help hold them together in the real world better now. But there was a time when forced induction meant short life.

Cujet, the temp spec you quoted was seen by me in the 60's in an HP Books publication which credited Ford for the research. But since it was done with old motors on old dino oils it may not be as applicable today.

 

[sciphi]

Considering my turbo car runs at 220*F (yes, it really does run hotter than boiling!) and is above 160*F within 3-4 minutes of a cold start (yes, it really does warm up that fast thanks to an electronic thermostat that stays closed a long time), I'm not too concerned about wear on the engine itself. I'm more concerned with the turbo and transmission being excessively worn on cold operation.

GM built a lot of safeguards into this engine. With this one in particular and my driving habits, I'm not too concerned.

 

[rjundi]

My wife drives the same warm or cold motor. Not easier but not really hard either.

Her 2005 Legacy turbo gets on the highway within .5 mile of her work and she has it doing 80MPH quickly.

We are at 120k and no issues with the motor at all.

 

[morris]

lite it jam it.

 

[artificialist]

Most modern turbos have engine coolant routed around the turbo bearings for durability, and that might get the engine up to temp more quickly.

 

[rationull]

Good discussion. The general topic here has been interesting to me for a long time. Not even necessarily restricted to comparing between FI and NA engines, but different cylinder counts/configurations as well. The great thing is there are so many variables it can keep you occupied for a while, thinking about it, but in the end it probably doesn't really matter anyway

I like to think of FI engines as NA engines with a wider throttle "range". That is, with a given NA engine you can get a certain size air charge into the combustion chamber (based on barometric pressure as well as intake tract/valve design), and FI just increases that amount.

It seems logical that you could design a turbo engine to take the extra pressure and power output, especially when it comes to parameters like bearing area and oiling. If you built an NA engine to the same standards, it seems like that would just make it all the more durable. Adding more cylinders (for the same power output) also seems like it would be easier on these types of parameters for the most part, although at the expense of more rotating/moving mass, and more friction.

The most interesting question to me has always been which engines (or how many engines) are developed to be able to live a long life even when used to capacity, vs to have high capacity but live a long life only when used moderately. Related to this (and what prompted my post originally) is the question of what affect engine type (e.g. cylinder count/displacement, NA vs FI, oversquare vs undersquare, etc.) has with respect to this.

 

[Thermo1223]

Considering most if not all turbo motors have piston cooling jets installed to squirt oil at the underside of the piston. I really wonder if cylinder wear is really an issue. Not many N/A motors do.

Also I am into boost within 2 minutes after startup due to a hilly road leading to the highway. Not hard boosting but boost non the less. I still keep it under 3500 rpm.

I say use a good synthetic oil and don't worry so much about it.

 

[rslifkin]

My general rule of thumb for driving a cold engine is no more than 1/2 throttle or 1/2 of redline until warm. If it's below 40*, I'll be even more gentle for the first couple of minutes, no matter how slow that is.

 

[rjundi]

In my previous 04 WRX my wifey would leave it revving away and likely boosting at 3500 RPM with a cold motor to get the heat working well.

WRX in that vintage had absymal heat. Beyond hot at high RPM but running around town in traffic it got cold. Annoying to regulate but in 2005 they added automatic climate control.

 

[rationull]

Originally Posted By: rjundi
In my previous 04 WRX my wifey would leave it revving away and likely boosting at 3500 RPM with a cold motor to get the heat working well.

WRX in that vintage had absymal heat. Beyond hot at high RPM but running around town in traffic it got cold. Annoying to regulate but in 2005 they added automatic climate control.


Hah. What ended up happening to that car?

 

[rjundi]

Originally Posted By: rationull
Originally Posted By: rjundi
In my previous 04 WRX my wifey would leave it revving away and likely boosting at 3500 RPM with a cold motor to get the heat working well.

WRX in that vintage had absymal heat. Beyond hot at high RPM but running around town in traffic it got cold. Annoying to regulate but in 2005 they added automatic climate control.


Hah. What ended up happening to that car?


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