I regularly drive on motorway where there are steep down hills. These are long very steep downhills. In my 3.8 litre V6 I simply ease off the accelerator early and apply brakes once or twice on the descent. It is easy on the brakes and car stays in top gear (older, simple car). Some drivers sit on the brakes most of the way down the hill, which is not a good practice (show of brake lights). I go a little over the speed limit near the bottom of the hill, which makes the climb up the other side easy. The car might shift down 1 gear to get up the other side.

My wife's NX200t F Sport is not so sweet going down steep declines. Cruise control on or off, the car downshifts 2 gears and engine noise is loud. There is still a need to brake twice on the downhill. I sometimes give it gas when it has downshifted and this causes it to go back up a gear or 2. Trouble is I will then be over the speed limit. I recently used manual shift and kept it in 6th gear. hence not screaming engine.

Problem is I forgot it was in manual mode and on the way up the hill slowed down a great deal before I changed down. My wife is not inclined to do the 'fancy' stuff.

Engine braking is not needed on these hills and it is annoying when engine screams (also not good for engine, transmission etc and not good for fuel efficiency). What effect on turbo?

Rant over, what are your thoughts/experiences.

 

2016 NX200T. While on cruise control and going down steep inclines , mine will down shift to maintain set cruise speed. I always disable cruise and use brakes on and off to check speed. Brake pads are cheap in comparison to tranny/engine/turbo repairs. Mine will not down shift on its own if cruise is off. Another practice I use is to have vehicle speed down as much without pissing off traffic behind me before I start the descend ( I live in the boonies so traffic is sparse and not bumper to bumper ).

 

I agree, with cruise on it downshifts, with cruise off it doesn't. With cruise on it shouldn't downshift so much that it gets annoying as it just lets off the throttle as well. This works well for me even when towing a fairly large 2800lb camper. Have never had any issues even while up in Banff and Jasper with the camper.

 

Wont affect the engine. The turbo as well as there is not much exh gasses to turn it. The rest is just annoying engine noise on the overrun.

 

Thanks for your comments everyone. That is true, not much exhaust gas moving the turbo.