Lag then Quick Acceleration from electric to gas?

[301BOBBO]

I have a "23 and drove a '24. Big difference since the belt start.

Sponsored

 

[Lefty665]

Mine's a '24 so I've never experienced the belt start. The HV motor start is reasonably quick but not instantaneous. It would not surprise me if that was quicker than the belt start.

The HV motor start is a clutch and a 1:1 rotation ratio. It also has much more torque than the belt starter so it comes up to rotational speed quicker. The belt starter ratio was 2:1 or more depending on what the ratio of the belt starter pulley to crank pulley is. If the delay is longer for belt start trucks that gives a bigger window, and perhaps incentive, to push harder on the accelerator pedal. That would make the acceleration once the ICE fires up even more abrupt.

The issue is how hard the accelerator pedal is pushed. Once it starts, the ICE responds faithfully to that. If it is heavy footed the ICE accelerates vigorously in response, just like we've asked it to. That can be disconcerting from a stop or low speed.

It's sorta like the old joke. Guy goes to a doc and says "Doc, it hurts when I do this." Doc responds "Don't do that."

My solution. Slow speed or stopped, foot on brake then gentle throttle to start the ICE so it is ready to respond quickly and smoothly when more throttle is applied.

 

[Snakebitten]

Even trucks equipped with the belt starter don't always light the ICE up via the belt starter.

 

[Lefty665]

Delay using the flywheel starter would be even longer. What's that rotation ratio, 10:1 or more?

Think I remember in an old thread you remarking that due to the technology these engines are quick to fire up. Even so it is a noticeable delay. It is especially noticeable if it occurs while other things are happening that would like throttle response.

 

[Snakebitten]

Delay using the flywheel starter would be even longer. What's that rotation ratio, 10:1 or more?

Millions upon millions of non Powerboost F150s equipped with auto stop/start ONLY have the bendix starter as an option.

I'm not convinced that "time" (delay) is the culprit for the lack of elegance being reported by some. Sounds more like mechanical engagement slop of some kind? Something operating out of design tolerance parameters?

 

[Lefty665]

Could well be, I was just speculating about what the delay between throttle request and ICE fire up was due to. Now that you mention it, there must be lots of variables in that sequence. My Duh!

I do believe that throttle position determines how the ICE responds after it fires up. If that request is for significant power, as it might well be if there's a delay after power is requested, then the acceleration can be abrupt as the truck tries to catch up with what we've asked it to do. It wants to be a good truck and get a pat on the head.

 

[Goldeneye36]

From my experience, the truck will always initially start from a stop using electric only in Normal and Eco modes. How hard you are trying to accelerate will determine how harsh the engagement and power surge from the engine will be once it kicks on.

If you are trying for a holeshot from a red light you are usually better off in Sport mode, lol. I only wish the engine wouldn't do it's faux auto start/stop thing in Sport so that you don't have to fiddle with the brake to keep it running for the green light.

 

[Snakebitten]

Tow Haul is one turn to the left. Don't even have to look. And I actually prefer Tow Haul after a cold start, at least until I see fluid temps get at least luke warm.

Sponsored