Lean Cruise Settings

General Tuning Questions And Discussions
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DeathSammich
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Joined: Mon Feb 05, 2018 8:18 pm
cars: VT Commodore

Lean Cruise Settings

Post by DeathSammich »

Just wondering if it's safe to set lean cruise to a road speed of 55 rather than the stock 70? In doing so is it also best to have the afr set to 15.4 rather than the stock 18? Will I gain fuel economy if I do this? Thanks
Last edited by DeathSammich on Mon Jun 25, 2018 2:49 pm, edited 1 time in total.
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vlad01
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Re: Lean Cruise Settings

Post by vlad01 »

yes for the temp, also there is a time out setting before it engages after steady state cruising, default I recall was around 1 min, I set it to about 5 sec.

about 15.6-16 is ideal, v6 can operate around 17 with no issues but generally gain slightly from a mid to high 15 range.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.
DeathSammich
Posts: 18
Joined: Mon Feb 05, 2018 8:18 pm
cars: VT Commodore

Re: Lean Cruise Settings

Post by DeathSammich »

vlad01 wrote:yes for the temp, also there is a time out setting before it engages after steady state cruising, default I recall was around 1 min, I set it to about 5 sec.

about 15.6-16 is ideal, v6 can operate around 17 with no issues but generally gain slightly from a mid to high 15 range.
Can i lower the road speed to 55 I mean not the temp.
And will I lose economy setting it to 15-16 rather than the stocks 18
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vlad01
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Re: Lean Cruise Settings

Post by vlad01 »

The 15 range will improve economy by 1-2% as 17-18 is a bit too lean and torque starts to fall away.

I set my road speed somewhere around 30 or 40, temp was about 60 iirc, what ever the min temp where all the spark and fueling tables/scalars were at normal operating range.

In some tunes I disable lean cuise completely and work out the light load cruise areas in the AFR table and change the numbers there so it permanent all of the time regardless of anything else. HSV did this I recall in the VN SV3800. It actually works great and no noticeable down sides. But you need to make sure any hot restart heat soak lean outs are sorted as it will overlap and cause hunting and bit of sensitivity in stalling. This is because of the fudged charge temp and inverse temp terms from factory, they weren't the best in the V6 tune but pretty decent in the V8 tune so you can borrow some setting from there and work on it to fix the V6 tune.

Even if you don't bother 12P is way better than some of the vn/vp tunes which came with a free random stalling feature :thumbup: :lol:
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.
DeathSammich
Posts: 18
Joined: Mon Feb 05, 2018 8:18 pm
cars: VT Commodore

Re: Lean Cruise Settings

Post by DeathSammich »

vlad01 wrote:The 15 range will improve economy by 1-2% as 17-18 is a bit too lean and torque starts to fall away.

I set my road speed somewhere around 30 or 40, temp was about 60 iirc, what ever the min temp where all the spark and fueling tables/scalars were at normal operating range.

In some tunes I disable lean cuise completely and work out the light load cruise areas in the AFR table and change the numbers there so it permanent all of the time regardless of anything else. HSV did this I recall in the VN SV3800. It actually works great and no noticeable down sides. But you need to make sure any hot restart heat soak lean outs are sorted as it will overlap and cause hunting and bit of sensitivity in stalling. This is because of the fudged charge temp and inverse temp terms from factory, they weren't the best in the V6 tune but pretty decent in the V8 tune so you can borrow some setting from there and work on it to fix the V6 tune.

Even if you don't bother 12P is way better than some of the vn/vp tunes which came with a free random stalling feature :thumbup: :lol:
Oh okay wicked thanks! I might just set it to 15.4 and put road speed for it to kick in at 40 or 50 and see how it goes before bothering changing the fuel tables.
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