My new setup will be a GSR block with a b16 head. All stock except I might use ITR cams.

Anyway, with this setup I should be running ~ 9.8:1. This is about where I want to be for a motor I plan to boost next spring.

For the time being, I'm going to leave it as is. It will have a GSR or ITR base map, depending on cams.

I'd really like to pick up an S300 and play with cruising fuel mileage. With a wideband, what AFR's am I looking for at cruise? I'd like to lean it out as much as possible on the low throttle percentages, as long as it's safe. I'd like to see over 35mpg with enough time behind the laptop.

Thanks!

 

bump

 

Flat ground and keep the cruise control on. Take fuel out until either A) it starts surging (lean misfire limit) or B) injector duty starts to creep up. Repeat at several speeds.

 

Wish I had cruise control So you don't tune for a specific AFR like 15.3-15.8? Just curious.

 

I think the afr will be different at different loads/speeds so you tune it the way Paul_VR6 said.

 

in my boosted GSR i've seen 34-35mpg on the highway (70mph) and regularly see 24-27mpg in town....just thought i'd toss that out there

 

Thats not that great of gas mileage, pretty standard.

 

Under cruise leave it lean and flat. I usually aim for 15.5 at cruise on my own car. I aim for mid 14s under light throttle, high 13s at WOT (n/a). I vary the AFR richer as the rpm rises so it doesn't buck or misfire and I keep the rpm low during DD (under 3k). Remember whatever the fuel value at that point on the map says is multiplied by how many times it's firing per second, so even if the values are the same top to bottom, it's using more fuel as rpm goes up

 

get a egt gauge, as you lean an engine out the egt will go higher to a point then start coming down. so you want it lean enough that egt are not threw the roof (= burnt engine) but rich enough you dont get a lean misfire.