Mileage Increase on Trucks

[MSURacing]

What have you guys been seeing for a fuel mileage increase on the full size trucks and SUV's? I have an 01 Yukon XL, 3" lift, 325/60R18's, 3.73's and I am seeing right around 16 now. I haven't done a comparision to the stock cal in a long time, but I thought it was around 14 to start.

Also, i put it on the dyno here at work and got 252 hp and 279lb ft. Not to bad for an intake and cat back.

[cmitchell17]

With my 2000 5.3 ext cab Since Ive lowerd O2 switch points and added some timing based off the optimal timing table I can get about 21-23mpg crusing at 45-60 and about 17-20 avarage city/hyw.

So far Ive probably got on avarage about 2-3mpg more especially on cruises.

[horsehaulin]

With my 2000 5.3 ext cab Since Ive lowerd O2 switch points and added some timing based off the optimal timing table I can get about 21-23mpg crusing at 45-60 and about 17-20 avarage city/hyw.

So far Ive probably got on avarage about 2-3mpg more especially on cruises.

When you say you added timing, what do you mean, could you help me out a little. I am tuning my step dads truck for better economy.

Tony

[cmitchell17]

So far I havent noticed anything from adding timing in part throttle non pe.

You can experiment with it but I don't think it will help.

I think the factory timing would be the best timing, except the timing in PE high throttle beucase the stock tune is always consiveritive in the high load regions.

[dc_justin]

So far I havent noticed anything from adding timing in part throttle non pe.

You can experiment with it but I don't think it will help.

I think the factory timing would be the best timing, except the timing in PE high throttle beucase the stock tune is always consiveritive in the high load regions.

You might not feel it seat of the pants, but a load bearing dyno definitely shows a worthwhile power gain at part throttle.

Justin

[n6oli]

I have a 1999 5.3 ext. cab, and I lowered my O2 switch points to:

CL Mode Bank-1 Bank-2
0 460.015667 460.015667
8 460.015667 460.015667
16 460.015667 460.015667
24 460.015667 460.015667
32 460.015667 460.015667
40 465.000356 465.000356
48 469.985046 469.985046
56 475.003646 475.003646
64 479.988336 479.988336

What did you set yours at cmitchell17?

[dc_justin]

I have a 1999 5.3 ext. cab, and I lowered my O2 switch points to:

CL Mode Bank-1 Bank-2
0 460.015667 460.015667
8 460.015667 460.015667
16 460.015667 460.015667
24 460.015667 460.015667
32 460.015667 460.015667
40 465.000356 465.000356
48 469.985046 469.985046
56 475.003646 475.003646
64 479.988336 479.988336

What did you set yours at cmitchell17?

Drop the CL Mode 0,8,16 to something quite a bit lower... 250-300mv and you should see a slight improvement. Your table is still richer than 14.7:1 across the board (450mv).

[n6oli]

Could you copy with labels from your tune, and then paste in a message what you have yours set at?
Sorry, I didn't see who sent the message. I thought you were cmitchell17?

[n6oli]

Why does GM have the O2 switch points set so high in their tunes?
This is the factory switch points.

LABELS bank
CL Mode Bank-1 Bank-2
0 480.022245 480.022245
8 480.022245 480.022245
16 480.022245 480.022245
24 480.022245 480.022245
32 480.022245 480.022245
40 480.022245 480.022245
48 489.991625 489.991625
56 509.998203 509.998203
64 520.001492 520.001492

[cmitchell17]

Hey mine are:

372.495363 372.495363
372.495363 372.495363
372.495363 372.495363
373.343100 373.343100
375.208120 375.208120
380.565813 380.565813
450.012377 450.012377
450.012377 450.012377
450.012377 450.012377

Let me read up on Dc Justins post to see what he said to do.