Switchable Lean-Burn for highway on tbi 454?

[Sam454]

Hi. I’m wondering if there is a way to switch tunes on the fly in a TBI 454. My idea is to have my regular tuned chip be on most of the time and install a switch that changes it to a secondary lean burn chip for the highway. I figure if I’m not towing anything it would help with efficiency. Is there any way to do this?

 

[skylark]

T

Hi. I’m wondering if there is a way to switch tunes on the fly in a TBI 454. My idea is to have my regular tuned chip be on most of the time and install a switch that changes it to a secondary lean burn chip for the highway. I figure if I’m not towing anything it would help with efficiency. Is there any way to do this?

He factory did that on the 88-91 350 with the SM465 4 speed. There was a switch on the shift tower to signal when shifted into 4th gear. I don't know if they did that with the 454 or not. Although I'm not a huge fan of some of his claims in the past, https://harristuning.com/Tbi/ would at least be able to tell you if is feasible with your 454.

 

[someotherguy]

T

He factory did that on the 88-91 350 with the SM465 4 speed. There was a switch on the shift tower to signal when shifted into 4th gear. I don't know if they did that with the 454 or not. Although I'm not a huge fan of some of his claims in the past, https://harristuning.com/Tbi/ would at least be able to tell you if is feasible with your 454.

"Lean cruise" GM called that, I believe. Probably described a bit in the factory service manuals for those years. The SM465 used in those trucks had a different top cover with the provision for that switch.

Richard

 

[PlayingWithTBI]

There is an emulator that can use an SST 27SF512 which is large enough to load 2 separate .bins that you can switch back and forth. Unfortunately, I can't remember which one it is - maybe Ostrich 2.0 or the APU1 from Moates who went dark a while back but, you may be able to find one for sale or go to BoostedNW and ask them, they have a chip adapter + 2 timer.
www.boostednw.com/

BoostedNW.com

BoostedNW - Your source for the latest obd1 tuning essentials

boostednw.com

Or, you can set your Hywy-Max MAP in your .bin to a level that will go out of Lean Cruise when you need more power. You can set your AFR levels depending on MAP values too.

 

[PlayingWithTBI]

Another note - you can adjust your SA (Spark Advance) based on MAP also.

Here's some of the parameters.

You must be registered for see images attach

Here's an example - 41° Timing and 16.5 Commanded AFR (with a WBO2). Running with no Knock Counts and not overheating in OD.

You must be registered for see images attach

 

[L31MaxExpress]

17.65:1 target here with 42* of timing advance.

You must be registered for see images attach