Adding Flex Fuel to non factory flex fuel Denali

[WindyCityDenali]

First post so don't kill me.

Picked up a 2008 Yukon Denali with the 6.2. I would like to change it over to flex fuel, I have done some research here and in FB groups. Doesn't seem too many people have done it, and those that have don't post TOO much technical info. I would like it to be a true flex fuel, I have had everything from mild to wild previously and enjoyed the performance and flexibility of running any fuel. Especially in the suburbs of chicago where 93 prices are crazy. Not sure if these benefit as much from e85 as my old mopars, but regardless of the performance gain or not, the cost of fuel is beneficial to me. e85 is around $2.25 and 93 is around $4.50.

My knowns are that I will have it tuned with HP Tuners as I am familiar with it.
I will need a physical flex fuel sensor, something like this appears to be a good fit if applicable. https://dsxtuning.com/collections/f...-2006-2009-trailblazer-ss?variant=55854380235
New injectors, likely go FIC or IDs
A wideband that will likely need to read through the OBDII for the tuner to log AFR. https://www.aemelectronics.com/prod.../x_series_obd2_can_bus_wideband/parts/30-0334

What else am i missing? Has anyone done this that has had success?

 

[Joseph Garcia]

What you are trying to accomplish is to convert your L92 motor to a L9H motor. Listed below is a synopsis of the differences. You can contact Summit Racing to identify the specific parts that you will need.

Intro to the L92, L9H, and L94​

LS Family: Gen. 4, 6.2L, Aluminum Block, Truck Engines​

L92​

The L92 was introduced in 2007 for GM luxury pickups and SUVs. It was the first 6.2L LS truck engine. It was commonly known as the Vortec 6200.

L9H​

The L9H replaced the L92 in 2009. It was upgraded with Flex Fuel capability. The L9H was also known as the Vortec 6200. It was available until 2013.

L94​

The L94 was introduced in 2010. It was a premium option in the Escalade and Yukon SUVs until 2014. The L94 added Active Fuel Managment (AFM) technology for better gas mileage. It was also known as the Vortec 6200.
For specific details about these engines, please follow the links below:

• Chevy L92 Engine Specs
• Chevy L9H Engine Specs
• Chevy L94 Engine Specs
• Upgrading the L92, L9H, and L94 Engines

Benefits​

These engines are truck versions of the high performance LS3. The stock engines all make over 400 hp.
The engine blocks have the same casting number as the LS3 and L99. They share a 4.065 in. bore, Variable Valve Timing (VVT) and rectangle port heads. The blocks also have the internal oil passages for AFM.
The cylinder heads are dimensionally the same as the LS3. However, they have different casting numbers. They used different valves, camshaft, intake manifold, injectors, pistons, etc. This helped them make more Torque lower in the rpm range. However, it did limit the top-end Horsepower.
These engines can be bored and stroked up to 427 c.i.d. (7.0L). With upgraded internals, they can handle around 1,000 hp.

What's the difference?​

The easiest way to tell the difference is to check the 8th digit of the VIN code.

• Follow this link to Identify an LS Engine by VIN.

The difference between these engines is the special technology they used.

• For fuel compatibility, pull the injectors.
• • Standard injectors have 2 holes in the end of the nozzle.
  • Flex Fuel injectors have 4 holes in the end of the nozzle.
• Follow the links provided above to identify AFM and VVT engines.

RPO Code	AFM	VVT	Flex Fuel
L92	No	Yes	No
L9H	No	Yes	Yes
L94	Yes	Yes	Yes

 

[WindyCityDenali]

Hadn’t thought of trying to go the stock parts route thanks I’ll do some digging here

 

[LSCALADE]

Mine is a Flex Fule since its L94 2011 however I too run mine on 87 and I add E85 to boost the octane to around 93, and there are some calculators out there but as a rule of thumb its 2:1 so for every 2gal of 87 I add 1gal of E85 and my knock retard sensor has not indicated any adjustment similar to how it runs on 93, however if I run just 87 it would spike to 5-8deg of knock retard under load with low rpms but with some Ethanol in the tank around E30 its absolutely fine. I would suggest going that route.