Plus gas to unleaded

[Ventura139]

Was trying to find the right place to post this. But I have a 6.0 2001 Yukon denali with 200k miles. I’ve had it for 3 years and the previous owner told me he always used plus grade gas. I’ve always used but now that gas is crazy high and plus usually .25 more per gallon am I able to switch to regular unleaded? Or will it damage the engine or limit performance?

 

[swathdiver]

Was trying to find the right place to post this. But I have a 6.0 2001 Yukon denali with 200k miles. I’ve had it for 3 years and the previous owner told me he always used plus grade gas. I’ve always used but now that gas is crazy high and plus usually .25 more per gallon am I able to switch to regular unleaded? Or will it damage the engine or limit performance?

Well, your motor was designed to run on 87. If yours were mine, I'd keep running 93. I run 93 on mine instead of 87, don't care about the cost. Fuel is less expensive than new pistons and rings.

 

[tom3]

With the higher compression on these motors I do run the mid grade gas too. I know the ECM will control the timing to protect the engine but I'd rather have a safety cushion - and maybe some extra performance and economy with the higher octane. I do see the mid grade BP that I run is now 4.99 a gallon. The Tahoe will be sitting quite a bit more now.

 

[Joseph Garcia]

It's a high compression engine. Stay with at least mid grade gasoline.

 

[Blueinterceptor]

What about ethanol free gas as a substitute. 89 octane?

 

[Fless]

What about ethanol free gas as a substitute. 89 octane?

Ethanol or non-ethanol, go by octane. The only time it makes a difference is if your truck is Flex Fuel and you run more than E15 (like E50 or E85). I've never seen them post octane numbers on Exx fuel. Might be able to find a chart online, but I run E85 whenever I can. She runs great on it!

 

[Sam Harris]

Ethanol or non-ethanol, go by octane. The only time it makes a difference is if your truck is Flex Fuel and you run more than E15 (like E50 or E85). I've never seen them post octane numbers on Exx fuel. Might be able to find a chart online, but I run E85 whenever I can. She runs great on it!

I miss my corn gas..!! Boohoo..!! Running 93 in mine now, only because there is no E85 within 80 or so miles.

 

[rockola1971]

High compression engine????? Isnt the C/R of the 6.0L from that era 9.4 or 9.5:1? I wouldnt consider that high compression. Now if it were 10 or 10.5:1 then yes. I run what octane is recommended by the manufacturer.

 

[S33k3r]

The LQ9s were high compression. I think only the Denalis and the Escalades shipped with them, though. Anything else would be added after manufacture.

 

[rockola1971]

The LQ9s were high compression. I think only the Denalis and the Escalades shipped with them, though. Anything else would be added after manufacture.

Oh yeah the alum block/ alum head 6.0L LQ9 is 10.1:1
My 05 Denali is a 6.0L LQ4 Alum Head/ Iron Block and it is 9.4:1 and I feed it 87 octane every time at the pump. Maybe I missed it but OP didnt say whether he has the LQ4 or the LQ9. Putting higher octane gas in the engine than what is required by the manufacturer is just throwing money out the window for normal street use.

 

[Mudsport96]

If it is the LQ4 87 is fine. How many hundreds of thousands of 2500 and 3500 LQ4 trucks have been fed 87 for 20 years while towing far more than these rigs will ever see?

 

[rockola1971]

If it is the LQ4 87 is fine. How many hundreds of thousands of 2500 and 3500 LQ4 trucks have been fed 87 for 20 years while towing far more than these rigs will ever see?

Plus the Denali's. (K1500) They all come with 6.0L and the vast majority of them have LQ4's. I believe the Escalade came with the LQ9 only?

 

[Mudsport96]

Plus the Denali's. (K1500) They all come with 6.0L and the vast majority of them have LQ4's. I believe the Escalade came with the LQ9 only?

Yeah not sure what all got the LQ9 so couldn't comment on that. But yeah, unless you have the LQ9 i wouldnt waste the cash on premium... unless towing heavy. As a disclaimer i will say my dads 2500hd 6.0 saw a smidge better mpg towing on 93 than 87. I attributed it to the timing tables staying on the more aggressive side, thus helping mileage some. Im talking .7 to 1 mpg over 87. But unloaded it saw no difference at all.

If you are worried about octane i say get a flex tune and some bigger injectors and do e85.