Blackbear, Diablew, or other Tuned - using 91+ or 87/89 tune?

[Haus_Z71]

For those of you with a Blackbear, Diablew, or other tune, what octane of fuel are you using and why? I've used the 91+ tune and am thinking of going to 89 octane with the 87/89 tune.

 

What are you thoughts?

[truckguy82]

Dunno but I'm getting tuned in 2 days by blackbear.

 

I was curious about the 87 tune. If I could safely fill my truck with 87 and atleast get the same performance it'd probably be the most responsible move.

[bronco2977]

I have a hypertech. I've used both 87 and 89 octane to see if there is a difference in running the 89 over the 87. I see a slight difference.

[Haus_Z71]

Dunno but I'm getting tuned in 2 days by blackbear.

I was curious about the 87 tune. If I could safely fill my truck with 87 and atleast get the same performance it'd probably be the most responsible move.

Man I wish i could find the post, but someone had given a detailed explanation on why you should run 89 over 87. Something about direct injection engines performing their best with the compression created by 89+ octane. Maybe someone is familiar with this and can explain it way better?

[truckguy82]

Man I wish i could find the post, but someone had given a detailed explanation on why you should run 89 over 87. Something about direct injection engines performing their best with the compression created by 89+ octane. Maybe someone is familiar with this and can explain it way better?

 

Yeah I mean they are high compression, and I know it's certainly better to run high octane.

 

I just wasn't sure if blackbear does something pulling timing or richening AFR to make it more conservative than stock so it can safely run on 87, but at the same time remove any other bullshit GM tuning issues and the net result is the same power level as stock but has the ability to run on 87.

 

I wouldn't be surprised at all if the inherent design of the engine prevents 87 from being a good move no matter what kind of tuning he can do.

[truckguy82]

Random question for anybody that knows

 

At point in the compression stroke does the DI inject the fuel? Wondering how close it is in time to when the spark plug fires.

 

I don't know much about the DI motors, but I'm kinda surprised they pre-ignite no matter what fuel you use.

[emeryz28]

I went from stock and running mostly 91 octane sometimes 93 and a few times 89.

 

I am now using a Diablo 91 tune, with AFM disabled and running 91 octane almost always. MPG went up around 1.2, truck drives so much better now that it stays in v8 mode, but I haven't noticed a performance increase. With that said, I don't really "get up on it" very much either

[Dnt]

6.2 with Hypertech currently running 93 octane but thinking about going to regular fuel tune and trying some 89 octane just to see if I can tell any difference. Kind of fun to manipulate. Just waiting on hypertech to come out with more options on the hand held I cannot currently change any of my 8spd transmission settings. Need to grab a bit of rubber in the first 3 gears BARK Vroooom Bark Vroom Bark Vroooooooooom

[blwright]

6.2, HP Tuners, 93 exclusively. My truck pings with low octane gas.

[RyanbabZ71]

Blackbear

 

Truck E85

Car 93

 

 

Sent from my iPhone using Tapatalk

[ChevyRoofer]

Dunno but I'm getting tuned in 2 days by blackbear.

 

I was curious about the 87 tune. If I could safely fill my truck with 87 and atleast get the same performance it'd probably be the most responsible move.

 

I'll be going for the 87 tune as well, since that's all my company offers.

 

Can't beat a free gas card!

[truckguy82]

If it is of any help, when justin from blackbear was tuning my truck he was very surprised not to see any knock even though I was using 93. He complimented the NJ gas.

 

I have a feeling if you spoke with him you'd want to do high octane only.

 

He asked me what I was using, I said 93, he said "good because I don't want to have to talk you in to continue using it." I didn't bother asking why.

[Jennabear]

Compression dictates what octane you should be using. For the OP with a 2015 5.3L, you should be running a minimum of 89.

[bobbobtar]

Blackbear

 

2016 LTZ 5.3L

 

E-85 $1.69 a gallon

[gone_fishing]

My engine is stock with factory tune. I have a ScanGauge that monitors KR and timing advance. When running 87 octane, I see quite a bit of KR. I maybe get a little at WOT but I mostly see at at low RPM with high loads. Example is with cruise set on a flat road. Come to a bridge overpass or any grade increase I'll see 3-5 degrees of KR. I have even seen KR when driving into a stiff wind. V4 mode is even worse. Engine struggles to stay in V4 because KR will pull some much timing that total advance is down to only a couple degrees. At this point it will go back to V8 mode. Because of this I now stay away from 87 and stick with 89 and sometimes 91 if it's not that more expensive. I've also noticed when running E85 that the partial throttle KR is all but gone. Very little KR in V4 and timing advance is much higher (maybe around 15-20 degrees vs. struggling to keep 8-10 degrees on 87 gas). These engines so seem to be octane sensitive.