Long term owners of BlackBear Autocal tunes.

[Drok]

Yes! Burn the fuel you want the motor tuned to.

10/4. Ill have to burn through this tank and put it back to 91/93. I was being cheap last week and used 87 lol

 

[Joseph Garcia]

For future reference, is there a noticeable difference between an 87 vs. 93 octane tune?

I work from home, don't commute any more, and used to have turbo cars that all required 93, so I don't care about paying a little bit extra for 93 octane at every fill-up.

Thanks.

Here is an example that I can share with you for your question. The 07 Yukon XL Denali with the 6.2L motor is marketed to run 87 octane (though 91 octane is 'recommended'), and the stated HP for the motor is 380. The 07 Escalade with the same 6.2 motor is marketed to run 91 octane, and the stated HP for the motor is 405. According to Justin from BBP, the two motors are identical, except that one is factory tuned to run 87 octane and the other is factory tuned to run 91 octane.

 

[George B]

Here is an example that I can share with you for your question. The 07 Yukon XL Denali with the 6.2L motor is marketed to run 87 octane (though 91 octane is 'recommended'), and the stated HP for the motor is 380. The 07 Escalade with the same 6.2 motor is marketed to run 91 octane, and the stated HP for the motor is 405. According to Justin from BBP, the two motors are identical, except that one is factory tuned to run 87 octane and the other is factory tuned to run 91 octane.

So, what if you run 87 in a truck tuned for 91? Subpar performance..

 

[Joseph Garcia]

So, what if you run 87 in a truck tuned for 91? Subpar performance..

That would be my thought. It does not necessarily mean bad performance, however.

 

[George B]

That would be my thought. It does not necessarily mean bad performance, however.

I tend to overthink things and then get analysis-paralysis.

 

[Drok]

I tend to overthink things and then get analysis-paralysis.

Ha yeah me too sometimes

 

[swathdiver]

So, what if you run 87 in a truck tuned for 91? Subpar performance..

There will be a knockin' and a pingin' going on. Do it for too long and the pistons and or rings may break up in protest.

 

[BlackBearPerf]

Yes! Burn the fuel you want the motor tuned to.

Exactly.

 

[George B]

There will be a knockin' and a pingin' going on. Do it for too long and the pistons and or rings may break up in protest.

I know I am asking dumb questions. And, I understand octane and performance and how preignition plays a roll. I guess I am wondering if the PCM would pull timing and detune due to the lower octane or if it would let the engine self destruct.

I wouldn’t want to run on 87 and my truck runs like crap on it stock anyway so I run on the 88/E15, E85 or whatever is available in a mid grade fuel like 89/E10.

Hypothetically, If I tuned on 89/E10 and then went to E85 the truck should still perform well.

 

[Peacock]

Engine Masters did a dyno flog on octane and if it helped your motor run better, they did a base line pull with the cheap stuff, then 91 octane and then to race gas, E85
They ran an LS3 on engine dyno with 87, 91 pump gas, 110 and 113 race gas and E85 - adjusting timing and AFR for max power/torque.

Results can obviously vary for different engines with different compression ratios (and boost), but in this case, every single fuel except E85 resulted in basically same power and torque. Makes these discussions where people swear on running 93 - let's say - interesting.
I believe at the end they threw more timing in it from 29 total to 34, still had the race gas in it, and it actually lost one horsepower as compared to the 87 octane and 29 degrees timing. The EGT's were worse too, pretty interesting episode.
Now if you had an engine that was 14-1 compression and built to run on race gas of course it wouldn't last long going down in octane rating, it would eat itself up from detonation.
I have the 91-93 tune on mine, I assume they throw a few degrees timing into it with a different fuel curve to work together.

 

[swathdiver]

I know I am asking dumb questions. And, I understand octane and performance and how preignition plays a roll. I guess I am wondering if the PCM would pull timing and detune due to the lower octane or if it would let the engine self destruct.

I wouldn’t want to run on 87 and my truck runs like crap on it stock anyway so I run on the 88/E15, E85 or whatever is available in a mid grade fuel like 89/E10.

Hypothetically, If I tuned on 89/E10 and then went to E85 the truck should still perform well.

George, it pulls timing after the fact. After it detects pre-ignition or knocking, then it pulls timing, every time. It's not like it has a set of tables for 87, 89, 91, etc. Toyota and Dodge I believe have something like that but ours do not yet save for ethanol.

 

[swathdiver]

Engine Masters did a dyno flog on octane and if it helped your motor run better, they did a base line pull with the cheap stuff, then 91 octane and then to race gas, E85
They ran an LS3 on engine dyno with 87, 91 pump gas, 110 and 113 race gas and E85 - adjusting timing and AFR for max power/torque.

Results can obviously vary for different engines with different compression ratios (and boost), but in this case, every single fuel except E85 resulted in basically same power and torque. Makes these discussions where people swear on running 93 - let's say - interesting.

They did one motor in a dyno cell, I did twenty or thirty cars over thirty five years. The only engines that proved me wrong are the direct injected motors, Gary @Miami-Dade ran a comparison for me a few years back.

I'll never forget the first time I ran Sunoco's 104 unleaded in my Buick. The engine idled smoother, coolant temperature was lower and boy did the motor make more power without making any adjustments. Part throttle power picked up... it was a joy to drive around town and at the drag strip in Bowling Green.

Plenty of fellas on here have also seen the difference in how their motor runs by switching to higher octane and better quality fuels as well, it's not just me. Even my wife can tell the difference between running 87 and 89 and 93 in her old minivan, besides the increased gas mileage.

 

[George B]

George, it pulls timing after the fact. After it detects pre-ignition or knocking, then it pulls timing, every time. It's not like it has a set of tables for 87, 89, 91, etc. Toyota and Dodge I believe have something like that but ours do not yet save for ethanol.

That makes sense. Not sure where my head was at.
I guess my question for @BlackBearPerf is if choosing between E15/88 octane or E10/89 octane which would you choose to tune on. I tend to run on the E15/88 more but run E10/89 when I cant get the 88.

Am I making any sense?

 

[Rocket Man]

They did one motor in a dyno cell, I did twenty or thirty cars over thirty five years. The only engines that proved me wrong are the direct injected motors, Gary @Miami-Dade ran a comparison for me a few years back.

I'll never forget the first time I ran Sunoco's 104 unleaded in my Buick. The engine idled smoother, coolant temperature was lower and boy did the motor make more power without making any adjustments. Part throttle power picked up... it was a joy to drive around town and at the drag strip in Bowling Green.

Plenty of fellas on here have also seen the difference in how their motor runs by switching to higher octane and better quality fuels as well, it's not just me. Even my wife can tell the difference between running 87 and 89 and 93 in her old minivan, besides the increased gas mileage.

I know I can tell in my 02 with the supercharger. I have 2 tunes available from Blackbear that I can install in minutes with my Autocal and i know for sure the 92+ tune along with the corresponding fuel makes more power.

 

[Charlie207]

Engine Masters did a dyno flog on octane and if it helped your motor run better, they did a base line pull with the cheap stuff, then 91 octane and then to race gas, E85
They ran an LS3 on engine dyno with 87, 91 pump gas, 110 and 113 race gas and E85 - adjusting timing and AFR for max power/torque.

I love Engine Masters, and reference it all the time to people who claim you "need" exhaust back pressure, and smaller diameter exhaust tubing, to make N/A power. They showed, on the dyno, that the less back pressure you have = better engine breathing = more power.

Results can obviously vary for different engines with different compression ratios (and boost), but in this case, every single fuel except E85 resulted in basically same power and torque. Makes these discussions where people swear on running 93 - let's say - interesting.

I could certainly feel the difference between 97 and 93(ethanol free) in both of my previous BMW E39 540i v8s, and in an older Nissan Pathfinder R50 v6, especially when towing a U-Haul across the country.

Some engines respond better to premium fuel. Shocker.

 

[swathdiver]

That makes sense. Not sure where my head was at.
I guess my question for @BlackBearPerf is if choosing between E15/88 octane or E10/89 octane which would you choose to tune on. I tend to run on the E15/88 more but run E10/89 when I cant get the 88.

Am I making any sense?

Perfect sense! I would choose the E15/88 if he'll do it. Nice thing though is that Justin could make you another tune for E15/89 or whatever and you could flash that when you want to.

I'm certain that if Justin tuned for those combinations, or even a mix of E85 and 93, we would get even better mileage and more horsepower. An E85/93 mix is about 96 octane.

 

[Drok]

Went to purchase the tune and noticed the section where i need the sn and auth code for the device, Guess ill have to wait till i get home

 

[Rocket Man]

Went to purchase the tune and noticed the section where i need the sn and auth code for the device, Guess ill have to wait till i get home

Put that money away for a minute!

 

[Drok]

Put that money away for a minute!

already on it. LoL its taken too long to get this far to spend it on other stuff now.

 

[kbuskill]

I love Engine Masters, and reference it all the time to people who claim you "need" exhaust back pressure, and smaller diameter exhaust tubing, to make N/A power. They showed, on the dyno, that the less back pressure you have = better engine breathing = more power.

More peak power, yes, but where does it make that power and is it usable power for a DD?

Also, there is a difference between "back pressure" and smaller primary tube headers.

Smaller primary tubes, especially ceramic coated, keep the hot exhaust gases from expanding rapidly, along with keeping the heat in the pipe. Hot gases flow faster than cooler gases and will help with scavenging.

Obviously there is a limit to everything but a N/A 5.3l doesn't need 1 7/8" primary tubes and you will lose a lot of torque down low where it is most beneficial to a 6k lb truck.

I could have saved them some time and money on that dyno test with this... lol

It is clear that the 600+ HP engine needed 3" exhaust.