Which Tune: 87/89 octane or 91/93 octane tune

Vetteran · December 21, 2016

I purchased a custom tune from Lew at DiabLew Tune. But I'm uncertain whether to get the regular or high octane tune. For those of you who have been down this road is it worth the higher fuel costs to go with the high octane tune?

slee3247 · December 21, 2016

It seems if you watch the livestream data on a good scantool like a snap on or bosch unit (one that has a higher refresh rate for the data PIDs) the knock retard is actually quite prevalent even in stock tunes. I like to think that higher octanes even with stock programming are a good idea. To each his own, but someone reputable like Lew or Blackbear should be able to make a tune with a good safe timing advance that's worth at least a few horsepower. And if you're like some of us, any form of added horsepower is worth the cost of admission.

My advice - if you're comfortable spending the extra cash on high octane, then a performance calibration may be in your best interest!

Vetteran · December 22, 2016

It seems if you watch the livestream data on a good scantool like a snap on or bosch unit (one that has a higher refresh rate for the data PIDs) the knock retard is actually quite prevalent even in stock tunes. I like to think that higher octanes even with stock programming are a good idea. To each his own, but someone reputable like Lew or Blackbear should be able to make a tune with a good safe timing advance that's worth at least a few horsepower. And if you're like some of us, any form of added horsepower is worth the cost of admission.

My advice - if you're comfortable spending the extra cash on high octane, then a performance calibration may be in your best interest!

Thank you for your reply. I like the idea of running 91 or 93 because it is apparently better quality gas yielding better engine performance and in many situations there is no ethanol added. I just don't like paying the extra price but as the old saying goes, you get what you pay for (hopefully).

KARNUT · December 22, 2016

When I did the research on these new high compression engines it seem the general opinion was the higher grade the better. I had good access to E85 that was much cheaper than 93 gas sometimes even 87 grade gas. I was pretty satisfied with with the way the truck ran on E-85 with the exception of the V-4 and wanted a little more bump out of the transmission. I went with a hand held ( hypertec) and it worked great. On trips I ran midgrage gas ( when I couldn't get E-85) or reg gas. Couldn't see upping the timing by tuning the engine and being forced to run 93 gas when most people claim we should run it anyway for maybe 10 HP. I was getting 25 more on E-85 with choices on what grade to run. My truck ran, shifted very good.