DCR and 93 octane, daily driver
Thread Starter
TECH Fanatic
Joined: Mar 2003
Posts: 1,946
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DCR and 93 octane, daily driver Waaaaay over asked question ( yes, I have searched much ). I am looking for folks actually doing it... in a daily driver.
What are you able to live with (DCR) on 93 octane???... again a daily driver
...@ .006... @ .050
Intake Duration - 273 224
Exhaust Duration - 277 228
Lobe Center Angle - 114 114
Intake Centerline - ICL 110 110
DCR 8.68
Static Compression 11.07
Heads are 63 CCs chambers
Head Gasket is .045
Pistons measure around .006 -.008 out of the hole
Any help much appreciated...
What are you able to live with (DCR) on 93 octane???... again a daily driver
...@ .006... @ .050
Intake Duration - 273 224
Exhaust Duration - 277 228
Lobe Center Angle - 114 114
Intake Centerline - ICL 110 110
DCR 8.68
Static Compression 11.07
Heads are 63 CCs chambers
Head Gasket is .045
Pistons measure around .006 -.008 out of the hole
Any help much appreciated...
TECH Fanatic
Joined: May 2016
Posts: 1,292
Likes: 436
From: St. Louis
I'm running a small cam with an IVC @ 0.006 of 65° in a 376" LQ4 with flat top LS3 pistons and stock 61.5cc 706 heads. It's about 11.87: 1 static and the DCR calculation with this cam is 9.3:1
The car runs fine on 89 though I mostly use 93 to be safe. I live in St Louis where the weather fluctuates immensely and I have never experienced any detonation Even on mid-grade.
This is the highest DCR calculated engine I have ever put together and It's very very torquey and responsive.
That being said what you were doing will run just fine on midgrade or 93 as well, Just make sure the tuning is spot on so you get the most out of it.
Remember also the more efficient the engine is the less spark advance it will need to run at its best.
I'm running a small cam with an IVC @ 0.006 of 65° in a 376" LQ4 with flat top LS3 pistons and stock 61.5cc 706 heads. It's about 11.87: 1 static and the DCR calculation with this cam is 9.3:1
The car runs fine on 89 though I mostly use 93 to be safe. I live in St Louis where the weather fluctuates immensely and I have never experienced any detonation Even on mid-grade.
This is the highest DCR calculated engine I have ever put together and It's very very torquey and responsive.
That being said what you were doing will run just fine on midgrade or 93 as well, Just make sure the tuning is spot on so you get the most out of it.
Remember also the more efficient the engine is the less spark advance it will need to run at its best.
Here's a few set ups, compression & octane used.
My Experience
99 T/A 416, 237/245 114 LSA, RM LS3 heads, ~68cc, ~11.7 to 1, +3cc pistons, no issues with 93 octane 2017 to current
99 T/A LS1, 224/224 113LSA, TEA S2 5.3, ~63cc
10.9 to 1, SBE, no issues with 91+ with a mail order LS1 Edit tune, ran 2002 to 2017
91 RS 383 LS1, 229/229 114LSA, TEA LS6 S2.5, ~64cc, +3 cc pistons ~11.4 to 1, no issues with 93 with HP Tuners tune 2015 to current
72 Vette Dart 400, Demon Carburator, Dart Pro 1 heads, 230/236 cam, 10.85 to 1, 3200 still, 3.08 gears. Normally no issues with 93 octane 2012 to current. Will ping at light throttle in summer if 95+ degrees if air is dry on 93 octane.
My Opinion
Given my iron block old school 72 Vette can get away running 10.85 to 1 with a carburator, I'd want at least 10.85 to 1 on anything NA if 93 is available.
Given we can get a tank of bad gas, I personally get nervous at the idea of compression over ~11.8 to 1 on 93 octane.
After cars sit over winter, I like to drive the old tank of gas with Stabil out and refill gas tank with fresh gas before beating on any of the cars.
My Experience
99 T/A 416, 237/245 114 LSA, RM LS3 heads, ~68cc, ~11.7 to 1, +3cc pistons, no issues with 93 octane 2017 to current
99 T/A LS1, 224/224 113LSA, TEA S2 5.3, ~63cc
10.9 to 1, SBE, no issues with 91+ with a mail order LS1 Edit tune, ran 2002 to 2017
91 RS 383 LS1, 229/229 114LSA, TEA LS6 S2.5, ~64cc, +3 cc pistons ~11.4 to 1, no issues with 93 with HP Tuners tune 2015 to current
72 Vette Dart 400, Demon Carburator, Dart Pro 1 heads, 230/236 cam, 10.85 to 1, 3200 still, 3.08 gears. Normally no issues with 93 octane 2012 to current. Will ping at light throttle in summer if 95+ degrees if air is dry on 93 octane.
My Opinion
Given my iron block old school 72 Vette can get away running 10.85 to 1 with a carburator, I'd want at least 10.85 to 1 on anything NA if 93 is available.
Given we can get a tank of bad gas, I personally get nervous at the idea of compression over ~11.8 to 1 on 93 octane.
After cars sit over winter, I like to drive the old tank of gas with Stabil out and refill gas tank with fresh gas before beating on any of the cars.
