Register or Log In To remove these advertisements. |
|
|
View Poll Results: Which octane rating are you using? | |||
87 or lower | 8 | 33.33% | |
89+ | 5 | 20.83% | |
93+ | 11 | 45.83% | |
Who cares; as long as it will run and it's cheap.. | 1 | 4.17% | |
Multiple Choice Poll. Voters: 24. You may not vote on this poll |
|
Thread Tools | Display Modes |
10-24-2010, 05:53 PM | #1 |
Registered User
Join Date: Dec 2008
Location: Lawrenceville GA
Posts: 64
|
Poll comments: What octane with what compression ratios?
Searched around trying to decide what octane pump gas to run on original block and heads; rebuilt, torqued 350 w/ Holly carb; torquer cam; around 10:5:1 comp give or take :5. Been burning 93 but trying to decide if 89 is ok enough to slow foot it around town. What octane are you folks running and why; what motor?
Comments welcome; decision time |
10-24-2010, 06:37 PM | #2 |
Registered User
Join Date: Oct 2010
Location: Buckeye Arizona
Posts: 470
|
Re: Poll comments: What octane with what compression ratios?
I'm pretty sure that will lead to detonation.
I'm puttin my new motor in soon that will have flat top, 4 valve reliefs, so it should be around 8.7:1 or so and only gonna run 91 or better. Both of my 327's came apart with cracked pistons from junk fuel. I'd rather spend the extra few dimes a gallon then build, ANOTHER motor. |
10-24-2010, 06:43 PM | #3 |
Registered User
Join Date: Dec 2008
Location: Lawrenceville GA
Posts: 64
|
Re: Poll comments: What octane with what compression ratios?
Thanks, this one has only seen 93 and runs smooth. May stick to 93.
|
10-24-2010, 06:43 PM | #4 |
Registered User
Join Date: Jun 2010
Location: Jefferson, MD
Posts: 2,397
|
Re: Poll comments: What octane with what compression ratios?
I'm trying to decide right now. 87 is giving me about 10-11 mpg, 89+ is running almost 13 mpg. Truck runs fine on the cheap stuff, though.
Mine's an almost stock '80s 350 with I think a mild RV cam.
__________________
'68 Dodge Dart 270, 225, 904, 2.76--"Lucy" 1996 Gmc 1500 Z71, 350, 4l60e, 3.73s 1995 Jeep Wrangler Rio Grande 2.5, AX5, 4.10s 1989 Toyota Pickup 22re, auto, 3.73 |
10-24-2010, 07:56 PM | #5 |
Registered User
Join Date: Jan 2010
Location: Elgin Mn
Posts: 112
|
Re: Poll comments: What octane with what compression ratios?
Short answer....I run the best gas I can find. .20 pr gallon times 16 or so gallons = 3.00 or so for a refill. I don't worry about 3.00 a tank.
Long answer, depends on what heads you have in conjunction with piston top design and quench area cam design. How about methanol injection? I run measured 9.98:1 and can run cheap stuff ifn I have too. Sorry to muddy the waters
__________________
In the beginning of a change, the patriot is a scarce man, brave hated and scorned. When his cause succeeds however, the timid join him , for then it costs nothing to be a patriot. I am a revolutionary...so my son can be a farmer...so his son can be a poet. If there must be trouble, let it be in my day, so my child may have peace... 72 short step w/ 388 /4l80e/ and 3.08 gears. Last edited by llowlife; 10-24-2010 at 07:57 PM. |
10-24-2010, 08:13 PM | #6 |
Cruzin
Join Date: Dec 2009
Location: on the road
Posts: 2,835
|
Re: Poll comments: What octane with what compression ratios?
87 no problems 350 bored .60 no major mods
__________________
Lime Wife's 67https://www.google.com/url?sa=t&rct=...wZEMODaS2d94u8 Back to the Fifties 59 https://www.google.com/url?sa=t&rct=...NAeStpydfrcj_U Proverbs 3:5,6 "Thanks to the Interstate Highway System, it is now possible to travel across the country from coast to coast without seeing anything."Charles Kuralt In memory of our first baby daughter, daddy and mommy love you. Danica Grace 6/26/14
|
10-24-2010, 08:29 PM | #7 |
406 Powered
Join Date: Aug 2009
Location: waynesville,n.c.
Posts: 877
|
Re: Poll comments: What octane with what compression ratios?
406 small block....93 all the way
__________________
70 GMC 68 c10 2002 silverado 72 4x4 |
10-24-2010, 08:46 PM | #8 | |
Registered User
Join Date: Dec 2008
Location: Lawrenceville GA
Posts: 64
|
Re: Poll comments: What octane with what compression ratios?
Quote:
no ping at all on 87, hmmm... Any mods? |
|
10-24-2010, 09:08 PM | #9 |
Registered User
Join Date: Nov 2002
Location: Charleston, South Carolina
Posts: 1,370
|
Re: Poll comments: What octane with what compression ratios?
93 is fine for me when it's a good brand. I've had problems with the cheap places. 350, 40 over, 10.75 compression roughly, aluminum heads. The aluminum heads and a tight quench is what's helping me.
__________________
2006 Silverado CCSB, 1939 Ford Sedan, 1962 BelAir Wagon, 1976 Vega Panel Charleston, South Carolina |
10-24-2010, 10:50 PM | #10 |
Devil's in the Details
Join Date: Sep 2008
Location: Southern Utah
Posts: 353
|
Re: Poll comments: What octane with what compression ratios?
Also, remember that altitude will have an effect on minimum octane. I live at 5500 ft and run 85 octane in my Jeep with a 4.0L even though the manual says to use 87 at a minimum. I've got another straight six with an aluminum head and good quench that's right at 9.3:1 and can be run fine at my elevation on 87 octane with no ping even though I normally use 89.
__________________
'70 K10 Suburban - TBI 454, 4L80E, NP241C, Dana 60 & 44 - The 10+ Year Project Thread Datsun 240Z, 510 2 door and an old Honda motorcycle Last edited by Beelzeburb; 10-24-2010 at 10:54 PM. |
10-25-2010, 11:22 PM | #11 |
Registered User
Join Date: Mar 2003
Location: San Francisco, CA USA
Posts: 2,454
|
Re: Poll comments: What octane with what compression ratios?
Why guess about it when you can find out for the cost of a few gallons of gas? Run it out, or nearly out, of whatever you have in there now. Put in say, 5 gallons of the 89 and see what happens. If it runs ok you are golden. If it is really bad, just fill up the rest of the way with 93 and shake well.....
Ray |
10-25-2010, 11:51 PM | #12 |
Registered User
Join Date: Jun 2004
Location: Bastrop,Texas
Posts: 61
|
Re: Poll comments: What octane with what compression ratios?
I have a 327 bored 40 over with double hump head 2.02/1.60, 30/30 Duntov cam and flat top pistons. It will run fine on 87, but 93 or higher and it really comes alive. I only get 8.5-9 MPH either way so for me it comes down to what I am wanting to do. If I am racing high octane, driving to see the folks I don't really give it much thought.
__________________
Ain't no way in the world I'm going out that front door. 69 SWB Fleetside 327/5spd 76 blazer 383/700R4 95 2Dr Tahoe 5.7 4x4 LT |
10-26-2010, 12:50 AM | #13 |
Registered User
Join Date: Jun 2009
Location: Dub VC Utah
Posts: 364
|
Re: Poll comments: What octane with what compression ratios?
I've always been told anything 10:1 or higher should use 91. Of course 91 here is equal to 93 around everyone else. 91 is our premium.
__________________
'70 K10-- 4" lift on 35"s-- For Sale http://www.ksl.com/index.php?sid=733...iew&ad=4578305 |
10-26-2010, 12:50 AM | #14 |
Registered User
Join Date: Oct 2006
Location: Temecula,CA
Posts: 309
|
Re: Poll comments: What octane with what compression ratios?
I don't see why you couldn't run 89 octane. If I were you I would take some timing out tho. just my $0.02.
__________________
Nick Old pic of my 72: http://img340.imageshack.us/my.php?image=img0435co5.jpg 04 Silverado Daily Driver 68 GMC short step http://67-72chevytrucks.com/vboard/s...d.php?t=379665 "I'll beat you to the gas station!!" |
Bookmarks |
Tags |
octane; compression; carb |
|
|