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Author
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Topic: Fuel octane #'s
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z pyro
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Member # 3745
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posted
 
 
do you guys think using 89 octane rather than 87 would make a noticeable difference (as in, is it worth the extra $)? I filled up with it and used some fuel injector cleaner, and don't necessarily feel any difference.
Also, I'm pretty sure of this, but aren't those "octane boosters" a waste of $?
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'95 Integra LS
'08 Buell XB12R Firebolt
'65 Mustang 289 - soon to be 306
Posts: 1732 | From: Fresno, CA | Registered: Nov 2003
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JoeT
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Member # 298
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posted
depends on a lot of things, but buy the lowest octane you can that allows your car to run it's 'optimal' timing, whatever that may be. For most of us 9:1 302'ers no power adder, that would be your humble 87 is the best bet ![[Razz]](tongue.gif)
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1984 Ford Tempo AOD--- RIP
Posts: 6785 | From: San Jose | Registered: Jun 2001
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88gt
Custom
Member # 579
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posted
Don't waist your time with boosters. What is your timing set at? Does your car ping?
Posts: 1482 | From: Santa Clara/Bay area | Registered: Nov 2001
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z pyro
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Member # 3745
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posted
timing is stock (10* btdc). no pinging. I didn't adjust the timing at all, I was wondering if using higher octane fuel with the stock timing would change anything. with a higher octane I *could* advance the timing a little bit, right? and when it starts knocking (cuz of advancing the timing), it's a definite sound, not something only a 50 yr old mechanic would know what it sounds like? about how much could I advance on 89 octane? 91?
and I haven't bought any of those octane boosters, I look at the labels and they say they raise the octane level by 7 points, but that's only .7 octane #. I only got the injector cleaner cuz I've heard people say that they use it and it gradually increases gas efficiency.
and btw, it's a 5.0 SO, compression is 8.9:1, if it makes any difference
[ December 11, 2003, 09:43 PM: Message edited by: zpyro35 ]
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'95 Integra LS
'08 Buell XB12R Firebolt
'65 Mustang 289 - soon to be 306
Posts: 1732 | From: Fresno, CA | Registered: Nov 2003
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88gt
Custom
Member # 579
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posted
My timing is at 13 and I run 91. If you don't want to advance your timing then you are fine at running 87.
Posts: 1482 | From: Santa Clara/Bay area | Registered: Nov 2001
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z pyro
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Member # 3745
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posted
well, what difference would it make using 89 over 87? does it make no difference @ 10*? would it be safe to bump it up a degree? would that even make a difference?
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'95 Integra LS
'08 Buell XB12R Firebolt
'65 Mustang 289 - soon to be 306
Posts: 1732 | From: Fresno, CA | Registered: Nov 2003
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h8louzn
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Member # 1075
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posted
If you use 89 over 87 the only thing you will notice is less fuel milage! That is with the stock timming.
Posts: 593 | From: Sac. | Registered: Mar 2002
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Stimson
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Member # 51
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posted
quote:
Originally posted by zpyro35:
well, what difference would it make using 89 over 87?
About 10 cents per gallon ![[Wink]](wink.gif) Just use 87 octane and spend your days worring about something more worthy ![[patriot]](graemlins/patriot.gif)
Posts: 2373 | Registered: Jun 2000
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JoeT
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Member # 298
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posted
I try to run 16-17 BTDC timing advance and 91 octane at the track.
I am not convinced it's any better than 87 octane and say 14-15 BTDC I dyno'd the car on 91 between 15-17 BTDC and the HP difference was *well* within dyno error (approx 1 HP). every car is different though, if you're in ping-land getting out of ping-land will be worth a LOT!
(I have aluminum heads though)
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1984 Ford Tempo AOD--- RIP
Posts: 6785 | From: San Jose | Registered: Jun 2001
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THE King Cobra
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Member # 2011
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posted
try 100 octane and you'll notice the difference! ![[Whoo Whooooo!]](graemlins/woowoo.gif)
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RPM Racing Team
-96 Cobra. HCI MOTORSPORTS block
-More cops in the family = more write-offs
508 RWHP @10.0lbs @6100 RPM..wait till I hit 8K RPM's
Posts: 315 | From: Bay Area, CA | Registered: Oct 2002
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KCmustangboy
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Member # 1927
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posted
I have had 3 5.0s and they always seem to love 15 degrees of timing with 91 octane. Never pings and runs very good. Worth the extra 20 cents a gallon IMO.
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03 Cobra... Factory long block, with Whipple and AED tune... 812rwhp 10.0s @ 140... almost there!
WWW.AEDHP.COM
Posts: 1691 | From: San Jose, CA | Registered: Oct 2002
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Gear Head
JARED
Member # 779
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posted
I went from 91 octane down to 89 because of lack of funds and I actually felt like I gained power doing so. I think running the lowest octane possible(taking into consideration timing and compression ratio) gives you the best power results.
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Support our troops!
Posts: 5685 | From: EASTBAY | Registered: Jan 2002
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z pyro
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Member # 3745
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posted
I haven't done so on my car, but don't you turn the distributor to advance/retard the timing?
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'95 Integra LS
'08 Buell XB12R Firebolt
'65 Mustang 289 - soon to be 306
Posts: 1732 | From: Fresno, CA | Registered: Nov 2003
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Gear Head
JARED
Member # 779
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posted
quote:
Originally posted by zpyro35:
I haven't done so on my car, but don't you turn the distributor to advance/retard the timing?
Yes, but you must remove the spout connector while doing this.
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Support our troops!
Posts: 5685 | From: EASTBAY | Registered: Jan 2002
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z pyro
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Member # 3745
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posted
and that's the little electrical connector coming off of the distributor, right? I've done a bunch of work on a '72 240Z, but of course that engine was super simple compared to the 5.0 ![[Roll Eyes]](rolleyes.gif)
so with a healthy 5.0 SO, 8.9:1 compression, how much (generally) can I advance the timing without pinging on 89 octane? would the difference in power be worth it? or am I just wasting my time?
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'95 Integra LS
'08 Buell XB12R Firebolt
'65 Mustang 289 - soon to be 306
Posts: 1732 | From: Fresno, CA | Registered: Nov 2003
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FasterDamnit
Bad Attitude
Member # 442
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posted
Set it to 14* initial and throw 87 in the tank. Drive it and see how she does. The timing increase is a MUST on these cars. Why give away power? If it does not ping, try 16*. If it does go up one grade of gas. If it still pings, try 91. Most 5.0's in stock trim really like 14 to 16* initial. Mine sure did (16* on 91, 14* on 87)
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'92 LX T5
Looked stock, went 11's 11.90 at 115mph.
'65 Mustang 347
www.fordmuscle.com
Livin' in the Carolina Pines
Posts: 2971 | From: NorCal | Registered: Sep 2001
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z pyro
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Member # 3745
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posted
obviously while experimenting you don't want to get a whole bunch of that kind of gas and fill the tank...should I just get some gas cans and fill them with a gallon or 2 of each?
also, would messing with the timing make the car screw up on smog? the car needs to be checked soon and I don't want to mess with it til after the check if it does.
and btw, fasterdamnit, thanks for your answer, that's what I've been looking for. thanks for the pipes too! ![[Big Grin]](biggrin.gif)
[ December 15, 2003, 05:17 PM: Message edited by: zpyro35 ]
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'95 Integra LS
'08 Buell XB12R Firebolt
'65 Mustang 289 - soon to be 306
Posts: 1732 | From: Fresno, CA | Registered: Nov 2003
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FasterDamnit
Bad Attitude
Member # 442
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posted
You bet. For smog just set your timing back to 10*. I would do testing on 1/4 tank over at least a day or two. If it pings bad, then just add the higher ocatne to the tank. Have fun!
Posts: 2971 | From: NorCal | Registered: Sep 2001
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z pyro
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Member # 3745
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posted
quote:
Originally posted by FasterDamnit:
If it pings bad, then just add the higher ocatne to the tank.
or retard the timing a bit?
so is the difference with advanced timing and increased octane definitely noticeable, or is it just miniscule (or in between)?
thanks for the help! I'll try it out when I actually have $$ to spend.
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'95 Integra LS
'08 Buell XB12R Firebolt
'65 Mustang 289 - soon to be 306
Posts: 1732 | From: Fresno, CA | Registered: Nov 2003
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Gear Head
JARED
Member # 779
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posted
You can defanatley feel the differnce after you advance the timing.
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Support our troops!
Posts: 5685 | From: EASTBAY | Registered: Jan 2002
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FasterDamnit
Bad Attitude
Member # 442
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posted
It can be as much as 15-20hp.
Posts: 2971 | From: NorCal | Registered: Sep 2001
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