87 octane wha???

Rodoggx · 10-21-2003, 11:15 PM

Hey guys,
Here's the deal. Timing is set to 14 degrees btc. For a while I ran 87 octane and had lotsa fun with the car. Then I've been using 93 octane cuz 14 degrees should take advantage of the extra octane right? Well, it runs more sluggish with the 93... what gives? seriously, it feels faster and lots more fun to drive with 87... any ideas? Motor is totally stock, btw.

SmokinStangGT · 10-22-2003, 12:59 AM

the octane that STOCK mustangs perform the best at is midgrade and if/when you used premium fuel the car can get sluggish a bit... i used to know the reasons, but it might be something how it effects the sensors.... but im 100 percent sure mustangs are recomended to use mid-grade fuel. There was an article on the HP stock mustang produced and the order is...
1. mid-grade... most power
2. regular... a few hp less
3. premium...was way back in the HP
-hope i helped

HiFlow5 0 · 10-22-2003, 02:06 PM

Unfortunately, many people assume that higher octane fuel is better for all engines, no matter what. This is absolutely false. Ultimately, the best octane for any vehicle is the lowest one you can run without detonation (pinging) occuring. It's not the fuel that increases the performance, it's the fact that the timing has been advanced. The higher octane permits this to happen. In your case 87 should be just fine.

Octane, for all intents and purposes, is used to slow down, or control the burn rate. Modifications that increase performance, such as increased compression, or advanced ignition timing, will cause the mixture to become too unstable, and pre-ignition (aka: detonation, pinging) will occur. This is when the mixture fires on it's own, at the wrong time. Severe damage will occur if left untreated.

People often think of high octane fuel as being more flammable, and easier to explode, whereas that is actually the opposite of the truth. 93 octane will be tougher to ignite than 87 octane. Because of that fact, 87 octane will burn quicker, and 93 octane will burn slower. That's why you feel sluggish with higher octane.

bigred90gt · 10-22-2003, 02:29 PM

http://www.ricehatersclub.com/vbulle...=&threadid=360

Coupe50h · 10-22-2003, 06:09 PM

I've run 12.91 @ 105 mph on 87 octane, i get no detonation, but with my old stock e7's i HAD to run 93 with advanced ignition, even in the cold weather.
on 93 i have the same results you do, i tried some VP 104 one day, and it made my car sputter, and slow down.
Good thread here.

Hethj7 · 10-22-2003, 07:51 PM

It has been a while since I have seen a thread like this. It seems like it comes up every so often and facts about octane always get jumbled up. Glad to see that that good info was presented quickly here.

Hethj7 · 10-22-2003, 07:54 PM

Oh, no wonder good info is out there. It came straight from Chris, kind of

!

At least give the man some credit and show where you came up with that info, or paraphrase it next time

!

PKRWUD · 10-22-2003, 09:08 PM

I thought my ears were burning because it's in the f-ing 80's here today. Now I see why.

LOL

As long as the facts get out, I don't care if I don't get credit. What would really piss me off is if someone wrote something bogus, and then said I said it. lol.

PKRWUD · 10-22-2003, 09:10 PM

Hey! That was my 8900th post! I need to stop by more than once a month.

1jimmy__d · 10-22-2003, 09:47 PM

i was actually going to post a similar question to this. i have always used super when filling up my stang. when cold it would pop under hard acceleration. i also got like 11-12 mpg. i decided to switch to regular gas and i have no popping at all when cold and get more mpg's!! does this make sense? mym mods are in my sig! thanks,

jim

Hethj7 · 10-22-2003, 11:30 PM

Every car will be a little different. Like it was said before, you want the lowest octane gas you can run without getting detonation.

It is very possible that you don't need high octane gas with your combo.....look at Coupe5ho running 12.9 on 87 octane.

Rodoggx · 10-23-2003, 12:11 AM

Awesome guys! thanks for all the info. I guess its 87 from now on.... phew what a relief on my wallet, heh. That premium was killing me.

HiFlow5 0 · 10-23-2003, 12:23 AM

Quote:

Originally posted by PKRWUD
I thought my ears were burning because it's in the f-ing 80's here today. Now I see why.

LOL

As long as the facts get out, I don't care if I don't get credit. What would really piss me off is if someone wrote something bogus, and then said I said it. lol.

Sorry I didn't give you credit Chris! I have so much info saved as text files on my computer, that I can't remember where half of them came from. Anyway it was good info you gave, that must have been why I saved it. No hard feelings?

-Craig

Coupe50h · 10-24-2003, 01:53 PM

Quote:

Originally posted by Rodoggx
Awesome guys! thanks for all the info. I guess its 87 from now on.... phew what a relief on my wallet, heh. That premium was killing me.

I still like to run midgrade every now and then, just to be safe, especially when it's 100 degrees outside, and im cruising through traffic ect......toodles

tireburner163 · 10-26-2003, 02:16 AM

Quote:

Originally posted by Coupe50h
i tried some VP 104 one day, and it made my car sputter, and slow down.

That's because you weren't spraying enough nitrous

-Josh, aka the tireburner

10-21-2003, 11:15 PM	#1
Rodoggx Registered Member Join Date: Oct 2002 Location: VA. Posts: 71	87 octane wha??? Hey guys, Here's the deal. Timing is set to 14 degrees btc. For a while I ran 87 octane and had lotsa fun with the car. Then I've been using 93 octane cuz 14 degrees should take advantage of the extra octane right? Well, it runs more sluggish with the 93... what gives? seriously, it feels faster and lots more fun to drive with 87... any ideas? Motor is totally stock, btw. __________________ 1990 Mustang LX 5.0 - All STOCK!!!! Wha?!!! Stock???.... no money for mods..

10-22-2003, 12:59 AM	#2
SmokinStangGT Registered Member Join Date: Sep 2002 Location: IL Posts: 105	Use mid-grade the octane that STOCK mustangs perform the best at is midgrade and if/when you used premium fuel the car can get sluggish a bit... i used to know the reasons, but it might be something how it effects the sensors.... but im 100 percent sure mustangs are recomended to use mid-grade fuel. There was an article on the HP stock mustang produced and the order is... 1. mid-grade... most power 2. regular... a few hp less 3. premium...was way back in the HP -hope i helped __________________ 89' GT with 5spd Hurst short throw, Keith Black 12:1 comp. pistons, Sealed Power drag racing rings, Fms F303 Cam, Ported and polished upper and lower intake with Ported E7TE heads that contain comp. cam double coiled springs with titainum locks and steel retainers, Fel-Pro Head Gaskets, 9mm ford racing wires, BBK chrome unequal shortys, Power Throttle bodies 70mm, Edlebrock 70mm EGR plate, 15inch K&N, Bassani X-pipe, Flowmaster 40 series, Eibach 1 1/2 lowering springs, Cobra R rims 17X9 with p235 on front and p275 on rear with Falken Zeix tires-RUNNING!

10-22-2003, 02:06 PM	#3
HiFlow5 0 Registered Member Join Date: Mar 2000 Location: Springfield, Ma, usa Posts: 706	Unfortunately, many people assume that higher octane fuel is better for all engines, no matter what. This is absolutely false. Ultimately, the best octane for any vehicle is the lowest one you can run without detonation (pinging) occuring. It's not the fuel that increases the performance, it's the fact that the timing has been advanced. The higher octane permits this to happen. In your case 87 should be just fine. Octane, for all intents and purposes, is used to slow down, or control the burn rate. Modifications that increase performance, such as increased compression, or advanced ignition timing, will cause the mixture to become too unstable, and pre-ignition (aka: detonation, pinging) will occur. This is when the mixture fires on it's own, at the wrong time. Severe damage will occur if left untreated. People often think of high octane fuel as being more flammable, and easier to explode, whereas that is actually the opposite of the truth. 93 octane will be tougher to ignite than 87 octane. Because of that fact, 87 octane will burn quicker, and 93 octane will burn slower. That's why you feel sluggish with higher octane. __________________ NewEngland Auto www.baystategearheads.com -91 Mustang Coupe, ex 4cyl (sold) -99 F150, 3" lift, 35" Procomps, Magnaflow exhaust

10-22-2003, 02:29 PM	#4
bigred90gt 2 Stangs in the Stable Join Date: Apr 2002 Location: Baytown, TX Posts: 1,209	http://www.ricehatersclub.com/vbulle...=&threadid=360 __________________ '90 GT Under construction Best E.T. = Fast @ High Speeds - OK So I Lie. So What!!! 04 F-150 STX 4.2L 5 spd Rice Haters Club Member #128

10-22-2003, 06:09 PM	#5
Coupe50h Registered Member Join Date: Aug 2002 Location: SanAntonio, Tx Posts: 957	I've run 12.91 @ 105 mph on 87 octane, i get no detonation, but with my old stock e7's i HAD to run 93 with advanced ignition, even in the cold weather. on 93 i have the same results you do, i tried some VP 104 one day, and it made my car sputter, and slow down. Good thread here. __________________ X-Texas highway patrol ssp 1990 coupe - exploder Gt-40 iron heads, Explorer intake, 19 lber's. E-cam. crane 1.7 rollers. 190fp. 75mm maf. 65mm tb, tubular subframe connectors, mac cai, Asp crank pulley, T-5, king cobra clutch, flowtech 1-5/8 unequals, mac X-pipe Frpp driveshaft, lakewood Lca's. race weight 3,160 12.69 @ 107.35, 1.71 60' 26x8.5 drag's 3.90 gear 13.20 @ 106.91 - 235/60/15 firestones 2.3 60' 3.27 gear

10-22-2003, 07:51 PM	#6
Hethj7 Mizzou Tigers Join Date: Apr 1999 Location: weston, MO United States Posts: 1,455	It has been a while since I have seen a thread like this. It seems like it comes up every so often and facts about octane always get jumbled up. Glad to see that that good info was presented quickly here. __________________ 2006 Mustang GT 1990 LX GT-40 motor 262 horsepower, 307ft-lbs (sold but forever loved) 1998 Contour SVT Rice Haters Club Member #244

10-22-2003, 07:54 PM	#7
Hethj7 Mizzou Tigers Join Date: Apr 1999 Location: weston, MO United States Posts: 1,455	Oh, no wonder good info is out there. It came straight from Chris, kind of ! At least give the man some credit and show where you came up with that info, or paraphrase it next time ! __________________ 2006 Mustang GT 1990 LX GT-40 motor 262 horsepower, 307ft-lbs (sold but forever loved) 1998 Contour SVT Rice Haters Club Member #244

10-22-2003, 09:08 PM	#8
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	I thought my ears were burning because it's in the f-ing 80's here today. Now I see why. LOL As long as the facts get out, I don't care if I don't get credit. What would really piss me off is if someone wrote something bogus, and then said I said it. lol. __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

10-22-2003, 09:10 PM	#9
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	Hey! That was my 8900th post! I need to stop by more than once a month. __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

10-22-2003, 09:47 PM	#10
1jimmy__d Registered Member Join Date: Apr 2002 Posts: 299	i was actually going to post a similar question to this. i have always used super when filling up my stang. when cold it would pop under hard acceleration. i also got like 11-12 mpg. i decided to switch to regular gas and i have no popping at all when cold and get more mpg's!! does this make sense? mym mods are in my sig! thanks, jim __________________ 90 lx hatch, holley systemax II kit, rebuilt 302, BBK 155 lph fuel pump, pro M bullet mass meter wtih BBk cold air intake, 30 # injectors, 70 mm TB, jacobs ignition system, edelbrock water pump, BBk longtube headers with h-pipe, flowmasters, b&m ripper shifter, 3.55 gears, Proform electric fan, subframe connectors/removed smog pump and ac! 75 shot of nitrous! 13.2 at 112 1/4 mile- no traction!

10-22-2003, 11:30 PM	#11
Hethj7 Mizzou Tigers Join Date: Apr 1999 Location: weston, MO United States Posts: 1,455	Every car will be a little different. Like it was said before, you want the lowest octane gas you can run without getting detonation. It is very possible that you don't need high octane gas with your combo.....look at Coupe5ho running 12.9 on 87 octane. __________________ 2006 Mustang GT 1990 LX GT-40 motor 262 horsepower, 307ft-lbs (sold but forever loved) 1998 Contour SVT Rice Haters Club Member #244

10-23-2003, 12:11 AM	#12
Rodoggx Registered Member Join Date: Oct 2002 Location: VA. Posts: 71	Awesome guys! thanks for all the info. I guess its 87 from now on.... phew what a relief on my wallet, heh. That premium was killing me. __________________ 1990 Mustang LX 5.0 - All STOCK!!!! Wha?!!! Stock???.... no money for mods..

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Min Octane for 1999 GT recommended by Ford	Ort	Modular Madness	3	04-08-2004 10:40 AM
octane/HP rumors?	gizmo83	Windsor Power	48	08-23-2002 06:19 PM
110 octane safe?	HellRaiser92	Blue Oval Lounge	9	03-30-2002 05:38 PM
89 octane vs. 104 or 110 octane	Nitrous Al	Windsor Power	3	03-05-2002 10:12 PM
Octane Rating?	Fostang	Windsor Power	6	05-15-2001 03:17 PM