Highest timing with 87

1.8kmint · Feb 7, 2008

Whats the highest timing you may run with 87 octane and still be safe as long is there is no pinging?
Also when setting the timing is a timing light completely necessary or can I do it just by ear and driving it?
If someone has an approximation of about how many mm is a degree or so that would be cool also...

Whats the best way to go about checking to see if the timing is too high after bumping it a little? I know drive it, but like WOT runs or drive it easy or what?

Darkwriter77 · Feb 7, 2008

You could, in theory, set the timing by ear, but it's more of a PITA than it's worth, and you don't have an exact means of knowing what your timing is set to ... especially if you want to set it back to the factory 10* for any reason (even if you mark the dizzy's base position). Invest in a cheap, simple timing light and do it right.

As far as what timing with 87 octane ... 12* would be about the safe max for most cars. I can hardly even get away with that on my GT without pinging, so I usually wind up having to at least run 89 octane - I guess because it's an AOD, and the auto ECM's are programmed with a slightly more aggressive timing advance than manuals.

Basically, get the engine up to full operating temp on at least a 70*F day and see if it pings at WOT, especially at high RPM's or (if you're running a manual) in a high gear at low RPM's (bogging it).

Mustang5L5 · Feb 7, 2008

Depends on the car.

You really need a timing light. If you try to do it by feel you will be there forever. If oyu go too far, you may never get it back to 10 and will need a timing light anyway.

bloopbloob · Feb 7, 2008

i'm running mine about 18* right now, and about 16* in the summer, on 87 octane. I use a timing light, and i know it's abnormally high compared to average, but it can handle it i guess. don't know why. at 18 in the summer, i have had a slight ping on the hottest days, and only over 4k rpm, so i drop it to 16 all summer just to be safe. i think it really depends on the car. most can only run around 14* from what i've seen...

25thmustang · Feb 8, 2008

I run 89 octane on 18 degrees and have an AOD computer (5-speed car now). Every car is completely different in this area, there is no broad answer. I would say don't touch the timing until you have a light.

Mustang5L5 · Feb 8, 2008

Sometimes the timing marks are slightly off.

So you are more or less just concerned with finding the point of advance where it doesn't ping than actually reaching a specific number.

cobrat56 · Apr 5, 2009

timming

hey i have an 88 gt stock wit some bolt ons i put my timming to 14*an i use 93 an at about 4000 rpms it starts to breck up anybody got answrs for me thanks

Strippt88 · Apr 5, 2009

25thmustang said:
I run 89 octane on 18 degrees and have an AOD computer (5-speed car now). Every car is completely different in this area, there is no broad answer. I would say don't touch the timing until you have a light.

What he said. I don't recall ever using anything less than 89 unless I had no cash- you can do it by ear, using the marks, but you have to drive it in between adjustments, and if its off, well, you don't want to break it trying to fix it!

85_SS_302_Coupe · Apr 5, 2009

Basically, get a light and run it up until it starts pinging, then back it off until it goes away. Pretty simple.

When i took my car in to get it tuned, i had set the initial timing to 14...but it never occurred to me that i have mechanical advance and i should check total timing...it was at 42 degrees. The tuner was shocked and couldn't believe it wasn't pinging. But, we backed it down to 35 total and it picked up 5hp...so having the most timing in won't necessarily make more power. The important thing is that you have ALL the timing in by about 3k RPM.

Darkwriter77 · Apr 5, 2009

FWIW, I've been running 12* on my '84 lately and running 87 octane without any issues. Sort of an experiment out of desperation in that funds are tight and I can't afford premium gas all the time, but I'd already bumped the timing on that car and I was too lazy to roll it back. Lo and behold, on that car it runs just fine like that. Of course, when the temps go back up into the 90's or higher, the pinging might be an issue again, as it tends to be on teh Notch - anytime it's above 100*, I can't run more than 12* even with premium gas because it'll ping and rattle a bunch.

nunly94gt · Apr 5, 2009

I always set by ear, Pull the spout loosen the bolt and turn away. You hear it increase the RPM's, then reach over and rev it up. Listen and look for rich exhaust. retard a bit and do it again. I just did it yesterday for the first time in a long time, I still got it!!!!
I di check with a light and it was at 16* with 93 octane.

Highest timing with 87

1.8kmint

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Highest timing with 87

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