Advancing Timing to 18 Degrees

I got to 17* before pinging....shaved a tenth of a second too.

you should really use 87 octane and bring your timing down to around 14. Why are you using 93? These cars were meant for 87.

i ran 18 degrees with 93 octane with my H/C/I setup.

Fast63 said:

you should really use 87 octane and bring your timing down to around 14. Why are you using 93? These cars were meant for 87.

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I disagree, after returning my vert to a completely stock motor & trans ( only mods are a full exhaust & 3:73 gears ) I had to return my timing back to 12 degress to run 89 in it. I was running 15 degress with 91-93, but when I put 5 gallons of 89 in to see how it would run, well it ran fine under normal driving but started to ping under WOT, especially in 3rd and 4th when the engine has more load on it.

To the OP, the pointers are known to possibly be off a little, so you may really have closer to 16 deg. If you dont hear pinging your ok, but you need to keep an ear on it.

As long as it doesn't ping, you're good to go.

im at 18 or 19 degrees timing, with just a few mods done to the engine, no pinging at all.

Fast63 said:

you should really use 87 octane and bring your timing down to around 14. Why are you using 93? These cars were meant for 87.

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With stock compression and stock timing....yes. But I would say that most people on here do not have stock compression, nor stock timing. If you advance the timing, you need to up the octane.

Mustang5L5 said:

Keep in mind the timing pointer isn't always 100% accurate.

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Nor is 93 octane always the best quality from one station to the next.

Also keep in mind performance (acceleration). There's a point before pinging occurs where performance drops off. It's a reason to not run on the ragged edge of detonation.

I'd put your (or your friend's) timing light on it just to double check things.

Good luck.

Fett said:

With stock compression and stock timing....yes. But I would say that most people on here do not have stock compression, nor stock timing. If you advance the timing, you need to up the octane.

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You're right, most people here don't have stock compression. The OP does though. So why does he need more octane than I use in my 10.5:1 setup?

The point is, you shouldn't be upping timing to the point where you are upping octane to. It doesn't do anything. In fact, you're probably losing power by doing so. If you're running 18 initial timing with 93 octane, you're probably running at least 38 degrees total. What for?

Didn't you know, just4bob50 too, that 87 octane has more energy in it than 93 does? So, using a stock or near stock engine, stick with 87 and just advance it a couple degrees (don't let it ping. If you get that far, it's too much). In pretty much any N/A application, the experts will tell you somewhere between 32-36 degrees total timing will give you the most power, depending on exactly what your setup is like. So if you're running 38+, you're really losing power. I have tried this time and time again at the track, 91 octane and more timing doesn't get me down the track any faster (sometimes slower) than when I use 87.

Fast63 said:

You're right, most people here don't have stock compression. The OP does though. So why does he need more octane than I use in my 10.5:1 setup?

The point is, you shouldn't be upping timing to the point where you are upping octane to. It doesn't do anything. In fact, you're probably losing power by doing so. If you're running 18 initial timing with 93 octane, you're probably running at least 38 degrees total. What for?

Didn't you know, just4bob50 too, that 87 octane has more energy in it than 93 does? So, using a stock or near stock engine, stick with 87 and just advance it a couple degrees (don't let it ping. If you get that far, it's too much). In pretty much any N/A application, the experts will tell you somewhere between 32-36 degrees total timing will give you the most power, depending on exactly what your setup is like. So if you're running 38+, you're really losing power. I have tried this time and time again at the track, 91 octane and more timing doesn't get me down the track any faster (sometimes slower) than when I use 87.

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When I first started taking my full weight vert to the track it was a stock long block with GT-40 intake, 70mm TB, 75mm MAF, UD pulley's,and a short belt. My best times with this exremely mild set up were in the 13.50's @ 102mph with a 1.82 60ft. This was with 91 in the tank and timing at 16 deg. It was at Cecil County Dragway and the air was in the low 60's. On the last run of the night I put the timing back to 12 deg and my run was a 13.71 @ 100.5 with a 1.85 60ft. despite the air being about 2 degrees cooler. The next time down to the track the air was in the mid 70's and I tried to run 16 degrees again, but couldnt because of a slight ping. So now on the next trip to the track ( just for curiosity sake ) I started with stock timing, and then bumped it up in 2 degree incriments at a time. I was looking at the MPH more than ET at this point, because that tells you weather your making more power. Air was 67-70 for all runs. 1st run 99.98 mph, 2nd 100.64, 3rd 101.85, 4th 102.10. The 4th run was the best. When I tried to put more timing in for the next run I heard pinging and got out of it. Now I realize that this was done with 91, but it is obvious how much of a change the timing was making. I doubt 87 would have let me put that much timing in.

This topic has me thinking that when my 92 LX is finally up and running I may run my vert to see if there is a difference between 87 and 93 and how much timing each will allow and what the benifits are.

Dont get me wrong my vert will be running 87 with the stock timing, or whatever 87 will allow, but it is now just my weekend cruiser, and Im not looking for every last bit of power.

You have to run with 87 down the track to make any real comparison. I don't think anyone would argue that in your setup, at 16 degrees with 91 you would get the best run. Try running 87 at 12 degrees and tell me what happens.

timming question?

im new to stangnet and hope im posting this the right way. i had a guy pull my distibuter today and replace the o'ring. the timming was retarded to run 125 shot of nitrous as i bought the car. i was not planning on the nitrous so i wanted to advance the timming for some lower end grunt. im not a mechanic by no means. i watched him set up the timming light when another mechanic walked by and said with a large cam in it it he was better off to hook up a vacuum guage on it and adjust untill he reached peak vacuum. ive never heard of this, but the car has a lot more bottom end power. im not sure what the pinging sounds like that everyone here is talking about but i am hearing what sounds like the valves chatter just a little bit in 3rd and 4th gear at a high rpm. it has a lunati cam in it im not sure all the numbers but its hell under 2k rpms. any advice would be appreciated. ive learned alot from stangnet and have lots i hope to share with everyone in the future. i feel better at this point because i just pulled and put my t-5 tremec back in with awesome results.

:SNSign:

To the OP, your statements seem pretty accurate. 18* timing is probably riding the ragged edge, which is unnecessary. Optimum timing in mild n/a motors comes well before detonation. So, you will reach peak power, and still have several more degrees of advance before you reach detonation. Let's say you actually peak at around 14*. You're not likely to see any difference at 15, 16, or even 17* advance. At 18*, you're flirting with detonation, and before you hear the motor ping, you're likely to start losing power. So, you'll see it on a dyno before you pick it up by listening. Adding any more advance is only going to make the detonation worse, and your power output will suffer as a result.

Fast63 said:

You're right, most people here don't have stock compression. The OP does though. So why does he need more octane than I use in my 10.5:1 setup?

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Because he wants to run more timing, and make the most power he can. Plus, 10.5:1 is only one part of your motor's story. What are the cam specs, and how much timing are you running on 87 octane?

[qoute]The point is, you shouldn't be upping timing to the point where you are upping octane to.[/quote] That's an opinion. Others are willing to pay a bit extra for the extra power or the added insurance against detonation.

It doesn't do anything.

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not true

In fact, you're probably losing power by doing so.

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Explanation, please?

If you're running 18 initial timing with 93 octane, you're probably running at least 38 degrees total. What for?

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For the fact that some cars want 18* initial timing. My old car ran a best ET and trap speed at exactly 18* initial. Of course, it had AFR165s, and a custom cam. I had that car on multiple dynos and was at the point of tuning fractions of a degree of timing, and 18* on the nose it what worked best.

I'm not saying that this timing is right for the OP's car. In fact, I'd tend to believe his pointer was off before I believed his motor liked 18*. However, the likeliest possibility is that he's advanced his timing beyond MBT, and is running at the ragged edge with no gain in performance. Backing it off is probably right, but dropping octance probably isn't, if he's going to shoot for peak power.

Didn't you know, just4bob50 too, that 87 octane has more energy in it than 93 does?

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Theoretically this is true. However, the difference in thermal energy is negligible, and the difference in power from more advanced timing is not. In other words, the thermal efficiency gained in the combustion process by advancing timing with higher octane fuel outweighs the loss in its chemical potential energy.

In pretty much any N/A application, the experts will tell you somewhere between 32-36 degrees total timing will give you the most power, depending on exactly what your setup is like. So if you're running 38+, you're really losing power.

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Are you sure that the A9L strategy advances base timing by 20*? Second, we cannot establish with certainty that he is really running 18*. The pointer may be inaccurate. Third, my pointer was not inaccurate when I got my best performance from 18*. So, the expert apparently has a flawed opinion. Something tells me that there's more to the story.

I have tried this time and time again at the track, 91 octane and more timing doesn't get me down the track any faster (sometimes slower) than when I use 87.

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How much power were you expecting? Is your driving consistent enough to see a 5-10hp difference? Were you keeping track of your coolant/engine temps, and the tracks are temps? If every other variable is held constant, you should see only a delta of .05-.1 in ET and .5-1mph in trap speed.

Chris

My 89 liked 17* on a dyno, it had aluminum heads though.
I think 87 octane will have its timing sweet spot too low for some combo`s, with an auto you will most likly have better results with the 92 and timing bumped a tad.
I don`t worry about it anymore, im carbed
I just toss in some tolulene and 24* for a total of 34* and go for it.