Ignition Timing Thread

[CoreyB]

I wouldn't be to worried, I would be very surprised if you blow your engine from too much timing. It will likely run terrible before you actually start doing damage. However, running too much timing for a long period of time, even on a low horsepower engine isnt exactly very good for the life of the bearings. You need to remember that pretty much all the story's you hear about people knocking and destroying these engines were people that were boosting and running out of fuel or detonating.

[Greg E]

So with that being said, without using a dyno to tune which is obviously preferred:

Should I see if I can keep increasing Timing, until it knocks? I feel like I am already running alot of timing especially compared to how much I was running during my last few dyno runs I did. The car definitely feels great, and is responding well to it; but if there is a safe amount of room for more then I am down to keep going. (I always fill up with 93, never 91, or lower grade fuels if that contributes to the answers I seek) Currently I have it set at 9.5* for the Base Timing, which in my logs is about 34-35 Degrees @ WOT in the high rpm range. (4600-7200rpms)

Tuning till you see knock with race gas or ethanol will lead to a blown motor long before you see knock. Todd has now lost 2 engines from this tuning approach and is now scared to run any kind of alcohol fuel...

Without a Dyno you really need to just go by instinct. This just takes experience and research. If so and so with a similar setup put down such power and is still driving around the then its probably safe to assume you might be able to do the same.

[DG]

All else being equal, I would expect low octane/pump fuel (93 is low octane; I ran 118 in the race car) to have a smaller timing window than with high octane. But this isn't something you can nail down discussing shit on the Internet; this has to be tested in the wild.

Let me say that again - the only way to know is to test.

Also, testing is the only way to know.

DG

[CoreyB]

Does he have to test?

[Blackmount]

Tuning till you see knock with race gas or ethanol will lead to a blown motor long before you see knock. Todd has now lost 2 engines from this tuning approach and is now scared to run any kind of alcohol fuel...

Without a Dyno you really need to just go by instinct. This just takes experience and research. If so and so with a similar setup put down such power and is still driving around the then its probably safe to assume you might be able to do the same.

That is why I started this thread; I don't see a whole lot of ignition timing being talked about in depth with the 3/s platform, or really any Import for that matter; but there is the possibility maybe I just haven't been paying as much attention as I think I have.

I don't want to make this about N/As OR my car, but this seems very uncharted, and I'm trying to make power the right way. "Make power smarter, not spending money harder." I believe there is power to be had through just timing in itself, and I would really like to see how much.

All else being equal, I would expect low octane/pump fuel (93 is low octane; I ran 118 in the race car) to have a smaller timing window than with high octane. But this isn't something you can nail down discussing shit on the Internet; this has to be tested in the wild.

Let me say that again - the only way to know is to test.

Also, testing is the only way to know.

DG

And that is what I am doing but I was looking for a little bit of advice and maybe some comfort before I did what I felt like was might pushing the limit, and or wasting time. (Loosing power)

I've never run one of MY cars on anything but pump gas, so 93 is high to me. LOL.

Does he have to test?

Troll :P

I will play with the timing some more and report back, and see what I can accomplish. I will maybe post logs if anyone is interested; speaking of which, Is there any other sensors I should monitor in my logs? I am using the the Android Version of MMCD. I usually just do Timing, TPS, RPM, Knock, and Coolant Temp.

Maybe I can see about getting the car to a dyno tuner, and really get some solid results. I would happily post online here as oppose to my butt dyno and a few logs. I would be really happy if this information could be used to benefit others who have questions on timing.

[familyMAN]

That is why I started this thread; I don't see a whole lot of ignition timing being talked about in depth with the 3/s platform, or really any Import for that matter; but there is the possibility maybe I just haven't been paying as much attention as I think I have.

Spend some time on evo forums. Plenty of discussion on various setups. Every setup is different, cams, header, turbos, intake mani, fuel, afr all make a difference on what timing you can run or what your motor wants.

I am certainly no expert and have a blown headgasket as proof Trevor has posted his timing maps and experience several times, especially with his 3.7 setup. I can attest to his conclusion that the 6g74 wants MUCH less timing advance than the 72s. When it gets new head gaskets soon, I will be leaning it out under boost (e85) and low single digit timing at peak tq.

Great topic though.

[Blackmount]

Spend some time on evo forums. Plenty of discussion on various setups. Every setup is different, cams, header, turbos, intake mani, fuel, afr all make a difference on what timing you can run or what your motor wants.

I am certainly no expert and have a blown headgasket as proof Trevor has posted his timing maps and experience several times, especially with his 3.7 setup. I can attest to his conclusion that the 6g74 wants MUCH less timing advance than the 72s. When it gets new head gaskets soon, I will be leaning it out under boost (e85) and low single digit timing at peak tq.

Great topic though.

Would the reason it likes LESS timing be because the piston is traveling a further distance?

[familyMAN]

No idea. Thought a bigger bore would need more timing? I'm 10:1 though. Trevor is 9:1, but I believe it was Hans that also said less timing for 74 swaps.

[Blackmount]

Well the biggest different in displacement with the 6g74 is the stroke correct? The point of adjusting timing is to get the flame front to hit the piston right as it hits TDC, instantly forcing the piston down, no waiting time. As stated above it takes time for the created spark to travel and ignite the air fuel mixture, and then it takes time for that mixture to fully ignite to generate its full force.. well if the piston has more distance to travel you would need the spark to wait LONGER to fire...I would think.... I could be wrong...

[familyMAN]

Well the biggest different in displacement with the 6g74 is the stroke correct?

Correct, almost 10mm more stroke and almost 2mm more bore.

Didn't want to turn this into a 74 thread, just wanted to point out that there is some timing info out there if you look for it. Chris H has posted most of his timing info as well.