Ignition timing for Methanol vs Gasoline
Ignition timing for Methanol vs Gasoline
(OP)
My company has recently built a drag car that uses methanol fueling and high boost pressure. We are having some problems with burning through the head gasket, which I believe is due to an over conservative timing map.
Some info on the engine are: 3 liter of displacement (Toyota 2JZGTE), 40+ psi of boost pressure, 11:1 static compression ratio.
The timing that we used was similar to what we run on high octane leaded gasoline.
Some questions I have are:
1) How is the ideal timing of methanol compared to that of high octane leaded gasoline?
2) Could not having enough timing cause the combustion temparatures to reach a level which causes the head gasket to burn through?
Some info on the engine are: 3 liter of displacement (Toyota 2JZGTE), 40+ psi of boost pressure, 11:1 static compression ratio.
The timing that we used was similar to what we run on high octane leaded gasoline.
Some questions I have are:
1) How is the ideal timing of methanol compared to that of high octane leaded gasoline?
2) Could not having enough timing cause the combustion temparatures to reach a level which causes the head gasket to burn through?





RE: Ignition timing for Methanol vs Gasoline
There are many things that can be causing this issue. More likely than not you are pushing the gasket out then burning it or the head.
We run a traditional Chrysler Wedge motor 526 ci on methonal @ 37psi from a roots blower. Our timing is 32 degrees advanced with 10:1 static compression. Not gasket issues. We use copper o-ringed gaskets and had to run 1/2" head studs to get enough clamp load on the gasket.
If I had to bet you are producing too much cylinder pressure and pushing the gaskets. There are many ways to fix this but you first need to know if you are detonating or if you need to upgrade parts to handle the boost.
More info may help me give you some direction
RE: Ignition timing for Methanol vs Gasoline
The head studs are stock sized (7/16" I believe) but were upgraded to ARPs L19 material.
The timing was about 6 degrees advanced at 40 psi and 8500 RPM.
One thing that we noticed was that we were melting the ground straps off the spark plugs which leads me to believe we were experiencing pre-ignition.
Could our timing be too retarded and lead to high compression temperatures, pre-igntion, and melting the head gasket?
RE: Ignition timing for Methanol vs Gasoline
If you were to far retarded you would have high exhaust temps and be in danger of burning a valve, damaging a turbo, and overheating the engine. Is this a turbo car or SC.
Burning the head gasket is the least of you worries here!!! You are in line foe some seriuos piston and head damage if your burning ground straps off plugs!!!!
On our rig we don't even take 10% of cadnium plating off the ground strap.
More detail on the set-up would help
RE: Ignition timing for Methanol vs Gasoline
We definately are not experiencing a lean condition as our datalogs showed that we were tuned at about 0.65 lambda.
This is a turbocharged car.
For reference we also have another race car running methanol which uses a Mitsubishi 4G63 engine which has more material between cylinders than the Toyota 2J engine. We initially had similar timing curve in the Mitsubishi as the Toyota engine and found that by advancing the timing 10 degrees we were able to obtain an additional 100 hp on our dyno (540 vs 645).
What I am really wondering is how much more aggressive you can be on the timing with methanol vs. Race gas?
RE: Ignition timing for Methanol vs Gasoline
If it were me I'd recurve the timing to a safe point and add some fuel just in case. Then creep back up on the tune-up.
Just for my knowledge, what's the .65 lambda mean? We are restricted to mechanical FI and can only monitor EGT's on the car.
RE: Ignition timing for Methanol vs Gasoline
RE: Ignition timing for Methanol vs Gasoline
0.65 lambda for methanol is 9.85:1
At 40# boost and 11:1
you need to be quite rich to suppress detonation.
a:f of 4:1 is lambda 1.6 which is very rich.
I would think a:f of 5.0:1 which is lambda 1.28 should be rich enough.
9.8:1 is so lean I am surprised it ran at all. If it has only blown the tips of the plugs and blown a head gasket, you have been very lucky.
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RE: Ignition timing for Methanol vs Gasoline
so lambda = .65 is an AF of 4.16
RE: Ignition timing for Methanol vs Gasoline
it's tuned to 4 to 1 afr. What's good on paper isn't what works in the real world.
when I multiply 14.64 by .65 I come up with 9.55.
How do you get to 9.8?
RE: Ignition timing for Methanol vs Gasoline
14.7 multiplied by .65 is 9.555.
RE: Ignition timing for Methanol vs Gasoline
.65*6.4 = 4.16
You are thinking of gasoline's stoich A/F ratio.
What I really need to know is what type of additional timing we can add with the methanol vs. Gasoline. Is there a rule of thumb like: with methanol you can add __% more timing??
RE: Ignition timing for Methanol vs Gasoline
RE: Ignition timing for Methanol vs Gasoline
brobards
How do you know the lambda reading. Is it average, maximum or minimum. Is it dyno or track data. Is the gasket and plug burning at the track, dyno or both. You might have a fuel supply to the engine problem that only occurs part way down track caused by something like collapsed or restrictive fuel line, g force on the fuel in the line, restrictive fuel filter, uncovering the fuel pickup, aeration of the fuel in the tank from poor return line design, inadequate tank vent.
You might also have bad methanol with jelly like lumps, to much water or corrosion by products causing an instantaneous temporary lean out.
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RE: Ignition timing for Methanol vs Gasoline
RE: Ignition timing for Methanol vs Gasoline
I am asking because you should not be blowing tips of plugs and burning gaskets at that timing, CR and boost. You should be close to the limit, but not past it.
With a 4" plus bore and wedge head, high 20s, low 30s deg timing is conservative. A pent chamber central plug 4 valve with low to mid 3" bore should need maybe 10 deg less timing, so I would think 15 deg would be a good starting point, BUT THIS IS A GUESSTIMATE not based on specific experience with a similar engine to yours.
If I were you, I would be very keen to see the piston tops and valves.
i think this was already mentioned, but how high is the exhaust manifold pressure, is it higher than boost pressure and do you have a lot of valve overlap, allowing a lot of hot exhaust gas to flow into the chamber and overheat the charge and cause detonation.
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RE: Ignition timing for Methanol vs Gasoline
I really don't think timing is your issue, you need more fuel. the huge amounts of fuel being run through the intake will cool the motor down so much that detonation should be non existent, allowing gobs of timing.
You should be shoving enough fuel through the motor that the intake will frost up.
The plugs should allways look clean, like brand new. The only thing you should see on the plugs is slight discoloration down the electorde side strap towards.
RE: Ignition timing for Methanol vs Gasoline
I look for the plating to be burnt off of 3 threads on the electrode side of the plug with less at other points around the plug, and the earth strap to have gone shiny and discoloured to just before the bend.
A/F ratio has more impact on heat in the thread area, and ignition timing has more impact on the earth strap, but adjusting one will effect both to some degree.
This method only shows the maximum heat reached during a run, not the average or what variation.
A data logger with EGT will show variations along the track but are not reliable re actual mixture, just good for cyl to cyl or for variations during the run. O2 sensor also useful. Very good for A/f ratio, but not for indicating chamber condition during combustion. Also I think they react a bit slow, so not as good as EGT for indicating exactly when change happened.
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RE: Ignition timing for Methanol vs Gasoline
I have been running methanol injection in our supercharged and turbo charged 2.7L Hyundai V6 engines as an octane booster for higher boost levels on pump gas, 93 octane. I understand that gasoline is 14.7:1 stoich and methanol is 6.4:1 stoich. When supplementing approximately 20-30% of the gasoline with methanol and we look at a wideband that is calibrated for gasoline, the wideband shows extremely rich. If I tune the car to 12.2:1 A/F with the added methanol, how do I figure out what the actual A/F ratio is with the addition of the 25% methanol. I was told that even though I see 12.2:1 A/F on the wideband, the mixture is actually leaner than what I am seeing because of the difference in stoich between the two fuels and beacause the wideband is calibrated for gasoline. Can anyone help me understand this a little more cleary with some sort of formula that I can use to calculate the actual A/F? I would greatly appreciate it.
Thanks T.C.
Next Generation Motorsports
RE: Ignition timing for Methanol vs Gasoline
So for 20% methanol, .2(6.4) + .8(14.6)= 12.96
This still doesn't help you since your A/F meter is calibrated for a stoich. ratio of 14.6. You can set your meter to read Lambda, then multiply by your combined A/F ratio to find your correct A/F.
RE: Ignition timing for Methanol vs Gasoline
I went to a colder range plug and the problem went away
Cheers
I don't know anything but the people that do.
RE: Ignition timing for Methanol vs Gasoline
P.S. Here is a little chart to clarify the Alcohol vs. Lambda vs. Gas numbers
Alcohol Lambda Gas
6.4 1 14.7
6.2 0.96875 14.240625
6 0.9375 13.78125
5.8 0.90625 13.321875
5.6 0.875 12.8625
5.5 0.859375 12.6328125
5.4 0.84375 12.403125
5.2 0.8125 11.94375
5 0.78125 11.484375
4.8 0.75 11.025
4.6 0.71875 10.565625
4.5 0.703125 10.3359375
4.4 0.6875 10.10625
4.2 0.65625 9.646875
4 0.625 9.1875
3.8 0.59375 8.728125
3.6 0.5625 8.26875
3.5 0.546875 8.0390625
3.4 0.53125 7.809375
3.2 0.5 7.35
RE: Ignition timing for Methanol vs Gasoline
RE: Ignition timing for Methanol vs Gasoline
We run 7.86 at 185 mph in a 2600# car.
I never used an oxygen sensor.
I tune by the spark plug reading method In my 09/01/07 post.
I never blew a hole in a piston nor blew the electrode of a plug when my tune was used.
We start at 30Deg, and 1/4 track passes to get the fuel close, then increase distance at WOT to get fuel right, then go full track and sneak up on timing, normally to 36 deg, while constantly fine tuning fuel.
A 4" bore wedge head will have significantly different timing requirements to a pent roof 4 valve head. Something to do with flame path, quench patterns and distance to edges of chamber if anyone cares to actually think about it.
Also with a wedge head, spark requirements can vary widely from engine to engine, depending on
A:F ratio.
Spark plug position.
Cylinder head material.
Fuel quality.
Spark energy.
Deck clearance.
Boost.
Compression ratio.
Cam timing, especially inlet and exhaust closing points and lobe centres.
Piston dome shape re shrouding of flame travel.
Piston dome shape re quench, swirl, tumble etc.
Cylinder head cooling.
Piston cooling.
Rod to stroke ratio.
Spark plug heat range.
Surface finish and edge details of valves, chamber, piston top and possibly head gasket.
Regards
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RE: Ignition timing for Methanol vs Gasoline
As far as timing goes, we ran fixed advance magneto with as much as 50 deg. But this was a big bore motor too at about 85-8800 rpm. About 45 was normal. We ran a lot of fuel for the day but with a very,very hot magneto so we probably got more bang than most for the time period. Remember we only had our wits for data recording. haha Yes our manifold frosted heavily and was often wet at the end of a run.
I agree with Pat that the subject motor is very lean and to only suffer a blown HG is very lucky indeed. Torching the block and or head would seem more likely.
99 Dodge CTD dually.
RE: Ignition timing for Methanol vs Gasoline
So I understand what is being said about all of these variables. Brobards is not that far off on fuel at 9.5:1 gas scale or .65 lambda or 4.2 methanol(nobody has mentioned intercooling this plays a big role in heat in the combustion chamber and overall fuel consumption even with methanol), if anything once he brings the timing up he is going to find himself on the fat side of things if he stays with these numbers, air-fuel changes with timing(if you haven't ever used wideband maybe you haven't seen this but it does). The Toyota 2JZ 3.0L motor will not run on 6 degrees of total timing turbocharged with methanol(maybe on the two step for antilag), if you think this info is inaccurate call Titan Motorsports in Florida they hold the world record with the Toyota 2JZ turbocharged on methanol see what they think about 6 degrees of timing. Get yourself some EGT probes so you can see what the timing is doing to your temps, bring it up into the thirties on timing, dyno it there and you'll find the sweet spot, and if you are going to run 40+ lbs of boost get yourself some o-rings and copper head gaskets it will make your life much easier.
RE: Ignition timing for Methanol vs Gasoline
I'm also considering the move to methanol on my 2.6 rb26. it dynoed 610RWHP on 98 oct pump gas.
This site is huge and i apologize if i should have searched but i did and came up with nothing. a search didnt even catch this thread google caught though :>
Anyways off to my questions.
first off what are the maint requirments/differences on an engine running methanol vs Hi OCT racegas. ie oil changes, engine overhauls ect ect
Second will the methanol effect the way a big turbo spools. I'm running a t88-34D (big) and it usually dosnt spool till about 5000+ rpm. or can you just tune to make it spool just like race gas.
As for the original post.... from what i have seen sounds like you are lifting the head and pushing the gasket out. maybe upgrade to a metal head gasket and go with larger diameter head studs. thats what i had to do on my rb26 to keep the gasket from blowing.
Thats it for now thanks
RE: Ignition timing for Methanol vs Gasoline
RE: Ignition timing for Methanol vs Gasoline
In my opinion, by far the best site for MFI methanol and nitro methane tuning.
Regards
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RE: Ignition timing for Methanol vs Gasoline
RE: Ignition timing for Methanol vs Gasoline
If so is it the same cylinder that has the problem or does it move around? You may just have an uneven sealing surface problem also.
RE: Ignition timing for Methanol vs Gasoline
RE: Ignition timing for Methanol vs Gasoline
just a newbie question, when you guys talking about igniting timing. Those figures are total timing? or base timing?
RE: Ignition timing for Methanol vs Gasoline
What changes fixed the problem.
Did you pull the head and was there any piston or valve damage.
Regards
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