Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


Ignition timing for Methanol vs Gasoline

Ignition timing for Methanol vs Gasoline

Ignition timing for Methanol vs Gasoline

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?

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

We are running the stock Toyota head gasket, but I am aware of other people that are running the same gasket on methanol with no problems.

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

How do the rod bearings look?  If the chamfer on the bottom bearing half 180 out from the rod beam is being hammered out you are experiencing detonation for sure.  Any ring issues?  Look for missing chromoly on the top ring this also indicates detonation.  From your coment on the ground straps it sounds more like a lean condition.

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 are waiting to get the car back before we can tear into the engine, as it is currently getting a new intercooler installed.

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

Unfortunatly I don't see a cannned answer for this one.  So many things are nvolved as I'm sure you know (cam timing, ignition timing, piston geometry, chamber geometry, ect).  

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

methanol on a drag car should be tuned at 4 to 1 afr....  your afr of 9.5 to 1 (.65 lambda)is too lean.


RE: Ignition timing for Methanol vs Gasoline

Stoich for methanol is 6.4:1

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.


eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

RE: Ignition timing for Methanol vs Gasoline

lambda=(AF actual/AF stoich)

so lambda = .65 is an AF of 4.16

RE: Ignition timing for Methanol vs Gasoline

I've got a car that runs 8.2 in the 1/4 consistently.  1000 hp, 20 #'s of boost on methanol.

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

I'm sorry, when i multiply 14.64 by .65 I get 9.516.

14.7 multiplied by .65 is 9.555.

RE: Ignition timing for Methanol vs Gasoline

You have to multiply .65 by Methanol's stoich A/F ratio which is 6.4

.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

I can't say that I have any experience with methanol. On E85 we run about 3-4 degrees above base timing on an NA engine. I would think that 6 degrees total (is that total or on top of your base timing??) wouldn't be nearly enough. EGT's will definitely get high if have too much advance or too much retard. Do you have the ability to monitor EGT's on your dyno? That's how we used to tune our ignition map.

RE: Ignition timing for Methanol vs Gasoline

I quoted another internet post that lambda is A/F stoich divided by A/F actual. It was from an unreliable source and I  did not verify, so it could be (most likely is) wrong, so I will accept your version.


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.


eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

RE: Ignition timing for Methanol vs Gasoline

A/F was fine as we have logged every pass that was made with the car whether it be on the dyno, or track.

RE: Ignition timing for Methanol vs Gasoline

Is your oxygen sensor accurate and working as designed.

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.


eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

RE: Ignition timing for Methanol vs Gasoline

Brobards in answer to your timing question.  My drag car has timing at 45 degrees btdc.

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 tune methanol fuelled engines by reading heat discolouration of the plugs in the thread area and the electrode. You need cad plated plugs in silver or gold colour to do this.

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.


eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

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

The combined A/F is simply %A/F 1 + %A/F 2
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

The last time I burned a plug was a heat range problem

I went to a colder range plug and the problem went away


I don't know anything but the people that do.

RE: Ignition timing for Methanol vs Gasoline

Brobards to answer your first question the timing will be significantly higher. To answer your second question YES!!! I don't know how many of you have actually ran boosted methanol except for dynotuner but timing IS!!!!! the problem. Boosted engines on methanol do not like anything below 30 degrees of timing period. I know that is a pretty bold statement, but anyone that has played with it knows. If that engine is truly running 6 degrees of timing that is the problem. That low of timing will get the exhaust valves smokin' blushing hot and cause pre-ignition therefore causing head gasket to squirt out of its original location.

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

brobards - Have you confirmed that the timing marks are at 0° when the piston is at TDC?

RE: Ignition timing for Methanol vs Gasoline

I tune a blown methanol injected doorslamer with a SBC and a 6:71.

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.
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.


eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

RE: Ignition timing for Methanol vs Gasoline

I ran alcohol FC for a long time years ago and use Pat's method also. 3 threads on the plugs was the rule. While we ran a bit harder than that and did toast a few pistons and "removed" the ends of a few plugs, it was in the quest for the last hp and last .01 sec.  If a few parts got trashed and the race was won, well that was the price of going fast.

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

  Good point about all of the variables that comprise the characteristics of an engine and timing. Just for a little background here are a few engines that we have tuned and some rough timing numbers they use. Blown alcohol 377ci small block chevy mechanical injected (roots type blower because it does make a difference to inlet ait temp) that makes 1000 HP 36-40 degrees of timing depending on altitude, air, and how agressive tune needs to be (not very agressive right now 20% underdriven had to detune to run a nostalga class, this is where we found this motor will not run on less than 34 degrees of timing @ 5000+ feet elevation went to 600 feet then we could make it run at 32 degrees), target AF of 10.1:1 gas scale and roughly 4.4:1 on methanol scale, 480ci blown alcohol big block chevy EFI 2200 HP(Procharger, much more efficient than the roots = less heat and less fuel 10.7:1 on gas scale roughly 4.68:1 on the methanol scale 34-36 degrees of timing, Honda 2.3L Turbo EFI 1018 HP(pent roof 4 valve head mentioned earlier and the small bore, 33-34 degrees of timing, GM 3.98L (our own custom 4.2L out of the Trail Blazer and Envoy, Procharger compounded into twin 76mm turbos EFI, BTW we are sponsored by Procharger and Garrett on this one, again the 4 valve head with a 3.5" bore) 2000+ HP cant be specific on the horsepower numbers lots of people watching this one, timing is 33-36 degrees. These ranges are conservative sometimes higher but we hardly ever go lower EGT's go through the roof, it is like bentwings1 said will you pay the price of the parts to win a round???

  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.big smile

RE: Ignition timing for Methanol vs Gasoline

Hello guys,

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

Oh yea ... Does anyone have any links?how to's for tuning with  methanol injection? I'm new to the arena but the guy helping me is a pro mod racer that has been tuning with methanol for a long time. just wanna try and get smart before i take the plunge.

RE: Ignition timing for Methanol vs Gasoline


In my opinion, by far the best site for MFI methanol and nitro methane tuning.


eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

RE: Ignition timing for Methanol vs Gasoline

Another question i forgot to ask .... what is a "normal" if there is one, EGT when running methanol.

RE: Ignition timing for Methanol vs Gasoline

So how is this going now? Still have the problems?
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

Well we ended up making 1070hp to the wheels through a TH400 transmission. The problem now is that we are having a hell of a time finding a torque converter that will allow us to stall at 5500. So now it looks like we will need to throw a 225 shot of nitrous at it to get it to launch...

RE: Ignition timing for Methanol vs Gasoline

truly awesome thread.
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

So what timing did you end up running.

What changes fixed the problem.

Did you pull the head and was there any piston or valve damage.


eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close