Ignition timing for Methanol vs Gasoline 2

[brobards]

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?

 

[thundair]

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

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



Cheers

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

 

[5secondracing]

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' :~/ 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

 

[a70duster]

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

 

[patprimmer]

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.
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

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.

 

[bentwings1]

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.

 

[5secondracing]

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.:-D

 

[stony7]

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

 

[stony7]

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.

 

[patprimmer]

http://www.hre.com

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

Regards

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.

 

[stony7]

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

 

[dicer]

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.

 

[brobards]

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...

 

[gunluvS14]

truly awesome thread.
just a newbie question, when you guys talking about igniting timing. Those figures are total timing? or base timing?

 

[patprimmer]

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.

Regards

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.