Methonol and lambda

[steve cowan]

A friend has a old school six cylinder engine with mechanical injection, it is fairly low compression and has a cam with a lot of overlap that doesn't start running till over 4000rpm plus.
At the track the lambda stays fairly consistent at 0.70-0.71.
Methonol having a stoich of 6.5:1 is been 30% richer normal by the lambda scale in most cases???
We look at spark plugs at the track as well but to be honest I find it hard to see a fuel ring so to speak, ground strap /timing mark /heat range seems good.
Any advice or forum links appreciated.

[Rick!]

.70-.71 lambda is about 4.50ish AFR so if it's naturally aspirated, it's pretty conservative on the rich side.

Is the cad burning on the plug at all? Porcelain is bright white?

[steve cowan]

Hi Rick,
I figured it is a bit rich but let's say for pump gas I run 8-10% richer than stoich 14.7:1
Do you run 10%richer on methonol when trying to optimise fuel curve?
The porcelain is white but ground strap doesn’t show enough heat in the chamber to take off cad. We use NGK plugs
My friend has been told that 30% richer fuel curve is where it needs to be but I question that, but I have been wrong plenty of time before, and yes I understand that you give the engine what it needs not what we think it needs.

[tuffxf]

G,day,
With ngk plugs, new one in the leanest hole each pass.
For a 1/4 pass you want to see up to a 1/3 of the cad burn't off the base ring assuming you are close timing wise.
Look at the o2 sensor then and see how it trends going down the track.
Be careful of trying to tune for a specific number.
Cheers

[202ci EH]

Hey steve, is it a holden red 6?

I run a holden red 6 in a sedan, methanol & 3 su carbs.
It runs good around .8 - .78 lambda, you can go .010 of main jet dia either side without much of a swing, it et's within .03 of pb every pass. Water grains knock it around a lot but mostly at peak torque.

30° has a heat mark on the bend of the earth strap, ngk bp8fs plugs.

If it is a red 6, 3 & 4 are your best cylinders, the others are compromised.

Without getting cocky, i've never burnt one down n/a, they just don't seem to make enough heat in 1/4m, even with the float bowls drained and leaning out.

[steve cowan]

202.
Yes mate its a red 202 but hyper pistons, duggen headed motor that Max Carpenter ran in super stock back in the day.
My mate has had the engine for a long time and now he running fogger system and C16 as well, but my opinion unfortunately it just doesn't get it done.i personally think with the mechanical injection and alcohol it just puts the fire out.
I would think it should make good power being 10-12% richer than stoich because at the moment it is 30% richer as per afr, I understand the afr guage is a tool for tuning and I personally think they work well in conjunction with plug reading and mph at the track. Thanks for the information Much appreciated

[Rick!]

It runs good around .8 - .78 lambda, you can go .010 of main jet dia either side without much of a swing, it et's within .03 of pb every pass. Water grains knock it around a lot but mostly at peak torque.

That's pretty much where I've ended up after several years of refinement. Cad burns fine at .8-.81 and barely changes color at .78-.79.
Not a Holden but timing and fueling are nearly identical and it runs within .004-.009 when it's happy and the track is there.

[202ci EH]

Sounds pretty close to mine rick, better to give it what wants rather than chase a number

Steve, I'd bet I know the car ~ brown LJ torana 4 door?
I've abused plenty of cast pistons on alcohol n/a, not an issue.

[steve cowan]

Sounds pretty close to mine rick, better to give it what wants rather than chase a number

Steve, I'd bet I know the car ~ brown LJ torana 4 door?
I've abused plenty of cast pistons on alcohol n/a, not an issue.

Yes mate,that's the car.
My mate Craig has had that torana for close to 40 years
It has gone 11.90 @ 117 with a 202 red and triples and 2 stages of spray 25 years ago

[gruntguru]

0.7 is super fat and almost certainly costing power. Best power will probably be somewhere between 0.8 and 0.9 and will probably require timing changes.