Torco and AFR

[MomsDuster]

I added one quart of Torco fuel additive to approx 12 gallons of 91 California E10 swill. Without making any other changes or adjustments I’ve noticed my AFR’s down about 1-1.5 points at idle and at low speed cruise (still in the transition I’m sure). Is this a condition of a higher octane rating, additives in the Torco, or is it all in my head? I will also add that so far the engine seems to be happier. I added it because I had it, and I now have access to LL100 and before spending $ on that wanted to see if there would be any benefit to the additional octane with my build. Further testing is certainly required and in the near future, just curious to see what the FABO Brain Trust thought.

 

[85glht]

"Down" as in from example: 12-13 or 13-12?

 

[MomsDuster]

"Down" as in from example: 12-13 or 13-12?

Yes, idle was 12.5-13 now 11.5-12 in gear. Low speed cruise is similar.

 

[85glht]

My guess... Pump gas is oxygenated... the additive isn't. This is only a guess. I'd lean it up if it is that "fat"

 

[Newbomb Turk]

You are using way too much. A quart in 12 gallons is way too much.

I forget your compression ratio but you can use 91 pump gas into the 12's as far as compression ratio but you have to get everything else correct.

I'd spend some time working on that and then start at 1.5 ounces per gallon. And that's still quite a bit.

Octane (like a lot of other things) is grossly misunderstood. The magazines from days past did a massive disservice by hammering into people not to use any compression because the octane was low and the fuel was "bad".

It's not great but 91 octane will easily handle 12:1 and not lose a single HP.

And that's not to say that the Torco won't add some power. It has every time I've used it. But it wasn't because of the increase in octane, but rather that Torco is also a fuel conditioner. It is engineered to grab onto the fillers and junk in pump gas and it will make them at least partially combustible.

I'd say don't get so caught up in octane numbers, use less Torco and maybe do some other things to keep you out of detonation.

 

[Hysteric]

Do the spark plugs look different?

 

[MomsDuster]

Do the spark plugs look different?

I haven’t pulled any yet. But when I used the Torco before it gave the plugs a reddish tint. I stopped using it because it made the plugs hard to read. Now that I have the tune pretty darn close IMO, I thought I’d toss some in just to see if there was any improvement. I haven’t made any hard runs yet. Hope to get her out in the morning and put her through a couple of Dragy runs to see if there is a noticeable difference either way.

 

[Newbomb Turk]

I haven’t pulled any yet. But when I used the Torco before it gave the plugs a reddish tint. I stopped using it because it made the plugs hard to read. Now that I have the tune pretty darn close IMO, I thought I’d toss some in just to see if there was any improvement. I haven’t made any hard runs yet. Hope to get her out in the morning and put her through a couple of Dragy runs to see if there is a noticeable difference either way.

Yeah, if you are seeing orange on the plugs you are using too much Torco.

How much compression do you have?

 

[MomsDuster]

True compression is unknown. I have 180psi cranking with a Comp xe275hl cam. (231/237 @ .050) so I guesstimate it’s near 10:1 ish.

 

[Newbomb Turk]

True compression is unknown. I have 180psi cranking with a Comp xe275hl cam. (231/237 @ .050) so I guesstimate it’s near 10:1 ish.

One ounce per gallon of Torco would be plenty. I’d probably start at 1/2 an ounce per gallon and test it. You can always add more if it needs it.

At your compression ratio you won’t need much.

 

[Hysteric]

I haven’t pulled any yet.

Well what are you waiting for?

I have 180psi cranking

That's enough for pump fuel.

I’ve noticed my AFR’s down about 1-1.5 points at idle and at low speed cruise

Ultimately meaningless without a corresponding change on the plug. You can do an experiment where you increase 1 jet size at a time and see what the plugs look like after each change and correspond that with what the AFR is on your gauge. Then if it all corresponds you can assume its a reasonable tune and consistent.

 

[MomsDuster]

Thanks for all the input folks. I’ll throw a couple of fresh plugs in it before I head out to romp on it. Then see what they look like. Like I said in the original post, I put it in because I had it and wanted to see if it made any improvement. Sounds like it may just be a waste of time. But at least I’ll know from experience.

 

[MOPARMAGA]

Does the torco contain mmt ?
At 12.9:1 compression I use 1 ounce of any octane booster with mmt to 5 gallons, that is in 100LL Av gas.
Your richer condition is probably caused by slower burning fuel.

 

[MomsDuster]

Does the torco contain mmt ?
At 12.9:1 compression I use 1 ounce of any octane booster with mmt to 5 gallons, that is in 100LL Av gas.
Your richer condition is probably caused by slower burning fuel.

I believe it does contain mmt. I wonder if the reason it seems run a bit better (assuming it’s not all in my head) is the additives or maybe she just wants a little more fuel. I’m not hung up on the actual afr numbers, just keeping an eye on the changes +/- when I do something different.
What I will likely do is run this tank out without any changes. Run a tank or two of straight 91 through keeping an eye on the numbers. Then maybe add the appropriate amount of Torco, with fresh plugs and go from there.

 

[MOPARMAGA]

I believe it does contain mmt. I wonder if the reason it seems run a bit better (assuming it’s not all in my head) is the additives or maybe she just wants a little more fuel. I’m not hung up on the actual afr numbers, just keeping an eye on the changes +/- when I do something different.
What I will likely do is run this tank out without any changes. Run a tank or two of straight 91 through keeping an eye on the numbers. Then maybe add the appropriate amount of Torco, with fresh plugs and go from there.

Yep, that sounds like a fine idea.
Have fun burning that tank.

 

[TT5.9mag]

The orange on the plugs is the telltale for mmt. The reason for the change in AFR is because the stoichiometry is different for the different fuels. When the chemical composition changes, so will the stoichiometric ratio for combustion.

 

[MOPARMAGA]

The orange on the plugs is the telltale for mmt. The reason for the change in AFR is because the stoichiometry is different for the different fuels. When the chemical composition changes, so will the stoichiometric ratio for combustion.

Nice & correct.
That's exactly how I would have never been able to explain it lol

 

[TT5.9mag]

Nice & correct.
That's exactly how I would have never been able to explain it lol

It’s just words that mean things.

 

[MOPARMAGA]

It’s just words that mean things.

Lol

 

[ValiantS]

I added one quart of Torco fuel additive to approx 12 gallons of 91 California E10 swill. Without making any other changes or adjustments I’ve noticed my AFR’s down about 1-1.5 points at idle and at low speed cruise (still in the transition I’m sure). Is this a condition of a higher octane rating, additives in the Torco, or is it all in my head? I will also add that so far the engine seems to be happier. I added it because I had it, and I now have access to LL100 and before spending $ on that wanted to see if there would be any benefit to the additional octane with my build. Further testing is certainly required and in the near future, just curious to see what the FABO Brain Trust thought.

How much octane do you need if you're cruising?...if you're racing etc? What is your combo? (things like accurate quench and comb chamber hot spots) and what is the cranking compression? Outside air? Coolant temp? Do you need to run spark advance high? I never believe the measured A/F ratio is absolutely correct especially measured in a home-built car/exhaust with transient conditions and bank collection points. (So don't get caught up with the value you're targeting being ideal.) While it may not answer the specific question you asked, generally speaking I'm sharing relevant/applicable information for you to consider.

 

[MomsDuster]

How much octane do you need if you're cruising?...if you're racing etc? What is your combo? (things like accurate quench and comb chamber hot spots) and what is the cranking compression? Outside air? Coolant temp? Do you need to run spark advance high? I never believe the measured A/F ratio is absolutely correct especially measured in a home-built car/exhaust with transient conditions and bank collection points. (So don't get caught up with the value you're targeting being ideal.) While it may not answer the specific question you asked, generally speaking I'm sharing relevant/applicable information for you to consider.

Thanks for your input. I agree 100% with what you’re saying. I learned early on in this process that AFR numbers are not something to be chased. I use them to quantify changes made in the tune, along with vacuum readings, rpm changes, Dragy numbers and the never failing butt dyno. As for a lot of the other dynamics you mentioned like quench and such, they are things well beyond my ability and will likely never know. I’m chasing knowledge, and most of what I’ve learned has come from this forum and trial and error. Probably more error than anything. LOL As long as you folks keep giving me input and I keep testing I’ll keep learning. Thanks to you all!