Techron = pre-detonation?

tiorio · 09-09-2003, 10:43 AM

Ok, so here's the deal.

1989 930, bone stock

Mixture and everything set ok (slightly richer than factory spec), runs fine.

Add Techron +9 gals premium to almost empty tank.

On boost, at about 5000+ RPM I get VERY NOTICABLE PINGING!

Next tank of gas + 50 miles or so and no pinging anymore.

Why? Does the Techron affect the way the gasoline burns and make it more succeptible to pre-detonation, or (theory 2) does it affect the sensors controlling mixture (forgive my ignorance re: CIS on the 930s, still trying to wrap my head around it).

1fastredsc · 09-09-2003, 10:59 AM

Well it isn't going to fool any sensors in the cis since it's all mechanical, but i have noticed that my mom's mercedes had noticably less mpg on that gas tank that i added it too.

Eric Coffey · 09-09-2003, 11:07 AM

It might have had something to do with the amount of Techron you added. You said you added it to only 9 gallons of fuel, and I believe a bottle of T is good for up to 20 gallons right? So, mabe too much T is a bad thing? Could it be "diluting" the octane at such high percentages? Interesting.

1fastredsc · 09-09-2003, 11:33 AM

Well, not sure if i'm reaching for the stars here, but techron technically isn't fuel and therefore doesn't burn. So maybe because it's technically not fuel, but flows with the rest of the fuel as if it was fuel, may have made you go lean on top end as you push the limits of your fuel flow. Just a guess.

JP911 · JP911's Garage

From what I know about turbo setups, pinging = too low octane for the engine timing. So, either up the octane or retard the timing.

tiorio · 09-09-2003, 12:20 PM

Quote:

Originally posted by JP911
From what I know about turbo setups, pinging = too low octane for the engine timing. So, either up the octane or retard the timing.

I think that's true for just about any engine (timing and compression) but in this case, it only happens when I have Techron in the tank.

As far as the amount goes, the bottle I had said 'treats up to 12 gallons!' right on it and the instructions said to add as much. I had probably 2.5 in the tank and added 9 with the Techron (all 91 octane as per usual)...

This is the second time I noticed this with Techron but first time the engine wasn't in that great of tune so I dismissed it. Now it's running well and tuned up with no pinging at boost when there's no Techron added to the fuel.

I kind of like the 'it doesn't burn therefore the engine is running leaner' idea but I think the 1/100th of fuel that would be lost (or so, probably even less) would be statistically insignificant, no?

Thanks to all who respond(ed) with more knowledge than I (read: everyone)!