My 68 has a bored out 454, 12.5:1 compression. Right now I have a holley commander 950 EFI system on it. I REALLY want to drive this thing with the 02 sensor but they told me leaded gas would destroy it in a few minutes. Do I have any options for this animal?

 

Hey, a home-town boy! I talked with a guy from Wilton a year or so ago, maybe it was you! At any rate, the standard O2's won't survive long on leaded race gas; doubt it would fail in a couple of minutes, but it wouldn't go long. I ran leaded race gas in the past with the wideband O2 that comes with the FAST EFI; worked great and no damage. But that's a completely different O2 from what you have.

I'd ask the question over here:

Chevytalk EFI forum

Doug Flynn is the moderator over there and he's a Holley EFI engineer.

Jody

 

they have a 101 or 105 octane thats unleaded,import guys run it, but it should be fine for 12.5to 1 compression.I ran it once in my buick and its got the same compression as yours and I had no detonation

 

Some Sunoco stations sell unleaded 104 octane at the pump. I've ran 108 octane unleaded from VP and CAM2.

Frank

 

We don't have Sunoco out here, and the highest unleaded race gas I've found was 101/102 octane. And at over $5. per gallon it gets expensive in a hurry. I have had great luck mixing 5 gallons of Xylene per tank of unleaded to get it to about 97/98 octane which runs most anything.

Jody

 

Out at the track they have 100 unleaded but its just over 6 a gallon....

BTW I've seen the yellow beast driving around! I will stop ya next time!

 

Cool! I don't have the yellow car anymore; until the twin turbo is done you'll likely see me in a Sonic Blue Lightning.

Xylene/Toluene is another good option. 5-6 gallons of either per tank will get you between 98-100 octane depending on your tank size and they don't harm the O2.

Jody

 

where do I get that stuff?

 

I bought it in 5 gallon cans from Sherwin-Williams at about $5.75/gallon. Good thing is you don't need much per tank to really up the octane and it's safe for O2's. I also bought a 55 gallon drum at $3.20 per gallon, but by the time freight was added in it was closer to $5. per gallon. Got the drum from Tarr Inc.

Couldn't find anyone in Northern California to even come close in price; they were more money per gallon in drums than SW was in 5 gallon cans!

I also believe you can use that system without the O2; won't get closed loop but if your fuel map is right it will run fine. That eliminates the issue completely.

Jody

 

Yea I dynoed the engine without the O2 but I don't think the guy running the dyno was adept at all with EFI systems. Where do you get your stuff dynoed?

 

I have recently dynoed at Midnight Performance and Dynamic Motorsports, but neither can tune the aftermarket systems as far as I know. I either did the tuning or had an EFI tuner friend do it, but he has never tuned the Holley system either as far as I know.

There is a place I found inYuba City who's tuned some high horsepower aftermarket systems. Still not sure if he is familiar with yours.

Force Fed Performance
Keith Fletcher
530-755-0337

I know one other tuner in Woodland but not sure if he's done the Holley either; he usually uses FAST which is what I run.

Jody

 

Thank you very much for the information! Do you think it would be better if I changed out my ECM? Would that work with my wiring harness!

 

I wouldn't change the computer; that's a nice system. I'd contact Holley or Doug on that link I gave you above and see if they have a tuner in this area. There is likely one, I've just never run across them because I'm using a different system.

If you do swap to another brand like FAST, you will have to change the complete harness, as all the different brands use their own harness (other than a few that "piggy-back" onto a factory ecu).

Jody

 

there are also o2 sensors that resist lead fouling, you might need to replace once a year, I cant remember which brand it was, a search should find it