Converter Flash Question

[Bobby Fazio]

Is there something to be said for timing/air fuel ratio relating to how long it takes for the engine to go from a two step rev limit up to its flash point? What would rev quicker, hotter cylinders with more timing or vice versa?

[Dragsinger]

Bobby,

to greatly simplify ---- anything that makes the engine respond quickly to wide open throttle will get to converter flash quicker.

I suppose there is always some exception, consider this.

Think of fast cars in most any class, those fast car are "instant" on the throttle, like a light switch.

I think it is all part of a completely sorted out package.

[Alan Roehrich]

Originally Posted by Bobby Fazio

Is there something to be said for timing/air fuel ratio relating to how long it takes for the engine to go from a two step rev limit up to its flash point? What would rev quicker, hotter cylinders with more timing or vice versa?

Absolutely the "tune up" is huge for converter flash.

A few years ago, I had a converter built for a guy with a turbo charged Regal. It was real common for those guys to run a really sloppy low RPM tune up, and just use a real loose converter. Well, he took it to a big race, with a really crappy low RPM tune up. Of course, I hear "it won't stage, it won't build boost, it won't leave". So I ask him to look at his timing and fuel map down where it should be starting to make torque and build boost. And the damned thing is at 10.5:1 A/F ratio, and has 10-12 degrees timing, down where it has very little boost. Remember this thing has 8;1 compression. So, he can't make it work, and loses early. He gets home, and calls me again. I tell him to lean it out to 12.5:1, and put about 36 degrees timing in it. All of the sudden, it easily makes 10-12 pounds of boost, flashes to 3500 RPM. Now I hear "this thing is a beast!"

So yeah, the tune up where it flashes is critical if you want it to go fast.

[buzzinhalfdozen]

As Alan stated anything that can help the engine accelerate faster will allow it to reach your stall speed quicker. Seems like different engines come off the 2 step in different fashions, some come off it clean some do not. I'd imagine barring different rev limit strategys the difference is the tune.

[Bobby Fazio]

Mine always smokes. But my af ratio when I hit the converter isn't that bad. It's roughly 12.5 but it also smokes while on the two step so I'm wondering if it is just the nature of the EFI two step. My reaction times have been poor as of late also so I was wondering if it wasn't flashing as quick as when I was running lean earlier in the year.

[RJ Sledge]

Bobby

We had an issue with our efi 352 2010 Mustang auto Stocker. Ran very rich at idle, plugs were very sooty, gas consumption was off the charts, and very hard to cut a "lite". Seemed to have a slight delay on the 2 step.

Had our computer/efi guy re-program the BS3 for when it went into closed loop. Basically raised the rpm from 3000 to 4500 rpms and it changed everything. All the issues went away.

Not saying that is your problem but you need to take it to somebody and fine tune for driving around the pits and on the starting line.

Good Luck

RJ