[gtobird]

Originally Posted by hgerhardt

It's a great idea and many of us have already done it and reported about it here! I suggest you spend some quality time in the archives of this forum. I remember at least one guy adapted a GM ECU to run a Pontiac, and I think it was an early LS one.

I've had multi-point sequential EFI on my '66 GTO since 1998 and would never go back to a carb.

For a Pontiac retrofit, I really don't see the value in sequential EFI... batch-fire would be just fine and if I was doing this again, that's what I would do. There's no way any of us has the patience, dyno time nor $$ to accurately set up sequential injector timing throughout the engine's range. But if you have your heart set on an LS ECU, then of course you'll have to come up with a way to measure the camshaft TDC for the sequential part. I did it by modifying a small-cap HEI from a TBI SBC truck engine.

That's the kind of inventiveness I was hoping to see. How is it for reliability, performance and gas mileage compared to carburetion?

[hgerhardt]

Originally Posted by gtobird

That's the kind of inventiveness I was hoping to see. How is it for reliability, performance and gas mileage compared to carburetion?

Mileage improved 10% (from 10 to 11 mpg), but the biggest improvement is the drivability. Hot or cold, A/C on or PS pump at full lock, in Drive or neutral, none of that matters thanks to the idle air motor. With a big street cam, any of the above messes with the precarious balance of idle settings on a carb, and that just all goes away with EFI. Plus I can park the car for 4 months and it will start like it was last run yesterday.

Performance-wise it's about a 10th quicker in the 1/4 than the best carb setup I ever had (on a Street Dominator), and I spent a lot of time tuning that before the EFI. Most of that 1/10th is probably due to my home-made manifold rather than EFI though.

Another cool thing is N2O. There's a nozzle in the intake duct upstream of the throttlebody and the ECU increases pulsewidth and retards timing while spraying. Really nice to tune that way, although you'll need an aftermarket ECU to do that.