Boost tolerance in different gears

[Brooks]

I've been playing with the boost scalars in the stock chip for 3rd and 4th gear with the idea in mind of running more boost in 1st and 2nd gears.

Unfortunately I've been kind of under the weather for the last few days and haven't been able to go play with the car so I figured I'd try to strike up a bench race here on the board. I was wondering if any of you have tinkered with the boost scalars and if so, what kind of difference have you seen in the level of boost the engine will tolerate in the lower gears?

Same question for those running an electronic boost controller. What have you prgrammed the boost for in each gear? Did you try to optimize the EBC for the maximum boost in each gear for a given octane/timing setting or did you use a "rule of thumb" for setting the curve in your controller?


Charles Brooks

 

[salvageV6]

BSTC controller.

Without alky. I was using 18psi. in 1st and 2nd, scaled to 15 psi. in 3rd and 4th with 94 octane sunoco and 18* timing.

With alky. same boost in all gears no scaling.

 

[terryk]

I've played with the scalars and since the wastegate control only works over a limited range, the scalar's are limited to. They do "scale" the duty cycle, but as you know the duty cycle isn't 0-max boost.

To get some idea of the range, I set it high and then low and checked the boost levels.

Conclusion? It's pretty empirical. I just kept adjusting them until I got the boost I wanted in third and fourth once I had the wastegate table set.

There's also a wastegate scalar by %TPS that's set to 1 and not really used but I've tweaked it a bit so the throttle doesn't act so abrupt on the boost.

Terry

 

[Brooks]

Thanks Salvage, exactly what I'm looking for


Terry, how much boost were you able to run in each gear?

Charles Brooks