question about "spool up"

I've owned a grand national and turbo t bird in the past. Spooling up the GN turbo for launch was easy... hold break, press gas, build spool, launch! I never raced the bird but was never able to build up spool on the street before launch. How do the 6 speed drag racers build the spool up at the strip?

I just heard about this tonight from a guy, I'm sure he will post later.

But basically you can use a feature in aftermarket computers (like a FAST) that will put an rpm limiter in place at 0mph. You can then hold the gas to the floor and let it bounce off of that rpm, but once you start rolling there is no more limiter.

Someone will get on here and explain it better, but I think you get the idea:)

normally referred to as a "stutter box"...

I just heard about this tonight from a guy, I'm sure he will post later.

But basically you can use a feature in aftermarket computers (like a FAST) that will put an rpm limiter in place at 0mph. You can then hold the gas to the floor and let it bounce off of that rpm, but once you start rolling there is no more limiter.

Someone will get on here and explain it better, but I think you get the idea:)

Two Step ;)

Two Step ;)

Yup. I'm running a Delteq and MSD DIS-4 box. The DIS-4 box has a built-in 2-step.

hold down 2-step button. push gas to floor, dump clutch & release button.

Some people with manual transmissions use a line lock to let them build some boost at the line, but it's not generally recommended.

Some people with manual transmissions use a line lock to let them build some boost at the line, but it's not generally recommended.
I really wouldn't recommend that idea... Either you'd be doing a burnout or frying a clutch. A 2-step is really the only way to build boost for launch.

I don't know much about tubos, but does having the revs up under no load (even with a WOT) build much boost? Doesn't seem like it would???

Rich

I don't know much about tubos, but does having the revs up under no load (even with a WOT) build much boost? Doesn't seem like it would???

Rich

It's all about air flow, which you don't get with the throttle blades closed. You rev limit and open the throttle blades to use the engine as a big air pump, which spools the turbo.

without the heat and pressures of the engine at full load, you won't spool enough to reach full boost, but you will get the turbo spinning a whole lot faster than it would be at idle and will be able to launch under boost.

2 step is a must (aftermarket PCM is a definite plus) but other than that its all in the timing.