[idesigner]

Anyone else notice throttle lag when pressing on the accelerator?

I couldn't have been going more than 45 or so mph in 4th gear (around 2k rpm) and when pressing on the accelerater there was a noticeable one-second lag between my foot and the engine turning? I have a paxton supercharger and its a 99 cobra. Any ideas or is this standard? If it is because of the supercharger than I can understand but I thought superchargers are directly linked to the engine unlike turbos which there is lag. Any ideas?

[weems]

Sounds like your belt might be slipping.

[Trick Tuners]

Originally Posted by idesigner I thought superchargers are directly linked to the engine unlike turbos which there is lag. Any ideas?

While a centri blower is linked with a belt, there is still a lag while the turbine blade spins up to generate pressure. This is the nature of the centri blower, there is space around the blades so it has to spin REALLY fast to get the pressure up (due to the leakage). At 2000rpms you won't see much boost, maybe 20% of peak boost. Centri blowers usually have tq curves that increase with rpm. A positive displacement blower (roots, screw, KB, whipple, eaton, etc) doesn't have that leakage and outputs a given volume of air for each rpm.
Please excuse the crudeness of the drawing.

[weems]

Ahh I read it wrong, I agree with Joe.

[idesigner]

Ok thanks for the information guys.

However, would this correlate with accelerator lag? Am I supposed to feel the engine pulling a second after I press on the accelerator?

Maybe it is because I'm in 4th gear at 2000rpm and the engine just doesnt have a lot of torque at that point as opposed to say in first gear at 2-2500rpm where there is no lag in engine response?

[weems]

That's because in 4th gear you have a good amount of load, and it's not going to pull like 2nd gear at 2000 RPMs.

A centrifugal supercharger will work somewhat like a turbo, mine on my bullitt would make 3-4 lbs of boost until 3500 rpms where it would make the full 8 lbs, and you could noticeable feel it come on. The car still pulled ok up until 3500, but you could really feel it pull once it hit full boost.

1st gear is so short and that's why it feels like it pulls so hard, because there is hardly anytime before you reach full boost.

[idesigner]

Ok that makes me feel a bit better and makes a bit more sense. I can definitely feel a large amount of pull around 3500+ when the fan is producing a good amount of boost. I just hardly ever push the engine that hard.

[weems]

Originally Posted by idesigner Ok that makes me feel a bit better and makes a bit more sense. I can definitely feel a large amount of pull around 3500+ when the fan is producing a good amount of boost. I just hardly ever push the engine that hard.

That's one of the great things about centri superchargers, because for everyday driving they drive just like stock, and then when you mash on it its a whole other ballgame.