Anybody out there heard of a car getting slower drag times AFTER installing a supercharger?

I just spent 10k on a vortex supercharger for my 98 chevy SS and my quarter mile time went from 13.1 before the instal to 13.5 after!!!

What happened?

 

Yeah, for several reasons.

First, what boost are you running and have you verified you are getting more HP? Do you have before and after dyno pulls and A/FR charts to verify its making more power and running well? Did you have the car professionally retuned afterwards (a mail order tune, or a comes-with-a-programmer tune is no substitute).

When we first put the Procharger on my 'vette (there's really little difference between a Vortech and Procharger - both are centrifugal designs, I view it's just which one you get the best bargain on at the time you buy), RWHP power dropped from 525 NA to about 485 - even though Procharger had 'sized" the kit for my engine, the SCr was not spinning fast enough to really build enough boost to make up for both the power it consumed and theair restrrictionsall of its air passages and intercoolers were adding.

Even if you have a kit "made" for you car there are a dozen reasons why it might be down on power. We had to play with a bunch of pulley sizes and tunes on my 'vette before we got the SCr adjusted well.

 

hi thanks,
yea i had it done at a shop.its a Vortech v9 kit.so it came with a tuner and a pully.its suposes to
put out 5 to 8 psi but mine only puts out 4psi.i had it dyno ed befor and after,333hp befor 374hp
after but slower times at the track went from 13.1 to 13.5 got micky tompsands street slicks.
so you think pully and custom tune?
jim