What are some actual #'s people are getting with simple bolt ons and a VAFC?

 

A VAFC will net the biggest gains on a stock car. Once you start adding "good" bolt-ons, the gains from the VAFC will actually go down.

This is because a VAFC type piggy back uses the MAP voltage to alter fuel and timing. If you add good bolt-ons, the air / fuel mixture will become leaner and leaner, and your tuning margin for the VAFC will go down.

 

That said, I made about +12 rwhp with just an AEM V1, test pipe, and VAFC type piggy-back in my '02 AP1.

 

so the apexi units such as vafc neo and vafc II can only remove fuel? these units cannot add fuel?

 

Technically, they can add fuel. But the stock ECU won't like it since you will be altering the MAP sensor output to go above atmospheric, which will trigger a CEL.

 

I think you can add 2-3% before the ECU will freak out. However, you might be able to add fuel everywhere with an FPR, then remove what you don't need with the VAFC. I've never tried it, but I can't see any reason why it wouldn't work.

 

Never liked the idea of a piggy back. Being able to tune fuel and timing separably is a must.

 

Being a piggyback doesn't preclude having both. Example: Greddy Emanage. You can tune timing and fueling directly.

 

There is a local guy s2000junky who does this very thing. Uses stock injectors with an 8 psi CTSC, trimming fuel with a VAFC.

 

I dont have the $$ to go FI for a little bit so i thought a VAFC would be a good buy.. I'm running a AEM V2, Apexi 70mm catback, SOS 70mm test pipe.. so you think i will be able to harness about 12rwhp with what i got?