Let's start with the mods:

Comptech SC with AC & 7lb pulley
550cc saturated injectors
VAFC
ACT clutch/Toda flywheel

Ok, my issue is that my car feels like it has an on/off switch when I feather the gas pedal. Let me explain- as I'm going about 15mph in 1st, if I barely let off the gas, the car acts as though I've pushed a pause button (almost like it's out of gear/not getting fuel). As soon as I give just a teensy bit of pressure to the gas pedal, it lurches forward. The process repeats when I barely let off the gas. It's very smooth when I'm accelerating, it's only when I take my foot off and then apply pressure after that I get that "lurching" feel. What are the possible causes? Clutch and injectors were replaced at the same time. I know it's not my driving style since the car didn't have this issue before I got the clutch/injectors installed.

Thanks!

 

Bumpity. Help!!

 

Sounds almost like you have too much pressure, like the SC isn't bleeding off excess boost when you let of the gas. But that's a guess.

You'd probably have better luck moving this post over to the FI discussion group where more people with SC'rs hang out.

 

Two things I am thinking...
1.) 550cc injectors running off a stock computer? I didn't think the stock ecu could do that. Like stitos2k said... the FI group would help out more than us.

2.) 15mph in first and you let off the gas... could it just be engine compression. The Toda flywheel makes this worse (when I say worse it is not detrimental... it is just a driveability issue). There is no boost at 15mph, especially when feathering the throttle, so I don't think that would be the problem.

Is it just low speed? Does it occur at the same RPM each time? Everyone always says did you check your ESM connections so I guess I will ask that one too. : )

 

1.) By stock computer, you mean that the VAFC piggybacking on the stock computer can't handle the 550cc injectors?

2.) I've been thinking that it's probably a combination of the new flywheel and the injectors that are causing the rough accel/decel when I push the gas pedal or let off. The problem occurs at any speed up to a point, but I wouldn't say it occurs under boost because I'm usually hammering the throttle then . My vtec doesn't kick in at 6k like stock 2001, but instead is spread out in a linear fashion from about 4k on. The times when I notice it the most are when I'm going through a parking lot with a bunch of speedbumps. That constant clutch in/clutch out giving a little gas, then letting off slightly that causes the lurching motion.

 

To my knowledge, correct. But the only experience I have with this is from reading other people's posts. The FI group should be able to help you out with a more definitive answer!

All the VAFC does is tweak the MAP voltage to lean/richen the mixture. It does not have direct contact with the injectors (ie: duty cycle change). I had a VAFC on my 01, and have a VAFC2 on my 04.