I only get a small puff of smoke (with either nozzle) when I get on it over 50% throttle below 1800 rpm until the MAF catches up, otherwise nothing, completely clean. I put my stock nozzles in on Sunday in an attempt to get rid of a shutter that I've had since ~christmas time. Didn't change much, is a little smoother and less powerful, but the shutter is more/less the same. Will put the 502's back in today/tomorrow and try someting else. Maybe check my lift pump or fuel filter?
I've only driven the RC6 with the 502's for a day. I also still have the stock size MAF housing and the tune is setup for the larger R32 housing and I think the 11mm pump (mine's only a 10mm). Need to source or make these items.
The RC6 has 2 minor things that I'd change - keep in mind the above, I don't know if they would effect the below things or not.
1) The engine speed hangs between shifts when really getting after it and will actually rev up if I don't take my foot completely off the throttle between shifts. Kind of had to re-learn how to shift and have missed a few as it makes it harder to shift into the next gear.
2) The throttle response is too coarse for me* in the 1600-2000 rpm range. There's a very small difference between 5psi boost with acceleration and overrun. Stick in in 5th and drive on flat ground or a slight downgrade at those engine speeds and you'll see what I mean.
*I've found that I am much more sensitive/aware to these things than most people. I've only found one person that had to point out a drivability issue to me to find it, otherwise I'll usually pick out things that most others won't even notice. Peter, you might remember my test drive of IBW at DGD's GTG back in April last year.
Otherwise I really like it, Smoother and easier revving than the RC4ish tune I had before. Boost control is better as well, no part throttle overshoot, higher sustained boost (~26psi) with lower N75 duty cycle. It just keeps pulling as the tach dissappears behind the boost gauge
