Got quite a bit of work done on my car this weekend. Got the new header gaskets installed (sadly, I got some Felpro gaskets from Autozone because my cool Remflex gaskets didn't come and this weekend was my only time to wrench for over a week because I have to travel for work). New valve covers (Billet Specialties swanky)- did those when we did the header gaskets because the turbo gets in the way of removing the valve cover on the passenger side. New breathers and oil catch can (yeah, no more oil blowing onto the down tube during boost!). Pulled the carb and played with the jets once again- after the exhaust was fixed the AFR was rich (had it perfect before per the gauge, but due to the exhaust leak we were not seeing true AFR). Also put in a 1" phenolic carb spacer to get rid of the 4 gaket "spacer" that was on there. Without the gaskets the accelerator pump was hitting the intake... Changed the jets and put new fuel bowl and metering plate gaskets in- changed the squirters for the accelerator pump down one size up front too- ran much better but still bogging down off the line. Bumped the squirters down one more size and still bogging down but not as bad- WOT it is now running great, but part throttle it bogs down (great for the track but not so good for cruising). AFR is reading lean when you give it gas off of idle but we are thinking it is actually so rich it is not burning the fuel and giving a false lean reading. Have a 30cc accelerator pump coming- stock pump is a 50cc unit. Also going to up the gap in the plugs- they are only .035 but with the MSD I think I can get away with .045 or possibly .050. I am going to pick up some new plugs too- these may have been runnig too rich for too long, and having just gotten the car I have no idea how old they are. The good news is when we pulled the valve covers I got the casting number off of there- I was told when I bought the car that it has a ZZ4 crate motor in it. Turns out this is a ZZ4 Fast Burn 385- it has the fast burn heads (not sure if they were ordered this way or added on later)- these are much nicer heads than the L98 heads on the normal ZZ4. These heads also make the ZZ4 only 9.6:1 and not the 10.5:1 of the ZZ4- and develops 30 more HP. Checked the timing too- 32* total advance and we are pulling 1.5 per lb boost (a little conservative, but this is a street car too).
Have a 30cc accelerator pump coming- stock pump is a 50cc unit. Also going to up the gap in the plugs- they are only .035 but with the MSD I think I can get away with .045 or possibly .050. I am going to pick up some new plugs too- these may have been runnig too rich for too long, and having just gotten the car I have no idea how old they are. DON'T do this leave the gap down low, even the .035 your running is close to begin with. Boosted applications need small spark plug gap. You will start to have misfire issues due to "spark blowout". Again stay in the .028 range. These heads also make the ZZ4 only 9.6:1 and not the 10.5:1 of the ZZ4- and develops 30 more HP. Checked the timing too- 32* total advance and we are pulling 1.5 per lb boost (a little conservative, but this is a street car too).[/QUOTE] You are pulling TOO much timing. This will really hurt power, I would pull between .75 degree and 1 degree per pound on your setup. Sounds like its coming along nicely as well.
What carb? 50cc stock on a blowthrough throws up huge red flags. I also think you should be able to run more timing, but totally get the conservative at the beginning angle. What size shooters did it have? The need to pull a bunch of nozzle out suggests that something else is too rich.
Carb is a Quickfuel 750 blow through with the annular boosters. We had jetted up the carb as it was reading lean- lean was due to the exhaust leak and we were so rich that it was dumping unburned gas through- jetting up the carb was showing more lean on the AFR and not richer. Have it much closer but quit trying to tune it until we got the new exhaust gaskets in. Yeah the QF blow through carbs are known for running rich- was hoping to go to the track tomorrow to get some more tuning done but we have an 80% chance of rain. Yeah I plan on pulling only 1 degree per PSI once I get the tune closer- not worried about building power until I have it running right- it still stumbles when you first give it gas it spikes so rich. The stock jets were 72/76 I believe, with 33 squirters. Going to go with a 30 cc pump and the 35 squirters and see how that goes.
