Demon Problems - any suggestions? - Lateral-g Forums

Jerebus67 · #1 06-06-2005, 03:55 PM

I am not too technical but wanted to see if anyone else has this problem and any suggestions? I have a ZZ4 crate motor and purchased the 650 Barry Grant carb for it. We have had nothing but problems setting the carb up. It idles well and runs ok but it seems like the low end power just isnt there. When putting the car in the garage after I drive it the garage just stinks of gas. I am thinking about pulling it off and putting an edelbrock on it? I would really like to obviously tune this carb so if anyone knows anyone in the Bloomington IL area that is good please let me know.
The garage stinks up the whole house, any idea why it is so rich?

Twin_Turbo · #2 06-06-2005, 06:03 PM

many of those BG carbs are jetted way too rich out of the box, jet it smaller and test it w/ an O2 sensor, or even better a wideband O2 kit. It isn't hard to do, jsut takes some fiddling around. You might want to check if there's a book available on tuning holleys & demons.

Blown353 · #3 06-06-2005, 07:50 PM

I agree it's probably the jets. Several years ago when I was still carbed and unblown my 750 Speed Demon came with 78/83 out of the box (!!!) and the instructions said not to touch the jets. Yeah, right! It was pig rich.

Ended up being happiest right where I guessed they would be, which was 72/74. Your application may vary but I've always found most out of the box carbs, especially Demons, to be WAY on the rich side. I suppose it's probably for liability reasons, so a guy doesn't bolt it on, run lean, and blow up his motor.

You may very well have to tweak the power valve, idle mixture, etc. They tune just like a regular Holley, except the newer ones with the idle-eze (haven't messed with one of those yet.)