I had my car to the track last night. I was watching the O2 readout on my second pass and it was showing dead lean. Pulled a plug and it was real white. In the end, I ended up going up 9 jet sizes in the primary side only. The car ran better. Now, however, my cruise is real fat (as would be expected). I think what I wasn't to do is up the secondary jet 2 sizes and enlarge the PVCR's on the primary to make up another 5 jet sizes. How much do I need to enlarge the PVCR's to accomplish that? I have read roughly .003" increase is equal to 2 jet sizes when you are less than 80 jets. Anyone have any experience doing this?? Does my plan of attack make sense??

 

Okay, drilled my PVCR's out to .061". They were .055" stock. I also upped the rear jet to an 80. Now my split between the primary and secondary jets is 70/80. If it is a little lean under full throttle, I will just up the primary jets.

I had no complaints about my BG Mighty Demon until now. The stock jets were in so tight that I had to use a pair of vice grips to get them out. Also, the slots in all 4 jets were destroyed by whomever tightened the jets at the factory. That was ridiculous!!

 

What made you increase just the primary jet Jeff? Tuning for WOT I like to start at factory number and split and move both primary and secondary in equal steps till the WOT comes around. Say 76/83 and you end up with 80/85. Then lean out the primary side to get a clean cruise. Then correct the PVCR to bring the WOT back in line.

Sucks about the jet install. I hear BG has improved but I haven't bought a product since my one and only Demon I still run. Maybe I got a wednesday carb...

 

I only messed with the primary because of time (between rounds). I like the 70 jet in the primary. It seemes to cruise just a tad fat (based on my narrow band O2 sensor). What you suggest above is what I am shooting for. I only emlarged the PVCR's enough to cover 4 jets. I want to fine tune next time at the track and see if I should go more or live with what I have.

All in all, I have been pleased with the carb. I didn't have any issues with junk in the carb. The jets...maybe someone at the factory has been lifting too many weights or arguing with a spouse!!

 

Jeff,

Sounds good. Just a lil scary when I first read it! I like the plan. I wish I could get to the track that often....

 

I wish you could too. I wish I could get there when the DA isn't 3000'!! I want to run in the 11's again bad with my stock short block L98 before it finally blows up.