Advanced carb tuning needed.

[soslojoe1970]

I recently installed 2 wide band oxygen sensors one in each collector and trying to tune in carb, then tuning in nos. The sensors are reading 14-1 at the time the converter locks up at launch off the trans brake. Then 5 seconds into a 5:80 pass it reaches 11-1. Now correct me if im wrong dont you want it to do the opp of that. Fat at the starting line for better 60foot times and then leaning out at the top end??? Now I guess I have to change the air bleeds? The carb has 6 air bleed for the front and 6 for the rear of carb. Thanks in advance

[sunsation540]

what's the question sounds like you know where you are going the thing is how big is the carb? larger carbs respond diffrent than smaller ones IE as the air speed increases the fuel pulling out of the boosters can fall off.. the air bleeds outer idle mid are interm, and the inner most are high speeds if this helps..

[soslojoe1970]

Its 1150 dominator hp, 6000 trans brake and about 8500-8600 shift.

[sunsation540]

how big is the engine? make the mid jets about 4 numbers larger will clean up the transition( lean out the inital wot) and the inner high speeds make them 3-4 smaller this will richen up the top>

[soslojoe1970]

Making the air bleeds bigger doesn't that lean out the circut, and don't I want to faten the starting line and lean out the top end? It's sm block 390 inches.

[sunsation540]

yes just backwards from what i said ,, are you dead heading your fuel reg?

[soslojoe1970]

I'm not sure of your term ... think your asking if I have a return line to the tank. I do not have one. I have a bg 400 to a bg 4 port reg and two exit ports one to each bowl. Return line help? Right before the 4 port I have a Y block and one line goes to a 2 port bg that feeds the fogger kit.

[John_Heard]

This isn't a Nitrous car is it?

[soslojoe1970]

Well sort of. I race in a 5:80 heads up index class which I race on motor (that is what Im tuning for now). I want to race in a heads up no index class, which will be spraying. My though process was to get the carb tuned the best I can then introduce the nos into it at that time and tune on that.

[John_Heard]

I was wondering why Mr. Cook was asking about the return line - pretty important for maintaining pressure on a nitrous car, but with a carb only deal I would think it was not so important. FYI Rear mounted cells & pumps that are dead headed will drop psi at launch which would affect a nitrous car.

[soslojoe1970]

Where would be a good place to put a return line, how big do you need to run it? I have a -10 going all the way up to a Y and one goes to a 4 port and then to carb.... the other goes to a 2 port and feeds the fogger. Any suggestions.... was thinking of a fuel log and the regs mounting to that?? Don't know

[John_Heard]

Couple older posts on this subject that address the return line setup

viewtopic.php?f=3&t=2644

viewtopic.php?f=2&t=2893

[soslojoe1970]

Thank you John

[soslojoe1970]

Looks like im ordering some parts for a redesigned fuel system. It definitely spikes lean when the kit comes on. I'll give you an update. thanks for your help John