I forgot which number is important when ordering. I have .080 primary now, I want to go a tad leaner, Im thinking .077
One jet size is a “tad,” two is a real change. If everything is working well, I’d stick with changing jets two sizes at a time until you dial it it into a single number change. Are you reading the spark plugs or have an air/fuel gauge?
I think 2 number size is about 2%. The number size from holley doesn't not directly mean a hole size as several jets can share the same hole size but have different entry and exit angles effectively increasing or decreasing flow. If the slots get puckered up that too can effect flow size. Bigger numbers flow more than smaller numbers
A/F gauge. Its showing 12.5 12.8 13.0 around town Highway (32/3500 rpm) no leaner than 13.5 Car drives flawlessly, plugs look ok, darkish tan. I just wanna lean it a tad, so just go leaner by a couple numbers then?
With the dual plane and divider cut down, I ran 77 / 90's on the last setup. With a Wilson 2" tapered spacer.
I've been round and round with this. Trying to lean out my carb and watching vacuum readings at cruise. Usually two jets will show obvious changes and you can correct or compromise one back if it is too much. Probably little gain though. 10% ethanol stoich is like 14:1. Ignition timing also determines how lean you can burn. It's a balancing act for sure.
Currently I have 80 front 90 rear in my AED on the SP3 I have absolutely no issues now, but I wanna see how the A/F changes and how the engine responds taking some fuel away. BUT, I gotta keep a keen ear for detonation Like 69a-body said its a balancing act
True! I think I'll leave the fuel alone, and move the distributor around for something to do! Im only at 32/33 total
Looking at those pics you can see the timing line is close to the turn, might be able to go 2 degrees, fuel does look s touch dark on the base ring.......but if adding timing I wouldn't pull fuel
Those plugs look pretty nice, not sure I'd mess with it Mark. Like others said, a little fat is safe, and since your plugs look so clean I'd be content with that AFR IMHO unless you're at the track chasing every .01 you can. I'd throw a few degrees at it and see what she does.
My experience with a Holley has been , once it's tuned the temp changes and you start over. Problem is you need to be a little fat since there is no progressive fuel enrichment until power valve pops. So really it's always a compromise. A well sorted quadrajet in my opinion always will win in efficiency.
Good point! That's why I ask here, you "more seasoned" guys know better than I do 11 to 1 with iron heads is always in the back of my mind, no issues yet, and I certainly don't wanna create any
I think I'll just play with the timing then! A theory I have is the looser the convertor, the more timing the engine should tolerate up to a point, being the engine is seeing less load down low, until the convertor starts loading the engine, say 3400 rpm and up, in my case. This theory hold any water??
Holley jets have a pretty good spread of tolerance to them so you should always go 2 numbers different from the way you want to head to a definitive change take place. If most of the color time on your plugs is from crusing then leaning the jetting may not buy you much improvement, as you might want to try a .5 higher rated power valve first!
I bumped my total to 36 deg. Took it for a ride, didn’t hear any pinging, it’s tough to listen for it as the mufflers are quite obnoxious when you lean into it, also the engine does not run much more than 175, that’s with a 160 T stat, even when it was 90 plus out. Well we’ll see what she does next trip to the track, gonna put 5 gals. of 110 in just as Larry suggested at Quaker
We are going to Norwalk this weekend....be nice to not be the only buick there. You can always use avgas its about 105 octane and only about 5 bucks a gallon. We run it only in out car, have for decades
Whats going on at Norwalk this weekend? I "plan" on going to 42 next Friday afternoon for TNT, haven't been there since the remodel.
Nothing special just a sat night. I am going to big no box event there at the end of the month.....so figure I would go get some track time there, I've been to 42 on a thursday night and went to the finals and sat a few weeks ago and went to the semifinals, but those are the only 2 times I've been out and still trying to get these shocks dialed in