Anyone here get into carb tuning??

[PST]

By and large, I have always steered clear of them.. Up until I had a good mechanic friend ask me to help him with a carb'd setup he was working on. At first I didnt even know what screws to turn, but I could tell him by the air/fuel ratios and basic knowledge what needed to be changed. That led to another friend asking me for his help, this one not mechanically inclined whatsoever. So it was all up to me to dial in the accel pump, main jets, idle bleeds, and re curve the distributor to get the best possible performance out of the setup.

In my area I cater to a bit of a niche market. The vast majority of my customers are retired men with the muscle car of their dreams (new or old), with either LSx or Modular powerplants. They are all wanting to be able to smoke the myriad of Ferrari's, Lambo's, etc. that our area is littered with; or are actually going to the local drag strip religiously. I thankfully am able to mostly avoid the young kids spending daddys money, they are all just a pain in the ass.

But it never fails, and just when I think Im good and clear of carbs, a friend of a friend recommends me to someone and I get drawn in by their practically beging me to help them. Mind you, these are people that grew up with carb'd vehicles, and I have only ever owned one carb in my life... On my dirtbike I had as a kid. And that thing just ran, I never touched the carb, lol.

Anyway, I have an appointment tomorrow to set valve lash, tune a QFT 1050 Dominator carb, tune the ignition timing (Programmable MSD thankfully), and Tune in a 175shot all in the same day.. The car is a 68 Camaro with a 408ci SBC, and as the owner describes it.. "Big Heads, Big Solid Roller Cam, Full Manual Turbo 400, and a Big Shot".. Old mans dream from his younger years.

Here we are looking at brand new generations of Engine/Trans Controllers, and I keep getting these admittedly refreshing strolls with ancient setups.. Anyone else indulge in such 'refresher' tunes?

[Eric@HPTuners]

When I had my shop I got the occasional carb guy. Fortunately for me, a close friend of mine was very good with carb setups, and all I had to tell him was which way to go with it.

[ElecTech]

Yes, I get them from time to time and thankfully I've worked with a lot of classic cars in my early years under some pretty sharp guys so I learned a lot. What surprises me more is how many carbed guys run around town not even wondering about the tune on the car as long as it cranks, runs, and doesn't stall out or foul plugs. Most fuel injection guys don't think twice about getting a tune once a car is built, but carb guys just take it out of the box and go. Racers are a different story.

[PST]

I definitely find tuning carb setups fun.. Due largely to the simplicity of them. My tune session got postponed due to some inclement weather (no windshield wipers or trailer), so I was kinda bummed with that.

Eric, your scenario is exactly what my first couple experiences with carb went like. The guy knew what to change, I just advised on which way to go and how much.

Jaime, it is indeed surprising how the carb guys largely are. Ive met quite a few that even think that having to change plugs every oil change or two is acceptable as long as it runs, drives, and doesnt stall the rest of the time. Then you get the old guys swear by tuning a setup by ear and reading plugs.. Ive had the pleasure of showing a few of those guys what modern technology and use of hard data can do for their so called 'perfectly tuned' setups. Thats probably why I keep getting these tunes too.

Most of the carb guys that come to me are looking to have their race carb behave like a fuel injected engine. I get probably 50% of them to convert to EFI, while the rest opt for having me do the best I can with what they have due to budget concerns.

[jimmyblue]

I've used my wideband to select rods for my Edelbrock
carb, but I wouldn't say I'm "into it". But that's what I
like about carbs - get them right, keep the fuel clean,
run them every so often and you just don't have to keep
messing.

[jpliss]

Carbs are still here and staying for the near future

Carbs can be like an old car or girlfriend. Stroke them play with them and after a bit they work the way you want.

I used to tune alot of quadrajet and holley's. The Q's take more tunning to get right but when they are on they stay on. Holley a little more finicky when it comes to wether changes but a little easier to tune.

AFB are a pain in the butt

I still do carbs and still love them. I use my WB and plug reading to get them right.

Whats usually funny is the fact that Tuning a EFI car, there is so much to change to make that little bit.
Carbs there is so little to change but usually take just as long to get them right.

Depending on the carb, Idle circuits are adjusted by the screws. You will on some holleys have for corner idle adjustments. Use a vacum gauge and tach to get the smoothest vacuum and highest idle, by adjusting out or in each idle mixture screw Check your plugs and make sure all looks good.

Now run your engine to about 2000 - 2500 with fresh plugs and WB if you can. Now Adjust you Primary circuits. Depending on the carb this can be a compination of screws, needles and jets. Move up and down in sizes as needed.

Once this is complete, from idle snap the throttle wide open and let engine speed get to 2000 or 2500. Check WB and Plugs / listen to the engine. Any flat spots, spits pops or extremely rich / lean conditions correct by adjusting the accelerator pump and or primary using assorted legs, needles, positions, springs, jets or combination there of.

Once you have that complete now go some 1500 to 3500 to 4500 rpm pulls under load. Using WB / plug reading adjust your secondary fueling to richen or lean mixture as needed using assorted legs, needles, positions, springs, jets or combination there of

Once this is complete now go to the WOT and do the same process.

Once complete, now under full load redo the process from idle to WOT a number of times to fine tune the range.

Once complete now do load tests on hills or using a dyno with loading capabilities and just test say 55 to 70 slow throttle WOT and items like that at various speeds.

After this install a fresh plugs, set the timing to what the car likes and put 1000 miles on it and recheck adjust as necessary.

This has worked for me over the last 3 plus decades and the process has not failed me yet.

[bigjacksauto]

still tuning modifying and rebuilding carbs here
running two carbs on my supercharged car boost referenced. i still get into tuning and rebuilding carbs on n/a ,supercharged and nitrous cars.
still learning the hptuner software as time permits for the newer cars.great to see the sharing of info on here.