Carburetor-specific tips?

[VetteOwner]

hehe yup, i have noticed that tho, if i run midgrade(havent tried premium yet) in my chevette i instantly get 10 mpre mpg...vs regular(87 octane, mid is 93 hi is 97) im currently on my 2nd tank of testing with midgrade and its taken alot longer to use the fuel than expected so thru most if it cold weather has pinched in on the mpg. (still seems good tho). so we will see. its been like a month(driving truck lately) so it might take awhile to get it used up.

[jcp123]

Interesting stuff. A lot doesn't apply since the engine is brand spanking new rebuilt, and the carb is a brand new unit as well. Although, having sat for a couple of years the carb may need some spray - it idles rough which it didn't used to do. Berryman B12 to the rescue! It has automatic choke, which I'm not a huge fan of, but just a jab of the gas and it turns off anyway. The dyno showed the carb mixture was stoichiometrically correct already, though with the soot in the exhaust and its good-natured manner in the cold, I wonder about that. Original air cleaner assembly with the snorkel is long, long gone, and no exhaust crossover either. Already have upgraded ignition with PerTronix solid state ignition and 45k volt coil (original coil was rated 20k volts, but bench testing showed them putting out closer to 12-15k...ouch) and 8mm wires.

As for hot air intake...it's an open-element air cleaner with headers under the hood heating it all up...does that count

I may upgrade the plug wires as one already has a hole in it, and if I get ahold of a timing light I may play with that as well, but I don't want to be running anything more than 87 octane. I'll try double platinums, but I've heard these cars aren't too fond of anything other than copper-cores. I may also try the t-stat, although the clutch fan should solve the problem of it running too cool (runs @ about 160* with the solid fan). How effective are vacuum gauges? I've heard they help a little but are mediochre at best...?

The hard part is with my right foot...going from a gutless 4-banger to this car, the loud exhaust and racy lines of the Mustang have folks begging me to hit it, and it's all too pleasurable to let the engine have its head and let that jet-smooth stream of torque pull the car...but I can see the potential. With a light foot, the trans shifts @ about 1100-1200rpm, and the car easily cruises at 900rpm in top (about 20mph). That's what I'll have to concentrate on for now.

[8307c4]

It seems you're doing fine, I would replace the wires one day, Accels are pretty good too, if nothing else you'll have even more power (just what you need lol).

On the plugs the only reason I use 2x platinums is they run better, longer.
No, I don't think they're any different when new, but over time.
Same with premium, it runs better, longer... And something about carbs and higher octane, but that's your choice, might be worth the experiment for a few tanks full, I do know the trade-off can only be seen over the years and many many miles later.

As for the foot, you don't have to tell me

I'm a fan of high power rwd cars, my first was a 1984 T-bird w/ a V8, I later bought a 1988 T-bird w/ 5.0 engine, those were just the start, I also tried a 1976 Nova with a 350 cid 2bbl but it was falling apart... Now I have two lower end bmw's (still VERY fast) and a D-2500 truck (don't laugh, that 5.9liter cooks up some power, I think it has 400hp, maybe not thou, sure gets off the line thou).

But over time I did learn, it almost always takes time to get used to it, but the longer I drive them the less it tempts me anymore. It's hard, that's for sure.

Best way I can explain it is driving is about control, and control refers specifically to the ability of NOT using the power

Age helps, too.
But it does take time, I can't claim perfection by a stretch yet.

[VetteOwner]

Originally Posted by 8307c4

It seems you're doing fine, I would replace the wires one day, Accels are pretty good too, if nothing else you'll have even more power (just what you need lol).

On the plugs the only reason I use 2x platinums is they run better, longer.
No, I don't think they're any different when new, but over time.
Same with premium, it runs better, longer... And something about carbs and higher octane, but that's your choice, might be worth the experiment for a few tanks full, I do know the trade-off can only be seen over the years and many many miles later.

As for the foot, you don't have to tell me

I'm a fan of high power rwd cars, my first was a 1984 T-bird w/ a V8, I later bought a 1988 T-bird w/ 5.0 engine, those were just the start, I also tried a 1976 Nova with a 350 cid 2bbl but it was falling apart... Now I have two lower end bmw's (still VERY fast) and a D-2500 truck (don't laugh, that 5.9liter cooks up some power, I think it has 400hp, maybe not thou, sure gets off the line thou).

But over time I did learn, it almost always takes time to get used to it, but the longer I drive them the less it tempts me anymore. It's hard, that's for sure.

Best way I can explain it is driving is about control, and control refers specifically to the ability of NOT using the power

Age helps, too.
But it does take time, I can't claim perfection by a stretch yet.

certian engines run like crap with certian plugs. maybe the older ones are more "universal" but i know my truck runs liek crap on any other plugs besides the standard AC delcos, im not the only one thats noticed that either... but wires, generally the thicker the better and dont get the liek $16 cheapos either...

hehe if i drive my chevette for a week and get in my truck and have to gun it it seems liek its got a huge v8 or somehitng, even tho its just a 4 banger...

[jcp123]

Yeah, believe it or not my SVT Focus really came to life with copper core plugs - rumour is that the platinums really rob them of a lot of throttle response if not peak tq and hp. I haven't tried platinums on any of my Mustangs yet, but that's because I always figured there must be a reason nobody ran 'em on vintage steeds like mine. After a few more tanks to get a baseline MPG, I may switch over to some platinums though just to see...the wires are pretty good ones, the only reason to change them really is because of the hole in one of them. It doesn't arc, but I just don't like to have a hole in my wires. Even if nobody else sees the hole, I feel like it's trashy...

I'll try some higher octane gas too, again after I have a baseline, although we specified on the rebuild we just wanted to run 87 oct.

Now, does letting it idle in N at lights and such have the same fuel-saving effect in a carb'd vehicle as in an EFI? I can't see how it would, but I've been surprised before...

[VetteOwner]

well, some theres no sensor computer crap, slower the engines turning less vacum its makign thus less fuel beign sucked down/pumpped, so in theory maybe staying in drive would lower rpm's and save gas.... but i dunno i dont belives anyones tried since theres no real way to measure them equally.

[bones33]

Weld in a bung for an O2 sensor and monitor your mixure for a while. Adjust mixture accordingly. Advance the ignition until you hear ping, then retard 4 degrees to get max safe cylinder pressure.

BTW I'm thinking of doing almost the same thing! Gotta love those old Mustangs. RWD with good power and handling is often a great driving experience - smiles per gallon.

[GasSavers_BMac]

Originally Posted by 8307c4

My older 1986 D-250 truck was a carbed 318 cid 2bbl, standard 3 speed auto.
With a 12 foot landscaping trailer and a mower and the rest of the equipment on there the truck and trailer weighed around 3 tons, I used to get 14 mpg with it.

My 98 Dakota Sport with a Magnum 318 is giving me 14mpg now in this cold with hot air and a few ignition goodies but all the other mpg mods don't take anymore. I'm getting a 95 and modding the hell out of it and going carb! This I know I can gain some! I've got rare carbs to test!

[VetteOwner]

yea im just waiting (hopefulyl not anytime soon) fo rthe 4 banger in my truck to die then in goes a 350. S-10's with a v8 are common swaps, tons of info, can snag a 350 outa almost anyhting old, LOTS of room engine bay wise. power to weight ratio is crazy

[GasSavers_Bruce]

Originally Posted by Erik

The 3:1 rear axle is a good thing

3:1 is okay, but if you can get longer legs and first won't be too high, go for it. My `78 Malibu had a 5L V8 and 3A/T w/o lockup; it had a 2.29:1 rear. Full-throttle shifts were 45 MPH in 1st and 65 MPH in 2nd at 4000 RPM.