(REQUEST: fluid dynamics) help me get my carburetor running more efficiently; multiple equations

I am tuning up an old car that runs a mechanical fuel pump and carburetor. Some time in the last 34 years or so someone added an aftermarket carburetor but did not read the instructions. This carburetor runs most efficiently at 3-4 psi fuel pressure, but the stock mechanical fuel pump puts out 8 gallons per hour. Ideally a device to regulate the fuel pressure would be installed between the pump and carburetor, but I had a thought: why spend $40 on a regulator when I can use fluid dynamics?

It seems that the longer distance and more degrees of bends the fuel has to travel through the line, the lower the pressure at the end would be. Like drinking through a straw versus drinking through a silly straw. In addition, I have a problem with the fuel lines being too close to the cylinder heads causing it to vaporize in the line resulting in vapor lock, so why not reroute the lines in such a way that keeps them cool and brings the fuel pressure down enough to operate the carburetor at peak efficiency?

Unfortunately I do not know how to convert gallons per hour to pounds per square inch, nor do I know how much pressure is lost in fluid per foot or degrees of bends in the line.

Relevant info:

-pump output: 8 gallons per hour

-inside diameter of fuel line: 1/4”

-specific gravity of gasoline: approximately 0.75

-desired outflow pressure: 3.5 pounds per square inch

So part one is converting the outflow volume in to pounds per square inch pressure. Part two is finding the magic number of feet it takes to lower that pressure to between 3 and 4, as well as how many degrees of bends so it can actually fit in the engine compartment.

Mathematicians and physicists of Reddit, this tired old Toyota Tercel is counting on you!

I have a small generator that I've gone through the normal troubleshooting process with. The carburetor is all fixed, no adjustments possible, and no disassembly possible except a drain port.

I removed the drain port screw on the bottom of the carburetor's bowl and stuck a straightened out paperclip all the way through the bottom of the bowl and can see it poke out into the airway assembly, so I'm certain it's not clogged. The bottom of the jet ends right at the screw, so I thought there might not be enough clearance or gunk on the screw is forming a seal with the bottom of the jet, so I cleaned it and shimmed it, but that didn't help, so I undid that.

What did work is this:

There is an overflow or priming port on the top of the carb, and if I fill the bowl with gas, then turn off the gas valve, then apply 80psi of pressure from an air compressor into the carburetor, gas finally flows through the jet when I crank it. Unfortunately this only lasts 10 seconds at most, until the bowl empties of gas or I stop applying pressure or if I open the gas valve, allowing all the gas to flow backwards under pressure into the gas tank.

How can I get the jet to draw up gasoline naturally on its own without pressure behind it?

If pics are needed I can go take some.

I’ve been restoring a 1979 Holden Gemini TD (Opel Kadett equivalent) and the exact fuel pumps are basically impossible to find so I’m looking for an alternative. I tried a EFI in tank fuel pump but the carby can’t handle all the pressure (only a 1.6L engine also). I’d rather try find another fuel pump then keeping it and going down the fuel regulator path as it’s just another part that could fail.

I’ve done a lot of research and I’ve just about given up so any thoughts/ideas would be greatly appreciated.

Do you "have to" upgrade other parts like starter, fuel lines or intake manifold? I sure do hope not because I have spent a good deal of money servicing those recently. Thanks again great group of mechanics here all help is appreciated!

I don't want to step on anybody's toes here, but the amount of non-dad jokes here in this subreddit really annoys me. First of all, dad jokes CAN be NSFW, it clearly says so in the sub rules. Secondly, it doesn't automatically make it a dad joke if it's from a conversation between you and your child. Most importantly, the jokes that your CHILDREN tell YOU are not dad jokes. The point of a dad joke is that it's so cheesy only a dad who's trying to be funny would make such a joke. That's it. They are stupid plays on words, lame puns and so on. There has to be a clever pun or wordplay for it to be considered a dad joke.

Again, to all the fellow dads, I apologise if I'm sounding too harsh. But I just needed to get it off my chest.

Thanks in advance

So, as title says, I bought it brand new. It ran fine for the first small snowstorm we had (3in or so). Second snowstorm, I had trouble getting it to stay running after warming up on full choke for a good 10-15 minutes. Then it kept shutting off while I was using it. I figured it was too much snow (only about 5in), so I put it into lower gear and started doing narrower passes. Eventually, it wouldn't stay running for more than a minute or two, so I ended up just shoveling most of my driveway.

Now I can't get it to stay running for more than 30 seconds. First pull it'll run for close to a minute. Every start after I can only get about 30 seconds. It starts right up, even with a slow pull, but won't stay on.

I read online that it could be the carburetor or the spark plug. Spark plug was easier to get to, so I changed that out with a new one. There was carbon on the old one (strange for being brand new...). Unfortunately, the spark plug didn't work. In order to take off the carburetor, I will have to remove the gas tank, because there's a small bolt and piece of metal on the side of the muffler cover to prevent someone from accessing most of the engine without removing the gas tank. Can only imagine it's to make it more difficult for at-home repairs.

Unfortunately for me, I wanted to support small business with a big purchase, so I got it from a local hardware store instead of a big box retailer. They won't take it back. I'm going to contact Husqvarna to use their warranty to fix it, but there's a snowstorm tonight which will be about 5in that I'd rather not shovel if I can help it.

Does anyone have any ideas I can try without having to take the whole thing apart?

Edit: just read a recent thread about a pressure washer not running well, and in the comments someone said high octane is not good for small engines. I had premium gas on hand, so that's what I put in it. Could that be it? And if so, would it fix it if I drained the fuel and replaced with regular gas? Or are there extra steps involved?

I was checking out some muscle cars and the Monte Carlo caught my eye, after several tune attempts i think this is the one but i was wondering if it'd be possible to improve it? I'm not the best tuner so there might be some basic mistakes! I also managed to get a time of 01:15.006 on the Horizon Mexico Circuit.

Upgrades

Conversion

Aspiration -> Supercharger

Stock engine and drivetrain

No aero

Rims and Tires

Tire Compound -> Vintage Race Tire Compound

Front Tire Width -> 255mm Front Tires

Rear Tire Width -> 305mm Rear Tires

Rim Style -> Specialized Rim Style -> American Racing Outlaw II

Front And Rear Track Width -> The first, 100 Cr option

No changes to rim size

Drivetrain

Clutch -> Race Clutch

Transmission -> Race Transmission

Driveline -> Race Driveline

Differential -> Race Diff

Platform and Handling

Brakes -> Race Brakes

Spring and Dampers -> Race Spring and Dampers

Front and Rear Antiroll Bars -> Race Front and Rear Antiroll Bars

Roll Cage -> Race Roll Cage

Weight Reduction -> Race Weight Reduction

Engine

Intake -> Race Intake

Carburetor -> Race Carburetor

Ignition -> Race Ignition

Stock Exhaust (i love the engine note it has)

Camshaft -> Race Cams and Valves

Valves -> Race Valves

Displacement -> Race Engine Block

Pistons -> Race Pistons

Supercharger -> Race Supercharger

Intercooler -> Race Intercooler

Cooling -> Race Cooling

Flywheel -> Race Flywheel

Tune Settings

Tires

Front Tire Pressure - 2.4 Bar

Rear Tire Pressure - 2.2 Bar

Gearing

Final Drive - 3.46

1st - 3.59

2nd - 2.86

3rd - 2.00

4th - 1.40

5th - 1.00

6th - 0.80

Alignment

Camber

Front - -1.8

Rear - -1.3

Toe

Front - 0.2

Rear - 0.0

Front Caster

Angle - 6.0

Antiroll Bars

Front - 26.00

Rear - 43.80

Springs

Springs

Front - 135.3 kgf/mm

Rear - 113.7 kgf/mm

Ride Height

Front - 20.9 cm

Rear - 20.4 cm

Damping

Rebound Stiffness

Front - 12.4

Rear - 9.9

Bump Stiffness

Front - 6.2

Rear - 4.9

Brake

Braking Force

Balance - 55%

Pressure - 100%

Differential

Rear

Acceleration - 25%

Deceleration - 15%

Assists

Braking: ABS On
Traction Control: Off
Stability Control: Off
Steering: Simulation
Shifting: Manual

EDIT: Added units to springs aswell as relevant difficulty settings

Do your worst!

When I forget to completely empty the gas out of my lawnmower/snowblower/pressure washer it ends up gummed up leaving a machine that surges, sputters, etc. Other people let me repair their equipment that they let fuel sit in too.

Ive tried cleaning it by removing the carb and the plastic/rubber parts then soaking the metal parts in brake cleaner/degreaser/sea foam stuff like that. I would scrub it down and use metal wire/small drill bits to clean out and open up clogged holes. That takes me 1-2 hours to do including the removal and reinstalling. It would sometimes not make a difference or it still doesn't run great.

Now I just buy brand new carbs from Amazon for 20 or less dollars and replace the carb in about 30 minutes and it runs like new. I feel like I'm saving a lot of my own time doing this vs trying to clean a carburetor. Is this the case for other people or do I just suck at cleaning and I'm wasting money on new carbs.

Hello Guys!

I'm trying to make this good old Pontiac Rivals worthy, and I'm getting into 1% easily but from there it's really hard to progress. There were a '70 Camaro posted here and I'm not really getting close to my times with it on short tracks, usually 1-2 sec behind. On longer races it's ok, but not good enough, just not easy and enjoyable to drive, something is missing, and I'm trying to fix it for weeks, sometimes it's better sometimes it's worst, so I decided to post the current status here, maybe you can check it out and see what's missing. Tried with Front Aero too, but then on long straights I'm loosing too much top speed so removed it for now.

One thing I want to stick is the original engine because of the sound and because I feel it would be more fitting in A800 than starting with an engine swap.

There are some body roll, but if I stiffen the ARB too much it'll wheelspin all day out of corners, so now it's need some throttle control, but not that bad.

Here is the tune:

1977 Pontiac Firebird Trans-am, Stock Engine A800

Share Code: 618 835 928

Upgrades

Engine

Race Intake

Race Carburetor

Race Ignition

Race Exhaust

Race Cams and valves

Sport Valves

Race Engine block

Race Pistons

Race Positive Displacement Supercharger

Race Intercooler

Stock Oil/Cooling

Race Flywheel

Platform and Handling

Sport Brakes

Race Springs and Dampers

Race Front and Rear ARBs

Sport Chassis Reinforcement

Race Weight Reduction

Drivetrain

Street Clutch

Sport Transmission

Race Driveline

Race Diff

Tires and Rims

Horizon Semi Slick Race Tire

Front Tires: 265/50R17

Rear Tires: 335/40R17

Rim: Speedline Corse F1

Front Rim Size: 265/50R17

Rear Rim Size: 335/40R17

Rear Track Width: First Upgrade

Aero:

Front: Stock

Rear: FH Race wing

Hood: FH Street Hood (Last)

Conversion:

Stock Powertrain

Stock RWD

Aspiration: Positive-Displacement Supercharger

Stats:

Power: 538HP

Torque: 883Nm

Weight: 1436Kg

Front: 55%

Displ: 7200

Tuning

Tires

Front: 29.0 PSI

Rear: 29.5 PSI

Gearing

Final Drive : 2.76

Alignment

Front Camber: -0.3

Rear Camber: -0.6

Front Toe: 0.2

Rear Toe: -0.1

Front Caster: 6.0

ARB's

Front: 33.00

Rear: 37.70

Springs (LB/IN)

Front: 922.0

Rear: 952.0

Front Ride Height: 5.4

Rear Ride height: 5.4

Damping

Front Rebound: 11.0

Rear Rebound: 11.9

Front Bump: 9.9

Rear Bump: 7.4

Aero

Front: N/A

Rear: 265 lbs

Brake

Balance: N/A

Pressure: N/A

**D

I'm surprised it hasn't decade.

They were cooked in Greece.

I am referring to a simple, float-type carburetor. I understand how the lower pressure area is created and how that draws fuel into the venturi to mix it with the fuel, but I do not understand what exactly causes the fuel to go from liquid to gas. Im assuming it has something to do with the lower pressure in the venturi but I want to be more clear on exactly how that works.

Sorry if this is not the right place to ask a question like this. I was not sure where the best place to ask was

For context I'm a Refuse Driver (Garbage man) & today I was on food waste. After I'd tipped I was checking the wagon for any defects when I spotted a lone pea balanced on the lifts.

I said "hey look, an escaPEA"

No one near me but it didn't half make me laugh for a good hour or so!

Edit: I can't believe how much this has blown up. Thank you everyone I've had a blast reading through the replies 😂

It really does, I swear!

Because she wanted to see the task manager.

Heard they've been doing some shady business.

but then I remembered it was ground this morning.

Edit: Thank you guys for the awards, they're much nicer than the cardboard sleeve I've been using and reassures me that my jokes aren't stale

Edit 2: I have already been made aware that Men In Black 3 has told a version of this joke before. If the joke is not new to you, please enjoy any of the single origin puns in the comments

BamBOO!

They’re on standbi

A play on words.

Pilot on me!!

Christopher Walken

Nothing, he was gladiator.

I saw some minis in the leaderboard but no tune. Figured I could post one ! I'm not the best driver by far but I managed to get around 1'30.800. Best time I got so far and my first time in the top 100 !

Share Code : 984 318 551

Conversions :
Aspirations - Single turbo
Wide body kit

Aero : front and rear

Engine:
Race Intake
Race Carburetor
Race Exhaust
Race valves
Race pistons
Race turbo

Platform :
Race suspension
Race ARBS
Race weight reduction

Drivetrain :
Race diff

Tyres :
Slick tyres
245mm front and rear width

Tuning setup:
Tire pressure (bars) : 1.7f, 1.4r
Gearing : final gearing ratio 3.70
Camber : -0.9f, -0.4r
Toe : 0.2f, -0.1r
Caster : 6.5
ARBs: 32f, 35r
Springs (kgf/mm) : 37f, 37r
Ride height : 13f, 13r
Rebound : 6.9f, 8.2r
Bump : 4.4f, 5.1r
Aero : max
Diff : 31 acc, 7 dec

The trick (for me at least) is not to hit too many curbs. Even with low bump and soft springs the mini is so light that it tends to want to take off every now and then. One downside of the tune is no race transmission so only 5 speed and a 6th would be appreciated on the straights.

Still it's a fun car to drive and you can't have a FWD contest on a handling track without a Mini :D

Or would that be too forward thinking?

Dad jokes are supposed to be jokes you can tell a kid and they will understand it and find it funny.

This sub is mostly just NSFW puns now.

If it needs a NSFW tag it's not a dad joke. There should just be a NSFW puns subreddit for that.

Edit* I'm not replying any longer and turning off notifications but to all those that say "no one cares", there sure are a lot of you arguing about it. Maybe I'm wrong but you people don't need to be rude about it. If you really don't care, don't comment.