The Plausibility of Using a Rickshaw PZ30 Carb(s) on a Car

[zohaiR]

We've all seen these videos and discussions here on Pakwheels of people strapping a CG125 carburetor on to a 3-4 cylinder car and claiming it's giving them over 20km/l. While that may be true, we all know they're just literally sentencing their car engines to death. Yes, it will run - yes, it might go up to 100km/l, but what they're essentially doing is running their cars extremely lean. We all know what that does to an engine.

I'll admit I actually contemplated doing it myself on my beatup old 1300cc Nissan 86. But unlike your average backyard mechanic, I actually wanted to know the science behind it before moving on to the practical part of it.

Bear in mind, I am no engineer - but I do know the dynamics of an average internal combustion engine - atleast the old carbed ones.

So I'm just throwing an idea out here to see what you guys think. Your thoughts on it - if you will.

Turn over the carburetor of the carby e13 Nissan and you'll find two outlets through which the engine sucks in air and fuel.

One is linked to the throttle cable, and the other one opens up when you floor it. I don't have exact measurements but the primary throttle butterfly is around 30mm and the secondary one slightly larger - maybe 35mm-ish.

Second point that I want to raise is the air filter housing. To restrict and control the airflow, mechanics generally tape the opening up as below. It's been done on my car as well.

The crossed out vacuum actuated valve doesn't function anyway and remains loosely closed.

Now - keeping everything I've said above about the sizes of the throttle openings on the carb and the restrictions placed on the air filter housing - The following is what I thought of and want your opinion on.

a PZ30 carb, from what I've seen online, has a 30mm outlet through which the engine sucks in air and fuel in the correct stoichiometric ratio. Its roughly the same size as the e13 carb outlets.

Why not connect 2 PZ30 carbs in the following way:

Sorry about the quality of the image, but atleast you get the idea.

PZ30 Carb1 will act as the primary throttle connected to the accelerator cable. PZ30 Carb2 is connected to the same 2.25inch intake pipe via a one-way spring check valve. It will not be linked to the accelerator cable. It's throttle cylinder will be removed and jets re-fitted if necessary. The check-valve will open up and let in more air and fuel via Carb2 when you accelerate the car.

Considering the e13's own carb has 30mm-ish openings, this should work without compromising the engine right?

I know some of you will think, why not just properly tune the e13's own carb - less hassle and what not. I've tried that countless times - the max mileage it gives is 11km/l. If i can get this to work - and if properly tuned both carbs bump up the mileage to even 15-18 km/l, I'd be a happy man.

Considering my car mostly runs on CNG, I'm pretty much slow poisoning my engine anyway.

Worth a shot?
This isn't challenging the research that goes into building an engine. Like I said before, just an idea.
Let me know what you think

@Xulfiqar, @saboor73 , @salmang, @dani_kk, @nnabeel, @tahakhan125, @ulislam1997

[ulislam1997]

Here’s my 2 cents.
If you are experimental and want to find an extremely economical way of running your car.
Buy another car/swap yours with an old diesel.
Get old used vegetable oil (used for frying) from some restaurants (preferably a good restaurant that would actually use veg oil and not whatever else they use).
Build a cheap settling tank system.
Incorporate some low micron regular mechanic filters (the ones we use with water taps). (This is just an added measure as settling removes most of the bits and pieces in the oil).
Add some diesel to it
20% works according to some people, you need it to thin the oil down a bit as the higher viscosity can cause incomplete atomization in the combustion chamber.
Veg oil has a lower caloric value than diesel (average Thori se kam dega But it doesn’t matter).
But if filtered and thinned down properly.
It’s an extremely economical way of running an old diesel car for years with absolutely no issues (maybe an extra fuel filter swap every year).
W123s can run on veg oil for decades with no problems. Not suggesting a w123 (Cuz Pakistan) but you get the point.

Oh and, overall, it’ll be better for the environment if you care about that. You’ll have Less CO2s out of the Exhaust and it’ll smell like a restaurant if you floor it.

This is something I’ve been personally been looking at.
But sourcing the oil and for free shouldn’t be as easy here.
But here’s an idea if you actually want to find a cheap or theoretically free way of running a car for a sustained period of time.

[zohaiR]

...and it’ll smell like a restaurant if you floor it.

hahah this last bit cracked me up.

Thanks for your input @ulislam1997. Appreciate it. I must admit, I know very little about bio-diesel. It is quite interesting. I'll defeinitely be looking into it. I have a cousin who's opened up a restaurant, I'll find out if I can source vegetable oil from him and see where we go from there.

Will this work for a Nissan CD20? What engines do you suggest that are old like the W123?

Regarding the idea which I threw out there - yes, the aim is to find alternative fuels and cheaper ways to run a car. It slipped my mind to search of topics like Alternative Fuels here on Pakwheels. My question is does the above idea makes sense? - given the similar 30mm outlets of the e13 and PZ30 carbs and the way I've proposed they be setup. Will it work without making a sensible mechanic go NO! IT WILL STILL CHOKE THE ENGINE AND RUN THE ENGINE TOO LEAN!

[ulislam1997]

It’s a thing in the UK with lots of people actually doing it.
Diesel engines were designed to work on a type of vegetable oil by Frederick diesel back in the birth days of Diesel engines.
Honeslty I personally am hoping the mid 90s Toyota engines will work fine so I can get a car with a 2c motor or a Hilux 2.4 motor.
But this is still a massive topic to research.
Honeslty as far as the carb thing goes I’m not very knowledgeable on carburetors, they’re a bit before my time haha.
But if the concept is to lean out an engine during cruising and then have a slightly richer afr during throttle load, you could be onto something as it wouldn’t cause the motor to be lean during the time it has to work harder.
But if lean afr during cruising still poisons you’re motor, you’re back to square one, and I’m not too sure if it’s okay to ever run a car lean for a prolonged period of time.
However
If the cylinder temps are the issue
You could always look into ways of counteracting that
And I’m absolutely alien to the concept but methanol and lower cylinder temps rings some bell
But then again youll be stepping out of The realms Of practicality.

[saboor73]

We've all seen these videos and discussions here on Pakwheels of people strapping a CG125 carburetor on to a 3-4 cylinder car and claiming it's giving them over 20km/l. While that may be true, we all know they're just literally sentencing their car engines to death. Yes, it will run - yes, it might go up to 100km/l, but what they're essentially doing is running their cars extremely lean. We all know what that does to an engine.

I'll admit I actually contemplated doing it myself on my beatup old 1300cc Nissan 86. But unlike your average backyard mechanic, I actually wanted to know the science behind it before moving on to the practical part of it.

Bear in mind, I am no engineer - but I do know the dynamics of an average internal combustion engine - atleast the old carbed ones.

So I'm just throwing an idea out here to see what you guys think. Your thoughts on it - if you will.

Turn over the carburetor of the carby e13 Nissan and you'll find two outlets through which the engine sucks in air and fuel.

One is linked to the throttle cable, and the other one opens up when you floor it. I don't have exact measurements but the primary throttle butterfly is around 30mm and the secondary one slightly larger - maybe 35mm-ish.

Second point that I want to raise is the air filter housing. To restrict and control the airflow, mechanics generally tape the opening up as below. It's been done on my car as well.

The crossed out vacuum actuated valve doesn't function anyway and remains loosely closed.

Now - keeping everything I've said above about the sizes of the throttle openings on the carb and the restrictions placed on the air filter housing - The following is what I thought of and want your opinion on.

a PZ30 carb, from what I've seen online, has a 30mm outlet through which the engine sucks in air and fuel in the correct stoichiometric ratio. Its roughly the same size as the e13 carb outlets.

Why not connect 2 PZ30 carbs in the following way:

Sorry about the quality of the image, but atleast you get the idea.

PZ30 Carb1 will act as the primary throttle connected to the accelerator cable. PZ30 Carb2 is connected to the same 2.25inch intake pipe via a one-way spring check valve. It will not be linked to the accelerator cable. It's throttle cylinder will be removed and jets re-fitted if necessary. The check-valve will open up and let in more air and fuel via Carb2 when you accelerate the car.

Considering the e13's own carb has 30mm-ish openings, this should work without compromising the engine right?

I know some of you will think, why not just properly tune the e13's own carb - less hassle and what not. I've tried that countless times - the max mileage it gives is 11km/l. If i can get this to work - and if properly tuned both carbs bump up the mileage to even 15-18 km/l, I'd be a happy man.

Considering my car mostly runs on CNG, I'm pretty much slow poisoning my engine anyway.

Worth a shot?
This isn't challenging the research that goes into building an engine. Like I said before, just an idea.
Let me know what you think

@Xulfiqar, @saboor73 , @salmang, @dani_kk, @nnabeel, @tahakhan125, @ulislam1997

Carbs on cars are design to do a lot more than just maintaining air fuel mixture how are you planing to advancing distributor on high revs what about auto chock?

[zohaiR]

@saboor73 AOA Saboor! Just the kind of critique I was looking for. ones that question the practicality of it.

I've taken apart my e13 carb and put it back together with a mechanic friend of mine so I know the complexity of a carb - don't understand most of it - but yeah.

You might need to enlighten me on certain aspects here when I say that my 1.3 Nissan 86 is a daily driver in Karachi traffic. Not looking to high-rev. The only times i remember flooring it were times i was on Shahre Faisal raat k 3 bajay, on the Lyari Expressway or on my trips to Maymar. Otherwise, i'm pretty light on the foot.

Auto-choke - another complexity. Found out my car's auto-choke's been shot for years - wire wasn't even connected. Car runs fine without it, starts up half-self on petrol, and flawlessly on CNG - even during winters.

Ac kabhi tha nahi gaaddi mei so I'm not even considering that part.

@saboor73 Keeping in mind that the objective of my post was to find out if such a contraption would work or not - Can the contraption I proposed above work and would it achieve decent mileage gains as a daily driver.

Bottomline: If I get the blessings of seniors such as yourself and @Xulfiqar and a host of others, then I MIGHT consider building it - Xulfiqar ko mei waise he tung karta rehta hu with random ideas