Blocking air for CNG? fuel economy & power?

[naveed_sid]

Experts, I have suzuki fx 1986, engine overhauled 10 months back. I have Landirenzo kit. venturi is installed.

i want to ask if it is necessary to block air from air filter or i think venturi does the same thing using venturi principle.

but when i block air engine rpm increases and i have to press less accelerator which shows it is better.

what about fuel economy??? some people say me if u block air more fuel will be fetched by engine and more fuel will be used. while other say that if less air come inside engine then less fuel will be used. which logic is correct experts? specially for cng

[Xulfiqar]

if you need to block the air inlet, you are using venturi with a very large inlet, get a smaller one - or the 2 pipe suzuki mehran one

[naveed_sid]

experts pls advise something.....logas and other exters???

[naveed_sid]

experts...where are u?????

[mehrozniazi1]

@naveed

actually CNG needs less air to burn and petrol needs more

son in terms on CNG u need less air from yr intake pipe

now their is differance ..as yr car is carb engine and other fe are efi.....efi to be correct you have to block some air

but in carb engine as yr is....some ppl do block and some ppl dont.....but as i am also using a carb 1000cc khyber engine

blocking or not blocking does not effect on yr fuel economy on GAS..but it do effect some performance when you rev it hard

i am getting same fuel economy with or without blocking the pipe even with cold intake i got the same fueleconomy which is almost 140km in 380 full tank

[Xulfiqar]

the reason for blocking air is to create a suction in the gas regulator for the gas to actually flow into the engine, Like I said - you need a smaller venturi or twin port block type feeder system and a feed pipe not exceeding 15 inches length..

its not like the weird illogical science the guy above posted of CNG needing less air,

[Naweed]

@naveed
Well here is my theory

Engine runs on a mixture
Mixture = fuel + air

For different fuels the ratio of air changes
With optimum setting you'll get a lean mixture

Conclusion
set you air and gas input at a setting where u get max output but then donot increase any of these ... i mean min gas required with minimum air to get full throttle .... You definately get performance and "economy"

[Proverbial_Slang]

I would advise against blocking air. I improved the performance of my Charade by removing blockage. Used to do Re 1/Km and took it upto Maalam Jabba on CNG.

[Xulfiqar]

@naveed
Well here is my theory

Engine runs on a mixture
Mixture = fuel + air

For different fuels the ratio of air changes
With optimum setting you'll get a lean mixture

Conclusion
set you air and gas input at a setting where u get max output but then donot increase any of these ... i mean min gas required with minimum air to get full throttle .... You definately get performance and "economy"

I always get the best economy setting when the engine can suck gas volume quickly till full throttle and with the original paper air cleaner element without any blockages.. works super.

when an ORIGINAL gas venturi is used you'll be amazed that you dont need massive ignition advance to compensate lost power; about 15 degrees additional works good; and you dont need to block the air snorkel etc.

the CNG traders here dont sell you the original precision machined gas venturis that come with the regulators.

[aref]

its not like the weird illogical science the guy above posted of CNG needing less air,

hehehehe....

@OP
i am using a mushroom airfilter with cng cause my car's filter box cracked due to several backfires. No air blockage whatsoever.
and i havent faced any cng consumption problem.
my car's fuel consumption is way way better than any other same make car.