Air Intake Restrictor with A-B test

[t vago]

You're adding a very inefficient air restriction in front of another very inefficient (variable) air restriction.

Ideally, you'd want to have a variable venturi to meter airflow, but such things tend to be very expensive to create. There'd still be the issue of pumping losses due to intake vacuum formation, but the variable venturi would pretty much remove losses due to throttling.

Nice try, though.

[Arragonis]

Originally Posted by suspectnumber961

Someone has claimed that with a Ford Focus...removing the tube going to the front of the hood (fresh air) and allowing air to directly go into the bottom of the filter box resulted in increased mpg. Less restriction and warmer air.

I'll eventually try this...but won't like the noise when it's punched....the throttle that is.

I'm trying this with my Aygo at the moment by blocking the front nostrils which (theory tells me) feeds cold air to the intake. The intake is on the left of the box on top of the engine :



EDIT - Apologies is some people got an email of nonsense, I got the image link wrong.

This has made no difference to the intake temps so far though because this is heated anyway by the fact it sits on top of the warm engine. A guy I link to in my thread measured temps with a CAI and found that made no difference either because of the heated manifold effect.

So I have a warm intake anyway

On some of my older cars they had a water heated inlet manifold too.

[itjstagame]

Originally Posted by mwebb

consider a carburated system from the 70s and a 2012 any car from now ....
same mass ,
FE is better by a huge percentage and emissions are greatly reduced on the
current systems compared to the 70s cars

While I agree this is true for american made cars there are exceptions and the 70s is a bad time frame to pick because of the gas crisis there were a LOT of very FE cars in the 70s. Additionally carbs and TBI were not that different FE wise in the 80s, we really only saw improvements with injectors and tuning improvements heading in to the 90s. Carbs actually vaporize fuel and I believe overall required less maintenance, injectors are just cheaper and easier to tune now.




I know this is the 80s, but I think it's worth noting this is 52MPG from a carb while GM was busy throwing a TBI on everything and still getting worse FE.

Anyway I agree with you overall, just wanted to point out that carbs could be quite amazing and while cars produce less pollution per unit of exhaust volume, I do not believe overall we're getting that much less pollution per mile.

Actually if you want to really go back you should look at when they first removed lead from fuel, only in the past 15-20 years have we really reclaimed that lost HP and FE from having to severally lower our compression ratios and tune for a cat that wouldn't really be necessary with the correctly build engine or tune.

[PaleMelanesian]

Yes, but those are the old-old unadjusted epa ratings. Knock 25% off that to compare with today's cars. Old 50 = (about) 38 new. We have a whole crop of new econocars that beat that with a 40 mpg rating.

[Frank Lee]

I was just reading somewhere about the old EPA ratings... you can basically ignore the "highway" number and go by the other one.

[mwebb]

i suggested that cars of equal mass were to be compared
a 1600 lb crx with a carb does not compare to a 2500 lb citation or k car with TBi -
when comparing cars of equal mass the system with fuel injection AND engine management wins a contest of fuel economy -

early CIS systems without engine management were only marginally better than carbs , but still , they were measurably better .

carbs are poor 2nd place even with engine management ... such as it was .

Originally Posted by itjstagame

While I agree this is true for american made cars there are exceptions and the 70s is a bad time frame to pick because of the gas crisis there were a LOT of very FE cars in the 70s. Additionally carbs and TBI were not that different FE wise in the 80s, we really only saw improvements with injectors and tuning improvements heading in to the 90s. Carbs actually vaporize fuel and I believe overall required less maintenance, injectors are just cheaper and easier to tune now.




I know this is the 80s, but I think it's worth noting this is 52MPG from a carb while GM was busy throwing a TBI on everything and still getting worse FE.

Anyway I agree with you overall, just wanted to point out that carbs could be quite amazing and while cars produce less pollution per unit of exhaust volume, I do not believe overall we're getting that much less pollution per mile.

Actually if you want to really go back you should look at when they first removed lead from fuel, only in the past 15-20 years have we really reclaimed that lost HP and FE from having to severally lower our compression ratios and tune for a cat that wouldn't really be necessary with the correctly build engine or tune.

[ConnClark]

Give me ceramic engine block and heads and no restriction on Nox emissions and I'll give you an engine that will spank the rest in FE with a carb.

Note Ceramic engine blocks won't need a cooling system.

[Mustang Dave]

Originally Posted by Frank Lee

I was just reading somewhere about the old EPA ratings... you can basically ignore the "highway" number and go by the other one.

Most people can. I've never gotten the "old" EPA city rating (19 MPG) with my Mustang. And since I found ecomodder.com, I only (occasionally) get less than the old "highway" rating on road trips. I must be doing something wrong.

[mwebb]

i think FL was referring to the EPA claims from the 70s and early 80s - your car is a 2007 and it is not equipped with a carb

Originally Posted by Mustang Dave

Most people can. I've never gotten the "old" EPA city rating (19 MPG) with my Mustang. And since I found ecomodder.com, I only (occasionally) get less than the old "highway" rating on road trips. I must be doing something wrong.

[mwebb]

i do not suppose such an engine actually exists nor will it ever find it's way to production because of durability issues -

and
in the real world , we do not want to use an engine that has no restriction on NOX production as NOX is very bad for humans , none the less , EGR can be used to limit NOX formation
on
any
engine

real , or imagined

Originally Posted by ConnClark

Give me ceramic engine block and heads and no restriction on Nox emissions and I'll give you an engine that will spank the rest in FE with a carb.

Note Ceramic engine blocks won't need a cooling system.