About fresh air induction

[John Smith]

good input...

Here in AZ hot fuel vapor lock is always a problem in the summer. On my project carburated Ranger, the fuel line has been rerouted to run next to the AC vapor line and then wrapped in header type wrap the keeps header heat out of the engine compartment. I have access to thermocouples and a data recorder, I had a thermocouple on the fuel line skin temp at the fuel pump outlet, I observed that when the fuel line skin temp would get around 200' that is when the engine would start vapor locking in city traffic. So that is when the fuel line was routed next to the AC vapor hose, the one that runs over the top of the radiator. but....it would still vapor lock after a 20-30 minute heat soak, like driving through traffic to the parts store, go in the store do business, then do a drive away. The engine had a bad sag until the cooled fuel got into the fuel bowl.

As far as getting rid of the cold air system, never. maybe disconnect it in the winter, but there is added power and fuel economy to be had even with the factory stuff. After working in the automotive testing business for over 30 years, I have learned that the factory does not add anything they have too unless there is a good cause....

As soon as I get my Ranger back from daughter I will post a picture of the fuel line.

Why would I put a thermocouple on a 83 Ranger? cuz it what I do... It has been a hobby since I was a teenager...

Glad you chimed in on the vapor-lock problem. When i change to my other carb, i want to re-route my fuel line and change the inline filter situation to a visible one. I happen to be in a milder year round climate, but vapor-locking still has been an issue during the HOT MONTHS of our summers driving different older cars when carbs were the norm.

Adding an electric fuel pump partly helped sometimes...

I have been trying to keep the mechanical pump in use on this Project B2..I'm not sure it's absolutley necessary we'll see..

Do you run an electric pump?..if so what brand/type..? an do you use a return style regulator if any?...if you don't mind the questions..

I usually prefer the KISS method...(Keep It Simple etc..) but i have been considering using an electric pump if nothing else than a small one to help prime from the rear tank..

One thing that isn't discussed much on this forum is carburated fuel management..surprising since most guys that go to carbs..generally have to engineer something in the way of reliable fuel delivery from changing the different fuel lines etc that are present depending on which donor year their project car happens to be...I suspect vapor-locking is more of an issue than we realize..especially for some in the warmer climates.

FUEL LINE ROUTING and MANAGEMENT...good topic...

 

[dangerranger83]

My lines are routed the way ford did them.

I will say that I switched to a clear fuel filter last year after a small metal one suddenly plugged up on me as I was taking off on a hill and had just left the gas station too. It caused bad hesitation on taking off and did make for a bit of hard starting.

Clear one takes the guessing out of when to change the filter.

 

[John Smith]

good morning..

My lines are routed the way ford did them.

I will say that I switched to a clear fuel filter last year after a small metal one suddenly plugged up on me as I was taking off on a hill and had just left the gas station too. It caused bad hesitation on taking off and did make for a bit of hard starting.

Clear one takes the guessing out of when to change the filter.

Good call on the "clear filter"..I have one all ready to hook up when I change the carb..but since I'm using that top thermostat housing..(it's kinda bulky) I'm working on making a new steel lower fuel line to re-route somewhat ..and incorporate it a little differently..

An update on the fresh-air intake..I can tell the engine is breathing better when warm...and overall performance is great...at least as great as it can be with this 2.8L. I have to say..the throttle snap is better than ever..of course the new head on the left side and new stem seals as well has made the motor run cleaner..

Hopefully we can now settle down for some drama-free driving miles..

 

[tx3nc]

Throw this out there for discussion.

http://www.legendarycollectorcars.c...s-see-and-hear-it-run-in-our-exclusive-video/

“Some parts of gasoline vaporize very easily at low temperatures to help get a cold engine started. Other parts have a much higher boiling point to prevent the fuel from vaporizing in the fuel lines enroute to the engine. What this all comes down to is that in today’s typical engines, only part of the fuel entering the combustion chambers is in a combustible state. To fully vaporize pump gasoline, and to keep it vaporized for complete combustion, the incoming air/fuel mixture needs to be elevated to between 400-440 degrees F.”

Those of you talking about vapor lock are talking about the fuel vaporizing in the fuel line. Once it goes into the combustion chamber, it has to be vaporized or it will not burn.

 

[John Smith]

Good info for sure..

Throw this out there for discussion.

http://www.legendarycollectorcars.c...s-see-and-hear-it-run-in-our-exclusive-video/

“Some parts of gasoline vaporize very easily at low temperatures to help get a cold engine started. Other parts have a much higher boiling point to prevent the fuel from vaporizing in the fuel lines enroute to the engine. What this all comes down to is that in today’s typical engines, only part of the fuel entering the combustion chambers is in a combustible state. To fully vaporize pump gasoline, and to keep it vaporized for complete combustion, the incoming air/fuel mixture needs to be elevated to between 400-440 degrees F.”

Those of you talking about vapor lock are talking about the fuel vaporizing in the fuel line. Once it goes into the combustion chamber, it has to be vaporized or it will not burn.

I never did follow this guy in my younger years, it seems I followed the automotive world in stages as life happened. Pretty neat way to get the job done. I have been familiar with different fuel atomization strategies over the years..I WILL say that my current carb choice is one of basic simplicity with the trade-off in mind we have been talking about. Carbs are just NOT the best choice but are a simple low-maintenance one..especially certain types of carbs..

My carb of choice (Autolite 2100) can share parts between my two vehicles (BroncoII, F150) that I probably will drive till the "rapture"...and they share

gaskets, (only 3 used venturi, powervalve, and horn)
accelerator pump diaphrams ($6 each)
and all of the other basic stuff..
and are pretty decent about atomization so I'll kinda make do "on the cheap" for now..but good discussion for sure..

Who knows, maybe with these high gas prices, we will "re-invent" some "new" OLD ways to make do....

 

[drgrcr]

Smokey's was working on the Fiero around 84, around the time when the automotive company's were trying their best to meet emission specs specified. It was a horrible time for the auto engine. Smoky was the best at getting the most with the least.

Ford tried something similar with the carburated 3.8's. If you find one in the junk yard with carb off the engine look in the manifold below where the carb bolted on, there are 3 stainless steel tubes that exhaust gas was routed through, the idea was to "homogenize, vaporize" the fuel for a complete burn. My experience with these engine was, if the spark control was not right, you were changing head gasket or a piston or 2....
If you were lucky the tubes would plug up and the engine would live, but was way down on power.

Now we have winter grade fuel and summer grade fuel, in the testing business we always used winter grade fuel during the summer for worst cause. And yes fuel injected engines do experience hot fuel problems, I have seen video's of fuel boil in a gas tank that would make you swear the thing was going to burst.

Here is a worst case for fuel injected engine's prior to returnless fuel injection, you are driving up a long steep grade, it is hottest time of the year, you have your foot in throttle fairly deep to maintain speed, no problem going up the hill because the engine is using a good deal of the fuel, you top the crest and back off the throttle, now the engine is not using as much fuel, but all the heat that has been generated is now being soaked up by the fuel that is being returned to the fuel tank at high temp and most of the return fuel is being dumped right next to the fuel pump and it starts boiling right there. The pump does not pump the boiling vapor, now you get to the bottom of the hill that you have been coasting down, and step on the throttle and the engine dies....
you wait twenty minutes or call a tow service, car ends in a shop where the fuel pressure is tested everything checks out, or you get stuck with a new pump, but the next time you go up that hill....the stupid car does the same thing..

So.....400' degree vaporized fuel, has to be managed. Probably more than most want to do.
Or buy a modern fuel injected car that has 10 to1 compression gets great mileage, great cold starts, hot starts....great engine performance. Good in crashes.....

And I have one that is used when the wife I do a road trip.

But my Ranger, that is a different beast, that is part of my obsessive car problem....

 

[John Smith]

Smokey's was working on the Fiero around 84, around the time when the automotive company's were trying their best to meet emission specs specified. It was a horrible time for the auto engine. Smoky was the best at getting the most with the least.

Ford tried something similar with the carburated 3.8's. If you find one in the junk yard with carb off the engine look in the manifold below where the carb bolted on, there are 3 stainless steel tubes that exhaust gas was routed through, the idea was to "homogenize, vaporize" the fuel for a complete burn. My experience with these engine was, if the spark control was not right, you were changing head gasket or a piston or 2....
If you were lucky the tubes would plug up and the engine would live, but was way down on power.

Now we have winter grade fuel and summer grade fuel, in the testing business we always used winter grade fuel during the summer for worst cause. And yes fuel injected engines do experience hot fuel problems, I have seen video's of fuel boil in a gas tank that would make you swear the thing was going to burst.

Here is a worst case for fuel injected engine's prior to returnless fuel injection, you are driving up a long steep grade, it is hottest time of the year, you have your foot in throttle fairly deep to maintain speed, no problem going up the hill because the engine is using a good deal of the fuel, you top the crest and back off the throttle, now the engine is not using as much fuel, but all the heat that has been generated is now being soaked up by the fuel that is being returned to the fuel tank at high temp and most of the return fuel is being dumped right next to the fuel pump and it starts boiling right there. The pump does not pump the boiling vapor, now you get to the bottom of the hill that you have been coasting down, and step on the throttle and the engine dies....
you wait twenty minutes or call a tow service, car ends in a shop where the fuel pressure is tested everything checks out, or you get stuck with a new pump, but the next time you go up that hill....the stupid car does the same thing..

So.....400' degree vaporized fuel, has to be managed. Probably more than most want to do.
Or buy a modern fuel injected car that has 10 to1 compression gets great mileage, great cold starts, hot starts....great engine performance. Good in crashes.....

And I have one that is used when the wife I do a road trip.

But my Ranger, that is a different beast, that is part of my obsessive car problem....

It's neat to hear of your experience. I can relate to your "obsessive car pproblem.

Doing some math 2day about my own "driving experience"..(a BroncoII brick)..I decided to do some quick calculations about RPM's at cruise etc.

Since this is a grocery getter that barely ever reaches 35pmh it will never will reach optimum engine temp around town..(short hops) but out on the open road..

I find that i like to drive it at around 45-50 mph (it just seems to keep the tire hum at the right pitch)..

the BFG/215's I run have a rev-per-mile of 746, so if X that time the R/A 3:73 I get 2782.58, then I divide that by 60 I get 46.3763 revs times 45mph I get about 2086.935 then multiply buy my OD ratio (.84) i am turning about "1753" rpm's at 45 mph and about "1947" at 50 mph...

(did i do that right) presuming I DID..since my "brick"doesn't push TOO much wind @50mph...my target optimum cruise would be....1800-1900 rpms...

Now if i can get my centrifugal timing "all-in" @1750rpms...then add what vacuum i want...and it shouldn't take much since we're not pulling too hard....

well, anyway...this is the method behind my efficiency search madness...Am I missing it.?

(let's see add 1 carry the two...no wait a minute...no, it's right..I think)...

I'm not expecting TOO much spirited driving in this scenario for sure...but I guess we'll see what kind of "brick-pushes-air efficiency" I can get in the 1800-1900 rpm range..

 

[dangerranger83]

I have always been told to run something at its max torque and that is where you will get your best MPGs and whatnot. For the 2.8 that would be 2800 rpm and my truck does that going down the road at 65mph with my 32inch MT tires with 3.73 gears and no OD.

 

[John Smith]

well..

I have always been told to run something at its max torque and that is where you will get your best MPGs and whatnot. For the 2.8 that would be 2800 rpm and my truck does that going down the road at 65mph with my 32inch MT tires with 3.73 gears and no OD.

I can see why your mileage may be down man..I don't see your driving conditions condusive to optimum MPG if I may be so bold..

I'm not an engineering expert by any means, and not an expert RE: the fuel efficiency specifics of the dyno-ratings of this 2.8L., but when you add the rolling resistance of the 32's, and especially in the heat of Texas?...not considering what tire compound you may be running, and then the added wind resistance of 65mph, somewhere in there must be added the rule of diminishing returns...at what point can you lose mpg at the benefit of max torque?..it maybe works on the dyno,,,but what about all those other bullets flyin' in from somewhere?...(that's a movie line ..)...

I'm sure some expert will have another opinion..let's hope so..I'm outa' bullets

I once did a study of the efficency of pulling 105Klbs of stuff down the hwy @55mph vs: 60mph..the mpg suffered by 12% less at the higher number

 

[dangerranger83]

Okay to break it down...

Before I did anything to my truck and it was all stock with the Duraspark setup being on it, I was still getting 10mpg so everything I have done to it has not effected the mpgs, all I have done is made it more capable of a truck to do things outside of a stock rig.

Now the calculator in the tech library says that I should be running 4.10 gears instead of the 3.73s I have with my tire size and other things.