Weber Fuel Economy Question

[benjamachine]

I just installed a Weber, and am getting pretty crappy gas mileage (was getting 31 mpgs with the Hitachi).

 

I used a transdapt one piece adapter to mount the carb. It idles well and runs decently, but it's DRINKING gas! I'm getting 21-22mpg on the freeway and way less around town. What can I do to fix that problem? I've seen people post on here saying they've been getting 27-28 mpg on the freeway. The tiny, almost unnoticeable power boost you get from a Weber (it really just makes a lot more noise) is nice, but not for a 10+ mpg reduction in fuel economy.

 

What gives, any suggestions? I'm thinking it could be:

 

1 - jetting (I'm currently at sea level, but put 170/180 air correctors on there to lean it out at 5,000+ feet, where I normally live ... I should add here that I have no idea how to change any but the main jets).

 

2 - distributor - Does that dual port disty cause problems? Should I seek a single port advance from somewhere (like Loyale 2.7 Turbo suggested)? The stock EA82 distributor <em>seems</em> to work ok, except that I don't have the retard port hooked up, so it pings under load.

 

3 - Fuel line routing: I have a main fuel line, a vent/return line going back to the tank, and I have the stock vent hose open. Should I plug the vent hose? I thought that would make the inside of the car smell like gas because of that vapor separator thing under the rear trim panel. The car doesn't appear to be leaking fuel.

 

Any other ideas? Thanks, amigos!

[ShawnW]

Not to pick on you but why did you mess with it if you were getting 31 MPG?!?! Wow.

 

Anyway, what is your timing set at?

Does it sputter or cough at all when you rev it?

Did you set it up with the screws like the Redline docs say to do?

[TajMan]

The experience I had, was a 2mpg improvement with the weber over the hitachi, probably around 26-28mpg average with the weber driving the car full throttle everywhere.

Also was a major improvement in drivability, better throttle response and better top-end pull with the Weber

 

Figure out why your weber is jetted wrong and how it should be jetted?

was it a complete ea81 weber 32/36 kit from JTSpeed?

[benjamachine]

I was willing to take a 2-4 mpg hit to get better driveability and power up grades, but it really didn't make much of a difference.

 

I set all the screws just like Weber said, but that's just idle stuff. It runs great and doesn't sputter.

 

Initial timing is set at 12 degrees BTDC.

[ShawnW]

You should be good at 12, I would go 16 degrees at 8700' but if you drop down a lot that would be better at 12.

 

What jets are in it? You should be able to see them thru the top if I remember correctly.

[ferox]

I set all the screws just like Weber said, but that's just idle stuff. It runs great and doesn't sputter.

One thing I learned from GD on setting the screws on the Weber was on the idle speed screw when it says 1 1/2 turns in maximum you really just want it less than one turn to start out with, maybe even try it with a 1/4 turn engagement with the throttle lever to start with. It seems to be fairly sensitive to that adjustment. I recently installed a Weber on my Jeep and knowing that little tidbit saved me a lot of tuning headache and time.

 

Of course if you did that already, then I am out of advice. I think the Weber tuning instructions are misleading. It says in bold 1 1/2 turns maximum so naturally people adjust it to the setting they read, rather than working your way up to maximum if needed.

[Loyale 2.7 Turbo]

...Should I seek a single port advance from somewhere (like Loyale 2.7 Turbo suggested)? The stock EA82 distributor <em>seems</em> to work ok, except that I don't have the retard port hooked up, so it pings under load...

 

Nope, it should work OK, just be Sure to plug the vacuum advance to the right port on the Disty and on the Carb.

 

...I have the stock vent hose open. Should I plug the vent hose? ...

 

Nope, if you close it, the Fuel tank's & Lines pressure goes Up to a Dangerous levels... I did that mistake and every time I went to the gas station, I had a lot of pressure coming out from the Gas Tank when I opened it to pour more gas...

 

I only placed a Small air filter in the vent line and let the other side open, routing it down, aside the Brake booster... no gasoline odors at all.

 

 

... The tiny, almost unnoticeable power boost you get from a Weber (it really just makes a lot more noise) is nice, but not for a 10+ mpg reduction in fuel economy...

 

That is not "Normal" somehow...

 

Let me tell you that the Main jets on the EA82 Weber kit I had, came stock with both Primary and Secondary at 140.

 

Ignition Timing does a Very much Noticeable Difference, let me Explain:

 

Even if the Subaru's sticker under the Hood says to place the Ignition Timing for a Carbureted EA82's at 8º (+/- 2º) ... with the Weber, the Best performance is Gained placing the Ignition Timing at 20º like the Fuel Injected EA82's.

 

I Kindly Suggest you to Try advance the Timing up to 20º with Premium Gas and let us Know if there is a Difference.

 

Kind Regards.

[benjamachine]

You should be good at 12, I would go 16 degrees at 8700' but if you drop down a lot that would be better at 12.

 

What jets are in it? You should be able to see them thru the top if I remember correctly.

 

Hey ShawnW, I have 140 main jets, and the two air correctors at the top are (per the Import Experts guy's recommendation) 170 and 180.

 

It has no balls above 5,000 feet (driving over grades that peak at 10,000' is normal driving in Colorado, just to get from place to place). The Hitachi actually worked better.

[benjamachine]

Nope, it should work OK, just be Sure to plug the vacuum advance to the right port on the Disty and on the Carb.

 

 

 

Nope, if you close it, the Fuel tank's & Lines pressure goes Up to a Dangerous levels... I did that mistake and every time I went to the gas station, I had a lot of pressure coming out from the Gas Tank when I opened it to pour more gas...

 

I only placed a Small air filter in the vent line and let the other side open, routing it down, aside the Brake booster... no gasoline odors at all.

 

 

 

 

That is not "Normal" somehow...

 

Let me tell you that the Main jets on the EA82 Weber kit I had, came stock with both Primary and Secondary at 140.

 

Ignition Timing does a Very much Noticeable Difference, let me Explain:

 

Even if the Subaru's sticker under the Hood says to place the Ignition Timing for a Carbureted EA82's at 8º (+/- 2º) ... with the Weber, the Best performance is Gained placing the Ignition Timing at 20º like the Fuel Injected EA82's.

 

I Kindly Suggest you to Try advance the Timing up to 20º with Premium Gas and let us Know if there is a Difference.

 

Kind Regards.

 

Do you mean total timing, or initial timing at idle? You're not pinging under load?

 

I have the stock 140 primary/secondary jets in there, with 170/180 air correctors.

[GeneralDisorder]

Hard not to point out the obvious....

 

The reason the carb didn't make much difference in power is because you haven't got it tuned right . That much is clear by the large decrease in fuel mileage - obviously you are running rich. A rich running condition will be apparent by a bogging, loss of power sensation... or in your case... "Hitachi performance" because you haven't experienced what a properly tuned Weber feels like.

 

Beg, borrow, or steal a Wideband O2 sensor and find out where you really are AFR wise. Makes tuning a lot easier for those that aren't familiar with how a carb works and what the different jets do.

 

GD

[benjamachine]

Hard not to point out the obvious....

 

The reason the carb didn't make much difference in power is because you haven't got it tuned right . That much is clear by the large decrease in fuel mileage - obviously you are running rich. A rich running condition will be apparent by a bogging, loss of power sensation... or in your case... "Hitachi performance" because you haven't experienced what a properly tuned Weber feels like.

 

Beg, borrow, or steal a Wideband O2 sensor and find out where you really are AFR wise. Makes tuning a lot easier for those that aren't familiar with how a carb works and what the different jets do.

 

GD

 

Thanks, magn! That must be what it is, because I could barely make it over Vail Pass yesterday. We were chugging along at 30 mph, getting passed by trucks.

[raymond338]

When I got my 1980 DL 1600 the previous owner had installed a weber (34/36 I think).

I got 21 or 22 mpg on the first tank.

I switched the vaccuums around (someone above mentioned this) and the next tank I got about 30mpg. I don't remember which went where, but the right one has to be hooked to the advance or no tuning in the world will correct the fuel economy.

 

After a second tank at 30mpg, I tuned mine by ear and averaged 32 mpg for the last 50,000 miles going interstate speeds (65-80mph). If I keep the car below 55mph I average 37mpg. The best I've gotten is 38.25.

I check my fuel mileage every fill-up, as it is a good indicator of other problems.

[GeneralDisorder]

As mentioned - you should also check the ignition timing and if the vac advance is working. They tend to have diaphram failure problems by this age. Without your full ignition advance you will not get proper performance or economy.

 

GD

[92_rugby_subie]

GD probably could tune a weber while changing the transmission on a mercedes

 

But hes great at it... the Weber 32/36 DGEV on my 86 GL feels so much faster than the SPFI I had on my 92 Loyale... and I get about 30mpg highway... kinda cruddy in town, Id say about 22, less if I mash the accelerator.... and I KNOW its running rich because I can smell the gas and watch it drop out the exhaust at idle... but that doesnt affect me, so I havent had it changed by GD.

 

I love the weber... and the way I drive... makes my "I hate the Toyota Prius" message that much more clear.

[benjamachine]

When I got my 1980 DL 1600 the previous owner had installed a weber (34/36 I think).

I got 21 or 22 mpg on the first tank.

I switched the vaccuums around (someone above mentioned this) and the next tank I got about 30mpg. I don't remember which went where, but the right one has to be hooked to the advance or no tuning in the world will correct the fuel economy.

 

After a second tank at 30mpg, I tuned mine by ear and averaged 32 mpg for the last 50,000 miles going interstate speeds (65-80mph). If I keep the car below 55mph I average 37mpg. The best I've gotten is 38.25.

I check my fuel mileage every fill-up, as it is a good indicator of other problems.

 

I have a ported vacuum line connected to the primary advance port on the advance bell. I've capped off the secondary. I'll check and see if it's working with a vacuum pump, but it was working pretty well until I hooked up the Weber.

 

I need to get out there and check my plugs and change the jets on the carb, too, though, which I suspect has a lot to do why this thing isn't running correctly.

[benjamachine]

My timing is set at 12 degrees BTDC. Jets are 135 primary and 140 secondary. Air correctors are 220/210, idle jets are 50/45. i need to get different jets, as i think it's still too rich.

[spazomatic]

Im in colorado, and run between 6500 and 9000 ft daily. In the weber on my '84s 1.8, the primary jet's a 25, and the secondary is a 27. Im getting around 26 mpg, and it runs stronger than with the stock carb ever did. Im not sure where my timing's at...i set it by ear and never put a light on it.

[Moosen]

I am constantly driving my weberized ea82 at 6000-9000ft elevation and I get 20-24 mpg. I just live with it. I have tuned that thing so many times and can't figure it out. 20 degrees advanced on disty, and i am running a 135 and 140 main jets and 190 and 200 air jets. I diesel a little bit when i turn the car off sometimes. but other than that she runs fine. would be nice to get better fuel economy though.

 

I have the disty advance hooked up to the port on the right front of the weber? under the choke linkage. is that correct?

[Loyale 2.7 Turbo]

...I have the disty advance hooked up to the port on the right front of the weber? under the choke linkage. is that correct?

 

Yes, and it should go to outer port on the distribuitor, as you can read on this post about the two ports on the Disty's advance:

 

... the one on the top of the vacuum unit is retard, the one on the outside is advance and goes to the carb.

 

Kind Regards.

[benjamachine]

Yes, and it should go to outer port on the distribuitor, as you can read on this post about the two ports on the Disty's advance:

 

 

 

Kind Regards.

 

By outer port I'm guessing you mean the one closest to the body of the distributor, or the widest part of the vacuum advance bell.

 

So I GOT IT!!! No more vacuum leaks at the base of my carburetor!!!

 

There was a problem with the mating surfaces on the intake and my Transdapt Weber adapter, so I filed/sanded the heck out of them and put them back on -- snug, but not ridiculously tight. Works like a charm now.

 

Anyway, thanks all for your help and advice.

[hanyou]

I am getting right around 20mpg in city.. 10btc or 12 btc.. still 20mpg city. Folks are bringing it back north this week so I will get an update on highway, but it was 17mpg when I got it.. Mechanic adjusted the carb and had it well outside what it should have been, but oddly enough I got the same mpg that way as I do now. Car runs really smooth regardless and was supposedly rebuilt 50k ago.

 

Unrelated, but... wife had the mechanic replace a CV boot while I was deployed and he claimed my thermostat was bad.. supposedly replaced it free of charge.. Wife pointed to my AC idleup and said he called it the thermostat.. also its the same piece as when I left :/ It doesnt idle any higher with it connected and the AC on though.. around 5-600 rpm, shaking the whole time.