Why am I getting poor gas mileage?

[metalmonkey47]

Holy Crap Monkey ! ,,, that would rob yo horsepowa :)

Putting a new one on next week ;)

 

Then FINALLY going for the header/ITB setup It's warm enough now.

 

Yea, no complaining about lack of gas mileage til everything is hooked up right!

 

+1 for that :rofl:

[metalmonkey47]

Forgot to mention this!! I know it's partially related to my fuel economy in some small way.

 

My engine never heats up past about160 degrees on a warm 70 degree day. It's got a brand new 192 degree thermostat in it. I know the gauge is correct because I checked the engine's physical temperature with a temp gun and only had about 120 degree thermostat housing.

 

Suggestions?

[Laecaon]

Brand new thermostats mean nothing. They can be DOA. But that should cause over heating. Have enough coolant for it to actually reach the thermostat? What did the heat gun say about the rest of the engine? like the block or the hoses?

[Laecaon]

Also, your waterpump working? I got my 93 Tbird with a broken water pump, didn't know that. Got in the winter, heater never got warm. Temperature gauge never got a good reading. Car never over heated. Then one day spring rolled around. it was a 75 degree day and I had ran the car for 3 straight hours. The temperature gauge finally started to read HOT!, though my heater still barely worked. Eventually replaced the water pump and all was well (well for 6 months then the HG blew).

 

Does your heater blow hot? Or is it initially hot and then get cold?

[I'm BLUE]

Forgot to mention this!! I know it's partially related to my fuel economy in some small way.

 

My engine never heats up past about160 degrees on a warm 70 degree day. It's got a brand new 192 degree thermostat in it. I know the gauge is correct because I checked the engine's physical temperature with a temp gun and only had about 120 degree thermostat housing.

 

Suggestions?

 

Use a GOOD BRAND NAME THERMOSTAT ( no autozone shit :P ) ,,, dealership or Napa Premium is what I use naow :D

 

Really Cheap Thermostats never work right ,,, or die soon if they don't work right out of the box !!!

[ggzilla]

The vaccum advance won't make a big difference in fuel economy, it will make a small difference

My advice: keep it plugged and don't buy a new advance unit. At half throttle or more there will be no power difference. At light throttle it would help a little.

 

You still have mechanical advance.

 

The weber is a power hog unless carefully jetted. Put a good used hitachi on there and you'll be getting 30mpg +. I was getting about 22 mpg with my old hitachi, I bought another one off ebay for $20 and now and getting about 35 mpg. The old one had a bad power valve rod/vacuum thingy.

[hogboy52]

Well I have a '79 210 and I was getting in the low twenties also, when I had been getting near 30 in town summer and 26 winter, local short trips only. It's a major job just to get the air cleaner off. The choke I set up in summer would take a long time to shut of in cold weather. Also the vacuum choke pull-off was leaky and did nothing. (I knew that already, I think they all leak). I set the choke back to half open when cold and on the first idle step-up. It ran fine there, after a few seconds of warm-up.

 

I then checked the timing and had only a lame 32 deg. at a fairly high rpm. Checked the vac. advance can and it had developed a small leak. I took the vacuum line off the carb fitting and onto manifold vacuum and could get a decent 38 deg. full advance.

 

Meanwhile, I managed to score a deal on Rock Auto on a new vac. can for just $10. Too cold and wet to put it on yet.

[datzenmike]

Proper vac advance will make it much nicer to drive at low speed. It increases the timing advance during light to moderate throttle settings which increases the efficiency and extracts more power. This applies at any RPM with less than 1/2 to 3/4 throttle such as highway cruise. Full throttle destroys vacuum advance but it isn't needed anyway.

[kmc63]

Something else to keep in mind,when you change the size of your wheels and tires your speedometer will not read correctly hence same with your odometer,mine is way off. So if your using your odometer to check fuel mileage you could be way off.Fill-up the tank,pre-determine a route w/mileage complete the journey and re-fill tank. Now take the number of miles you traveled and the amount of fuel you used to fill the tank and divide,you will have a totally accurate number with no doubts as to mileage. I had an old B-210 with the1300cc engine and it never got less than 35 mpg.Im sure the weber is dragging it down a little but thats way too much.

[metalmonkey47]

I'm not sure what brand thermostat I have in there, but I do plan on taking it out and testing it in a pot of water to see what temp it opens at.

Also going to replace the distributor with a reman unit in the next few weeks, but the GF's bday is coming up so I'm holding out on my car.

 

KMC63, that is a good suggestion. I actually have a correct speedometer though. I took it to a guy at a local speedo shop a few months back and told him it was off by about 5MPH, gave him a few bucks and let him tinker. He put it on a little rig played around. By the time I got it back a few days later it was spot on

 

 

 

 

I'm looking into rejetting the Weber to start. I figure the first step is making sure I know what jet's are in it so I'll have to pull out the jets. Any advice on rejetting it? I plan on using one of the kits made by the guy that did the tuning guide write up.

[datzenmike]

I'm not sure what brand thermostat I have in there, but I do plan on taking it out and testing it in a pot of water to see what temp it opens at.

Also going to replace the distributor with a reman unit in the next few weeks, but the GF's bday is coming up so I'm holding out on my car.

 

KMC63, that is a good suggestion. I actually have a correct speedometer though. I took it to a guy at a local speedo shop a few months back and told him it was off by about 5MPH, gave him a few bucks and let him tinker. He put it on a little rig played around. By the time I got it back a few days later it was spot on

 

 

 

 

I'm looking into rejetting the Weber to start. I figure the first step is making sure I know what jet's are in it so I'll have to pull out the jets. Any advice on rejetting it? I plan on using one of the kits made by the guy that did the tuning guide write up.

 

Do not waste your time testing. They are only $12 for a good one. Take out throw away put new one in. Done and done.

[izzo]

There should be a guide somewhere on jets per engine. If you pull the top of the weber off you can easily see what jets are in it, then look around a bit.

[metalmonkey47]

There should be a guide somewhere on jets per engine. If you pull the top of the weber off you can easily see what jets are in it, then look around a bit.

 

I'm gonna have to make sure I have a replacement gasket first, but I'm going to chock down the jet sizes for reference. I haven't found a jet chart for the A15 yet, but I'm still searching.

[ggzilla]

Stock 80 HP A14

jetting for Weber 32/36

 

Venturis: 26/27

Auxiliary venturis: 3.5/3.5

Main jets: 140/140

Emulsion tubes: F50/F50

Air correction jets: 170/160

Idle jets: 60/50

Jump jet: 50

Needle valve: 2.00

[racerx]

http://dimequarterly.tierranet.com/rt2.html

 

Check out this article by Road and Track, Datsun 510 getting like 24.5 mpg. I get like 21 mpg, L18, 15 X 50s tires, 4 speed. Also weber 32/36.

 

These cars are not like fuel injection today where 35 mpg 4 cylinder is the norm...our cars are carburated...

[ggzilla]

1972 B110: 38 mpg

1978 B210: 50 mpg

1980 B310: 47 mpg

 

All carbureted. Yes, not all of them got the advertised mileage, but many/most did. EFI cars are more consistent.

[sick620]

you arent getting the best gas mileage because you need more lower... its simple physics really.... for every 2 inches drop you get 10mpg's! haha :lol: