mpg?

[dcdcdc]

hi all,

just wondering how many miles per gallon everyone's getting with the verts. I think I average like 21 mpg for mostly city driving, maybe 15% highway. my tank goes completely dry at 260 miles, but I installed the walbro hi-pressure pump, which is slightly shorter than the stock pump.... I don't know if that makes a difference. I usually fill up 13 gallons.
Modified by dcdcdc at 6:28 AM 8/28/2005

[bigG]

I got my 93 vert (no aftermarket stuff - 100% stock) in July. It was 600+ miles away. Tank #1 was used from Moore, SC to Birmingham, AL. From Moore to Atlanta, I was following my friend at about 90+ mph. From Atlanta to Birmingham, it was 35 mph THE WHOLE WAY (the day before Hurricane Dennis). I got 27 mph.

The next day was Birmingham to Lafayette, LA. I drove straight 75 mph the whole way. I tanked up just west of Birmingham, then again just west of Baton Rogue. 360 miles, 12 gallons! 30 mpg!!!! I haven't done that in years!

I've been getting low 20's in the city. I drive 26 miles round-trip each day to and from work, and it's all city driving (50 mph max speed limit with no highways).

Hope the info is helpful.

[raxx]

I'm gettin bad MPG on my vert. I think I'm gettin about 16-17 MPG. I wonder why. If you have any ideas on oh to improve my gas mileage. Free free to speak your wisdom.

[240SX@MD]

I was getting 28-30MPG highway over the summer! (top down)Now it is about 25-27MPG highway. Colder weather=more gas consumption.City driving is about 20MPG.A high-pressure fuel pump would also be the cause for your bad MPG. Since you now have a higher fuel flow.The Spec for fuel tank capacity is 15 7/8 gallons. Hope it is helpful.

[raxx]

Well, I'm still getting really bad gas milage!!!

If anyone has any idea on what I should do to prevent all this gas consumption and my money, Just help me out. Give me some advice, these gas prices aren't fun.

I currently have about 190K miles on my car. With exhaust, I think (previous owner only told me it was a full exhaust, but I don't know what kind), but I do know that I have an exhuast leak. Could that also have something to do with the MPG??? Considering that where all the burnt gas/oil and fumes comes out from.

[nissanconvert]

It seems you are all suffering bad gas milage, i don't want to insult but i don't know the experience level of everyone here so here a a few tips on getting butter mpg's.-Replace the air filter if dirty or every 60k,whichever is first, poor air flow reduces mpg's ~$7-replace the PCV valve, this sends unburt gasses back into the chamber, it should be done every 60k, if yours doen't rattle when you shake it, its needs to be replaced or cleaned~$3-get a valvoline 3-part fuel system cleaner~$75, you can also do it yourself but valvoline instant oil change has stronger stuff then you can legally buy in the store, basically if done seperatly 3 things, fuel injector cleaner in the gas tank~$7, cleaning out the throttle body with a chemical swab, and running cleaner through the vaccum lines in the air intake, it bonds to the crap on the cylinderwalls and comes out the back as smoke. this should be done ~75k and add fuel injector cleaner every oil change for those willing to spend. this also helps give back lost HP.-Replace the fuel filter, this should be done ~60k or is can is rusty, adding a new fuel pump does squat if the fuel filter can is full. I've worked at an oil change place and done some pretty nasty filters, some were even full of brown sludge for who knows why~$40-obvious, change the oil every 3k miles, if the oil ever came out very sludgey try a clearner that goes in during an oil change to clean it out, also run the right type of oil, for a 240 during the summer it should get 5w30 and onlyrun 10w30 in the winter months.~$30-Replace transmission fluid, this helps the transmission from slipping and thus loosing mpgs and power, should do if fluid is darkand/or opaque in color(starts as bright clear red) or 75k,~$75 or ~$30 yourself-Replace differential fluid, a diff full of dirt,metal shavings and other crap slows down and ruins mpgs/power, about 60k or sooner if you drive heavy, should be a yellowish or light colored. If it is silvery or brown its bad, also clean off the magnetic catch if it has one.~$75,or $20 yourself-rotate you tires every 20k and check alignment, bad tires and alignment can give very poor performance, follow rotatiuon guidelines also~$0 yourself ~$20 otherwiseThose are the cheap and easy things, without getiing into too much time/hassle. Also beware product that claim to magically give you better mpg's, magnets/additives and othe rarely give any benifit then lightening you wallet. Hope this helps! Fell free to ask any questions on this stuff too, I did this for a living for a while

[col_blu]

I have a stock vert (well it does have a K&N air filter) with AT and I get 29-30 mpg on highway running regular gas. Cruise really helps and so does correct tire inflation.

[TurboChargedSE-R]

A high-pressure fuel pump would also be the cause for your bad MPG. Since you now have a higher fuel flow.

That's not correct. Yes, a higher-flowing Walbro will mean more fuel flow, but all unused fuel is returned to the gas tank. You could flow 500 lph and it wouldn't make a difference.

As long as your fuel pressure regulator is working properly and can handle the flow...the fuel pump being used is irrelevant.

Do like the others said and clean things that need to be cleaned, and replace things that need to be replaced. Chances are, on a 11-14 year-old car, there is buildup that is restricing fuel flow and/or causing the engine to burn more fuel than normal.

[keith1k]

Cruise really helps and so does correct tire inflation.

You have working cruise, Cool. I'm jealous.

[top_secret]

I used to get 35 mpg on the highway in my coupe with my ca18det but I swapped to my vert and installed a high pressure walbro fuel pump and its been running very rich, and I live/drive in the city now so its down to 20 on a good day and worse when I get on it a lot.

[redsilviavert]

My stock vert gets 21 mpg in the city some times 22mpg.

[top_secret]

That's not correct. Yes, a higher-flowing Walbro will mean more fuel flow, but all unused fuel is returned to the gas tank. You could flow 500 lph and it wouldn't make a difference.

As long as your fuel pressure regulator is working properly and can handle the flow...the fuel pump being used is irrelevant.

actually its been pretty well documented that the 255 high pressure pump from walbro outflows the stock fpr enough to make many of the cars that install it run rich. some people are able to run it with no other modifications with no problems. Most people that run the normal 255 (not high pressure) don't have any problems either. I had one of those but sold it and went with a high pressure one and now I have problems. I have a nismo adjustable fpr and adaptor but I'm waiting to get a gauge before I install it.

needless to say with the HP 255 you are likely to run significantly rich which will degrade your fuel economy.

[TurboChargedSE-R]

actually its been pretty well documented that the 255 high pressure pump from walbro outflows the stock fpr enough to make many of the cars that install it run rich. some people are able to run it with no other modifications with no problems. Most people that run the normal 255 (not high pressure) don't have any problems either. I had one of those but sold it and went with a high pressure one and now I have problems. I have a nismo adjustable fpr and adaptor but I'm waiting to get a gauge before I install it.

needless to say with the HP 255 you are likely to run significantly rich which will degrade your fuel economy.

I agree, and that's why I put the line "if your fuel pressure regulator is working properly". The turbo SR20 FWD guys have had the same issues with Walbros and stock FPRs.

[JSvert240sx]

I have a 93 with 152K miles and manage 24-26 mpg combined for all my driving usually. This consists of mainly back roads and some highway.

On long highway trips where I'm not in a huge rush I've managed 31mpg a couple times recently.

[240SX@MD]

At a 500 lph rate, without the proper updates to the fuel delivery system that can handle the new flow rate, it will likely leak fuel at the injector seals, line connections, rupture fuel hoses, etc...I do agree that car mileage/age; dirt build-up increases the gas consumption. And the recommended cleaning and maintenace as Nico members say are help ful to keep our 'verts on top_less condition.

Also

That's not correct. Yes, a higher-flowing Walbro will mean more fuel flow, but all unused fuel is returned to the gas tank. You could flow 500 lph and it wouldn't make a difference.

As long as your fuel pressure regulator is working properly and can handle the flow...the fuel pump being used is irrelevant.

I still think a high pressure fuel pump will increase your car fuel consumption. Any fuel pump will flow the fuel at its designed value, the fuel then will travel to the injectors which have a fixed flow rate. So the amount of fuel delivered into the combustion chamber is ruled by the injector on-time (injector opens.) The more time the injector is open, the more fuel is consumed. This is ruled by the PCM, depending on several inputs from the engine sensors (i.e. TPS, MAF, O2 sensors, etc.)

Say the injector is open, the fuel delivered will be the fuel flow on the amount of time it remains open. Now IF the fuel flow is increased (by any means, in this case a high pressure/flow fuel pump) and the injector on-time is the same as before, more fuel will go to the combustion chamber. Hence more fuel will be consumed. So the type fuel pump being used is not irrelevant.

All these, without taking into consideration the pressure regulator, which is at the end of the fuel rail, after all the injectors. The fuel pressure regulator task is to maintain the pressure of the fuel on the rail so the correct amount goes to the injectors (when open) and it will be completely closed when there is more load demand (wide open throttle) and will open when there is no load demand. When it opens, the fuel goes to the return line and ends in the fuel tank. The fuel return line is also smaller in diameter than the fuel supply line, which decreases the fuel flow rate back to the tank compared as when it was on the supply section.

Side tracking.... I haven't logged-in a while. Kudos for the great 240sxconvertible.com page. Awesome front pic AZ

Keep up the great posts at NICO - verts

Regards,Luis

[Darkwagoner]

We have been getting close to thirty. We are the second owner and it has had only sythetic oil in it. 170k miles.