Go Back   986 Forum - The Community for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Boxster General Discussions

Post Reply
 
LinkBack Thread Tools Display Modes
Old 01-28-2023, 08:58 AM   #1
Registered User
 
Join Date: Aug 2017
Location: Tucson,az
Posts: 726
why such Bad gas Mileage

GM...I drove my 02' 2.7 5 Spd in a round trip of 60 miles, mixed driving some Interstate and surface streets,and used a 1/4 tank of 91 octane fuel from Cheveron, that cant be normal..Ive never taken this car on any type of trip, so I don't really have a gauge for mileage RPM range was 3K to 5500. ?? any Info would be Great...Thank's Frank

flmont is offline   Reply With Quote
Old 01-28-2023, 09:58 AM   #2
1998 Boxster Silver/Red
 
Join Date: Sep 2017
Location: 92262
Posts: 2,979
You own a sports car and you're worried about mileage? I haven't done the mileage equation since... ever.

Seriously... you have to fill up the tank... drive a few hundred miles... fill it up again... look at the diference in fill amounts... and do the math. Look up the equation on the internets.

The math? I'm not sure because I've never much oncerned myself with mileage in this car (smiles per mile...).

Further... 60 miles is not much of a trip to be calculating mileage. The fuel level guage starts going low quickly as you get to that last quarter tank and, if corectly I recall... when it's filled up. When the gauge is in the middle 50% slowly it moves... down. I don't know... I don't pay attention to it. I just try to keep my tank at least 1/4 full.

Look up the math equation... online... and try it. Let us know the real results... not the seat of the pants answer.
__________________
1998 Porsche Boxster
Starter986 is offline   Reply With Quote
Old 01-28-2023, 03:12 PM   #3
Registered User
 
Join Date: Aug 2018
Location: Woodland Wa
Posts: 1,294
Quote:
Originally Posted by flmont View Post
GM...I drove my 02' 2.7 5 Spd in a round trip of 60 miles, mixed driving some Interstate and surface streets,and used a 1/4 tank of 91 octane fuel from Cheveron, that cant be normal..Ive never taken this car on any type of trip, so I don't really have a gauge for mileage RPM range was 3K to 5500. ?? any Info would be Great...Thank's Frank
going by the fuel gauge is not the way to figure fuel mileage.
I have a 2000 S 3.2 6spd.
I get 20-25 mph depending on how I drive it and where I drive it.
blue62 is offline   Reply With Quote
Old 01-28-2023, 03:45 PM   #4
Registered User
 
Join Date: Aug 2017
Location: Tucson,az
Posts: 726
Ok .I will try that method Sarter..I was just surprised it dropped that much in 60 miles..I thought I may have Injection issues or the timing is off..or something we shall find out Thank's


Thank's ! Blue62
flmont is offline   Reply With Quote
Old 01-28-2023, 06:11 PM   #5
Registered User
 
Join Date: Dec 2009
Location: Orange County, CA
Posts: 1,896
Quote:
Originally Posted by flmont View Post
Ok .I will try that method Sarter..I was just surprised it dropped that much in 60 miles..I thought I may have Injection issues or the timing is off..or something we shall find out Thank's


Thank's ! Blue62
Fill it up, zero the odometer and drive the thing for a couple hundred miles :-) when you fill up again, you divide the mileage between the gallons used..
Gilles is offline   Reply With Quote
Old 01-28-2023, 07:14 PM   #6
Registered User
 
Join Date: Aug 2018
Location: Woodland Wa
Posts: 1,294
Quote:
Originally Posted by flmont View Post
Ok .I will try that method Sarter..I was just surprised it dropped that much in 60 miles..I thought I may have Injection issues or the timing is off..or something we shall find out Thank's


Thank's ! Blue62
If your getting poor fuel mileage... to jump to conclusions about possible injector issues or timing issues is way, way over the top.
With any automotive issue always, always, always, simplest things first.
poor fuel mileage can happen from many many things.
driving style for one.
If I was to start getting poor fuel mileage.....
I would look at my air filter, my plugs, and do a vacuum test as some simple firsts.
blue62 is offline   Reply With Quote
Old 01-28-2023, 08:24 PM   #7
Registered User
 
Join Date: Aug 2017
Location: Tucson,az
Posts: 726
Thank's Guy's..I will ck it out to determine my mileage and Ill get back with a answer
flmont is offline   Reply With Quote
Old 01-29-2023, 06:57 AM   #8
2003 S, Arctic Silver, M6
 
paulofto's Avatar
 
Join Date: Oct 2014
Location: Winnipeg, MB, Canada
Posts: 1,346
Garage
The fuel gauge is far from accurate. It will tell you when you approach empty but to use it as a consumption gauge to determine fuel efficiency will not work. Do what the other posters suggest and do the math. Btw, my 03 S gets close to 30 miles per gallon if doing a steady state highway long distance drive at or around the speed limit. If I drive ‘with enthusiasm’ that mileage drops to well under 20.
paulofto is offline   Reply With Quote
Old 01-29-2023, 08:53 AM   #9
Registered User
 
Join Date: Aug 2017
Location: Tucson,az
Posts: 726
Thank's Paulofto,..Ive heard of the Temp gauge being off,..but everyone is now saying the fuel gauge too,And the another question is,why are the gauges off..I know thats a completely different topic,and I understand they do not need to be exactly dead on..but you would want pretty close especially for the Temp gauge. ??, anyway Thanks..I plan a run next weekend to see what's up..
flmont is offline   Reply With Quote
Old 01-29-2023, 09:00 AM   #10
Registered User
 
elgyqc's Avatar
 
Join Date: Sep 2018
Location: Laval QC
Posts: 759
Garage
Quote:
Originally Posted by blue62 View Post
... I get 20-25 mph depending on how I drive it and where I drive it.
You should get great mpg if you only go 20-25 mph
__________________
Grant
Arctic Silver 2000 Boxster S - bought with a broken engine, back on the road with the engine replaced
Green 2000 Boxster 5-speed and 1978 928 auto
1987 924S 5-speed (Sold) - Blue 2000 Boxster 5 spd (Sold)
elgyqc is offline   Reply With Quote
Old 01-29-2023, 11:56 AM   #11
Registered User
 
Join Date: Aug 2018
Location: Woodland Wa
Posts: 1,294
Quote:
Originally Posted by elgyqc View Post
You should get great mpg if you only go 20-25 mph
LOL didn't even notice that.
never use the top 4 gears either.
blue62 is offline   Reply With Quote
Old 01-29-2023, 05:18 PM   #12
Registered User
 
Join Date: Jun 2012
Location: Milwaukee, WI
Posts: 383
Fuel Gauge

On my '01S, the gauge is at 3/4 after about 75 miles. Because I do a lot of long distance road trips on back roads, I have to be aware of my car's range to make sure I don't get to the orange refill spot too far from a gas station.

The best mileage I ever got was 29 mpg on a 300 mile, non stop drive on I-80 through Nevada. Typical highway mileage is 24-26 mpg. Twisty road, aggressive driving is around 18-19 mpg.

With the base model, you'll probably see 1-3 mpg more than that. Just learn the range of your car under the most aggressive driving. Once you know that, don't worry unless you see a dramatic dropoff. My range, depending on driving conditions, is 270 to 340 miles.

DBear
dbear61 is offline   Reply With Quote
Old 01-30-2023, 07:49 AM   #13
Registered User
 
Join Date: Aug 2017
Location: Tucson,az
Posts: 726
Thank's Dbear...I can live with that..I'll be testing soon..my driving style is 75-80 on interstate as able and 40-50 surface street as permitted,..Frank
flmont is offline   Reply With Quote
Old 02-02-2023, 06:28 AM   #14
Registered User
 
Rob175's Avatar
 
Join Date: Apr 2013
Location: Lincolnshire, IL
Posts: 465
Hell....my 25 year old 5-speed Boxster (w/91,000 miles) gets 27-28 miles a gallon and always has.
__________________
98' Boxster
Rob175 is offline   Reply With Quote
Old 03-09-2023, 06:56 AM   #15
Registered User
 
Join Date: Aug 2017
Location: Tucson,az
Posts: 726
Talking

As it turns out, I get about 26-27 MPG as well, plus my oil analyst states no fuel delusion, which is what I thought was happening,..Thank's Frank
flmont is offline   Reply With Quote
Old 03-09-2023, 09:38 AM   #16
Registered User
 
Join Date: Jun 2014
Location: LB, Germany
Posts: 1,488
2003 S, MT

Fuel consumption really depends on how you drive.

At 80-90 Km/h i get an average below 7.5 litres / 100 Km.
Full throttle on the Autobahn i can get up to 15 litres / 100 Km.

In general in daily use the car is at around 10 litre / 100 Km.

It's up to you gentleman to convert to mileage per gallon.
__________________
My Porsche keyfob, instrument cluster and alarm ecu repair service: https://sportwagendoktor.de
Smallblock454 is offline   Reply With Quote
Old 03-10-2023, 08:07 AM   #17
PLP
Registered User
 
PLP's Avatar
 
Join Date: Apr 2021
Location: Lansing, MI
Posts: 363
Quote:
Originally Posted by flmont View Post
I don't really have a gauge for mileage RPM range was 3K to 5500. ?? any Info would be Great...Thank's Frank

Here is your problem - rpm range did not go below 3000... so the engine must eat.
Keep it below 3000 and it will give you much better results.
The engine is just fine at 1500 rpm pulling in 4th gear.
__________________
Current rides: 2003 Porsche Boxster MT (me), 2019 Bolt LT (me), 2015 Audi Q5 (wife), 2008 VW Rabbit (2.5 inline 5, MT, well, for kid... but you now, it is the 5 straight)

Previous: 2014 Fiat 500e, 2016 KIA Forte5 SX, 2016 Fiat 500X, and some old days: Trabant, Fiat 126p...
PLP is offline   Reply With Quote
Old 03-10-2023, 11:37 AM   #18
Registered User
 
Bill Ladd's Avatar
 
Join Date: Oct 2019
Location: Wilmington NC
Posts: 119
Garage
Quote:
Originally Posted by PLP View Post
…The engine is just fine at 1500 rpm pulling in 4th gear.
But not much fun, lol.


My 2000S gets terrible mileage. Turns out the nut connecting the steering wheel to the seat has a leadfoot.

Bill Ladd is offline   Reply With Quote
Old 03-11-2023, 05:18 AM   #19
On the slippery slope
 
JayG's Avatar
 
Join Date: Mar 2014
Location: Austin and Palm Springs
Posts: 3,794
Garage
Quote:
Originally Posted by PLP View Post
Here is your problem - rpm range did not go below 3000... so the engine must eat.
Keep it below 3000 and it will give you much better results.
The engine is just fine at 1500 rpm pulling in 4th gear.
Driving these cars at 1500 RPM s not really a good thing
__________________
2004 Boxster S 6 speed - DRL relay hack, Polaris AutoTop DIY
2004 996 Targa Tip
Instructor - San Diego region
2014 Porsche Performance Driving School
2020 BMW X3, 2013 Ram 1500, 2016 Cmax, 2004 F-150 "Big Red"
JayG is offline   Reply With Quote
Old 03-11-2023, 10:48 AM   #20
PLP
Registered User
 
PLP's Avatar
 
Join Date: Apr 2021
Location: Lansing, MI
Posts: 363
Quote:
Originally Posted by JayG View Post
Driving these cars at 1500 RPM s not really a good thing
Date to elaborate as to why?

I support my statement with... AT shifts mapping. If Porsche believed their engines are not supposed to experience low RPM they would upshift at 3000 RPM range, yet they upshift much lower.

Sure, I am not talking about running WOT at 1100 rpm - if you need power, rev it. But for everyday use - keeping between 1500-2500 is just fine.

__________________
Current rides: 2003 Porsche Boxster MT (me), 2019 Bolt LT (me), 2015 Audi Q5 (wife), 2008 VW Rabbit (2.5 inline 5, MT, well, for kid... but you now, it is the 5 straight)

Previous: 2014 Fiat 500e, 2016 KIA Forte5 SX, 2016 Fiat 500X, and some old days: Trabant, Fiat 126p...
PLP is offline   Reply With Quote
Post Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -8. The time now is 10:12 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page