Herman and Operation 30MPG

Post by **rspi** » 13 Feb 2018, 09:14

How old is the coolant thermostat?

WhatAmIDoing · Post by **WhatAmIDoing** » 13 Feb 2018, 09:43

My mpg record in my manual T5 is 36mpg... all highway, mostly downhill.

That and the 93 octane, low ethanol, midwest gas probably helped. I don't know if the same applies for the NA, but good gas is a must if I want good performance and fuel economy. I normally get 28 highway, 24 country roads, and best I ever did city was 19. Goodluck with your fancy intake.

callahanoffroad · Post by **callahanoffroad** » 14 Feb 2018, 05:11

rspi wrote: ↑13 Feb 2018, 09:14 How old is the coolant thermostat?

I honestly have no idea. It was supposed to be changed with the radiator hoses last week, but I couldn't get the bolts off the housing. One of them started to strip, so I backed off untill I could soak it it some bolt blaster.

Post by **abscate** » 14 Feb 2018, 06:47

One of them started to strip, so I backed off untill I could soak it it some bolt blaster.

Nice - Get a good new Torx bit on there and shock it a bit, too.

callahanoffroad · Post by **callahanoffroad** » 14 Feb 2018, 15:22

I was poking around in the engine bay today and I checked the ecu's and it turns out I have the jetronic LH 3.2 system and I wonder if that doesn't have something to do with the bad gas mileage consistently.

callahanoffroad · Post by **callahanoffroad** » 19 Feb 2018, 06:35

I wanted to update my thread and happily announce I've gotten Herman up to... 23.43 MPG! Looks like rumors of the pcv affecting MPG were true. Hahaha.

All I have left for a full "stage 0" would be the fuel filter in the line.

Getting an oil change this week and will switch to 10w-30 from 10w-40. Hopefully I'll see a small increase in mpg.

I think I'm going to pull the spare tire out as well see if that makes any difference. I run without anything frivilous in the car to save space already.

Also I fill up about every three days bc of my job. I drive about 500 miles a week. So I'm able to measure changes very quickly!

Post by **matthew1** » 19 Feb 2018, 07:31

callahanoffroad wrote: ↑19 Feb 2018, 06:35All I have left for a full "stage 0" would be the fuel filter in the line.

Easy step to do.

Getting an oil change this week and will switch to 10w-30 from 10w-40. Hopefully I'll see a small increase in mpg.

I'll be reading the outcome.

I think I'm going to pull the spare tire out as well see if that makes any difference. I run without anything frivilous in the car to save space already.

Yikes. Remember any downtime on the side of the road (how much is your time worth?) or paying for a tow will wipe out months of savings from MPG gains.

Also I fill up about every three days bc of my job. I drive about 500 miles a week. So I'm able to measure changes very quickly!

500 mi/week is important here. It's a lot. This makes your findings from these Stage 0 improvements a little more statistically interesting than someone driving fewer miles.

Thanks for posting this update.

Post by **mrbrian200** » 19 Feb 2018, 08:07

With regard to winter mileage, don't forget colder air is also more dense. It takes more energy to push the car through cold air with the negative effects of increased wind drag more progressive as speed increases over 45mph.

If you plug numbers into ecomodder aerodynamic and rolling resistance calculator, there's a drop down asking for the ambient temperature. Calculated econ at highway speeds for my car will be 2-4mpg less at 26F than is predicted in summer temperatures. I observe this on my car, absolutely. During the summer I will see 37-39 on a moderate speed strict highway run (not over 65mph). In the winter I never see over about 35. When temps drop way down around 0F or lower, it more like 30-33.

The best econ I've ever seen was the day I drove to Colorado from Chicago 2 years ago. It was 106-108F across the main stretch of US-36 through Missouri and Kansas that day. Used about 1-2/3 tank of gas on a little over 1000 mile run. Mileage was off the charts, over 40 with the AC cranked, of course.

Post by **Rattnalle** » 19 Feb 2018, 08:09

Extra weight barely makes a difference in my experience.

Lighter oil, maybe. But you might also see an increased oil consumption to go with that.

Post by **mrbrian200** » 19 Feb 2018, 09:17

27.5 on the highway in the winter should be about right for an 850.
http://ecomodder.com/forum/tool-aero-ro ... ep=40-65-1.

Documented figures for an 850 (scroll to bottom):
http://ecomodder.com/wiki/index.php/Veh ... _Drag_List

You want to tweak the figures so that the CDa displayed after submitting the query matches what is known for the vehicle. There is some educated guesswork involved for sake of simple 'is observed mileage in your car in the neighborhood' you tweak the CD figure (I used .323 instead of .32). Engine efficiency is tweaked down from the default to account for increased blowby on an older high mileage vehicle, drivetrain efficiency and electrical parasitic loads are educated guesses that might be typical for a 90's-something vehicle.

If you set the calculator for summer fuel and ambient temperature it hikes to around 30mpg at 60mph.

Herman and Operation 30MPG

Re: Herman and Operation 30MPG