Project: Hypermiler

[Satisaii]

I was getting tired of putting 110 miles a day on the S2000, so I picked up a 91 BRG for $2000. The eventual plans are for a car to rival Emilio's 95R, but with my take on how to do it... but first we are going to have some fun trying to maximize the mileage while I collect parts for the build. Plans are to document how the changes we make affect the gas mileage with the ultimate goal of getting the most out of it.

The car is a 91 BRG with 240K on the clock. We are pretty sure the engine is not original. But it is all stock. The suspension is Raceland, and it was slammed at one point. The alignment and corner balancing are way off. The wheels are 13x5" Honda... and slightly lighter than the stock Daises. So far I have only changed out the stock seat for an aluminum Kirkey racing one. The car came with a Buddy club seat that was not sized for my posterior... so I sold it to Sonny.

Sonny and Emilio are loaning most of the 1.6 specific parts since I have no long term plans to keep this engine. We will dyno the car after every change. We will also try to tune the car more for mileage than power. I will also do some performance testing using my phone as the data logger. Since some of the changes we plan on doing will change the odometer/speedometer, I will have correction factors such that the changes are normalized. Big thanks to 949Racing, Second Chance Roadster, Emilio, Sonny, Steve, and everyone else who helps me out with this.

Planned changes:
Alignment
Intake
Header
Exhaust
Computer
3.9 open differential
Possible 3.6 differential
Hardtop
Fastback hardtop
Lights up / lights down
Top up / Top down
MAYBE aero... flat bottom, spats, EP air dam, spoiler, diffuser, etc.

We may get an AEM dynoshaft, which would make it much easier to chart the changes. Basically we cold make a change, go for a drive, get the instant road load horsepower, and then make a direct comparison to before the change. Also a big maybe.

This car seems to have been well maintained. There is evidence of newish hubs, rotors, pads, recent clutch, new cat... And then there is the not so well done. The ride height varied by over an inch from high to low. The exhaust has been welded into one piece, missing the brace to the transmission housing, and has a cracked header. The fenders are horribly rolled. Relatively new top with one crack in the window. The heater core has been bypassed, but the A/C works great. Cruise is semi-functional.

Car weighed with stock seat:

http://i758.photobucket.com/albums/xx225/satisaii/91%20BRG/AsReceived.jpg

With the Kirkey and adjusted ride height:

http://i758.photobucket.com/albums/xx225/satisaii/91%20BRG/SeatSwapped.jpg

Notice the bad corner balance.

Some pics of the seat. My first victimizing of the car... I removed the stock seat mounts. No turning back now.

http://i758.photobucket.com/albums/xx225/satisaii/91%20BRG/Legroom.jpg

http://i758.photobucket.com/albums/xx225/satisaii/91%20BRG/Kirkeyfront.jpg

We then did compression and leakdown testing:

1: 210 and 40%
2: 200 and 26%
3: 205 and 7%
4: 215 and 4%

Not bad compression, not sure about the leakdown. Hopefully user error. Thanks to Steve for helping out with the testing and replacing the CAS o-ring and valve cover gasket.

Then we took the car to the dyno:

http://i758.photobucket.com/albums/xx225/satisaii/91%20BRG/Dyno.jpg

Really good for a stock 1.6

Just for fun, I painted the wheels:

http://i758.photobucket.com/albums/xx225/satisaii/91%20BRG/UnfinishedWheel.jpg

http://i758.photobucket.com/albums/xx225/satisaii/91%20BRG/PrimedWheel.jpg

http://i758.photobucket.com/albums/xx225/satisaii/91%20BRG/FinishedWheel.jpg

The brown did not like being covered. It wrinkled badly.

http://i758.photobucket.com/albums/xx225/satisaii/91%20BRG/Wheel1.jpg

And some shots of the victim:

http://i758.photobucket.com/albums/xx225/satisaii/91%20BRG/VictimSide.jpg

http://i758.photobucket.com/albums/xx225/satisaii/91%20BRG/Sunshine.jpg

On to gas mileage data...

[Satisaii]

http://i758.photobucket.com/albums/xx225/satisaii/91%20BRG/Mileage.jpg

Changing the wheels and tires makes a big difference.

[kung fu jesus]

Excellent!

Welcome to the site, John!

Do you still need a stock header? There was one pulled out at David's techday yesterday. I can see if it is layimg around still.

I cannot wait to see how this car turns out!

[I<3flippyheadlights]

On my local forum we are talking about lightness and how it affects the car. Also got into the topics of lowering, wider wheels, panels under the car to direct wind through. Things like removing the jack/spare, getting light wheels, taking out the soft top for a hard top, removing AC/PS, removing airbags, lighter steering wheel, removing charcoal canister, lighter battery and a lighter flywheel. You can drop lots of weight and work towards a better lb to hp ratio. So you will feel more nimble, faster and better mileage.

[kung fu jesus]

I have been considering lower-resistance, slightly narrower tires, too. I have already started by going into "chauffeur" driving mode; paying attention to my acceleration and braking, my input smoothness. I am shifting at 3-4k and I already find myself keeping with traffic just fine. I am also only travelling at 5-9 mph over the speed limit on the freeways. It is actually more relaxing. :lol:

My current wheel/tire set up is about 28.5 pounds. If I go towards a 185, I should be able to get around 25 lbs per corner.

I really like the hyper-miling ideas. I had a coworker who drove a Honda Insight from Santa monica to Irvine almost everyday. It was a 5sp and I have to admit, it was surprisingly fun to drive. I have wondered if a Miata could straddle the realm of sportscar and gas miser if properly planned and built.

[WASABI]

Thanks for posting this. It's always interesting what motivates people through their builds. I have a soft spot for the BRG & like the old school roadster wheel color. Out of curiosity, will you be getting the cruise fixed? I would think that it helps with gas mileage on the highway. Good luck, it also looks like you have plenty of support.

-Jim (subscribed)

[Phatmiata]

Perfect time for a Hypermiling thread considering how fast the prices are going up, again. Ill be watching this thread for some ways to save on gas. I have mostly highway miles but on the surface roads ive been trying to coast more to lights, and coasting to a stop. I think I have pissed a few folks off trying to hypermile my cars in the city but I don't care because I am the one paying for my gas.

(Off-Topic) I took the heavy 17" wheels off my MINI Cooper-S this year when I found a member selling stock 15" wheels w/tires, so not only did the gas mileage get better, the car is a bit faster on launches, and the tires are 75% Cheaper too! I did have to grind down the knuckles for them to fit over the larger brakes but Im totally happy with the results!

Thanks for posting about this project, hope to see more Hypermiler data here soon! And welcome to the forum!

[Satisaii]

For the purposes of this little experiment, I am trying to hold my driving pretty constant. I am not a very aggressive driver anyways. The commute consists of ~48 miles on I5 at 65 mph with ~5 miles on surface streets that have 50-55 mph limits and a few lights. I will try to get a map up later.

I would like to fix the cruise. It is a very intermittent fault. I can get it to work on almost every trip by persistently twisting the set switch. It will sometimes turn itself off. Sometimes it turns right on and stays on for the whole I5 run. The power light always remains on. I need to find a way to troubleshoot it on the lift.

I will be pulling bits to remove weight as part of the experiment. I think we weighed the wheels/tires in at less than 24 pounds. I will pull one off and reweigh it.

I think the next "mod" will be a good alignment. Hopefully I can get around to doing that this week. I will minimize the camber and set it to zero toe. I may even lower it some more. I don't want to make too many changes without gathering data. I can already see that it is going to be difficult to separate out meaningful changes from environmental noise.

Steve, if we can get a good stock header, I would switch it out. I don't know how it will affect the performance, but at least I won't have to listen to the leaking one and worry about carbon monoxide poisoning.

[NAautoxer]

fyi, to track your mileage, you should use fuelly.com.. :D i use it for my daily, 91 Civic Si that i get about 35mpg doing nothing special.

[AntiochOG]

^I agree about Fuelly. I've been tracking my mileage on there for a year or more. Curious to see where this thread goes. I'm always trying to save a little fuel.

[NAautoxer]

click link: makes graphs..

http://www.fuelly.com/driver/joeyz/civic-si

and makes me cry with how much i spend..

[moerdogg]

Any thoughts to playing with transmission gearing? It seems like putting in a taller 5th gear and making it more of an overdrive would really help with highway mileage. Probably end up being cost-prohibitive, but it's something I always wondered.

[kung fu jesus]

It is mentioned in the build plans. A taller R&P. 3.9 or 3.6

[moerdogg]

It is mentioned in the build plans. A taller R&P. 3.9 or 3.6

Yeah, I saw the differential changes. Thing is, I like the gearing of the car down low, and a taller diff gear will make the car sluggish off the line. If one were to raise only 5th gear by changing the trans internals, the car could still be peppy around town but more sedate for cruising on the highway.

[NAautoxer]

then just do a six speed swap, no?

[kung fu jesus]

Depends on the objective and overall goals, but I understand what you are saying.
Looking at what is available, the R&P change is a lot easier than tearing apart the transmission, no?

[moerdogg]

Depends on the objective and overall goals, but I understand what you are saying.
Looking at what is available, the R&P change is a lot easier than tearing apart the transmission, no?

Agreed, the R&P switch is definitely easier. I have no idea how one would accomplish changing out trans gears, and what would even fit. It's always been a question of mine, and I'm hoping someone with limitless resources explores it someday.

NAautoxer: According to the FlyinMiata gearing calculator (http://www.flyinmiata.com/tech/gearing.php), the 6-sp top gear is 0.843, versus 5-sp top gear is 0.813. So the 6-sp actually has a worse ratio :(

[Martin]

I've read about swapping an RX-7 5th gear into the trans to get low rpm highway cruising.

http://www.solomiata.com/Miata5thGearInterchange.html

[Satisaii]

I had an 86 Honda CRX that got 40+ mpg. I really would like to have another one, but the Miata was just easier.

We have a 3.9 open diff here. It is an easy swap for me. I think we have a 3.6 R/P here somewhere. Been a few decades since I have set one up. Should be fun.

Custom gears are possible. That could get very interesting.

My last tank was 36.6 mpg. I will set up a fuelly account tomorrow.

[KAL]

I like this project, sub'd!

[NAautoxer]

the R&P must be why my mom's 02 6 speed cruises at a few hundred RPM than my 94..

[kung fu jesus]

Yes. The 6sp is mated to the 3.9 r&p.

[Satisaii]

I did an alignment last night. Good thing I did... one of the anti-squeal shims was slicing the hat off of the rotor. Also found that the brake sliders were dry. They looked like they had been cleaned before installation.

Set the ride height at 4" front 4.25" rear, measured to the pinch welds. We also found the right front control arm, inner tie rod end, and end link are all bent. The range of camber adjustment on that corner is -1.0° to +1.5°. So I set all 4 corners to -1.0° and zero toe. We will see how that does. It certainly looks better. I could tell the alignment was off just by eyeballing it.

[Satisaii]

This is back on. I was just too busy to do anything with it, and then that car became my main project car. Now we are slow enough that I can play around some.

In the mean time I bought this:

http://i758.photobucket.com/albums/xx225/satisaii/IMG_20131223_160911_zpsc06211ec.jpg (http://s758.photobucket.com/user/satisaii/media/IMG_20131223_160911_zpsc06211ec.jpg.html)

92 with A/C and P/S. I am trying to add cruise, but so far have failed.

It has some mystery coilovers, rollbar, and a Kirkey Racing seat.

I ordered these today: http://www.tirerack.com/tires/tires.jsp?tireMake=Bridgestone&tireModel=Ecopia+EP150&partnum=855TR5EP150 They will get mounted on some 7" 6UL

I have I/H/E ready to go in after we get a base dyno. It has a 4.1 torsen, but I have a 3.9 sitting on the shelf... so why not?

We will do an EP air dam, undertray, possible flat bottom, other aero tricks.

Possible MS PNP to play with real lean cruise settings.

[kung fu jesus]

Awe. Some.

[949 Racing]

So we're playing around with ideas to get to 45mpg.

Reduce aero drag
-EP style air dam with much smaller radiator inlet
-Under tray
-Very small duck tail spoiler
- Shielding front tires from air flow

Reduce rolling resistance
-15x7 6ULs
-185/55/15 Bridgestone Ecopia 150's. OEM tire from 2014 Chevy Spark
- Gazillion psi in tires

Lower BFSC (google it)
-basic tune up
-RB intake
-Jackson Racing header
- Maybe an ECU?

Lower RPM
-185/55/15 tires are about .25" taller than OEM
- 3.9 Torsen I have collecting dust in the shop

We'll try to do as much A/B testing as we have patience for. We got a special config file from Racepak that allows us to calculate aero and rolling resistance from coast down measurements. Now to find a stretch of road around here to use as our private low speed test track.

[Rogue]

I also just picked up a '97 PEP recently. I plan to use it as a highway car.
It has a way to go, got 25.5 on a road trip this past week.
Granted that was in Rain and freeway traffic.
Gonna tune and see what that gets me and then maybe put the 3.9 torsen in.

Looking forward to following this.

[MazRoadAdmin]

The most effective hypermiling mod is the driver.

I did a couple years in a Toyota Yaris and did the hypermiling thing. Best in that car was 49.9 mpg while driving home from Sebring one Sunday evening. (I got about 16 mpg driving on the track, go figure)

My best hypermiling trip (specific mpg competition, late at night, back roads... top speeds around 60-65, average speed around 35-40) in my '91 netted 48 mpg. The car was stock with a hard top. I think the only relevant "mod" at the time was that I'd installed a kill switch to make it easier to coast with the engine off. And I was carrying a passenger.

All the gearing and tire diameter changes are good if you're trying to improve real world highway cruising MPG. For around town, it won't help much, if at all.

Aero is good. Ditch the outside mirrors if you can. (I've installed a wide-angle rear view and deleted the right side... haven't yet found a good enough interior convex mirror solution for the left side to allow deletion of the left mirror) Airdams and undertrays are good. If you can block enough air from the front, you don't really need the undertray. Boat tail is good. (like 5% improvement in MPG good)

Power mods are good (within reason, and if they are well-tuned) because they can raise the efficiency of the engine and make it possible to get more usable power for each bit of fuel burned.

But, again... the biggest gains will come from the driver. I can get 23-25 mpg running around town all the time by just driving normally. Can get 10% better (about 28) without trying too hard... and can get 30+ in town by applying serious hypermiling techniques... that's all without modding the car. Using the EPA 22mpg city as a basis... getting 30 mpg in city driving is a a 36% improvement. There is no mod or combination of mods that will gain you that much.

For me, best MPG comes from accelerating "briskly, but efficiently". Not full-throttle, but at least half... shift to keep the engine in the meat of its torque. (so about 2500-5000) And then COAST as much as humanly possible. Accel to a bit over your target speed, and immediately start coasting. If traffic allows, coast down to 10-15 mph below your target speed before putting the car back in gear and accelerating again. You don't HAVE to kill the engine while coasting, the engine doesn't use much fuel when idling... it might make a difference of about 0.5 mpg over a full tank. (I usually only do it for competition, or if I'm just in a hypermiling mood... engine-off coasting on a curvy road makes it sort of feel like you're riding a rollercoaster... kinda fun)

Caveat: If you coast with the engine off, you have no power available to accelerate. If you have power steering, you won't have it with the engine off. Your power brakes are good for only 2-3 normal applications before the accumulated vacuum is lost, then you loose brake boost. All of this is not a problem if you've practiced with it. But, I would be doing a disservice to not include this information.

Here's a little something I wrote a few years ago in my Yaris days about Basic Hypermiling Techiques (http://www.tamparacing.com/forums/green-motoring/498734-simple-hypermiling-techniques-work.html).

[Satisaii]

The idea is to see where we can take the car more than the driver. My preference would be to use cruise for the highway portion of the trip to eliminate me from the equation... if I can get the dang thing to work.

The old car was getting a very consistent 35.7 mpg (adjusted by GPS) for the trip. The new one is getting 31. https://www.fuelly.com/driver/satisaii/mx5-miata

The drive is ~50 miles on freeways and 5 miles on streets each way.

[kung fu jesus]

I love this project! I am really interested to see how this turns out!

[MazRoadAdmin]

Yeah, I get it. You're in the business of building cars and selling parts. Makes sense to learn what can be done to the car that makes a difference.

If you can be consistent in how you drive and the route is mostly the same, you should be able to collect some relatively scientific data about how your mods improved fuel economy.

[kung fu jesus]

Fuel economy mods/development should also be useful when applied to, say, I dunno...endurance racing? :)

[Satisaii]

Not sure what we will get out of it, other than a sense of satisfaction of finally doing it after 3 years of talking about it.

Consistency is an issue. The drive in is pretty easy since I do it at 4 am. I have a problem with the speed creeping up, but that is easily solved with cruise. The drive home can be rough. Some days I deviate by 30 miles to avoid traffic into downtown LA, and other days I just sit in it. Time smooths this out, but we don't want to be waiting a long time between changes to gather data.

https://www.fuelly.com/driver/satisaii/mx5-miata-2

Fill ups since I bought it.

I put a new damper on it and set timing to 15°. The old damper had debonded and could not be used to set timing. Also put in new plugs and Magnacore wires. Will take some baseline data on the engine next week (compression and leakdown.) I did not know that I had put that many miles on it. Time for an oil change since I have no idea when Sonny did it last, or what kind of oil he used. The good news is that it does not use much oil. It also passed smog last week FWIW.

[kung fu jesus]

Excellent baseline. Are you going to datalog? If so what parameters? Maybe interesting to tie that in with GPS tracking for elevation.

I often wondered what mods would be effective for reducing drag through datalogging, like a rear bumper cutout.

[Satisaii]

It may get a G2X for a bit (or byte?) We have some custom math channels from Racepak to do coast down drag testing.

We have discussed doing a couple of data points with no bumper, but I am not opposed to doing an "artful" cutout (when the helpful pictures get reloaded.) All in the name of science :) I watched him do one at Woolery's, but doubt I can recreate it without instructions.

[kung fu jesus]

Awesome! Jeremy is the master at those cutouts. I need pictures of it too!

[Rogue]

fyi, to track your mileage, you should use Fuelly.com.

are any of y'all using the app? Reviews are not encouraging.

[Sharpie]

What tire pressures are you running? Insight guys running 60+ psi. I increased my 97' civic hatch from 36mpg to 42 mpg minimal hyper miling techniques.

Cool project.

[AntiochOG]

are any of y'all using the app? Reviews are not encouraging.

I don't care much for the app, but you can text your fill ups in. This works really well for me.

[Satisaii]

Just did hot leakdown and compression tests for a baseline to refer to as the miles pile up on the car.

198 2%
195 9%
198 5%
185 18%

I would be busy swapping engines right now if it were one of the race cars. But it is not, so it will just be a reference for the future. I may consider doing an OEM rebuild at the end of the test... depending on my cash flow this year.

[kung fu jesus]

Was it coming from the block or head?

[Satisaii]

Exhaust valve

[kung fu jesus]

Easy.

[Satisaii]

You see the 1.6 SM head for sale on track hq? Must resist spending money on this car...

Been switching tires around. Finally got the Ecopias mounted and on the car. Of the 3 sets I have had on the car, they ride the best and are the quietest. No performance testing, but I bet they are not going to be the best track day tire.

So far I have run the following:

205/50/15 Dunlop DZ101 on 8" 6UL, weight 28lbs 9oz. These are almost worn to the wear bars.
205/50/15 Falken Ziex ZE912 on 7" 6UL, weight 30lbs 8oz. These are nearly new.
185/55/15 Bridgestone Ecopia EP150 on 7" 6UL, weight 28lbs 2oz. These are new.

I don't have the exact analysis sitting in front of me, but here is the gist so far:
Started out getting ~32 mpg on the Dunlops
Replacing the worn out harmonic balancer and resetting the timing to 15° from +20° dropped mileage to >30 mpg
Switching tires from the Dunlops to the Falkens got it back to almost 32 mpg.
No data collected on the Ecopias yet, but they feel like they are rolling easier. Good ol' seat of the pants HP measurement there.

Odometer correction is currently 55.1 miles actual vs 51.7 indicated, for a correction factor of 1.06576402

I need a good phone mount for the car, and possibly an app that can work as a running odometer. It would be nice if it could run on a phone with no data connection. I have a Galaxy S2 that does not read a SIM card (no phone) but everything else works on it. That would be perfect for just gathering GPS data. I have tried Torque, but it resets to 0 when it gets shut down.

[kung fu jesus]

I saw that head...ugh! So tempting!

Thanks for the update!!