Roman

I ruled out this option the day I bought a Toyota Echo

Yeah I'm doing ~3400rpm @ 100kph with a 4.3 final drive which doesnt help anything. If I could find a cheap S15 six speed box and swap 6th gear over into mine. (It's possible apparently) The rpm at 100kph would drop to ~3000rpm, without adversely changing 1-5th as you would with a final drive swap. A bit more of a mission though!

Imagine if some time in the future, your grand kids say "Grandpa, what was it like back when there was petrol? Did you have a car like Mad Max?" And you're like "I owned a pathetic car and then drove like a jerk to save myself an immeasurably small amount of money" Seeing them frown dissaprovingly would be awesome

Just make sure you're in 4th or 5th gear to get best Litres per skid kilometer.

Hey people, In honor of my proud Dutch heritage, sometimes I find it to be a bit of fun to try and drive a car economically. It's pretty amazing the difference that you can acheive with some simple differences. As an example... My daily driver. Driving "normally" I will average about 5.5 litres per 100km. Driving "economically" in the last few days I can get low 4l per 100km or even dipping into the 3s. It makes the drive to work a bit more interesting, even if the financial difference is irrelevant. Regardless of whether a car is old or new there are some techniques that can help shave down that gas bill. There are a few interesting things that I've found out while trying to be as frugal as possible: 1. Knowledge is power If you've got a non oldschool daily, that's OBD2 compliant. Get an OBD2 bluetooth unit and a smartphone app that can show you realtime and "trip" fuel consumption. Seeing the numbers as you go, is what turns the whole thing into a contest haha. If not, the best thing to do is write down results. Keep a little notebook. Fill your gas tank to the brim, and record the odometer reading each time you fill up. There is an app called "fuelly" which is essentially a digital version of this that's quite good. But having the realtime info is definitely best if you can. 2. Your car has a particular speed in top gear at which it is most economical. When you drive too slow, you use more gas because your engine is running for longer to cover that same distance. When you drive too fast, your engine is revving too high and/or the aerodynamic drag becomes too high and you use more fuel. Most cars have their sweet spot at around 80-90kph for best economy. For older cars that are a little less aerodynamic, or with 3 or 4 speed transmissions this speed may be a little lower again. If you have an OBD2 setup you should be able to keep an eye on speed and try find that best spot. If you have to take an educated guess, stick with 80kph. 2. Engine braking happens all of the time Everyone knows about engine braking, but what is maybe not obvious is that engine braking forces happen even when you accellerate. If you are driving along on a flat road and your engine is doing 3000rpm. You've got 3000rpm worth of engine braking force that you have to supply power to, before any power can make it to the ground to help maintain your speed. If you're on a slight downhill, just chuck it in neutral. You'll not have the engine braking force dragging on your drivetrain anymore, so the only power the engine needs to make is enough to idle which is generally bugger all. 2. "Pulse and glide" Relating to the above, you use a LOT less gas when coasting in neutral. So coasting for a bit, then speeding back up, then coasting etc etc is actually very economical. Especially on larger engines that may have high pumping losses at low rpm. So for example accelerate to 105kph then coast to 90, accell to 105 drop to 90, etc. You're spending a much smaller percentage of time battling against engine braking forces. As retarded as this sounds, it probably makes the single biggest difference out of anything that I've tried. Dont be a jerk holding up traffic, or nauseating your passengers with this technique. As it's quite annoying. It would also get rather tedious on a long trip. But if you're heading somewhere on your own, maybe somewhere that's a regular trip and you want to try do it on less fuel than you ever have before. This is how its done. 3. Sort the basics If your wheel alignment is terrible and you've got a half flat tire, it's going to cost you some gas. Generally pumping the tires a bit higher pressure helps with economy. Dont lug around 100kg worth of crap in the boot, you're using gas to speed all that stuff up for no reason. 4. Idle while stationary is the worst. The ideal situation is that you're going at a fast speed, with minimal fuel usage. If you're stationary then you're using gas to not travel ANY kms. Dont leave your car idling in the driveway to warm up, get in and drive straight away. Your engine uses a lot more fuel when cold, so you want to minimise the cold period and also make sure you're at least getting some kms out of it. Driving it up to speed straight away helps warm the engine up a fair bit quicker. If you're at a set of lights and you expect to be there for more than 5-10 seconds then switch your car off (assuming it starts reliably haha) 5. The brakes are stealing your economy You've used fuel in order to accelerate the car up to a particular speed, then from here you're using up your hard earned momentum to keep moving forward as the car slows down. When you hit the brakes its like you're throwing away the energy you spent fuel on. I'm not advocating avoiding the brake pedal... But the point is that if you only need to get up to 30kph to get to that next set of lights in peak hour traffic. Dont blitz it up to 70kph and then slam the brakes on right at the end. 6. Aerodynamics are your friend If you wind down your window at 100kph and put your hand out, you'll feel your arm get blown backwards quite strongly. Imagine that same force applying across the whole front of your car, you need to use a fair bit of fuel to overcome this and keep the vehicle moving forward. A more aerodynamic car (like a coupe) will use less gas than a sedan (boo) or a wagon (blergh) although there are huge variations on this depending on how much thought was put into the design. Generally speaking more modern cars have lower amounts of drag, because they started realizing it passively improves fuel consumption regardless of the drivers behaviour. The measure for how slippery a car is, is called the Coefficient of Drag (C.D.) Most modern cars have a known CD value that you can look up. The lower the number, the less fuel it needs to use to push an object of that size through the air. As an example, a Honda Insight Hybrid might have a CD of 0.26. A car designed with no aerodynamic consideration could have a CD of 0.4. If you're looking to buy a new car that will be economical at 100kph, try find out its CD value. A car with a bigger engine but lower CD value can potentially be more economical if you're doing a lot of open road driving. Anyone have anything else to contribute? Feel free to discuss anything relating to being a cheap arse on the fuel front. Thanks to some advanced driving techniques I saved about 90 cents on the way to work today

So I finished my real estate sign radiator side panel thingys. Before trying anything else I wanted to get some tests first regarding drag etc. According some coast down tests and the Excel sheet my car has a Coefficient of Drag of 0.39 which is pretty ugly. Sooooo according to this: http://www.wallaceracing.com/Calculate%20HP%20For%20Speed.php At 200kph my car needs 105hp just to push through the air. So there is less than half of my power left to accellerate with. If I could reduce my CD to 0.35, this drops to needing 95hp. If I could reduce it to 0.3 (unlikely/impossible) this drops to 83hp. Making my car more slippery would be the same as gaining ~20 horsepower. I find this surprising as I would have thought changing CD would make a greater difference than that. Maybe I should double check my maths haha. It seems easier to just keep it as is, and then just have the car make more power haha. Certainly not worth turning the car into a teardrop shaped abomination when you're only going 200kph. Maybe a different story on the salt flats though!

Wile E. Coyote gave it a go a few times.

By all means please do! Get a link to run it, I'll help you tune it. Then I can pass the baton to the next generation of people using a Carina to draw pointless graphs on the internet.

It's not for saving money so much as for interests sake and learning something new. Or, learning about the theory of things, but then seeing how the theory holds up with some practical tests. It's also about being smug, that's my real main hobby. The best way to save money with this car would be to put it in a crusher haha. I'm done with the idea of driving old or high km cars as a daily though. My next car wont be something so Echo-ey but will aim for something around the 30 thou kms mark again. Not a single dollar or hour spent on problems for that car, in ~60,000kms driven so far. That's beaten any previous vehicle I've owned by several magnitudes haha. 2GRs are coming down in price...

I can only imagine how many intrusive stares you'd get in that Civic while trying to drive around. You can only look back at so many repugnant stares in traffic before it starts to get to wear you down haha. Probably cops pulling you over to WTF at your car as well, that cant be good for mileage From factory the Carina did have an undertray under the front engine bay area, but I had to ditch it because the sump came down too low and the new swaybar hits it. But thats all behind the radiator line, nothing ahead of it. I should really dig it out and see what I'd need to chop out to make it fit, probably the easiest way to address that half of the issue easily. Probably the easiest ways to make it a bit more economical currently though: (Not planning on all of these things) 1. Switch fuel over to the modelled fuel equation so I can see realtime fuel consumption in datalogs. 2. Do some more testing with repeatable cruise control / motorway method to try leaner AFRs and see if there's any real economy there. Or whether it just means foot down further to make the same power. 3. Change final drive ratio to 3.7 or 3.9 (pfffttt) 4. Narrower tires on wheels that fit more inside the gaurds, so the tires arent exposed to airflow. 5. Fit a taller tire profile to reduce 100kph rpm some more. 6. Make front undertray thingy to reduce drag 7. vortex generator(s) on trailing edge of roof to keep the flow attached further down the rear screen. (Would look gross though, do not want) 8. drive the car in such a way that means I may as well be driving the Echo. haha.

Yeah something like a DC2 would probably be a better shape to start with, and still reasonably light etc. Variable valve timing engines can alter cam timing to make it work like internal EGR, intentionally sucking some of the exhaust gas back into the cylinder before combustion. I think it improves economy by reducing pumping losses? But that's why most modern engines dont have EGR pumps etc anymore, thank christ.

Yeah true, I guess it wasnt speed dependent to generate downforce either which is cool. The problem with the fan car though, and any aero car / ground effects I guess. Is that as soon as you clip over a ripple strip or something else that breaks the seal with the ground. You go from having 100mph worth of grip down to 40mph worth of grip (or whatever) Which was likely a death sentence in that era. Although I doubt this was the rationale behind banning it, didnt seem like many fucks were given about race car drivers safety in that sort of era!

To put that in context it would cost him about $30 to drive from Auckland to Wellington. I dont even think it's a particularly good engine for it either. Amazing. Yuck, but amazing.

Pretty much anything in F1 that gets banned, is usually awesome haha. The fan car was cool but I'd say a modern F1 car would make way more downforce anyway. Although its a bit of a laugh that the fan car pretty much looks like a big rectangle box, compared to having a zillion ugly winglets diverting every little tuft of air.

Haha yep thats the one. Hilarious looking, but need to keep in mind that with a shitbox civic and about $2k spend he's acheived better milage than any car manufactured including hybrids etc.

So I've had a bit of a nerd-on regarding fuel economy etc recently, Was reading about that guy that whale tailed his civic (which looks utterly rediculous) However he now gets 2.8l per 100km What the fuck!! I didnt even think that it would be possible to improve by that much. I want to keep this car looking standard, but there's some low hanging fruit in the aero department because the front of a the car, from underneath, is a frigging mess. Gonna have some side sections sealing off radiator entry so it uses the fan less. Then try get a flat tray underneath the front of the radiator area and a short distance behind it too. Might be worth a few KPH at the far end of the straight at Hampton. Found this cool excel sheet, will give this a go before and after and see if there's any difference. Not expecting miracles but I do think there will be at least some quantifiable change for the better by attempting reducing drag a little. If not, as usual, will chuck it in the bin. www.iwilltry.org/b/wp-content/uploads/2010/05/Drag_Coefficient.xls Made a start on some side panels for radiator, just corflute for starters. Will check with pressure sensor for before/after and see if it makes any difference. "When you've got carbon fibre taste, but a real estate sign budget"

So little air that it's truly negligible compared to what else is going on around the wheel. (in the example of this particular disc etc at least)

Absolutely! A very crude approximation of the wheel well etc is in the model, I've just hidden it for sake of pics.

Looking in plan view over a wheel Isosurfaces are my new favourite gimmick. really need to see the 3D model and rotate it to get an idea of shape though. Basically it draws a 3D mesh of where the flow is at a certain speed or pressure or whatever. So this is wheel going 120kph but showing where the flow drops to 90kph or below. Which is pretty much as per the picture above.

Julian Edgar is the man. Read one of his books back in the day, first time I'd seen anyone try to quantify changes for anything to do with modifying cars.

(Disclaimer: Below rambling is for sake of interest, not necessarily that I need extra airflow to brakes at this stage) Last night I drew a fairly accurate model of one of my front wheels, the hub, and the disc, and a big slab of "ground" No caliper or suspension yet but just for interests sake looking at the basics of how air flows around the disc / spokes / etc when its rotating. It seems that when the wheel is travelling forwards at 120kph, (and rotating...) There's virtually zero air flow through the centre of the wheel or near the disc. The tire builds a big wake that seperates at the leading edge of the tire and thats the last airspeed that the wheel or disc pretty much ever sees. Even with a crude representation of the front of the car covering upper half of the front of the wheel. The flow around the wheel only changes things ever so slightly because it's the high pressure zone down low under the front of tire which intiates the wake that then spills upwards. I was sort of expecting the spokes of the wheel to be stirring up some air in a semi meaningful sort of way, but doesnt look like it acheives anything useful. What's interesting to see is that without supporting aero mods ahead of the wheel. Aerodynamic wheel covers, despite looking sleek likely acheive next to nothing as there's no air speed going past them. Which is probably why they were last seen in the 80s. Even if they stuck out by say 40-50mm it wouldnt make any difference currently. I can now see the rationale behind "speed flaps" ahead of the tire mounted to the lower gaurd. Which are there to disrupt airflow before it gets to the tire, so it flows more uniformly around it. I'm not taking the above results as gospel but it was certainly a lot different to how I imagined flow in and around a wheel would work. Will post some pictures later so this rambling makes more sense.

I'm pretty keen to wire up sensors either way, for interests sake. Ferodos have been good in terms of braking feel / no fade / etc but yeah, its the wear rate thats the killer currently. Ahhh well at least my discs arent wearing by any significant amount so far. I'll try a different type of pad next time.

Thanks, not sure on brake temps but figuring out a way to measure is pretty high on my list. I've got an IR gun but it's hard to know peak temps if you're only measuring when you get back in the pits after a cooldown lap. I've been doing some joogles and I see there's a fairly popular sensor that goes to 1000cc and outputs pwm relating to temperature, so could wire some of those in. Or even better have some tire temp sensors as well and wire it all up as can/bus so I've still got inputs and outputs left. I definitely agree that getting some data about the actual problem is the first step before "fixing" it. I dont get brake fade at all, just high wear rates. My rear brakes havent gone through a set of pads at all yet, but front brakes do most of the work and a set of pads lasts about 4 trackdays. Keeping in mind that this isnt a dedicated race car with race pads, as per usual I'm trying to tip toe through that middle ground and keep a drivable car on the street. (Using Ferodo DS2200)

Your girlfriend is pregnant.

Then wait until after... You're dealing with 30+ year old parts so something unexpected will happen. If you just swap the guts over, your contact patch on the gears might not be correct anymore. In which case it's a bit more tricky to setup from there. So long as you leave the pinion gear completely untouched, and use the same bearings you might be right. Just dont back off the nut on the pinion flange EVER unless you're replacing the crush tube etc inside.