Fuel economy figures and wishful Euro thinking

[Hersbird]

Originally Posted by Rosieuk

I'm getting 41.8-42mpg out of it at the moment and I wouldn't be surprised at 47+ when the cat has been replaced.. but this is my point. I've now got 4 different figures for my car, including yours, one of which is cloud cuckoo land, and two of which can best be described as claimed, ie 44 & 47. I have managed to get 44mpg out of it on precisely one tank and I've driven the best part of 20k. As you say with the Getz, the 1300 is poorer mpg but yet if you look at UK road tax its lower co2 & lower road tax.. by £20! They make it up as they go along..

So this and the last post about it running better on 93 octain show it's not the rating that's bad, but you particular car has other mechanical problems. The most basic Hyundai 4 banger doesn't need even 85 octain fuel to run to the point there is no "better". If it runs rough on 85 It has other problems. If you think replacing the converter would give 47mpg then what are you waiting for there? Then you need to learn and practice some of the tips on this site and you should be beating that 47 mpg rating not blaming Hundai for just doing what the government tells them to do. Also all taxes everywhere are just made up as they go along, welcome to the path of Libertarianism my friend!

[BLSTIC]

I have found that every single one of my 17 cars went better on premium fuel, if they could be tuned for it (manually or by knock sensor). The two exceptions were my automatic large-displacement Australian cars, which didn't have a function to run more advanced timing and couldn't be driven at high loads consistently. The manual versions of one of those cars did benefit. I'm willing to bet that the manual version of the other would have improved, but I haven't driven one.

[cRiPpLe_rOoStEr]

Even though the enhanced anti-knock properties of premium fuel allow for a leaner burn, sometimes it's not activated in order to avoid overheating (especially in a low-cost econobox which might not have the cooling system dimensioned to handle the usually higher temperatures while running too lean) or due to emissions compliance.

[Hersbird]

"Went better" doesn't mean better mpg, if anything it means the exact opposite. If you are driving for economy you would never notice when a car is really making power because you would be running around at 3/4 throttle or less, shifting early in the rpm range, etc. If anything you want to make the motor make less power so it requires more throttle opening which reduces pumping losses. A big EGR or warm air intake helps with that. Again both of those things can make the car run what would feel like worse to you but it would be getting better MPG and still move along in normal traffic just fine. My van has an "economy" button with a little green light, the magazine testers hate the switch because it makes the van run like a dog, less throttle response, earlier shift points, etc. but it definitely helps with the MPG keeping it on.

I don't believe a leaner burn mixture is ever activated in any modern car because of NOx standards of today, at least in the USA. Volkswagen was basically doing this with their diesel scandal.

[cRiPpLe_rOoStEr]

Originally Posted by Hersbird

I don't believe a leaner burn mixture is ever activated in any modern car because of NOx standards of today, at least in the USA. Volkswagen was basically doing this with their diesel scandal.

The same cheating device could be fitted to gassers too. But anyway, if a fully-compliant engine could detect NOx levels, that would eventually enable it to go leaner on favorable environmental conditions such as higher relative air humidity in the air. Though I'm not sure how a higher-grade gasoline would interfere with NOx since it might require to take more latent heat of vaporization (thus enabling a smaller amount to be used).

[BLSTIC]

Originally Posted by Hersbird

"Went better" doesn't mean better mpg, if anything it means the exact opposite. If you are driving for economy you would never notice when a car is really making power because you would be running around at 3/4 throttle or less, shifting early in the rpm range, etc. If anything you want to make the motor make less power so it requires more throttle opening which reduces pumping losses. A big EGR or warm air intake helps with that. Again both of those things can make the car run what would feel like worse to you but it would be getting better MPG and still move along in normal traffic just fine. My van has an "economy" button with a little green light, the magazine testers hate the switch because it makes the van run like a dog, less throttle response, earlier shift points, etc. but it definitely helps with the MPG keeping it on.

I should clarify. By "went better" I meant ran smoother at high loads and produced marginally more torque (thanks to being able to run closer to MBT ignition timing, sometimes it was the difference between being able to use the next gear or not uphill). The cars I measured fuel economy on (about 5 of them) also improved to the tune of about 5-10% around town as a result of the combination of that and me being more likely to use high loads when the engine is running smooth. I didn't do open road testing between tanks as the only open road trips I regularly repeated were with engines that *needed* premium.

*edit* One particular car (An 800cc carbied 3-pot) even got the same $/km on premium and regular, such was the difference in performance and economy. Free horsepower, once I gave it a good tune-up

[Hersbird]

I'm sorry to confuse your words with the OP, I can see where it might help with low rpm, high load. I get the feeling that is not the case with the Hyundai in question.

My brother has a low mileage 2003 Mazda 3 that has started having MPG issues along with off and on codes. It seemed like it was running perfect but it sometimes started sucking gas even as much as twice normal. We replaced the mass air sensor and the front O2 but sometimes it still throws the light for a slow fuel/air response and then mileage drops (not as bad as before). We had to weld a new O2 bung on the manifold and I think it might have moved the sensor out of the exhaust stream too much. He bought a OBD2 bluetooth adaptor and just immediately clears the code and then it goes back to good MPG. I figure it's going into an open loop condition but it doesn't show up on the O2 data logging. Little stuff like this can make a big difference.

[Rosieuk]

Originally Posted by Hersbird

So this and the last post about it running better on 93 octain show it's not the rating that's bad, but you particular car has other mechanical problems. The most basic Hyundai 4 banger doesn't need even 85 octain fuel to run to the point there is no "better". If it runs rough on 85 It has other problems. If you think replacing the converter would give 47mpg then what are you waiting for there? Then you need to learn and practice some of the tips on this site and you should be beating that 47 mpg rating not blaming Hundai for just doing what the government tells them to do. Also all taxes everywhere are just made up as they go along, welcome to the path of Libertarianism my friend!

Arrogant little nerk aren't you? I've seen you around here and I've never seen you have a nice word for anyone. If you'd bothered to look at my other posts you would have found out the converter was changed yesterday. Its not solved the problem completely although it's a lot better and getting substantially better mpg best I can tell. Also a gas mask is not required on cold starts.
Second quoting a lower mpg and higher co2 figure for a vehicle with an identical drivetrain is ridiculous and it has nothing to do with "the government" telling Hyundai anything, that's their official figure on the car.
Thirdly, to my knowledge, there has never been 85 ron petrol sold in the UK, anywhere or anywhen, even if you include leaded - the nearest I can imagine is old ** which even a Ford Cortina would spit up on the basis it was half petrol, half kerosene with a cat urine chaser, and that was on a good day. Even the Renault 6 wouldn't run on it..
Fourthly that clanging noise you just heard is you missing my point. When I learned to drive and we bought a car with a given fuel consumption - driven sensibly that vehicle would meet or exceed said figure with ease. There was one figure and the figure was correct. For this vehicle I have.. 36/38/42/44/47 combined averages, all from different places, two which are supposedly official.. and the newer cars are worse, with combined figures you could only manage by dropping it off the Eiffel Tower in top (that's I'm France by the way, at least for the moment).
fifthly, having looked at many of the people you seem to enjoy chewing out, it's noticeable that you enjoy so far as I can tell targeting women on here. I wonder if you have noticed, as I have, being well read, a polymath and a published writer, that the device you are using was conceptually invented by a "sweeper of the chocolate chimney" (Alan Turing), and if you're using any phone or tablet (or for that matter, any vehicle with an ECU) that uses an ARM series processor you can thank a transsexual woman. I would think on that a little, of your brain hasn't entered an irreducible state of BSOD. I'd love to tell the current head of Isis/Palmyran CIA rep all about it just to see the look on his face.. (it'd be worth it even more to see terrorists trundling round in A35 pickups..).
In point of fact I've done a few things that I've found on here, most of which I was doing anyway, excluding of course the ones that are illegal (EOC and drafting trucks), not to mention suicidally idiotic in a modern car with hydraulic power brakes and power steering and having built, upgraded and tuned Autocycles I don't need condescension from you thank you *so* much.
Just a last point, the people responsible for the problems on that vehicle are all members of the genetically endicked and are all supposed to be trained mechanics. They put the wrong oil in it, replaced the isc using a hammer which smashed the number 4 injector harness so it's barely holding together, replaced a front suspension arm apparently with superglue as a lubricant and even the manufacturer dealer doesn't have the remotest clue what's up.. oddly enough, anything I've never taken to a garage and maintained or built myself has worked like a dream...

[Hersbird]

You are way out of line.
I think maybe something has gotten lost in translation. If you actually new me you would see I'm probably one of the nicest, easist going people you are going to meet. The kind that goes out of his way spend as much time as possible helping both friends and strangers alike. I'm sorry if my help isn't helpful to you, I never was trying to belittle what you are working on, but to help you maybe find a problem. Sorry again.

[cRiPpLe_rOoStEr]

Originally Posted by Rosieuk

I wonder if you have noticed, as I have, being well read, a polymath and a published writer, that the device you are using was conceptually invented by a "sweeper of the chocolate chimney" (Alan Turing)

Are you serious? What does Alan Turing being gay interfere with fuel-efficiency? Do you really think gays and women deserve some special recognition for their achievements? As I told to a gay dude who works at a regional clothing stores chain very popular in my hometown, and he agreed with me on that matter, all this left-leaning "political correctness" is as discriminatory as the Jim Crow laws and the Nazis. In the end, it's all discrimination based in social/cultural backgrounds and biological features.