Gtir ecconomy?

[Perrin21]

My concern would be that the obvious way to improve fuel economy is to run a leaner mixture (less fuel in = less fuel burnt), but that also means running hotter with the risk of more DET. - Obviously I'm not suggesting that the person mapping your car doesn't know that, nor that when there's no load on the engine that doesn't make a lot of difference.
I'm just cautious about the prospect of making a map lean about where you'd be cruising just so that you use less fuel; maybe it's just an aesthetic thing, and I like the idea of nice smooth fuelling curves rather than wobbly lines. Does that also give you a really odd power curve/delivery?

It seems to me like there's already a sweet spot where you're not making boost, but the turbo is no-longer acting parasitically; a balance point where the fuel economy seems to be best.

Ultimately this isn't a car that was designed to be cruising on motorways being really fuel efficient; it was designed to explode out of corners and hold on to loose surfaces. If you want fuel efficient, just buy a hybrid; as long as someone is supporting the technology it will mature and become better with each iteration.

Why does this question always seem to get the same replies. Forget fuel economy and buy a hybrid like the person asking it is some kind of dumbass? Of course the car is going to be thirsty when on boost and driven hard, however when off boost (cruising) theres no reason why there should be so many variances between peoples cars unless they have been modified out of their original tune significantly. Also the stock map is apparently very rich. You saw my car on the RR event Pobody and its running high 10s AFR which is far too rich. Im sure that explains my lousy fuel economy lol (Half tank Bpool to Preston Mway). I have zero ellusions about the pulsar (its my second one) but im sure this is an area that with a little improvement would enhance the enjoyment of the car for others as well as myself now that fuel prices are over £1.40 per Ltr and rising. Im also certain that it seems no co incidence that those experiencing better economy and improved performance have had mapping done at some point. That was my reason for resurecting this thread. Would adding wideband AFR improve the information being returned to the ECU? would this improve fuel economy?

 

[PobodY]

A wideband won't help you other than to tell you how rich/lean the mixture is; it's (generally) not talking to the ECU because that's reading the narrowband sensor. It will help you if you want to adjust your fuelling map, and will let you have some confidence that you're not melting the engine because of the changes.

I'm not saying forget fuel economy, I'm saying "try adjusting your driving style first"; my experience is that it seems to be best when it's only just starting to generate positive boost. Driving off-boost doesn't really help you because the turbo is parasitic and is restricting the exhaust until it has spun-up. - As for the variance; it's a 20-year old car, you can't really expect them to all be the same any more.

The stock map is rich to protect the engine from detonation as the boost increases; that's why I'm cautious of the idea of just leaning the map out. I'm not saying it's perfect, but equally it can't be that bad if it's been running like that for this long.

 

[geoff pine]

Why does this question always seem to get the same replies. Forget fuel economy and buy a hybrid like the person asking it is some kind of dumbass? Of course the car is going to be thirsty when on boost and driven hard, however when off boost (cruising) theres no reason why there should be so many variances between peoples cars unless they have been modified out of their original tune significantly. Also the stock map is apparently very rich. You saw my car on the RR event Pobody and its running high 10s AFR which is far too rich. Im sure that explains my lousy fuel economy lol (Half tank Bpool to Preston Mway). I have zero ellusions about the pulsar (its my second one) but im sure this is an area that with a little improvement would enhance the enjoyment of the car for others as well as myself now that fuel prices are over £1.40 per Ltr and rising. Im also certain that it seems no co incidence that those experiencing better economy and improved performance have had mapping done at some point. That was my reason for resurecting this thread. Would adding wideband AFR improve the information being returned to the ECU? would this improve fuel economy?

At the last rolling road but one (first time we used dyno demons ) mine ran high tens and had a strong smell of fuel re earthing the maf solved this last rolling road was in the 11,s have you had a sniff off your oil :lol:

 

[skiddusmarkus]

My concern would be that the obvious way to improve fuel economy is to run a leaner mixture (less fuel in = less fuel burnt), but that also means running hotter with the risk of more DET. - Obviously I'm not suggesting that the person mapping your car doesn't know that, nor that when there's no load on the engine that doesn't make a lot of difference.
I'm just cautious about the prospect of making a map lean about where you'd be cruising just so that you use less fuel; maybe it's just an aesthetic thing, and I like the idea of nice smooth fuelling curves rather than wobbly lines. Does that also give you a really odd power curve/delivery?

It seems to me like there's already a sweet spot where you're not making boost, but the turbo is no-longer acting parasitically; a balance point where the fuel economy seems to be best.

Ultimately this isn't a car that was designed to be cruising on motorways being really fuel efficient; it was designed to explode out of corners and hold on to loose surfaces. If you want fuel efficient, just buy a hybrid; as long as someone is supporting the technology it will mature and become better with each iteration.

Thats what you do Po, pick a speed you want to cruise at and then get it mapped lean at that rpm eg 70mph in 5th would be about 3500rpm.There's no real load on the engine and as soon as you put your foot down and exert load, it just richens up straight away.I have a wideband display and you can see it happening.

 

[PobodY]

Thanks for reassuring me. - Do you see temperatures going up when you're cruising like that, or does the lack of load mean that doesn't really happen?

I've mainly given up on this kind of economy because I really don't do that much motorway driving, and when I do I like to use the open road as an excuse to put my foot down... but not exceed the national speed limits obviously.

 

[skiddusmarkus]

Not really as the car is probably only making something silly like 50bhp, just enough to maintain the speed.