Improved MPG - how?
Discussion
I thought my consumption had increased, then after I had some work done in Oct which amongst other things involved all the basic running checks i.e check timing, base idle etc it came back again. On Friday I did 120mi from St Albans to Kent and back and used just over the first quarter according to the guage but I already knew it could crack 30mpg on a run since taking it around Europe last summer.
I can't help with the 'leaning' bit so this might not be very constructive, but I'd have thought a few sensible things would be to keep motorway speeds down below 70 and keep the roof on when doing it. Unfortunately that defeats the purpose of having a TVR somewhat!
To be fair, you'd spend around £600 in fuel on a trip that size. Is £60 really worth worrying about? Just have one less meal out.
To be fair, you'd spend around £600 in fuel on a trip that size. Is £60 really worth worrying about? Just have one less meal out.
dog man said:
I already knew it could crack 30mpg on a run since taking it around Europe last summer.
I wish mine did.
My S3 would crack 30 mpg on a run and, at the time, the V8S owners reckoned they were getting about 28, so in a way I'm not surprised, but I'm getting about 15mpg in mixed running.
Always good to monitor MPG. Best things to ensure I'd say are Tyre pressures, tracking, spark plug gap, ign timing, clean rotor arm/dist cap contact points, stepper motor and thermostat. Also the various temp sensors...do they have an air intake temp sensor in the AFM? that could be cleaned/tested. Also the track inside the AFM can become worn leading to poor resistance and incorrect signals - according to throttle position - being sent to the ecu
LordB said:
...is there a safe way of leaning off the fuel mixture without casuing any damage...
The fuelling system is pretty well set up. Unless there's something wrong you should be seeing 26+ MPG on a long European cruise.dog man said:
Also the track inside the AFM can become worn leading to poor resistance and incorrect signals
The Chimaera uses a hot wire AFM, not a flapper, so has no moving parts.Mark_S_24 said:
Best way to improve MPH is to adjust the way you drive.
Try not to accelerate or brake unless you really have to.
But who wants to drive like that? :-)
Mark
There may be more to it than that with a Chim. With mine it seems to use noticeably less fuel if you keep the revs quite high. It'll happily pull 2,000rpm all day long or even less without obviously labouring, but it seems happier from about 2,750rpm upwards. That might just be a fault with my car (duff AFM or something) but I do wonder if the erratic fuelling actually continues above the documented 'shunt' zone up to about 2,000rpm. It may well be running usefully leaner if you let it rev a bit more.Try not to accelerate or brake unless you really have to.
But who wants to drive like that? :-)
Mark
LordB said:
Im off on a 3000km tour of Europe in the summer and wondered if there is a sensible way (other than cutting off my right foot) that I could squeeze out another 10% fuel economy. Eg is there a safe way of leaning off the fuel mixture without casuing any damage.
The short answer is not really.The most obvious thing to do is make sure the car is running spot on before you leave. I have always found that not caning it on the motorways (keeping to legal speeds) saves quite a lot of fuel. My 400(economy model) has averaged about 27 > 29mpg on untold eurohoons I have been on.
When it comes to the twisty bits any kind of fun is going to cost in fuel, but worth it, no point in going if you are not going to enjoy it IMO.
Have a good trip
. Would welcome 6 miles to the gallon +.You cant alter the mixture to use less fuel, as the ECU clamps the mixture to produce minimum pollutants, at the expense of fuel consumption under crusing conditions. The non catalys fuel map allows the mixture to lean out some more, but you need the correct fuel chip ( The Mark Adams ones are optimised on both maps) and preferably no catalysts at all. Trouble is big engines will little load never reach their optimum compression ratio when the throttle is near closed so the engine is very ineffcient. A wider throttle opening in a higher gear will use less fuel.
Edited by blitzracing on Monday 24th January 18:40
I had the engine rebuilt in the Chim last year. Jason at Str8Six advised running it in for 1000mls with part-throttle and 3000rpm max. OK, the engine was probably still 'tight', but mpg when driving like Miss Daisy turned out to be not much better than when giving it large on a hoon.
The last thing I worry about when driving the Tiv is mpg...
The last thing I worry about when driving the Tiv is mpg...
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