I'm getting a little fed up of the regularity of fuel stops, on the road it's averaging a between 15 and 19mpg (2.1 Pinto, BV head, Dellorto
45s, race cam). I've been toying with the idea of changing to a milder cam (probably an FR32) as it doesn't really get going until 4000 at
the moment so I do need to use the revs quite alot (current engine spec below), and it should idle better so the idle jets could be closed up a
little.
If I were to change to injection (car or bike TBs) what sort of improvement in fuel economy and I likely to see? Would there be any difference
between them (I know bike carbs are meant to be more frugal than car carbs for instance)?
Has anyone else made changes to improve fuel economy? And what sort of figures are other people getting on big carbs?
Yes, I've saved a bundle recently. This because I stopped driving my car due to snow on the ground. How much is a bus pass?
I am very sorry now that I post this. It was a genuine question that deserves to be answered.
What are you using for ignition?
If you have a dizzy, whack a megajolt on it. That should improve road mileage.
Trade it in for a diesel, or even better a push bike.
Surely it's a second car, a fun car?
dont worry about the mpg, worry about it whenever you are in your other form of transport.
It will probably be a false economy anyway, you could spend £2000 on tb's and mapping, wprk out how long it would take to save on your fuel that
before you start actually saving money after paying for the conversion.
It's running megajolt already.
What got me started on thinking about this was the SKCC John O'Groats run, for me that'd be an 1200 mile trip, that's 280l of fuel
(£400) or 12 fuel stops, which is frankly madness...
The other day on here there was a set of Jenveys for £450, and megasquirt for £300. Yes I'd need a manifold (£150), and a return fuel line (say
£50) and a day on the rolling road, but it should be doable for about a grand, less if I went the bike TB route.
If I can do 30mpg, I'd recover that in 2 years, at which point it's probably worth doing, but I don't know if it might do 30mpg, hence
the thread...
When I changed from carbs to injection I went from low 30's to high 40's (motorway cruising) with a well tuned crossflow - allso gained a
bunch of power 
The V6 I have now will get near 40mpg on the motorway - fuel injection rules
It's easy to say that a fun car needn't be economical , but I suspect most of those saying this do no more than a few hundred miles a
year...................or wouldnt think of driving a couple of thousand miles in a two week holiday .
I know you don't want to hear this, but we drove a Diesel FIAT for 1000 km's through Europe once on one tank of fuel. Converting your kit car to a diesel has been done, but that is truly the way forward to save money on fuel, if that is what you desire. An engine change is in order, whether it's the aforementioned, or something else more modern. Otherwise you won't get the return on investment.
Hmmm a 2.5 Volvo D5 diesel engine with a tuning box gives my mate 200 bhp and 400ft lb torque (or very cloes to those figures) and 60mpg when cruising
in a 1+ ton Volvo S60. Goes like stink as well.
Even my 2.2 Mondeo Diesel has 155 bhp without out any goodies, and goes extremely well.
Trouble is, do you want all that electronics and calibrated injectors etc.
If its petrol, what about Bike throttle bodies, and Megasquirt or Emerald etc.
Rusty Nuts has bike TB's and Emerald. Where I used to be able to out accelerate him really easily when he was on carbs. Now I have to try that
bit harder to catch him. I can still do it, but I notice the extra effort I need to do what used to be very easy.
He's got a 1600 X-Flow, and I have 3.5L of V8.
I just need a pair of Manifolds for my Rover v8, as I have everything else. But at £650 just for a pair of manifold from Bogg Bros, they can keep
it!
There are plenty of us on here thinking or actually doing injection.
Jenveys are nice. However they are expensive, especially when new. Think about Bike TB's. Which are nearly, or just as good, and considerably
cheaper.
SO a simple set of Bike TB's and a good injection system set up properly will work very well.
With the right ECU you can sell off the megajolt and recoup a bit of cash.
Think long and hard before parting with any cash!
Just my 2d's worth.
It is VERY likely that the dellorto's have been tuned with just WOT in mind, pretty common, with little attention to partial throttle
settings.
With a zetec and dellorto's I would average about 35-38mpg when on the motorways, that wasn't a steady 70mph either.
It may be worth finding a dellorto specialist who can set them up better, and not treat them the same as webers (again,a big problem, especially with
emission spec carbs)
Of course, EFI should be a big improvement, as long as the mapping is good.
You already have the inlet manifold, and 45 carbs still fetch good money,possibly an almost straight swap for a pair of jenveys.
But don't forget the "extras" you will need, swirlpot, extra EFI pump, inertia switch and so on, adds up but do-able.
Changing the cam may reap benefits as well, especially if you use the car mainly on the road. It is very easy to stick an unsuitable cam in, I have
done it more than once, because the figures look good, but in the real world a softer cam gives a better driving experience.
I don't think efi will give you any noticable improvement in fuel consumption on long runs. Perhaps on short cold runs it might.
My Zetec 2.0 does 40 ish on the motorway on bike carbs. I don't hear of cars on throttle bodies doing any better mpg.
I think the answer to your issue is to get rid of the Pinto and fit a modern 16v engine.
Stu
[Edited on 18/2/12 by whitestu]
Diesel kit cars are an epic fail, if you are that desperate for economy don't buy a kit car?
If you get a wideband controller, you'll see how rich the car is running, rather than guessing the problem.
Tuning an old(er) design of engine will only make a not especially efficient design less so from an MPG point of view.
Fitting a race cam will only make the matter worse. There are a couple of possible options as I see it.
1, Fit EFI to your current engine. It should make it more efficient and therefore better on fuel. It may increase it's usability by making
it smoother to drive at lower speeds/revs with a race cam. But it will be expensive to get an unknown gain which may take years to pay off. Will you
own the car long enough to make it worth while?
2, De-tune your current engine. It'll be slower, but better on fuel. If you like the current pace of the car you will start to miss it and enjoy
the car less, but you won't spend as much on fuel.
3, Change the engine. A more modern 16V engine will give the same power for better fuel. And probably be more drivable due to a lower state of tune
for the power.
4, Don't worry about. It's a toy car. They're not meant to be good on fuel, and 20 MPG isn't all that bad. I used to have a mini
that did 8MPG. And it only had a 5.5 gallon tank. My Indy Bird also did 15 MPG flat out, but would do low 30's on a cruise.
5, Fit a bigger fuel tank. You won't spend any less, but you will fill up less often!
6, Slow down. Or use a lighter touch on the throttle. Both of which you're not likely to do if you've chosen to tune the engine as far as
you have. But it is an option.
They say the best way to be more fuel efficient is to change your driving style.
What diff are you using, a better ratio will mean less revs while cruising.
I have just swapped from a 2.1 pinto on twin 45s dizzy etc to a 2.0l blacktop zetec running zx6r bike carbs and mega jolt the difference in fuel use is amazing! I recon I have doubled my mpg easily and not changed my driving style.
It is a bit like the ancient joke about the American asking for directions in the scottish highlands "If i was going there I wouldn't
be starting from here.", for good MPG you have all the wrong ingredients in the mix, however here are a few ideas without dropping the boat
anchor.
DCOE style carbs particularly when used with wild cams produce a lot of "stand off" ie petrol mist gets blown out of the carb when the
engine is running in certain RPM bands. When the car is running on the road this fuel gets blown away a good airbox will catch this and allow it to
be re-ingested by the engine.
DCOE style carbs are quite economical at cruising speed if the engine is running just below the point where change over to the main jets occur if the
final drive ratio is high enough this can be just above the UK 70 mph speed limit.
Fit a wideband AFR meter and find out what is really happening to the mixture when driving.
Obviously fitting a more sensible cam and or going over to injection would give an MPG improvement but if you are going that far it would probably be
wiser to sell the Pinto and fit a Zetec or the much lighter Rover K,
[Edited on 18/2/12 by britishtrident]
I went from a X-Flow on DCOE's doing 22 mpg to a Zetec on injection doing 31 mpg. The Zetec has more power and is much better to drive. Did I do
it for economy, no, here's why.
The change cost me approx £2500 after I sold all the x-flow bits. Doing 2000 miles a year @31 mpg costs £380 approx, doing 2000 miles a year at 22 mpg
costs £540 approx thus the injected Zetec saves me £160 a year. At todays fuel price it will take over 15 years to recoup my outlay.
By all means improve what you have by perhaps putting a more "road" friendly cam in it and getting the jetting sorted to suit but don't
spend a shed load doing it. I changed from a race cam to a rally cam on my x-flow, lost about 13 bhp at the top end (was 175 bhp) but gained loads mid
range and low down, car was better to drive and economy went up from 16 mpg to 22 mpg, cost me approx £150 at the time, would have recouped money in
less than a year and had a nicer car to drive.
Get rid of the DPF, makes the engine freer and less stressed!
quote:
Originally posted by coozer
Get rid of the DPF, makes the engine freer and less stressed!
I would imagine the costs are not gonna be too dissimilar for all the guys in the SKCC who are doing the John O'Groats road trip. You built the
car for performance and not for economy, so accept that it's gonna cost £400 for fuel or don't go. Alternatively, trailer your car up and
just use it for the nice bits
Phil
quote:
Originally posted by coozer
Get rid of the DPF, makes the engine freer and less stressed!
quote:
Originally posted by cliftyhanger It is VERY likely that the dellorto's have been tuned with just WOT in mind, pretty common, with little attention to partial throttle settings.
With a zetec and dellorto's I would average about 35-38mpg when on the motorways, that wasn't a steady 70mph either.
It may be worth finding a dellorto specialist who can set them up better, and not treat them the same as webers (again,a big problem, especially with emission spec carbs)
Of course, EFI should be a big improvement, as long as the mapping is good.
You already have the inlet manifold, and 45 carbs still fetch good money,possibly an almost straight swap for a pair of jenveys.
But don't forget the "extras" you will need, swirlpot, extra EFI pump, inertia switch and so on, adds up but do-able.
Changing the cam may reap benefits as well, especially if you use the car mainly on the road. It is very easy to stick an unsuitable cam in, I have done it more than once, because the figures look good, but in the real world a softer cam gives a better driving experience.
quote:
Originally posted by lewis
I have just swapped from a 2.1 pinto on twin 45s dizzy etc to a 2.0l blacktop zetec running zx6r bike carbs and mega jolt the difference in fuel use is amazing! I recon I have doubled my mpg easily and not changed my driving style.
Well, the really good news is that with cars like this, the sky is the limit on what we can do with them. It's much better than thinking about
work, which has been close to driving me to the loony bin in the past.
Uncle Ron has a lot to answer for: how "Locost", and "Cheap Sportscar" got into the vocabulary, is totally and utterly beyond me.
These things are anything but, unless you want a car that looks like crap.
[Edited on 18/2/12 by RK]
Dont really care about mpg in the 7 but...
With my old engine (1.8 zetec 2L cams and twin 40's) i attempted to see how lower mpg i could achieve
I managed to get it as low as 23mpg if you went mental..
Ryan
[Edited on 18/2/12 by monck]
Hugh, just a a baseline for you, my car has a standard 2.0i setup, almost as Uncle Henry intended, std ECU etc. I get 18-24mpg when thrashing it, mid 30's when just driving to work and general stuff and 60+ when my speedaphobic Mrs is in the car, driving in 5th at speeds of less than 50 while touring Cornwall. With the EFI, the car will pull smoothly from 5mph in 5th so almost an auto!
http://www.classicfordmag.co.uk/files/2011/07/CLF166.bike_.pdf
Zetec bike carb conversion and ignition rwd kit car mk2 mk1 escort ford rs rally | eBay
found this on RHOCaR
[Edited on 19/2/12 by RK]
Yousaid you are already running megajolt, but is that in 2D or 3D mode? You can gain a lot by having more part load advance. I think my map in the
MS-extra pinto (running a single plenum chamber) goes up to something like 50 degrees of advance at part load.
Of course, changing to fuel injection (either a single plenum or throttlebodies) will make it more efficient too, but only if it is well mapped and
not just tweaked to get as much power at WOT as possible. Running the pinto lean with some more advance in part load will make it significantly better
on fuel.
ETA: I get around 30mpg on my setup with a standard head and fast road cam.
[Edited on 19/2/12 by sebastiaan]
Might be a stupid idea but can you do a LPG conversion?
quote:
Originally posted by YODI
Diesel kit cars are an epic fail, if you are that desperate for economy don't buy a kit car?
It's interesting to read people's view on fuel economy. As I'm just starting on the road to car ownership, one thing I was hoping for
is an 'option' to run economically. Yes, 90% of the time I will be enjoying myself, but I'd still want the car to save a bit of money
for the inevitable commutes to work.
I definitely wouldn't go down the diesel route (spoiling the whole concept of a superlight car), but I'd have thought a production engine
designed to shift 1.5 tons plus would use less fuel to move something less than half the weight?
Edit: Actually, rereading the replies Mark's car seems to have the behaviour I'd expect, ranging between 18 and 60 depending on who's
lead foot is involved.
[Edited on 19/2/12 by Slimy38]
quote:
Originally posted by tul214
Might be a stupid idea but can you do a LPG conversion?
Had the steadiest run out in the car yet this morning, due initially to damp/frosty roads and then traffic, lots of steady 50-60mph and managed the
heady heights of 23mpg! If I can get a steady run nearer 30 then I'll be happy. Had a stonking and somewhat faster 20miles after filling up
which convinced me I don't really want to change the cam.
I'm in the process of trying to negotiate a bit on an airbox (there'll be a thread about a possible bulk buy on Airbox
throttle caterham jenvey air filter westfield 7 small inlet manifold | eBay very soon after this post), and have ordered a lambda sensor/AFR
gauge. Hopefully a combination of the airbox and making sure I'm not running rich I will get somewhere nearer to that magical 30mpg!
quote:
Originally posted by sebastiaan
Yousaid you are already running megajolt, but is that in 2D or 3D mode? You can gain a lot by having more part load advance. I think my map in the MS-extra pinto (running a single plenum chamber) goes up to something like 50 degrees of advance at part load.
Of course, changing to fuel injection (either a single plenum or throttlebodies) will make it more efficient too, but only if it is well mapped and not just tweaked to get as much power at WOT as possible. Running the pinto lean with some more advance in part load will make it significantly better on fuel.
ETA: I get around 30mpg on my setup with a standard head and fast road cam.
Hi Hugh
i have more or less the same set up as you
2.1 pinto
285 piper cam
zx9r bike carbs
light fly wheel
modified head and i get 30mpg on a steady run down to about 20mpg is i put my foot down
Jacko
This is my table copied from the MSQ file. Mind you, the car is N/A but the table axes go up to 130kPa in anticipation of possible future boosting.
<constant cols="12" name="advTable1" rows="12" units="deg">
20 23 30 34 38 46 46 46 46 46 46 46
20 24 31 35 39 44 44 44 44 44 44 44
20 24 31 35 38 42 42 42 42 42 42 42
20 24 31 34 36 40 40 40 40 40 40 40
20 23 30 33 36 38 38 38 38 38 38 38
20 22 29 31 34 38 38 38 38 38 38 38
20 20 24 27 33 37 37 37 37 37 37 37
20 20 23 27 33 36 36 36 36 36 36 36
20 20 22 27 33 36 36 36 36 36 36 36
12 12 15 20 28 36 36 36 36 36 36 36
10 10 15 20 28 36 36 36 36 36 36 36
10 10 15 20 28 36 36 36 36 36 36 36
</constant>
<constant name="mapBins3" rows="12" units="kPa">
20
30
40
50
60
75
89
90
100
120
130
150
</constant>
<constant name="oddfire">"No"</constant>
<constant name="rpmBins3" rows="12" units="RPM">
300
700
1500
2000
2800
3600
4400
5200
5500
6000
6200
6500
If you look at the area around 2000-3000 RPM, my advance goes uo to around 36-40 degrees in part load. You've got quite a lot less. I'd get
the wideband and airbox installed and then spend some time at a rolling road to optimize the area between 2000 and 4000 RPM in partload. Up the AFR to
around 15-15,5 (if the engine takes it, with the lairy cam it might have too much internal EGR to put up with running a bit lean) and optimize the
advance to get max power at every throttle opening. This does take a bit of skill to do, but any rolling road operator worth his salt should be able
to do this.
An LPG conversion is a good idea, the tank can go above the diff (a 200mm cilinder should fit and give a decent fuel capacity), but don't do it
on a pinto unless it's got stainless valves and decent valve seat inserts or you'll be forever checking and setting clearances. Oh, and it
would only work satsfactorily if you install a multipoint injection system piggybacked off a decent EFI install, so probably a bit more involved than
you'd want.
[Edited on 19/2/12 by sebastiaan]
Yeh see what you mean there! I'll get the lamdba sensor fitted and the airbox in then have a play on a rolling road.
Is yours running a MAP load sensor or TPS? Mine is TPS and it seems odd that the load goes to 152 as TPS range is 0-100%? How does it translate TPS
reading to load?
Cheers
Hugh
Mine's running speed density (single throttle plenum) and uses MAP as load signal. Nice and straigtforward, lots of mid-end grunt and noting to
go out of tune.
Maybe your setup used AD counts (raw voltage/5*255) as load signal? I'm not familiar with the megajolt setup, but that might be the case.
Ok thanks, I'll get it hooked up to the computer again and check what load it is registering with throttle position.