Hugh_
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| posted on 17/2/12 at 10:33 PM |
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Thoughts on improving fuel economy (very boring I know!)
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?
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RK
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| posted on 17/2/12 at 11:35 PM |
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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.
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Xtreme Kermit
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| posted on 17/2/12 at 11:44 PM |
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What are you using for ignition?
If you have a dizzy, whack a megajolt on it. That should improve road mileage.
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wylliezx9r
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| posted on 17/2/12 at 11:55 PM |
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Trade it in for a diesel, or even better a push bike. 
I spent a lot of money on booze, birds and fast cars. The rest I just squandered.
George Best
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YODI
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| posted on 18/2/12 at 12:01 AM |
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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.
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Hugh_
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| posted on 18/2/12 at 12:17 AM |
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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...
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clairetoo
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| posted on 18/2/12 at 12:23 AM |
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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 .
Its cuz I is blond , innit
Claire xx
Will weld for food......
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RK
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| posted on 18/2/12 at 12:26 AM |
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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.
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wilkingj
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| posted on 18/2/12 at 12:49 AM |
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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.
1. The point of a journey is not to arrive.
2. Never take life seriously. Nobody gets out alive anyway.
Best Regards
Geoff
http://www.v8viento.co.uk
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cliftyhanger
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| posted on 18/2/12 at 07:04 AM |
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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.
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whitestu
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| posted on 18/2/12 at 08:40 AM |
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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]
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YODI
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| posted on 18/2/12 at 08:46 AM |
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Diesel kit cars are an epic fail, if you are that desperate for economy don't buy a kit car?
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MakeEverything
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| posted on 18/2/12 at 09:39 AM |
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If you get a wideband controller, you'll see how rich the car is running, rather than guessing the problem.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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DIY Si
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| posted on 18/2/12 at 09:44 AM |
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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.
Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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roadrunner
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| posted on 18/2/12 at 10:15 AM |
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They say the best way to be more fuel efficient is to change your driving style.
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roadrunner
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| posted on 18/2/12 at 10:18 AM |
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What diff are you using, a better ratio will mean less revs while cruising.
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lewis
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| posted on 18/2/12 at 10:33 AM |
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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.
I am a driving god!..........sort of
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britishtrident
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| posted on 18/2/12 at 11:25 AM |
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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] What use our work, Bennet, if we cannot care for those we love? .
― From BBC TV/Amazon's Ripper Street.
[/I]
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Paul Turner
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| posted on 18/2/12 at 11:44 AM |
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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.
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coozer
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| posted on 18/2/12 at 11:46 AM |
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Get rid of the DPF, makes the engine freer and less stressed!
1972 V8 Jago
1980 Z750
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britishtrident
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 posted on 18/2/12 at 12:37 PM |
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quote:
Originally posted by coozer
Get rid of the DPF, makes the engine freer and less stressed!
;-)
[I] What use our work, Bennet, if we cannot care for those we love? .
― From BBC TV/Amazon's Ripper Street.
[/I]
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Hellfire
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| posted on 18/2/12 at 12:45 PM |
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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
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Xtreme Kermit
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| posted on 18/2/12 at 12:50 PM |
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quote:
Originally posted by coozer
Get rid of the DPF, makes the engine freer and less stressed!
LMFAO.
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Hugh_
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| posted on 18/2/12 at 01:31 PM |
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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.
For all those taking the piss, it's a choice between driving the car less or sorting the fuel economy. I know which of those I'd rather
do. I have always just taken the fuel costs on the chin, but things have been pretty tight since I bought a house last year and consequently I
didn't use the car much; I was considering selling the car and had it up on here briefly last year, but I can't bring myself too.
It is still on its running in state of tune which was done at 75% throttle and up to about 5200rpm, I need to get it re-setup but was putting it off
until I'd decided what to do about the cam. I suspect the cam and gearing arent helping, at 75-80 it is doing 3500rpm, just on cam, and carbs
just on the mains.
I will definitely change the cam as what I lose right at the top I'll gain lower down the revs. Stand off is definitely an issue at present, if
it still is with a different cam I'll try an airbox of some description. I've been considering a wideband sensor, given that I can get
one for about the cost of a mapping session and have plenty of spare jets I can play around with I think I'll give that a go first. Any
thoughts on eBay - The UK's Online Marketplace ?
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.
Lewis if you don't mind me asking, how much did your conversion cost? I was toying with that idea but by the time I've got a shortened
sump, differing exhuast manifold I'd ruled it out as being just as expensive as going EFI.
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RK
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| posted on 18/2/12 at 02:26 PM |
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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]
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