How can I get better MPG out of my V8?

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landie man

landie man

New Member
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Location
Dover Kent
I dare say many have asked this question, but I would appreciate it if someone answered it one more time for me, as I cant really find anything about it using the search.

If I am going to keep my v8, and not convert to gas, is there anything else I can do to improve my MPG? I have just given it a full service, and am shortly to have it crypton tuned, is there anything else I can do? i.e. I am running on twin SU's on my 3.5. rover sd1 rover v8.

Are they the most economical carbs to use? or would it pay me to buy some new stromburgs, or webbers or something? I don't mind the initial outlay as long as it pays off in the long run. I'm desperately trying to think of ways to get more MPG out of my V8, as I want to use it for towing, and do more greenlaning, But it's hard to justify the fuel costs. It's a good engine apparently, and I would be happy if I can get it to use 20+ mpg if possible, rather than about 12-17 if thats achievable in a carbed V8.
 
In my experiance with running V8's the best carb was the SU's that you could have on.
I bought a second car when running my S2 V8 conversion as it was cheaper to run another motor and use the V8 at weekends only.
I would definately go gas, as it is in my opinion the only way to run a V8 unless you earn Bank manager money!:eek:
 
Stop thinking in terms of cost, think in terms of social investment;

- without you, what would those bazy lastards in Greenpeace have to complain about
- how would half the Middle East afford to drive nice cars
- the South West of England would not benefit from global warning

In future years, you will be looked upon as a visionary, self sacrificing member of humanity - so get that right foot down on the floor and damn the impudence of those who overprice fuel...
 
The only way you can achieve worthwhile improvement in MPG without LPG is is to fit Megajolt system as this will improve ignition efficiency. To be honest the only real way to get better value for money is to LPG convert everything else will just improve 3to 4 MPG. Cheers Nick
 
Countrymansussex said:
The only way you can achieve worthwhile improvement in MPG without LPG is is to fit Megajolt system as this will improve ignition efficiency. To be honest the only real way to get better value for money is to LPG convert everything else will just improve 3to 4 MPG. Cheers Nick
Click to expand...

only value for money if you do mega miles, buy the LPG kit secondhand, and then fit yourself assuming you work in a garage and can then get it certificated. if you miss any of these factors...forget it, the maths doesn't work
 
Do what I do, try not to think about it! My series V8 gets about 15-20mpg depending on how I drive it and the 300tdi disco is only getting 23mpg!! So guess which one I like to use most? :D
 
Seems that the only real way to improve mpg and not end up with a fubar engine from gas it tune it plain and simple here's some to free tips
1 give the whole motor a good service all the transmission oil
2 wash and polish it
3 remove the stupid off road tyre and fit some road ones worth nearly 2 mpg! Tyre pressures
4 genuine cap leads and rotor reset timing
5 tune and balance the carbs
6 when did it last have a cam how many miles has it done?
7 good free flow exhaust system
8 Kenlowe fan kit
9 fit a bigger engine to give even more bhp
10 even a good old comp test if good a decoke and reseat the valves
11 have the heads ported and gas flowed but on a 3.5 is lost

Ok let's dispel a few myths strombergs are a better carb and hold there tune over the su but as most people don't like the complex set up slate the carbs you can buy a carb adjuster kit from Sykes and pickivant which has all the screw drivers you need and all you need is a carb balancer to set them up
the one issue most do not understand is the diaphragm in the carb and usually what happens is people over fill the dash pot and flood the diaphragm with oil which then over loads the diaphragm causing bad throttle response
 
vougese39 said:
Seems that the only real way to improve mpg and not end up with a fubar engine from gas it tune it plain and simple here's some to free tips
1 give the whole motor a good service all the transmission oil
2 wash and polish it
3 remove the stupid off road tyre and fit some road ones worth nearly 2 mpg! Tyre pressures
4 genuine cap leads and rotor reset timing
5 tune and balance the carbs
6 when did it last have a cam how many miles has it done?
7 good free flow exhaust system
8 Kenlowe fan kit
9 fit a bigger engine to give even more bhp
10 even a good old comp test if good a decoke and reseat the valves
11 have the heads ported and gas flowed but on a 3.5 is lost

Ok let's dispel a few myths strombergs are a better carb and hold there tune over the su but as most people don't like the complex set up slate the carbs you can buy a carb adjuster kit from Sykes and pickivant which has all the screw drivers you need and all you need is a carb balancer to set them up
the one issue most do not understand is the diaphragm in the carb and usually what happens is people over fill the dash pot and flood the diaphragm with oil which then over loads the diaphragm causing bad throttle response
Click to expand...
At last a sensible reply! :lol: I didn't realize a kenlow fan would help. I don't have one, so I'll sort that . How much would it be for one suitable for a V8 with vat? When you talk about overfilling with oil, do you mean don't put too much in the SU carbs that you put in though those plastic screw on tops? I must admit I've just topped mine to the top, as someone said it would help against petrol evapouration that can happen in the carbs, causing breakdowns. I haven't driven it since I've done it, so I can use a syphon to take some out again.

The carb adjuster kit sounds good if I switch to stromburgs, but I've a feeling you will still have to know what your doing to set them up properly? I have little mechanical knowledge when it comes to complicated and fiddly stuff. I'm ok on the basics. Oh and thanks for the reply! :)
 
vougese39 said:
Seems that the only real way to improve mpg and not end up with a fubar engine from gas it tune it plain and simple here's some to free tips
1 give the whole motor a good service all the transmission oil
2 wash and polish it
3 remove the stupid off road tyre and fit some road ones worth nearly 2 mpg! Tyre pressures
4 genuine cap leads and rotor reset timing
5 tune and balance the carbs
6 when did it last have a cam how many miles has it done?
7 good free flow exhaust system
8 Kenlowe fan kit
9 fit a bigger engine to give even more bhp
10 even a good old comp test if good a decoke and reseat the valves
11 have the heads ported and gas flowed but on a 3.5 is lost

Ok let's dispel a few myths strombergs are a better carb and hold there tune over the su but as most people don't like the complex set up slate the carbs you can buy a carb adjuster kit from Sykes and pickivant which has all the screw drivers you need and all you need is a carb balancer to set them up
the one issue most do not understand is the diaphragm in the carb and usually what happens is people over fill the dash pot and flood the diaphragm with oil which then over loads the diaphragm causing bad throttle response
Click to expand...
Oh, forgot to ask, how much is a new cam to get fitted? as I can't be sure when it was last done.
 
V8jon said:
I got a standard cam kit for mine from Real Steel last year it was about £140 but I did it myself so don't know how much it would cost to get it fitted.
Click to expand...
Oh ok.Thanks for the reply, But I'm a bit confused here. is it the cam under the rocker covers with the followers your talking about? or is there another one somewhere? I'm asking as I saw a cam for sale for an SD1 v8, for £40.00 (they are differant apparently depending on what v8 you have i.e. defender, disco, and rover SD1 are different)

The one I'm talking about is NOS, and been kept in it's original box in oil, but it hasn't got the followers. Just want to make sure I get the right part. Also was it a big job for you to fit, i.e. do you have to have a reasonable idea of mechanics?
 
landie man said:
Oh ok.Thanks for the reply, But I'm a bit confused here. is it the cam under the rocker covers with the followers your talking about? or is there another one somewhere? I'm asking as I saw a cam for sale for an SD1 v8, for £40.00 (they are differant apparently depending on what v8 you have i.e. defender, disco, and rover SD1 are different)
Click to expand...

Mate, with all respect have good read of this:

http://www.landroverresource.com/35_39_42_V8_overhaul.pdf

Make sure you know what your getting into before you part with any hard earn't - learn about what your doing....


MX
 
Last edited:
There should be a no to LPG compain for v8's. want lpg dont ruin an 8'.

complete junior answers i know but...

Thinner typres help, i.e. less rolling friction - less power required maybe?
I drve with my mirrors tucked in, just feels well wierd with them out. thats gotta save 40mpg and give it 50bhp by halfords carpark rules.
Perfect rolling would be a factor i suppose, everything well grease/oiled and bearings tip top.
What headers do you have, i got the ****ty cast ones on my 3.5 st's, tubular ones giving better torgue would help i think then you would need less of the go pedal

depends how much you want to spend in relation to how much fuel you will use, i use my for playing basically and the odd random drive. (would love to blue print and full system on it, good tune and that would do me fine)
good luck
 
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