Weber DCOE. 40's & Fuel Consumption

[Sola]

Firstly, sorry if this is a subject that has already been covered

I'm going to be changing the carb on my 1.2 over the winter, from the Pierburg to something from Weber. I am seriously tempted to swap in a set of twin 40's, mainly because it is a well documented conversion, and the obvious performance/aestheitic benefits. I am only concerned about the increase in fuel consumption. Being nearly 40 means that (believe it or not), there is no increase in insurance premium.

However, although it isn't used every day, I don't want too much of a drop from the approx 45 mpg I'm getting now. Which is why I'm also considering a twin choke, single carb conversion.

What experiences have you had? What sort of mpg can I expect if properly set up?

Thanks for your advice.

[paul james]

Well if your that bothered about cost/mpg then leave the car as it is. However you can get great mpg out of twin 40s, even when combined with a more athletic camshaft, it just depends on how you drive it. Put your fut down and expect to see your petrol guage sink quite quickly, but if you drive carefully then you could get near the mpg you do know.

Its the cost of buying the carbs, inlet, other bits, a cam to make proper use of them, then having it propelry set up thats the cost issue. If your happy to pay for all that, then there seems little point in worrying about a few extra petrol station visits.

[mowgli]

fitting 40's to a std 1.2 won't release any massive amount of power, but the noise & revability would be pretty good. but then enjoying the noise will knock your 45mpg for six

[Sola]

Thanks for your reply. I know mpg will drop some, but it'll be worth it.

I have heard of people getting 15-20 mpg which is daft. I'm guessing that they weren't properly set up and the driver's had heavy feet.

[Novasport]

Weber DCOE's = less than 20mpg. Mainly because you will put your foot down everywhere just for the noise and the fun of it ;)

[mowgli]

on a tuned 1.3, 15-20mpg on a fast road trip is quite possible, injection is massively more fuel efficient

even a twinchoke is too much for a std 1.2, i ran a high compression 1400 on a 1.2 single choke carb back in the early nineties & it was pretty quick and all round gave about 35mpg

[Novasport]

Mine has the Irmscher 108 cam & a SCCR box so revs usually are high when driving but its not too bad. I did Derby-Billing-Derby on half a tank.

[paul james]

Does your 1.2 have a performance cam or a 5 speed gearbox? if your going the twin40 route it might be worth thinking about swapping your 1.2 to a 1.3 instead.

[Sola]

Thanks for your replies. To go with them, I'm also on the lookout for a 1300 head, which I'm told will free things up a bit too. I know it would be cheaper per bhp to drop a twin cam in, but I want to keep an old school, small block under the bonnet.

I have access to the necessary skills to set this up. I reasoned that this would be the best place to learn a bit more about this upgrade.

[paul james]

Unless I'm mistaken the 1.3 head is the same as the 1.2, the cam and block are the differences.

[Novasport]

Go C14SE with MPi or try and get an Irmscher injection for a more period mod

[chrisd1986]

I had twin 40's on a 2.0 16v golf and i got no more than 20mpg and i drove like a granny and they were propperly set up

[AndrewJenkins]

Unless I'm mistaken the 1.3 head is the same as the 1.2, the cam and block are the differences.

correct head wont make a difference cam will

[Royston]

My Sport does 27mpg on a run, going steady, 45mpg will go out of the window;)

My 1,3 SR on forties did 28mpg on a run, be interesting to see what mpg the Irmscher Injection is!

I know the injection flew through the emmissions at MOT:d, forties are a little more dubioslol

[waggygsi]

You Dont fit 40S to worry about Petrol bud

[Sola]

You Dont fit 40S to worry about Petrol bud

Well said that man!! I think I may go down the twin choke route instead as I want it to still be practical, it's never going to be a fast car anyway.

Thank you for all of your replies.

[waggygsi]

ive got a weber twin choke on mine from a mk2 escort 1600

[BRoadGhost]

Threads like this are problematic so let me just say this you don't get something for nothing.

That is, if you're flowing more air and fuel into the combustion chambers then you get more performance, noise and less MPG.

heh you wanna be flowing 200 horses worth of power through webers, then you'll understand what 6mpg is.