Originally Posted by Yachtsman
I live in England and have a Webber, I told my agent, but alas no kit, one isn't made drlling though fiddly is my only option.
You need to buy a carb setup fpr e85. If your webber is old it will probably get trashed by the ethanol. It will at least eat the seals and gaskets will give out and leak. All rubber will not fair well. Even regular fuel line is not safe from e85 ravages. Best to buy a carb setup for ot from the factory webber probably has a conversion kit or carb built to support e85 running.
One simple and easy to understand problem with drilling the jets. Is you need to make them bigger until they are too big and power goes away. If not the engine could starve for fuel and many bad things can happen over time with high compression the time is much shorter. So once you drill it too large there is no going back. Then you want the same soze that worked the best but you dont know the size. Also some jets are very close in size some really only have a chanfer added and the meetered orifice is just shortened so getting it dailed in will be a night mare.
Now if you want to tune it your self the proper way you will need a full jet kit. I usally buy them for my carbs but they are not really cheap. Then with all the other mods needed it will cost more than just buying proper setup e85 carb.
Now you want more mpg. Then you need less power pulses per mile. Higher hears maybe some timng adjustments and temp adjustments. Will gain you a few mpg in the real world. Add in some short shifting and maybe some areo dynamic updates and you will have saved 4 mpg in the real world with most cars maybe more in realy effecent car. My honda civic usally got 50mpg with short shift and mostly highway driving since it had no options like power steering worth easy 3 mpg and heavy interior updates or ac belts. But only rated at 39 or 38 mpg it was hard to actually get that bad a milage. Now with the current car is the same engine and cam with turbo ot gets about 25-30 mph in the real world. But make more power with less Rpm so should make better mpg but just is not the case.
Sorry for all the long post just trying to help if i can.