i think you should be able to do 20 to 25. with a 15 gal tank 300 at 20mpg your outa gas.

 

yeah the 6 speed would help a bit more than the a4...but i know cars loose a bit just being older, tired. i would think 14-24 is average for most auto cars and 15-25 for m6. depends on the gears.
my 86 mustang gt had stock 2.73 gears and on the freeway i was at 1500rpm doing 60mph and i would get 26mpg but i had alot of mods that probably helped like no clutch fan, no emissions, maf conversion and and stock tire height. i drove to idaho on $80 and back from everett thats when i got 26mpg but that thing was hell in town like 12mpg.
i fill my tank, rest o.d. and drive atleast 50-100 miles and fill back up till it clicks and do it that way, the math is more accurate the longer you go. i drove 20 miles in this car and filled up and the math showed 28 mpg but this car really get 17 tops, and yes crabby i know its probably the bad fuel pump. i really need a t56 ill be happy with 25, my turbo car doesnt even get that

 

Along with this, what is the best rpm for mileage? Ive heard people say the lower the better which is obviously not true, and others have said 2k.

 

has alot to do with the load on the motor. if your goin up hill in a higher gear and just give it more gas rather than down shift then your going to burn more fuel. on a flat road or down hill would be a time when lower rpms would be good. uphill or under load a proper rpm would be higher depending on the situation. there are gages that tell you what mpg you are getting. old ones where a vacumm gage.

 

Alright guys how the hell do I get to the plugs on the passenger side? I've been at this for an hour under and over... Whats the trick?

 

For plug #2, you have to remove the alternator to get to it. You will also be able to get to #4 a lot easier without the alternator in the way.

I did #6 and #8 from under the car, and even that was a pain.

 

I got 1,3,5,7, and 8. I'm out of daylight. I'll run the other 3 tomorrow. There has to be an easier way to this... I'll check back tomorrow. But im almost ready (can't believe I'm saying this) to take it to the shop and let some one else deal with it. This is my dream car. I'd rather not soil it

 

i took the starter out to get to 6 and the alternator to get to 2 and 4. lol. helps to have a helper with small hands. yep like i said a 8 beer project.

 

Ok, I dont want to lift this thing off the ground again but I guess I don't have a choice. I will take the alternator off and replace plug 2 and 4. Im a really big guy, my forearms are 13 inches around. this isn't gonna work well. I guess what I really want to know is, if I get the alternator off, and replace 2 and 4 is there a possibility of reaching 6 from the top? and once the alternator is off I should be able to replace wires without to much hell right? I know it sunday and I might not have a lot of traffic on this topic today, but any help I can get id appreciate. PM me and I'll send a cell # and maybe someone can talk me through this mess.

 

I have never replaced the wires unless I was also doing the whole OPTI change. And when you do that, you have most of the front of the engine bay taken apart, so getting to the OPTI to swap wires is pretty easy.

However, even with the alternator off, routing the wires from the OPTI around the waterpump and the accessory brackets on the passenger side is a complete pain in the butt. It can be done, but there isn't much room to work. I also have larger forearms and everything on the passenger side was tight.

Good luck, and keep a box of bandaids handy.