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Poor mpg..

Posted: Sun Apr 22, 2012 8:12 pm
by Smithy89
When my engine was changed from a 2l to a 2.5s a couple of bits from the old engine we're used, as it didnt come with these parts-the inlet manifold, idle control valve and throttle body. It seems to run fine just very juicy would this be why?

Re: Poor mpg..

Posted: Sun Apr 22, 2012 8:17 pm
by kam-325i
The inlet manifold and Throttle body are smaller on the 2.0l than on the 2.5l, so these will be restricting the engine.

Re: Poor mpg..

Posted: Sun Apr 22, 2012 8:18 pm
by Grrrmachine
M20s are generally juicy, but a 325i should return the same mpg as the original 2.0. Bear in mind, however, that by using the 2.0 throttle body and inlet, you are severely throttling the 2.5 engine.

If you're getting bad mpg, check your fuel lines, TEST your blue temp sensor, and send your injectors off to Injectortune for a refurb.

Re: Poor mpg..

Posted: Sun Apr 22, 2012 8:22 pm
by Smithy89
Ok will change that soon as then, how about the fuel pump-in tank type, not been changed. Sufficient enough?

Re: Poor mpg..

Posted: Sun Apr 22, 2012 8:24 pm
by kam-325i
pump should be ok, required pressure is the same, although volume is a bit more on the 2.5l

Re: Poor mpg..

Posted: Sun Apr 22, 2012 8:24 pm
by Smithy89
Fuel lines and injectors are getting done this week, have tested the temp sensor hot and cold seems to be fine. Hopefully after all this I will be getting more than 60 miles from £20! What should I be looking for from a 2.5s?

Re: Poor mpg..

Posted: Sun Apr 22, 2012 8:28 pm
by Grrrmachine
there's no appreciable difference in mpg between a 2.0 and a 2.5. No such thing as a 2.5s, unless you mean the sport which is still just a 2.5 engine.

MPG will very rarely get over 25.

Re: Poor mpg..

Posted: Sun Apr 22, 2012 8:31 pm
by kam-325i
£20 is around 13 liters = 2.85 Gallons,

expect around 30-65 Mpg depending on driving.....

Re: Poor mpg..

Posted: Sun Apr 22, 2012 8:38 pm
by Smithy89
Yes I mean sport. I'll see how I get on after I have changed and refurbished the parts, cheers!

Re: Poor mpg..

Posted: Sun Apr 22, 2012 8:41 pm
by kam-325i
Do you mean a 2.5l Sport engine ?

Re: Poor mpg..

Posted: Sun Apr 22, 2012 8:42 pm
by Grrrmachine
The sport engine is no different from any other 2.5 engine, so he just means M20B25 :D

Calling it a Sport when the car didn't leave the BMW factory as a Sport upsets a few people on here :)

Re: Poor mpg..

Posted: Sun Apr 22, 2012 8:51 pm
by Smithy89
I'm new to here and to e30's as you can probally tell.. :D

Re: Poor mpg..

Posted: Sun Apr 22, 2012 8:56 pm
by Smithy89
I got myself a year ago and old convertible which needed a lot of attention, head gasket went not long after I got it so got this engine off a friend, replaced existing suspension with a decent set of coilovers, and had it re sprayed alpina blue as it was a bit of a rust bucket. Fair to say I rescued an e30? Think I will stick with them too!

Re: Poor mpg..

Posted: Sun Apr 22, 2012 8:57 pm
by Smithy89
I've still got a lot to learn with the engine side of things yet but I'm getting there