[320touring]

Thanks for your post-very informative and helpful!

i've slotted in my responsed below:

Originally Posted by lowglider

It`s hard to add anything big because you`ve already mentioned most of the key improvements.

Me knowing a lot more about BMWs than a sane person should ever know, I would suggest looking at all the usual tune up things like the condition of the air filter and spark plugs. After that I would advise testing your oxygen sensor, even if those things still work enought to pass MOT, they tend to worsen fuel economy. Oxygen Sensor Information has a good procedure on doing it.

I currently have 2xe30's an e34 and this e36..my bro runs an e36 328 and has an e30 too- we're in a similar position to you-too many E/M numbers are bad for you

The vehicle has just had a new centre to rear exhaust fitted, but I've not checked that new fangled Lamda sensor.. Do you reckon a de-catting swould be advantageous?

Car had a service approx 3k ago with all new plugs/filters/oils- currently running on 10w40 semi synth as its the older 1798cc m42 lump

I thought of that because getting 40mpg on a 318is shouldn`t take much effort and with bumped up tyres and P&G you should get more.

Really? I was quite chuffed with the 40mpg, given two drivers and a trackday done in the car

Its fairly consistently about 39+mpg, and tyres are at 40psi, so still have some ride comfort.

Looking on sprintmonitor.de (logging site that generates my signature MPG icons) I'm apparently 3rd best MPG of all the 318iS on there, the ones above me appear to be about 42mpg.

Certainly using it exclusively on A road/Motorway I see about 42-43 at the moment

Otherwise the first thing to do is get back the engine bellypan, doesn`t matter if you get the original one or make one yourself, it will not only improve aerodynamics and economy but also reduce road noise.

Yeah, I believe the car should have both a front belly pan, and also a cover over the gap between teh grill and the slam panel at the top

Other than that a grill block is the key to faster warm ups and more mpg and like you have found out yourself, the back bumpers do tend to parachute on these BMWs but some easy underbelly manufacturing can improve that. I doubt full underbody will be worthwhile if you do the front underpan and remove the back parachute.

Fair comment re the underbelly pan- i'll certainly try the front/rear approach first.

Do you think inner grill blocks (to avoid stuff externally) would be effective enough?I'm essentially thinking I should try to seal the engine bay off as much as possible- the cooling system is in good repair.

As for electric fan conversion that is a great idea, just get a fan kit with electric thermostat that you stick into the radiator and throw out that old viscous coupling fan, those things are often the culprit for engine damage due to overheating and can be very parasitic on smaller engines. Going electric will not only get you better fuel economy, but also horsepower, easier revving and reliability.

Interesting point re the fan- Essentially I was thinking on adjusting the Cams as the engine mainly does high load, medium RPM work (pulse phases are done in 5th with the MPG needle reading 20..pulling through to approx 3500rpm for 70 mph)

Moving the torque band down would make the engine worke more efficiently in this spread?

I'm not a fan of the viscous anyways-esp the left handed thread and 32mm spanners!

You`ve also mentioned the diff. The 328i has a 2.93 diff and that would be the way to go, because the 318iS is very lowly geared for sporty driving thus economy suffers.

a 2.93 may be pretty long for the car, no? again, peak torque at 4500rpm and peak power at 6000rpm mean that along diff may be hellish slow to pulse?

I could see the benefit on the Motorway if driving at a steady speed though.

Do you know where there is a list of available diff ratios for the e36?

One thing that you may have not though of is replacing the engine DME chip. These improve low down torque and a 10% better fuel economy can be realistically expected. I`m not talking about the cheap resistors but about EPROM chips that can be found on eBay for a few tenners.

I'm aware of ECU rechipping, but I have my doubts regarding it- for better torque etc I'd probably look at going down the Megasquirt route-but thats too expensive for this project!

I'll see what I can find out though

Please update on this topic with the results you will get, because I`m eager to find out how much can be squeezed out of a 318iS coupe. These cars are great if you keep rust away from them, lots of these engines go beyond 400k miles without major overhauls.

TBH, its only a daily beater to me, too many valves not enough cylinders!

But I'm happy to do some basic modding to see the improvements.

Hopefully the aero mods could be applied to others in my fleet