e30 m50/m52

[sidewaysbill]

its available about five miles from where i live at the mo and hopefully about a mile away in a couple of mounts so it would be rude not to use it....! Would i be right in saying with the right map its possible to get more power...?

[dnb]

Me too - I specified everything on the Griff with a view to E85. 

There just isn't any available for the moment.

[rob@vems.co.uk]

E85 as it stands will not give much more power.  If you build your engine to run on it then you can get good gains.

By building it I mean increasing the engine's static compression ratio to make the most of the fuel's high octane rating, and using cams that will take advantage of the higher compression.

Turbocharged engines have the advantage that you can simply increase the boost pressure.  There's one Irish lad on the SXOC who's running his SR20 engine on E85, having bought larger injectors, a walbro pump, and had a remap.  He's very happy with it and reckons he's had good power gains without too much loss of MPG (as you have to inject almost twice as much E85 (Ethanol's calorific value is about 50% of petrol's) you have to expect lower MPG).

The fly in the ointment is the cold start issues that a lot of people have.

[sidewaysbill]

How high does the static compression need to be and what kind of cams are we talking about here to make the most of the higher compression?

[rob@vems.co.uk]

Thats going to be a tricky thing to quantify, if theres not already someone running a high compression M50 motor to lead the way then its down to you to do the development work.  I'm sure theres a few of us here that would help your research.

[dnb]

I have 11:1 (up from 10:1) on my Griffith.  It's a compromise really, if I could switch to E85 full time I would go for 12:1 or maybe even 12.5:1

As for cam, I went for the wildest road cam on the market, but that's just me... 

If it were my experiment, I'd start at a 5 to 10% increase in compression and see what happened.  Remember that it's easy to increase the compression, but as yet there isn't a "putting-back-on machine" for decreasing it again...  

On my engine I'd expect more gains than most because the ports and valves are really too small for making big power from petrol, but it all seems to work out better for ethanol.  (One of the snags of a 40 year old design of engine )

[sidewaysbill]

I was hopeing to run it at about 11:1 or 11.5:1 if needs be with a set of 272/264degree cams , yea or nea...?

Is there barometric compinsation built into the vems units ...?

[andersn]

you can see gains with E85 not changing anything on the engine as you can run some pretty angry timing. on a stock S50 gains could be as much as 30-40HP according to PPF (swedish bmw tuner)

as for injectors, calculate 30% bigger to use E85 on aprox same duty cycle.

E85 does make your car smell like your college buddies.

[Agriv8]

you can see gains with E85 not changing anything on the engine as you can run some pretty angry timing. on a stock S50 gains could be as much as 30-40HP according to PPF (swedish bmw tuner)

as for injectors, calculate 30% bigger to use E85 on aprox same duty cycle.

E85 does make your car smell like your college buddies.

I had heard this but usure if it was 'true fact' or 'WWW fiction'.

Hope to get arround to finding out one day timming and fueling will need to be fiddled with 

Regards

Agriv8

[dnb]

Increase req_fuel by 30% on the same injectors and you should be reasonably close for fuel.

Timing is another matter...

[sidewaysbill]

with the vems in place would be possible to get away with just using standerd injectors or lets say ones out of a e36 m3 or something as you can leave them open for a much longer duration than a standerd ecu can...?

[rob@vems.co.uk]

You're only going to be able to flow so much fuel through the standard injectors.  If you need 85% duty to run WOT up at MAX rpm then you're nearly out of headroom.

Rob

[sidewaysbill]

Rob whats the chances of the m3 injectors being bigger than the standerd 2.5 ones...?

[gox]

The stock ones from m50b25 are 192cc...i think for the m52 is the same....but never checked...
Read the bosch number on the injectors and use this info to find biger ones...
http://users.erols.com/srweiss/tableifc.htm

[sidewaysbill]

nice one for that i will check it out in the morning...!