Hi there
Well I am now up and running on BMW CSL map slightly altered to the scaling of the GM map sensor, but apart from that the map is standard, not remapped etc.
So apart from numerous error codes and my engine light being illuminated due to secondary air pump and de-cats I can conclude following:
- Oil level gauge does not work, my cluster is to old, need a C23/C24 version of the cluster present 2003 onwards, search shows these can be had for around £50 so might give one a try to satisfy my curiosity as I've have taught myself how to use NCS expert so know the code I need to add to get it displayed.
- Map sensor does exactly what it says, the slight/partial throttle drivability is a night and day improvement, no matter how hard I try I cannot get the car to stutter or cough, absolute silky smoothness and simply a nicer throttle.
- Performance it seems just a quick as the previous remap and the gear changes are the best they have ever being as my car now has both CSL SMG and CSL ECU software, an improvement there for sure.
- Idle at cold is a tad lumpy, almost like cams but the more cycles the car has done its pretty much spot on now, obviously because cams in CSL are different.
In short though the Alpha-N was good and made excellent power, it did have some drivability issues, for me they were minor but I knew they were there and in hindsight I'd never have gone with Alpha-N if I had known about the map sensor options, but we live and learn. In short if you have a CSL style air box on your M3, forget Alpha-N and go down the map sensor route and remap the cost is pretty much the same if you buy the kit from Frank Smith TTFS in America, was about £400ish including parts, cable and tune. If your on the older MSS54 ECU then you will need it converting to the newer MSS54HP as the CSL maps are twice the size due to higher resolution cam profiles and vanos tuning. Frank Smith TTFS also offer this service as do quite a few members on cutters such as M3Carbon.
So yeah its good, so now I cannot wait to get my actual TTFS remap and see how the car truly performs and to check all is OK running, I doubt the car will make any additional power but if it does then epic, but drivability is superb compared to Alpha-N and is also better than the stock M3 running of the MAF sensor, map sensor all the way.
Yes its a lot of money to spend but getting the throttle perfect transforms how a car is to drive and having to drive around potential issues caused by Alpha-N is never ideal so those of you who have a CSL style air box or CSL box your options are:
Frank Smith TTFS Kit (Includes GM sensor, harness, instructions, cable and remap)
If your ECU is the older type then you need it converting, you can send it to Frank for conversion and he will pre-load his map on for you.
Alternatively if you want to go only with OEM:-
BMW CSL air rail: £170-£200
BMW Map sensor: £350-£500
BMW CSL IAT sensor: £30-£40
Frank Smith TTFS tune: £300
Going oe route gets expensive and offers no gains on drivability or performance, confirmed by TTFS, but he can supply an air rail for those who want the oe look and are happy to pay extra for it.
So looking forward to trying out the remap when I get it and driving the car with the new finished wheel is absolute amazing I have to say also, as daft as it sounds it has transformed it, feels almost like driving a much newer model.
With the remap on and 3.91 final ratio in this car is going to be a rocket ship!
Having overhaul disc kit put in, it's a traditional salisbury type clutch diff with quite a high initial torque. Instructions say just to drive it for 300km in winding roads then change out the oil.
but luckily a fellow forum member had a 2005 one which had covered 60k miles in good working order, so I got that for a bargain £70 delivered. 
