BMW 125i Coupe E82
A modern tribute to a classic recipe
The idea behind this car for me was to create a final tribute the the classic BMW sports car recipe of a n/a straight-6, manual gearbox, rear drive small coupe. The name came from the idea of this recipe being regarded as purity by many, along with the car being specced in alpine white. Speaking of the specification, the car was my ideal base spec. It was an m-sport car, which meant I got a lot of nice bits all over the car, it was alpine white, black leather with a black headliner.
The engine in this car is the n52b30 which is the last n/a straight six engine BMW will likely ever produce outside of specials. It has many technologies such as valvetronic which increases throttle response as atmospheric pressure is right at the valve. The engine also has variable valve timing but you can hardly tell when driving as the power delivery is incredibly linear. This engine in the UK also featured the DISA flaps and was a b30 meaning 3.0 litre meaning that the engine was identical spec to a 130i which was not sold in coupe form in the UK. BMW instead opted to change the map to a lower power and sell as a 125i. A simple change of engine mapping gives back the performance this engine should have had. I have verified this performance by a visit to a dyno. My model is a later model with a lot of the issues such as cam journal bearings and some hydraulic lifter issues sorted.
This gearbox is mated to a 6 speed manual gearbox, a key part of that basic 3 part recipe that makes this car so enjoyable. From factory these cars had a CDV which made quick gear changes often tricky as an artificial delay was created. This was done due to the new extended warranty BMW was offering and likely aimed at helping inexperienced drivers. In my car has been deleted to help gear changes.
The chassis of the car is where the most improvements could be made from factory specification. The car was designed to understeer before it oversteered. Helping the inexperienced driver out of tricky situations however making the car behave in an uninspiring way dynamically. This has been fixed in my car via several changes. Firstly the narrow front wheels and tyres have been changed to a 245 square setup, increasing grip at the frontend. The wheels and tyres are the largest the front can possibly fit and only fit due to the negative camber. The front suspension control arms have been changed to parts from the 1M coupe to assist with negative camber and better characteristics. Springs and shocks all around have been replaced with ST parts (made by KW) along with dinan camber plates at the front. The car was an M-Sport, and has not been lowered from the M-Sport configuration.
All the suspension changes of course, would be pointless, without a really good set of tyres. For this reason I decided to go for Michelin Pilot Sport 4S tyres. Firstly changing to non-runflat tyres improves ride and handling dramatically. Secondly these tyres are a very good compound with higher grip on the outside edge, so when we are really pushing on the edge with the negative camber setup you just get more and more linear grip.
Finally some cosmetic changes were required to bring the car up to standard visually. A reiger front splitter, some black front kidney grills and a BMW M performance rear spoiler all bring a contrasting black element to the alpine white car.
The reason I decided to go for the static suspension, camber plates etc was I wanted to create a OEM+ car. A car that we all wish BMW would have made. I only used TUV certified parts when building this car, not because we have to here in the UK, but instead because it ensured high quality parts were used that have been certified in the country where the car was built. Resulting in a very high standard OEM+ style car. A final celebration of, in my opinion, the best BMW car recipe.
