I had my remap and CDV delete done on Saturday.
The results . . .
The short version . . .
It’s faster :evil:
The long version . . .
Since buying the car in June I had been running it as standard, and to be honest I couldn’t fault the driving experience. Despite this, I was greedy for a few more horses. After feedback from this thread I also became interested in the CDV delete mod. I had experience with remapping on previous cars, but hadn’t a clue what a CDV (Clutch Delay Valve) was, let alone why anyone would ‘delete’ one.
I investigated the CDV and the benefits of removing it, and why BMW in their infinite wisdom installed it in the first place. I have to say the reports of less jerkiness and a smoother gear change particularly in 1st and 2nd definitely appealed. If the reports were accurate, I liked the idea of the clutch engaging in a more direct way, especially from standstill. So I was very intrigued to find out for myself how the car would drive following the mod.
As mentioned, in addition to the CDV delete I was remapping a naturally aspirated engine in a car that was driving superbly. So there was a fair amount of trepidation, and also a feeling that perhaps the claimed power gains of around 9% wouldn’t be noticeable. I also realised the increases quoted were just projected numbers on a graph, and since I wasn’t doing a comparative dyno test, I wouldn’t know for sure what the actual power gain was (claimed increase: 265 to 288 bhp). However, a 30 day money back guarantee meant I could swap back to the original map if I wasn’t satisfied.
So, there were lots of unknowns and also a niggling feeling that I might be better off spending my money on something else. However, having done a lot of reading and talking with the mechanic, I felt reassured - plus his price was very reasonable. The cost of the remap was discounted due to going through a mutual friend, and the CDV delete was thrown in at no extra cost.
The first thing to make clear is that because both mods were done at the same time I’ve introduced 2 variables into the driving dynamics, therefore it’s tricky to discern the relative benefits of each mod separately. To make things even more fuddled my newly ordered ZHP gear knob arrived at the dealers on Saturday morning, and so I swapped it on immediately. So I had the drive to the garage (1 hour 20) to appreciate that little subtlety, before the real work began.
I’m well aware that having spent a fair bit on the mods (albeit hugely discounted), I’m hardly an objective observer - it’s very difficult to quell my excitement and temper my enthusiasm. Therefore, this feedback is highly subjective - so with that disclaimer, here goes:
First impressions: well it’s not a dramatic change like remapping a turbo diesel, but I wasn’t expecting a transformation. I have to remember that in standard mode the car is bloody fast, and I wasn’t trying to iron out flat spots or spread the torque over a wider rev range; I just wanted to squeeze a little more power out of the beast, and I believe that has been achieved – it does feel noticeably faster. There is definitely an increase in torque from 2,500 revs upward – and by torque I’m talking about in-gear acceleration or the ‘neck-snapping’ feeling. The car feels more urgent. Also the accelerator pedal feels different - in a good way; the pickup is smoothed out over the full pedal movement, if that makes sense. As for the CDV delete: I can feel a subtle difference engaging the clutch – more of a direct connection. The slight bunny hopping/jerkiness changing from 1st to 2nd has gone.
This feedback is based on Sunday’s drive to the Breakfast meet up at Scar Top – a 2 hour round trip on motorways, A and B roads, plus some tootling about in the afternoon (the drive back from the garage on Saturday was in torrential rain doing 40 to 50 on the M-way with standing water and poor visibility). So far I’d say the mods have delivered a smoother, punchier driving experience. On the strength of one day’s driving it was definitely worth the money, and the gamble has paid off. If there’s anything more to report over the next few weeks I’ll add to this thread.
p.s. I can recommend the ZHP gear knob too
It was a rhetorical question, I know my way around a motorcycle thanks 
