Thanks Beacon, the 28i. (Or other 4 pot) is the back up plan at present, I think I have settled on the 30i to scratch my BMW straight 6 itch, and tick something off the car bucket list 
30i v 28i
- Thread starter Big Bad Boris
- Start date
ronk said:
Thanks again ronk, that one works
ronk said:
Because the remap puts different parameters to the one the 28i uses, if an identical 28i map was loaded onto the 20i they would produce the same power.
A reputable mapping company will make sure the engine isnât over stressed, higher power figures would be available but could potentially cause unreliability.
Rob
Attleborough, Norfolk
ronk said:
Hi ronk,
The 18i is effectively a stage 0 tune (154bhp), the 20i is effectively a stage 1 tune (181bhp), and the 28i is effectively a stage 2 tune (241bhp).
The engines are identical and it is just the map that is different. The reason you can get up to a stage 2+ remap of 280bhp is that BMW has to be able to guarantee that they can get their quoted bhp figures all over the world with all the different allowable fuels. In the UK and most of Europe where we can get 95/98/99 octane the tune can take this into account and gives a bit more bhp without leaning too hard on the engine. The engine can of course be pushed to over 280bhp, but you then need to start changing engine components and you get diminishing returns. 280bhp is what most people with a remap end up with and remains within safe bounds is my understanding.
You can end up with slightly better fuel economy as the torque at lower rev ranges increases. But as with all power gains, the increased boost pressure from the turbo means more fuel is consumed when you're higher up the rev range. So town driving mpg should remain the same or better, but gunning it will use more fuel (as you're getting more power).
Downsides?
- You have to inform your insurance company that you have a remap. Chris Knott Insurance on this website worked for me as its a weekend toy and my insurance was lower than on compare the market.
- The 20i brakes are smaller than the 28i brakes, though most posts I've seen where someone has said they had a remap didn't feel that the car became underbraked.
If I was to go back and buy a Z4 all over again with the knowledge I have now, I probably would have gotten a 20i and remapped it than a remapped 35i. I just don't use 380hp and the savings in petrol/tax would be lovely. But that's my head talking, not my right foot
ronk said:Ah! I see what you meant now
So I was correct in saying the 20 and 28 have identical mechanicals and only the electronics differ?
Even the electronics are the same, just the software that is on the electronics that is different.
It is important to note that the 28i came with a better basic spec than the 20i so its still worth looking at the options each car has, but it will increase the number of cars you can look at and get what you want.
Beeacon said:ronk said:Ah! I see what you meant now
So I was correct in saying the 20 and 28 have identical mechanicals and only the electronics differ?
Even the electronics are the same, just the software that is on the electronics that is different.
It is important to note that the 28i came with a better basic spec than the 20i so its still worth looking at the options each car has, but it will increase the number of cars you can look at and get what you want.
Iâm curious as to what the 28i came with that the 20i didnât? :?
Rob
An 8.Smartbear said:Beeacon said:ronk said:Ah! I see what you meant now
So I was correct in saying the 20 and 28 have identical mechanicals and only the electronics differ?
Even the electronics are the same, just the software that is on the electronics that is different.
It is important to note that the 28i came with a better basic spec than the 20i so its still worth looking at the options each car has, but it will increase the number of cars you can look at and get what you want.
Iâm curious as to what the 28i came with that the 20i didnât? :?
Rob
Big Bad Boris said:
Yes, heated seats, idrive, folding mirrors, smoker's package!, uprated audio, 19" wheels, phone package, dual climate control, something about the lights but not sure what that is, etc...
I just kept looking till I found the right one. It came from Scotland and was delivered by transporter.
Beeacon said:
My 30i had active lighting where the headlights pointed whichever way the steering was turned, i think it was only active when the lights were in the âautoâ setting. I read somewhere those lights were ÂŁ2k each which unnerved me a bit.
The car destroyed its gearbox a few weeks later, sparing me further worry
Rob
I had those active lights on my CLS, in passing I asked a guy at Mercedes how much they were if one needed to be replaced, he replied âyou donât want to knowâ....ânuff said.