Grantham
Hi , is it possible or advisable to get a small power tune on a 2015 18i engine .
Engine tune
- Thread starter Nick groves
- Start date
Scottish Borders
With an 18i you will get more than a 'small power tune' with a remap. Around 90-130 bhp increase is the norm.
The 18i was completely strangled from the factory with it's map (on purpose).
Thanks , I thought it a bit strange that the 4 cylinder 2 litres all looked about the same , but with power differences. I suppose it would effect fuel economy .
Did it to my 20i. The increase in torque means that even with spirited driving I am averaging just over 1mpg MORE than I did previously
Hi , thanks for your reply . How far would you go with z4 18i ( 158 hp ? )
I would like to stay with remapping, no extra parts if possible .
Not a problem...
It's the same engine as the 20i, with a different map, so it should take the same remap.
Mine went from 188bhp to 279bhp.
With corresponding increase in torque, which if you're not sat on a bar stool, is the real figure that matters.
The torque curve rose to max at just over 1500rpm and stayed level until just under 6000rpm.
There are many 'generic' maps available for the N20 (in fact they will all be generic maps in one form or another). The two most common are 240bhp to align with the standard N20 output of 245bhp, and a 280bhp. Both are fine and need no hardware changes.
There should be no increase in fuel consumption on a remapped N20, even an 18i. The factory map just wastes fuel without turning it into oomph. The official mpg stats for all three N20 derivatives are exactly the same!!
All quoted figures for a remap will be using 99RON petrol, so will be a bit down using 95 or 97. You won't notice.
The best thing about mapping an 18i is that the difference is phenomenal, as it is so under powered as standard. The torque at low revs is a game changer.
North West Surrey
Need to think about my wants and potential costs . But , full blown tune would be smile inducing....
And thanks for everyone's input . 
Don't forget you'll need to tell your insurer, so that might affect costs.
Regarding costs, mine was ÂŁ295 about five years back.
The bloke used an off the shelf package initially, but with the car on a rolling road, once he'd installed that he then spent an hour adjusting parameters to fit my car. No two are quite the same, so just getting it done on your drive is fraught with potential issues, but the same tune, massaged to fit your car, will work well.
Rolling road set up is a must!
Thanks for the information , it has been very helpful .
Where's the disagree button when you need it?
The software files for the N20 maps were re-written over 15 years ago now by less than a handful of (very clever) software developers. One of which was Superchips. In 2010 they were probably the largest writers of software maps in the UK. I happen to know (because I asked) that they locked their maps, so they couldn't be tampered with by third parties; to make sure they were safe. They sold their software files to all and sundry for a price, as people do, and those people could call their maps whatever they wanted.
I firmly believe that these generic, locked, maps have been used by many with a rolling road to make no difference whatsoever, except to charge more money. It is easy to get a rolling road to say what you want, it's not so easy to unlock a locked software file.
The fact that ALL re-map files for the N20 are the same (they all quote the same two figures; 240 or 280 BHP) backs up my theory, along with what I was told by one of the pre-eminent companies in this field.
But if people want to pay the extra and get their car thrashed on a RR by 'Dave' from 'megahorsepower Ltd' and get a pretty bit of paper for the privilege, good luck to them.
As usual your generalisations are incorrect…
There are a set of common maps sold by various cowboys ..
It’s infinitely easy to pick one of these maps and tweak any number of parameters in any number of tables
Tuners can’t help but tweak because they know better
So you have no idea on the history of these OTS maps..they could be similar they may not..
Your target figures can come through boost, ignition timing, fuel / air ratio, valve timing etc etc
So any single figure , say 270bhp could be achieved with an almost infinite number of different permutations..
The headroom on any engine varies based on wear n tear, amount of carbon deposits in the inlets and cylinder / piston crown, the state of particularly the HPFP, plug and coil condition as well as inlet / exhaust related matters.
Having spend dozens of hours on dynos with the same guys you learn a lot.
There are dozens of posts from the dyno boys who show that some OTS tune was less than optimum.
Of course the reverse is true…for example MHD OTS maps are exceptionally well developed reflecting hundreds of hours of tweaking over many engines of the same type.
As my own case on my N20 shows..I had a stock OTS tune from Celtic ..and it was utter crap…who made it crap…Celtic or the dealer through some mishap who knows.
So the gold standard is a dyno based tune..no ifs or buts…cheaper can be nastier..N20 isn’t an engine I’d take a risk on.
And 'as usual' I was expecting your input!
My 'generalisations' come from speaking in depth (cos I'm nosey) to the people who wrote the maps. If you do some research on Superchips, you will find they were (not anymore cos they sold out) one of the first and a big noise in engine re-mapping going back almost fifty years.
Your 'gospel' is from you being a self-appointed expert on the subject from presumably reading more than knowing. Have you ever thought that maybe your 'tuners', who make a lot of money from you, just may be spinning you a yarn and blowing smoke up your arse?