M140i with remap - traction??

[Kiwi79]

Hey folks, giving some serious consideration to an MI140i and remapping it to make it a fair bit quicker than my current car (S3) but I've read a few threads saying they are a handful/traction is a pain even stock due to no LSD. In fact I watched a M135i nearly lose it on a roundabout at fairly low speed (completely sidewise just caught it and I don't think it was intentional...)

If you have one and it's mapped is the traction control forever kicking in or is the reputation undeserved? Is an LSD the panacea or minimal difference.

I tried an F80 M3 Comp in the summer and that wasn't too bad at putting it down with 440 odd bhp but I'm guessing different setup to the M140.

[320d is all you need]

My friend has a m140i and it has no traction issues that you wouldn't expect with a powerful RWD car.

Nice machine

As for LSD, it's more traction out of corners than straight line traction. Not a major issue.

[Pizzaeatingking]

I've got a 340i with about 390 bhp, it's not too bad in decent weather but poor weather the TC gets a good workout. That said it doesn't just fall off the road, I'd guess the M135 you saw either hit some fluid on the road or was running stty tyres.

I'm going to stick an LSD on before mapping, there's no point having all the power and not being able to put it down. Diffs aren't mega money, less than £2k and while I've not driven one with the diff fitted I have spoken to a few owners than have and every single one has raved about how it transforms the whole driving experience, puts the power down better and making the car more stable and predictable too.

What level of tune is your S3 at now?

[DVandrews]

I have fitted an LSD to my 440i; it is of benefit for straight line traction but is more noticeable when booting it out of corners where it bites well and gives predictable results rather than just losing the rear end.

Dave

[Court_S]

I think it depends on your driving style; I don’t have too many traction issues in my stock car with MPSS tyres even in the winter. The traction control light flickers but no more than I’d expect in a rear wheel drive car with reasonable power.

For me the bigger issue is the slightly unresolved rear damping. It makes itself known on bad roads / higher speeds. It’s not as bad as some would have you believe (people on PH have described it as dangerous) but it might be slightly disconcerting after the unflappable nature of an S3.

[Andy70]

my 335i has more than 400BHP i think, I'm still waiting to get it on a rolling road. I have put up a few threads on here regarding various issues, the first thing I done through advice on here is fit Michelin Ps 4s, they made the world of difference, but still slithers around a bit in the wet. I've looked into putting m3 wheels so I could go up 2 sizes for more grip but varying opinions suggest they wouldn't fit due to tyre spec and offset etc. so the best I can do is just go up a size to 265's on the rear and hope this helps, that's the largest tyre that will sit on my rims I think (9j)

In the dry and warmer weather its fine... But the best advice I got was to put winter tyres on for the colder wetter weather, it seems lots of people do that and I can see why now. I'll follow this thread closely to see what comes up

[Alex_6n2]

In weather like it is now a remapped 140 won't put much power down

400bhp on SuperSports which are only 245 wide doesn't equate to traction

LSD helps and I'm thinking of getting one for my M135i

However, I might as well buy an M3...

[320d is all you need]

Alex_6n2 said:

In weather like it is now a remapped 140 won't put much power down
.

My 320d doesn't put its power down in this weather

I think people perhaps expect too much from what is a very powerful car with a potent delivery with RWD.

[Driver101]

There's so many thread covering the M140i. There's no need for another.

[Andy70]

Driver101 said:

There's so many thread covering the M140i. There's no need for another.

There are lots of threads for everything on here, its sometimes easier to just ask a specific question and see what opinions you get regarding that... I'm sure half of my questions have been asked before.. I have a 335i with similar issues so I'm curious to see where this goes

How many tyre threads have been put on here over the years for example??? but people still ask

[nomis36]

Driver101 said:

There's so many thread covering the M140i. There's no need for another.

Why is it a problem if there’s another post on the M140i?
I’m genuinely curious why people always pop up saying things like “it’s been spoken about before, go do a search”.
Do new posts waste space?

[Krikkit]

Court_S said:

For me the bigger issue is the slightly unresolved rear damping. It makes itself known on bad roads / higher speeds. It’s not as bad as some would have you believe (people on PH have described it as dangerous) but it might be slightly disconcerting after the unflappable nature of an S3.

I think this is the biggest flaw from the sounds, I'd definitely consider a suspension upgrade and an LSD.

[Andy70]

Krikkit said:

I think this is the biggest flaw from the sounds, I'd definitely consider a suspension upgrade and an LSD.

I was considering uprating my suspension on my 335i as I know that can make the world of difference, but would it help straight line traction?...if so, upgrade to what?

[liner33]

An m140 is never going to have the traction of the S3 but that's kinda the point if you want an entertaining drivers car

These cars are hardly widow makers unless you have poor tyres and/or drive like a gimp

[handbraketurn]

I had a 340i MPPSK which I sold last year, same engine and diff.

Suppose to be around 370bhp, but I'm sure mine was more, it was very rapid.

The open (e-diff) is fine in a straight line, esp with Sport or + traction is still on. If you turn it all off, it's prone to wheel spin in low grip conditions (rain) but drive accordingly.

The problem with the open diff is that one wheel spins up out of corners, it makes oversteer snappy and it difficult to get controlled progressive slides, the TCS will reign that in my cutting power and applying brakes, if I had kept, I def would have gone for LSD.

Just as important for me, is getting the suspension sorted, the 140i is a better chassis out of the box than the 340i, but still at the least I'd be getting lowering springs and a good fast road geometry set up and the LSD over more power as my priority. And if budgets allowed coil overs. The geometry alone can transform these cars, the 340i was more likely to understeer than oversteer. As mentioned 140i is better handling as standard but these cars are tuned for safety of the lowest common detonator, geo makes such a big improvement IMO.

Also, get good tyres, I binned the run flats and went for Mich PS4S, they're amazing and made a big difference, very good in all conditions but particularly in wet.

Edited by handbraketurn on Sunday 14th February 14:05

[Krikkit]

Andy70 said:

Krikkit said:

I think this is the biggest flaw from the sounds, I'd definitely consider a suspension upgrade and an LSD.

I was considering uprating my suspension on my 335i as I know that can make the world of difference, but would it help straight line traction?...if so, upgrade to what?

Birds do an uprated kit which PH have reviewed and liked. I wonder if any of the suspension upgrades from the M2 might fit.

Better dampers will help everywhere, both straight line and cornering, but especially over bumpy roads.

[Tea Pot One]

I had an M240i which I was tempted to remap but never did due to potential traction issues .... so I bought an X3 M40i to map that

Not got round to it yet though due to Covid but DMS are suggesting 470 bhp from 355bhp !! I've seen M140i/240i to 430 on a map but not 470 ... ! I've had a DMS map before and loved it but wonder re this particular increase as it is huge ... 115bhp from just a map ?

[320d is all you need]

DMS are awful.

You can map yourself with MHD or BM3.

[liner33]

Tea Pot One said:

I had an M240i which I was tempted to remap but never did due to potential traction issues .... so I bought an X3 M40i to map that

Not got round to it yet though due to Covid but DMS are suggesting 470 bhp from 355bhp !! I've seen M140i/240i to 430 on a map but not 470 ... ! I've had a DMS map before and loved it but wonder re this particular increase as it is huge ... 115bhp from just a map ?

Take DMS figures with a large pinch of salt

[Tea Pot One]

320d is all you need said:

DMS are awful.

You can map yourself with MHD or BM3.

I used them a few years ago and found their map and service excellent. Their prices not so much to my liking though.

I don't trust myself to apply a map via my phone etc ....