Re-chipping and the promises made ……..

[Me Alec]

I've got a 2008 335i Beemer - 2008.

Thinking of re-chipping; I've been assured of an additional 77 bhp and an improved 20% fuel consumption - is this likely or bks?

[donkmeister]

Me Alec said:

I've got a 2008 335i Beemer - 2008.

Thinking of re-chipping; I've been assured of an additional 77 bhp and an improved 20% fuel consumption - is this likely or bks?

From experience of various remaps; additional power (and torque) is a given. Improved fuel consumption AND additional power/torque is not. I'm not saying it's impossible but I'm yet to find anyone who has genuinely experienced better economy.

Something else to bear in mind is that powerful/torquey cars such as a 335i will have torque limited in the lower gears from the factory to save the driveline... A reputable remapper will know how far to push things, but a less reputable remapper might not. I had a car that was remapped by a previous owner and whilst it would launch spectacularly there was too much torque in the lower gears (box was rated for 440Nm, no idea what it was pushing but I'd estimate 500+ from comparison with other cars) and it ended up with a slipping 2-3 gearchange.

[ging84]

77bhp extra from a 6 cylinder turbo isn't a huge ask

20% improvement in fuel consumption
maybe depends if you consider more or less consumption to be an improvement

[A1VDY]

With more power you'll find you use the extra more often negating any fuel economy gains.

[Brooksay]

Isn't the improved economy supposed to be from the increased torque allowing you to change up sooner, and down later? Rather actual engine-efficiency improvements?

[anonymous-user]

All remaps work by injecting more fuel, you won't save fuel, it's a myth.

[DuraAce]

Me Alec said:

I've got a 2008 335i Beemer - 2008.

Thinking of re-chipping; I've been assured of an additional 77 bhp and an improved 20% fuel consumption - is this likely or bks?

Power? Sure, no problem.

20% up on mpg? Not a prayer.

[F1 Chris]

Thesprucegoose said:

All remaps work by injecting more fuel, you won't save fuel, it's a myth.

Not true at all.

[anonymous-user]

F1 Chris said:

Not true at all.

Go on then explain how you make more power/energy without increasing how much fuel the injectors inject?

[Captain Obvious]

Thesprucegoose said:

Go on then explain how you make more power/energy without increasing how much fuel the injectors inject?

You're starting from the point of incorrectly assuming the AFR is always perfect

You can make more power on fine tuning the timing also.

When my Evo was tuned the first thing the tuner did was make sure the AFR was sorted as was the timing. The car picked up something crazy like 30bhp from that alone although that was a Japanese ECU so it wasn't setup to run worse quality fuel and we couldn't rule out someone having messed with the map in the past.

Then he upped boost and fuel to get the remaining power it gained that day.

I know what you mean and the above is being pedantic but its not wrong.

[Shanksy87]

The power gain you'll see I can't comment on, although from memory most tuners offer 60+ from a basic map on these cars.

Those stating you can't gain economy and power and sort of right and wrong at the same time. If you use the extra power more of the time, you'll be using more fuel. However, the map "should" improve efficiency of the combustion stroke by allowing the cylinder to compress the fuel/air mixture for longer, thereby increasing the efficiency of the cycle and gain you better fuel economy as you could run a little leaner and net the same torque.

I've remapped various cars, both turbo and n/a. All have seen strong power and economy gains for the above reasons. My TVR as an example, gained around 40hp, a huge mid range torque gain and an easy 20% economy when cruising. The original map was massively rich so it wasn't hard to tease out an improvement. Your BMW will however not come from this low starting point, but the engineers will have had to tune to map to suit the emissions requirements and not ultimate economy/power, which is what you should be able to gain from.

Hope this helps

[aeropilot]

Me Alec said:

I've got a 2008 335i Beemer - 2008.

Thinking of re-chipping; I've been assured of an additional 77 bhp and an improved 20% fuel consumption - is this likely or bks?

First question I'd be asking on a 12 year N54 engine, before letting it anywhere near an ECU reflash is what are the age and state of your turbo's...!!
It's highly unlikely they are the originals by now, so when were they replaced, how many miles ago?




Oh, and 77bhp.......yeah, maybe for a second of two, before the ECU backs it all off because of heat soak, due to the crappy standard intercooler.
As for the 20% mpg improvement............. have a

Edited by aeropilot on Monday 17th February 08:36

[BOR]

The worst thing you want to hear is some fool with a laptop promising 20% less fuel use.

At high RPM and at full throttle, the engine will be mapped to add additional fuel to cool the combustion chamber.

If you lean off the air fuel ratio from, say 10:1 to 12:1, you will get a power increase, but your combustion chamber and turbo chargers will see far higher gas
temperatures.

Over time, these will reduce the durabillity of the head/valves/turbo etc.

So in short, entirely plausible, and incrediblly stupid.

[Me Alec]

As I imagined, a load of bullocks.

I'm grateful for all your replies and the trouble that you've gone to - - ALL is taken on board.

Mention has been made of the age of the car - '08 and sub-50k miles. Curiously, a full service book with every entry from BMW Park Lane. Even more curious perhaps is that the car was prepped and sold to me by a Main Dealer - and rather than stick it in an auction, such was their confidence, they sold it to me with a full 12 month BMW Warranty - - - - and that to me speaks volumes.

I've had time to consider my opening post, and more fully;
Were re-mapping the system such a good idea, don't we think that BMW would offer it as an option?
Many years ago I had a Colt Lancer Turbo - a rally prepared car and from Brodie Briton. I sold it to a garage owning mate and he stuck a nitrous oxide kit on it. I drove this newly ponced up thing and in truth - the difference in power was barely noticeable. From the existing 300-ish BHP it apparently produced a further 60 BHP - or so it was claimed.
I came away believing that for road driving, I would probably need an additional 50% to really notice the difference, but at what probable cost to a 12 year old car?

Again, my grateful thanks to those who know what they're on about!!

[anonymous-user]

A remap by a decent company with RR is the way to go. They check parametres before remapping. The issue you have is most remaps push injectors past safe threshold, if they fail, engine fails. So better to invest in decent remaps before hand.

I would even say doing leak down test on injectors before hand and checking turbo boost.

[Me Alec]

…….. and just to add - Why a 335i? ……..

I was all set to buy an M5 - made the guy an offer with the proviso that the car went to his nearest Main Dealer for a full health check. He pulled out at the last minute and for some reason, I was relieved.

I had a 335i previously and loved it, including the near impossible run-flats on our Norfolk B-roads …….. F-roads would be a more accurate designation. I forgave the car it's tyres and accompanying suspension, because on fast A-roads, and for me, it set my pulse rate up, a bit!

Over the years, I've driven a few cars that were quick, but as I only ever seem to get to know a car which I live with, the previous Beemer was certainly the fastest and the most responsive car that I've ever owned. I maintained that it was a bit of a slapper - anywhere and anytime that I wanted - - I topped 140 in it once, and ran out of road.

I'm 73 - the intention is that this one will stay, providing that it doesn't catapult me in to the hereafter!

[aeropilot]

Me Alec said:

Mention has been made of the age of the car - '08 and sub-50k miles. Curiously, a full service book with every entry from BMW Park Lane. Even more curious perhaps is that the car was prepped and sold to me by a Main Dealer - and rather than stick it in an auction, such was their confidence, they sold it to me with a full 12 month BMW Warranty - - - - and that to me speaks volumes.

If you mean my post, you haven't answered the question which is about the turbo's.

If they are the original ones still, and I would be amazed if they are, these have known wastegate issue's, and its about £3k to replace both of them....
If its got a full BMWSH, then you need to ask whether the two turbo's have been replaced under warranty, and if so when. Many were warranty replaced, because of the known issues.
If you can't find this out or they are the original units, then I would be leaving it as is, and not letting anyone remap it.....!
As I'd be wanting to keep it in BMW warranty, unless you can afford the cost of turbo replacement?

There are also some goof ECU tuners firms out there that know there stuff with these engines, but there are many more that don't.

Edited by aeropilot on Monday 17th February 15:05

[Fishlegs]

Thesprucegoose said:

F1 Chris said:

Not true at all.

Go on then explain how you make more power/energy without increasing how much fuel the injectors inject?

You'd be correct if road speed was just a straight-line function of fuel injected. But it isn't. Combustion engines are not equally efficient at all RPMs, and gearboxes magnify or mask this effect. It's absolutely possible to increase fuel economy and get better performance by adjusting fuelling and boost across a range of revs, gear by gear.

It's entirely possible to do so without detrimental AFRs too.

That doesn't mean any off-the-shelf map is guaranteed to be good or safe though.

Have you ever mapped your own cars? If so, you'd know instantly (peak and usable) power and economy both improve noticeably. It's pretty much a no-brainer these days, I reckon.

[Me Alec]

aeropilot said:

If you mean my post, you haven't answered the question which is about the turbo's.

……..

Edited by aeropilot on Monday 17th February 15:05

I've just 'phoned Park Lane and they've said that it's a question best answered by e/mail. Should they reply, I'll let you know what they say - - thanks for the heads-up.

I'm told that the only Main Dealers, be it under warranty or not, who can research work carried out, are those who actually did the work - - which I find a bit odd.

Edited by Me Alec on Tuesday 18th February 09:55

[Me Alec]

aeropilot said:

If you mean my post, you haven't answered the question which is about the turbo's.

……..

Edited by aeropilot on Monday 17th February 15:05

I've just 'phoned Park Lane and they've said that it's a question best answered by e/mail. Should they reply, I'll let you know what they say - - thanks for the heads-up.

I'm told that the only Main Dealers, be it under warranty or not, who can research work carried out, are those who actually did the work - - which I find a bit odd.

Edited by Me Alec on Tuesday 18th February 09:56