[Grabla]

I've upgraded (or so I thought) from a 330D Xdrive to a 335D Xdrive, and its lacking power. My 330D was std, and I did 40K in 2 years from new, and it was a rocket. So I put the 335D on a AWD dyno and we did several power runs.

It made 290bhp and 419lbft, which are well below what BMW state for the 335D (313bhp and 465lbft). On the run down we measured 85bhp loss through the 4WD transmission.

Its only got 4000 miles on the clock, but even so, its definitely struggling to keep up with well driven 2.0TDI's and feels slow compared to my 330D. I've tried booking it in at BMW, but its a two month wait for a courtesy car, they really don't seem at all bothered by the fact its a "new car".

What are my options? Will it loosen up and the power will come in time?
There are no fault codes, no warning lights, it just doesn't go like a 335D should. I'm reluctant to put a tuning box on it, until the baseline power is as per the standard specification.

[Enabled]

Did you update all the electronics and auxiliary systems to 335d specifications?

[Grabla]

I think you misunderstand. These are two different vehicles, both F31's.
I haven't swapped the engine.

[xpro]

The loss accounted on the dyno for 4wd shouldnt be as much, as torque sent to 4wd is minimal unless the slip is detected so the car in general runs as 2wd most of the time.

For me the biggest difference between 330d and 335d was the turbo lag.

The 330d felt much more aggressive when the turbo kicked in, while the 335d had a smooth power delivery all the way.

Having 4000 miles only, the car will loosen up and be only faster as times go on, as I found I my case.

Stick on another 4wd dyno and see how it goes there, you'll find those figures can be hit miss at the best of times..

[Enabled]

Originally Posted by Grabla

I think you misunderstand. These are two different vehicles, both F31's.
I haven't swapped the engine.

You are right, somehow I missed that. Apologies.

[Liquidfox]

Originally Posted by xpro

The loss accounted on the dyno for 4wd shouldnt be as much, as torque sent to 4wd is minimal unless the slip is detected so the car in general runs as 2wd most of the time.

This isn't true, it runs with a 40:60 bias, hence my tyres wearing near evenly.

[xpro]

Originally Posted by Liquidfox

This isn't true, it runs with a 40:60 bias, hence my tyres wearing near evenly.

Hook it up to a diagnostic tool, look up the values and transfer clutch engagement and you will see it..

Basing the opinion on tyre wear is a pure guestimation.

[Grabla]

I'm running Android Torque on it at the moment, to capture data from the ECU over ODBII, its hard to find which channels to log though. I've tried adding the 335D CSV file to Torque to provide additional channels, and few of them return sensible data, but its a 2018 car so maybe they changed the format.

What I'd like to record is rpm, gear, air charge temperature and turbo boost pressure.

I'm seeing around 34psi I think, but I'm not 100% sure if Torque is logging the right channels.

And speaking of Tyres, it came with 20" Dunlops, and they're the worst tyres I've ever driven on. It just understeers at every opportunity. I'm looking forward to the day when I can get some Goodyear F1 Eagles on the car.

[Watsey]

More info would be useful. Where did you have the dyno run ? Have you had a full diagnostic via the OBD ? Could be a failed sensor, i.e. MAF/MAP, although faults seem to be rare on these units especially at low miles. Have you checked all hoses for boost leaks, checked the condition of the air filter (should be clean at these low miles), and made sure that you're getting sequential boost from the two turbos ? Also worth doing simple things like having the Sports Gauges on the iDrive and seeing what happens as you add throttle through the rev range (including full throttle and kick-down).

290/419 is low, especially as BMW is usually conservative in its published figures. 85bhp transmission losses also sounds very high. The engine may be tight and they do loosen-up, especially the diesel units, as the mileage increases. At this stage I'm doubting the dyno results, BUT, there's nothing like the butt dyno and comparing with spirited driving with other cars as a real test off the car's performance. Have you got a dyno graph that you can post, including the dyno settings (AT, IT, gear - the 30d/35d should be run in 5th, etc) ?

My 330d (RWD) made 274bhp in stock form at ~25K miles. Now 350bhp/525lb.ft with a DMS remap, and completely reliable over the past 60K miles.

335d units are regularly producing 370-400bhp with a decent map but obviously you'd need to get any problems resolved first.

[Watsey]

Originally Posted by Grabla

I'm running Android Torque on it at the moment, to capture data from the ECU over ODBII, its hard to find which channels to log though. I've tried adding the 335D CSV file to Torque to provide additional channels, and few of them return sensible data, but its a 2018 car so maybe they changed the format.

What I'd like to record is rpm, gear, air charge temperature and turbo boost pressure.

I'm seeing around 34psi I think, but I'm not 100% sure if Torque is logging the right channels.

And speaking of Tyres, it came with 20" Dunlops, and they're the worst tyres I've ever driven on. It just understeers at every opportunity. I'm looking forward to the day when I can get some Goodyear F1 Eagles on the car.

The OEM suspension setup is dreadful. If you want the car to handle well then from experience of several rounds of suspension upgrades on my car, you need a full geometry/alignment, decent suspension, and to get a decent amount of front negative camber.

[Grabla]

Originally Posted by Watsey

More info would be useful. Where did you have the dyno run ? Have you had a full diagnostic via the OBD ? Could be a failed sensor, i.e. MAF/MAP, although faults seem to be rare on these units especially at low miles. Have you checked all hoses for boost leaks, checked the condition of the air filter (should be clean at these low miles), and made sure that you're getting sequential boost from the two turbos ? Also worth doing simple things like having the Sports Gauges on the iDrive and seeing what happens as you add throttle through the rev range (including full throttle and kick-down).

290/419 is low, especially as BMW is usually conservative in its published figures. 85bhp transmission losses also sounds very high. The engine may be tight and they do loosen-up, especially the diesel units, as the mileage increases. At this stage I'm doubting the dyno results, BUT, there's nothing like the butt dyno and comparing with spirited driving with other cars as a real test off the car's performance. Have you got a dyno graph that you can post, including the dyno settings (AT, IT, gear - the 30d/35d should be run in 5th, etc) ?

My 330d (RWD) made 274bhp in stock form at ~25K miles. Now 350bhp/525lb.ft with a DMS remap, and completely reliable over the past 60K miles.

335d units are regularly producing 370-400bhp with a decent map but obviously you'd need to get any problems resolved first.

The sports displays were very over optimistic on the rolling road, and also when driving on the road, the torque goes right round to 465ftlb but the car is making nothing like that amount of power. I wouldnt trust the guages though, they're really just for show. I've been in a 330D with a tuning box, and the guages still maxed out at the std power figures, despite the car making significantly more power than stock.

Torque shows no errors when I perform a diagnostics scan. There are no warning lamps on either.

The dyno was at Street Racers in Leicester, I'm told its figures are normally reliable.

The video of they dyno run is here. It reached something like 120MPH, which was most impressive with all four wheels turning
It was done in 6th gear with the car in Sports + mode

I'll upload the power plot asap.

The car was fitted with the M-Sport pack, which meant 20" rims, I have no idea if the geo was altered to cater for the larger wheels, but the cornering abilities are diabolical. In anything but bone dry, it just wants to put me in to the kerb/ditch, so I have to be very careful. The 330D was the opposite with the Goddyears on it. Still run flats, but night and day compared to these Dunlops.

[Enabled]

Just so you know, the 8HP transmission module limits your tune torque maximums in 3rd and 6th gears.

Set up testo and see for yourself.

On the 8hp45, 3rd and 6th gear is limited at 380Nm from transmission software, sent in to ecu via canbus. If through some trickery you block the transmission torque maximum from reaching dde, you can get maximum torque in all gears, but then transmission shifts vaguely.

8HP70 will have a similar lower limit in 3rd and 6th. All other gears are at 700Nm. This is due to transmission clutch design. You need a top tuner that really knows these ecus to get around that.
Whenever xHP comes out with 8hp flashing, you will be able to raise that limit, but it can be risky for 3rd and 6th.



It is simply not ideal to dyno in 6th on the automatic.
It may not affect you as much since it's a stock car, but it will affect tuned cars.

[Enabled]

Also, if you're concerned about all the awd dyno detail... you can code the car to rwd temporarily and dyno that way.

[Grabla]

Very interesting. I did not know that. So on the rolling road, 6th won't give the true max torque figures.

What is testo?

[Watsey]

I didn't watch your dyno video previously, but a few things caught my eye :

The revs/power build-up is very gradual. Not necessarily a bad thing, but was full throttle, including kick-down, actually used ?
The engine note didn't seem to get to the point where it was clear that the car was giving everything it could.
The car didn't hunker-down at the rear, or climb-up on the rollers at all. This is unusual in my experience. Some say that there should be roller-climb; others say that there shouldn't. Either way, we should at least see the car trying to climb the rollers if it is only restrained laterally (as it looked like yours was).

Running the car in 6th (or 3rd) is a big miss. I'd try a different dyno and see what results you get. I've had my car on four dynos and have seen a 40bhp min-max variance.

[graphicjunkie]

I'm curious how you get it to run in 2wd mode? As far as I thought, the sport+ tweaked the ratio to more rear, but didn't turn off the front all together. I thought that was a new feature of like the new 8 series only. I am ALLL ears on how to do this!

[Enabled]

I coded mine to fulltime rwd, and I have been running it like this for a while.

I posted the instructions somewhere around here...




Testo is a program that uses the BMW diagnostic protocols to log a bunch of available parameters. Very helpful for testing and tuning as well.

[Grabla]

My wife's 220D had an EGR failure last week, so I called BMW Assist and they came out to fix it. I was chatting to the tech about my 'power loss' and he put the diagnostics computer on my 335D, and found no faults. Ironically only a warning about a slow-to-respond indicator unit.

I'm getting more used to the power delivery now. I'll just have to avoid 6th gear when I want to do a full power run

[daz216]

I swapped from a f30 330d also & my brand new 335 d was noticeable slower so when bmw contacted me to see if I was happy with my purchase I told him it's no where near as quick as my 330d.

His response was that you need to get some miles into the engine,I'm now on 14k & this machine is very quick now compared to when I first had it,all I can say that I put a tune box on for a year to compensate for the power loss.

I did start to feel it loosen up around 5k but now I'm more than satisfied.

[Grabla]

Originally Posted by daz216

I did start to feel it loosen up around 5k but now I'm more than satisfied.

I've got 4600 miles on the clock now, and its improving all the time. I've a spare DPT box in the garage that needs reprogramming, so I might put that on the car for some extra oomph.

Q) Does your car have AdBlue?

My display permanently shows

Range > 4500 mi
Refill 0.0 l

What does that even mean?

[daz216]

I'd put the box on mate for another year till it loosens up a bit more (removed mine at 8k it was pretty good then) but tell the insurance, mine went up about £300 as for the ad blue both of mine didn't have that.

Don't know if it's true but a friend told me this lack of power is programmed into the car too protect the new engine,all I can say is that when I put the box on it was rapid which too me says it is a software issue because a tight engine is a tight engine so putting a box on shouldn't make a difference if it was an engine issue.