E91 Straight Six Bearding

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Re performance: I guess part of it is because I came from a 1.6 petrol with 98bhp as my main car (my first car actually, 2001 mazda 323) prior to my n52 330i, and my other fun car is an RX-8…both of which lack in the torque department, that I really don’t find the car slow! I frequently find myself at the end of a slip road glancing at the speedo and going “oops, better back off” as the top of 4th gear is where I used to be pretty much at DC/Motorway cruising speed, and it’s basically a ton in this…, I can also line up at any lane at the front of a set of lights for a roundabout and make sure I’m first out to go anywhere I want without cutting anyone up…. It really doesn’t lack useable pace on the road, and I don’t feel I miss out on overtaking opportunities. Before in a little first car I’d be flat out absolutely everywhere!
Sure you can get a faster car – you’d have to have a good driver and an empty bit of road to make that count. Torque makes the driving easier/lazier, but also IMHO a bit more boring. Sure there’s a balance, and for me the n52 330i is perfect – that’s a very personal thing and I totally get why people would prefer more torque. If I’m not in the responsive gear, it pulls like a 320d with the zf 8 speed which does the gears for you – I’m really impressed by that gearbox and I’d be tempted by it if I had to drive in traffic all the time, and I was in a warranty period – I prfer my manual box being I’m north of 219k miles…

I had a brief period where I worked out I needed to fix/replace my DISA valve where the car was a bit tappy and the power delivery wasn’t as smooth. That’s about it…

Z4MCSL said:

Oh my days I am a doofus ??

Hello – you’ll fit in well here

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helix402 said:

For all you with fuel leaks:



(Nb-make sure this fits your car)

Best piece of preventative maintenance ever! Takes all of not many minutes to fit, and saves potential £50 new breather pipe and probably a day of faffing dropping the tank etc.

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Boobonman said:

Been away from the forums for a while, what’s the current consensus on upgraded exhausts? I had a Scorpion system years ago on an E30 325i which really made it sing, and I see they do a cat back for the 330i. I don’t want it too OTT, just find it a bit muted as standard ( already done the golf tee and noticed no difference ) . I love the sound of the BMW PE but they seem hard to find and quite dear, am I best off going to a fabricator and asking for as close as? Anyone got any clips of 6cyl E9x’s with non standard pipes?

I have the Scorpion system on mine (N52 330i), it came with the car (and the OE backbox). You can tell it's a straight six, maybe a bit more volume, but it's not anti social at all, I'm quite happy starting it up and it won't annoy the neighbours, I'll also do long drives on the motorway without noticing. You do have to cut the midpipe to fit it though..., so you'd need a new one of those if you wanted to revert back afterwards...
I did once drive without the backbox as it didn't have time to refit it following fettling with the suspension and my alignment being booked. That wasn't as silly as I thought it would be - it was just a bit droney....

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g3org3y said:

stevesuk said:

g3org3y said:

(Apparently the fuel filter is supposed to be replaced on every 3rd oil change also).

You what now? I changed mine when I reached 200k miles, I'm pretty sure mine was original to the car...and mine had full BMW service history when I bought it...
They're not cheap either....

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Hi everyone - OP here.

Been out of here for a lot of the year, a lot has happened in my life, getting back into the swing of things/life. Not done much to my E91 this year, but she's still going strong. Currently sitting at a healthy 55.3mph average over the last 8-10k miles and now on 222k miles (annoying missed the 222,222 odo money shot!). Have fitted a new prop centre bearing, rebuilt my rear calipers with new OE discs and pads (including shoes) and a respray, and I have 340mm BMW brembo 4 pots fitted on the front from a F32 435i (required minimal trimming of the dust shield to fit - otherwise factory!) - it all balances nicely and braking is sublime!

I'll post a handful of photos and stuff, and I wanna at least catch up with this thread.

chunkytfg said:

NOot that I'm in here very much but i'm leaving for good as of Monday. Copart are picking my 325 up after some numpty sideswiped me 14 months ago as the Ins Co have finally paid out on it.

Anything worth 'keeping' out of it to pass on to someone who still has one? things like the roof rack or Unused Gearbox and diff oil?

Maybe the rear parcel shelf?

Hi Tim - don't wanna seem like a vulture and I am genuinely sorry for your E91, but I'm in mid Suffolk and I would love to relieve you of a few bits of your car and guarantee them a good home! Please PM me, and I'm sure I can help

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Thanks for the warm welcome back to the party Swervin - you still got yours? Last I remember you were toying with putting her up for sale having just sorted your drowned ECU and sprucing up the stone chips.

Brake photos:

Took the rears apart entirely, new everything, cleaned them back and a respray in some halfords VHT...



New ATE shoes (I think they're OEM) because I had them - I think they were one of the first spares I bought and then never bothered changing them as I wanted to mate them to fresh discs...!



OE discs and pads


Wheelnuts let the side down now!


Front brakes comparison:



I had to snip the tiniest sliver off the edge of the dust shield to make the calipers fit, otherwise fits exactly spot on, brake balance is all perfect etc.


Snug fit behind my 17s, but the wheel weights do clear the caliper fine.

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toast boy said:

How are you finding them when driving Zippy? Is the performance significantly better? Looks like it should be by the size increase!

My experience may be slightly tainted by the ones before being cheapo brembo's from ECP from when I got the car and being well past it.... but brake balance is still good - maybe even better, feel is better (although again, that may just be because I gave them a good bleed! I have braided lines on the front, and originals on the back). It feels like they have a good amount of power, certainly better than stock - but I expect just new discs and pads of OE quality on the front plus a bleed would have made a big difference...They certainly feel like they've got more ooomph, I feel I have more control of the braking if that makes sense - not done anything scientific though!

Oh yeah, I'm pretty sure I've lost some rotating weight too!

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ferrisbueller said:

zippyonline said:

toast boy said:

How are you finding them when driving Zippy? Is the performance significantly better? Looks like it should be by the size increase!

My experience may be slightly tainted by the ones before being cheapo brembo's from ECP from when I got the car and being well past it.... but brake balance is still good - maybe even better, feel is better (although again, that may just be because I gave them a good bleed! I have braided lines on the front, and originals on the back). It feels like they have a good amount of power, certainly better than stock - but I expect just new discs and pads of OE quality on the front plus a bleed would have made a big difference...They certainly feel like they've got more ooomph, I feel I have more control of the braking if that makes sense - not done anything scientific though!

Oh yeah, I'm pretty sure I've lost some rotating weight too!

Go on......

OK, so I didn’t actually weigh them, they just felt lighter when handling them… I did briefly think of weighing them, but couldn’t be bothered and knew the weights were on realoem! So here's the weights from realoem...

Stock setup for 330i:
330x24 front disc 9.067kg
Caliper 2.347kg
Caliper carrier 1.765kg
Pads supposedly 2.025kg…. maybe that’s for all 4, so per side 1kg…maybe….
Total = 14.2kg

435i setup now on the car:
340x30 front disc 10.275kg
Caliper (all in) 3.652kg
Pads 2.546kg… (so maybe 1.25kg per side)
Total = 15.177kg.

Ah ok – I’m spouting rubbish! I put it down to feeling lighter as they’re waay bigger but not the associated weight increase due to a but more aluminium being employed. So an increase in rotating weight, and unsprung mass...nevermind!

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JakeT said:

A friendly reminder for owners of the petrol variety (namely N52) owners to have a check of those DISA valves.

I replaced the starter and CCV system in mine over the past couple of days, and found...



Followed by the flap and pin inside the inlet. Fortunate it didn't cause any real damage. I checked the smaller one, and that was fine. A new one from BMW is £260, though.

Yup, been there done that, got the t-shirt. Just to add some notes for others, like Jake I had a low speed idle/stumbling. Mine happened at just shy of 200k miles, I literally felt the difference in the car at the time (I'd been to Birmingham and on my way back when I stopped at the lights the silky smooth idle had gone), it was like a tiny misfire. I spent a while trying to find it and at the same time attended to a few little things that needed doing anyway.

Anyway - a non functioning (i.e. butterfly valve disappeared) on the DISA valve will probably be thrown up by the computer as a shadow code, so load Carly/INPA etc and it should show up - it won't throw a CEL. You can check the large one without dissembling the manifold, and you can change it without pulling it out - just a bit of a wiggle. However if it's broken - you probably have to take it out to find all the bits of your butterfly valve, mine were sitting in the head against the valve of cylinders 1 & 2..plastic butterfly vane, so no damage done! Found the shaft somewhere inside the inlet manifold...

BMW revised that part - they use a metal shaft rather than a plastic one now, so failure shouldn't happen again. Yes they are pricey! You can buy rebuilt kits for them - but you have to split the unit to rebuilt it...


084 (25-03-2017) by Chris Reeves, on Flickr

I did this to the small one as a "preventative" measure...turns out I could never glue the casing back together well enough and the back flow off and lost the sprockets inside. I've also not read of any failures of the smaller DISA valve inside the manifold (which if you're good with your hands and know where all the bolts are, you can do without removing the inlet manifold - I've done it!) - so don't worry about that! If your small DISA goes, it feels like a turbo car with a bit of lag.... I had to buy a new larger DISA. This and the water pump are probably the two big N52 things to worry about as far as I can tell, I've changed the water pump, and done this...and engine wise I'm still good at 223k miles now. Everything else has been to be honest general 3 series stuff and really wear and tear - which isn't unexpected at this age/mileage.

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stevesingo said:

JakeT said:

croissant said:

That's interesting. I have a 330i N52 and it has an occasional stutter in high gears at low rpm. I've just learned to keep the revs up when driving and don't experience it.

I've always suspected something might be up with the disa. Is it difficult to remove and have you noticed any improvement since changing to a good one?

I drove around it too. But sometimes it catches me out if I'm lazy with the gears.

It's not a mega job to check the large one. The inlet bits need to come off, and a bracket that holds a wiring bundle in my case. You might be able to get away without removing some bits though.

Mine's a silver top N52, so no help there, Mike. I think the N53 valve cover can come off without removing the injectors, though. You can get a new diaphragm though, I'd replace that first. Someone on here had a russian kit that works fine, and they said it cured an oil consumption issue they had. Is yours using some oil now?

Honestly, I don't think any stutter at part throttle is related to DISA issues as if a valve is inactive, stuck open or close, or missing (effectively open), then the symptom you would expect is lower torque in the rev range where the valve should be operating such as;

Small valve stuck open = reduced torque at low engine speed
Small valve stuck closed = reduced torque in mid range

Large valve stuck open = reduced torque in mid range
Large valve stuck closed = reduced torque at high rpm

Both Stuck open = Reduced torque low and mid rpm
Both Stuck closed = Reduced torque mid and high rpm

I have had a sticky large valve in the past and the car was flat at the top end. Sometimes it would open later than programmed and instead of a progressive increase in torque as the rpm passes 4500rpm, there was a pronounced jump at 6000rpm.

IME hesitation at low rpm, part throttle is VANOS issues where the cam position lags behind target. WHen the engine is on cat warm up during the first 90sec of so immediately after cold start, the issue doesn't show as the exhaust cam position is set to aid cat warm up.

I think my idle stutter was due to the bits of the inlet butterfly sitting on the inlet valves. It wasn't so much a stutter, as more an occasional hiccup. It maybe didn't help that I happened to lose a cylinder at a similar time (original coil packs at 185k+ miles, so I'll let them off!), but it was definitely a non normal idle, and the engine sounded a bit rattly (all relatively speaking for a silky smooth straight six - still sounded better than generic 4 pot!).

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JakeT said:

g3org3y said:

I am sad also...

Glad I'm not alone.

I have a very detailed spreadsheet....including every single fuel fill-up (& type of fuel!)

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JakeT said:

zippyonline said:

I have a very detailed spreadsheet....including every single fuel fill-up (& type of fuel!)

That's big! Normal year doing 25,000 miles in a year I don't bear totting up the cost of fuel.

I'm on vPower for now though, while the miles are low. Seems better than usual stuff, and filling the car once a month means the cost difference matters very little.

I have done 41,571 miles in mine (as of my last fill up on the 18th of November), although I did 167 miles on the fuel that came with the car I purchased...and I've wasted maybe 5 litres when I dropped the tank to change the fuel breather pipe and didn't want to put the fuel I'd put in a questionable bucket back into the car! Anyway, I've put in 6706.31 litres of fuel into the car at a cost of £8,951.36 pence in that time. Of that 6706.31 litres, it's all been V Power apart from 593.09 litres which has been BP Ultimate. I've also spent £1625.62 on tyres (and fitting), but that's not really a fair representative of running costs given my early life suspension issues which made short work of a few sets of tyres...!

Nerdery over, as you were!

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ferrisbueller said:

ferrisbueller said:

Me too! Suspect removing the inlet manifold would necessitate swapping CCV pipes, too, as they appear to fail as soon as you look at them.

I think:

DISA Outer 7579114
DISA Inner 7560538

Frail CCV Pipe 7522931, circa £60

I've bitten the bullet on this so it's a renewal of both DISAs and the CCV system. £500 worth of DISA valves. Inner ones less prone to failure but access isn't easy so will do that now, too. Inner and outer are about the same price, sadly, and it appears anything other than the BMW is a false economy.

The Febi CCV kit is 170-592 (around £88) and I bought a Vaico pipe V20-1565 (£13) as there are two different hose configuration and it's not clear which my car has until I take it apart, at which point I don't want to find I've got the wrong one. Bought the gaskets and a few odds and sods to make up the £150 required for free postage.

If you know where everything is, you can change the inner DISA more easily than the outer! The inner you can do loosening the the intake manifold but not removing and do the bolts by feel - whereas if I recall correctly the outer you need to remove the inlet manifold because there's not enough space within the engine by to slide it out. I mean, given you're doing both, it's entirely academic...

stevesuk said:

I used to have the BMW diagnostics software on a old laptop, but it died. So swapping them around would be the only thing I could try. The problem is, its our only car in the household and the wife depends on it for work - and I can't drive it to Eurocarparts whilst is broken

I've found someone local who's going to look at it on Tuesday. Other thought is that it could be a dying battery? Got a weird TPM warning earlier in the week (when none of the tyres were actually that flat). So I've put it on charge to just to see.

I diagnosed my dead coil pack the old school way. Started car, disconnected coil and listened for engine note change (or you can have a glass of water sitting on the rocker cover and see if the frequency of the water moving changes). You should hear the engine note/water vibrations change when you unclip the coils, if you don't, that one is dead. I didn't have any codes on mine for the coil pack at the time mine went, and given they were on 180something miles, I changed the whole set there and then.

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Main reason they break is that they seem to corrode like buggery....and you're effectively using the foam bit as the mount.

This is what's in the BMW kit (there's also the nut inside the car, but I don't see to have a photo of it...)



The actual mounting point in the car is pretty hefty:

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ferrisbueller said:

Could someone with access to the relevant information do a quick sanity check for me please?

Looking at diff parts for E90 330i Manual (3.15 diff) and searches suggest the diff is also used on 320d and some 1-series models?

I inadvertently worked out when I bought a whole rear subrframe including diff, driveshafts, hubs etc. that a 320d auto has the same diff as an E9x 330i manual (N52), but has a different input flange.

I also worked out that the driveshafts and hence hubs/wheel bearings are weedier on a 320d than a 330i/330d/335i/335d!

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ferrisbueller said:

zippyonline said:

ferrisbueller said:

Could someone with access to the relevant information do a quick sanity check for me please?

Looking at diff parts for E90 330i Manual (3.15 diff) and searches suggest the diff is also used on 320d and some 1-series models?

I inadvertently worked out when I bought a whole rear subrframe including diff, driveshafts, hubs etc. that a 320d auto has the same diff as an E9x 330i manual (N52), but has a different input flange.

I also worked out that the driveshafts and hence hubs/wheel bearings are weedier on a 320d than a 330i/330d/335i/335d!

Real OEM suggests they're all interchangeable but I'm not convinced that's the case given the proliferation of part numbers.

ETA. Does the input flange just slide out so it's a straight swap. Are the outputs different, too, then?

Edited by ferrisbueller on Wednesday 30th December 18:14

Output flanges are the same - standard e-torx bolt on drveshafts.

Input flange is bolted on I think - so you'd need to make sure you can measure the drag on that if you swap them over.

Sorry, I haven't got brilliant photos, but I've dug these up if they help - they should demonstrate the point.


320d auto. big round input flange.


320d auto part number

i think this is from a 2008 model...

and from my leggy 2005 330i manual:


3 point input flange - otherwise identical.


part number.

I did once know different case types etc. as I was looking into it all so I could refresh the bearings and put in an LSD....but I haven't got round to it and currently don't have the funds! I do have both diff's though, so if you really want some more info, I can physically look at them and take photos if you want.

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ferrisbueller said:

I think there's a low profile nut on the input. With that off you might be able to swap them over? Need to watch a tear down to have a look.

ETA (again) https://youtu.be/WSRgCX_LmOM?t=117

It seems if you release the nut the input slides out and could be swapped over.

Edited by ferrisbueller on Wednesday 30th December 18:55

Yeah, exactly that -you just gotta make sure you do it up to the same preload & drag etc. so it's all still in spec. Whilst you're carrying on researching, do share if you find the diff specs for preload etc. - I've not found a definitive set of numbers on the internet that I trust yet!

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eezeh said:

reading ISTA procedures bmw list a sunroof channel cleaning tool pn 54107306684 which I can order, if anyone has one and can give dimensions I could 3D print a few. Would save a few quid.

Sorry, can't help with sunroof - no experience with it (although will keep an ear out as my friend has a 335i with it). But jeez that's an expensive "cleaning" tool!

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ferrisbueller said:

Swervin_Mervin said:

I don't think the early ones have IBS.

I'd have to look again but I don't think mine does (I think it's a late 05 build).

I bought an Exide battery of similar, if not same, capacity and swapped it in. No issues a couple of years down the line.

Mine doesn't have it (Nove 2005 build, no nav or idrive) - and sounds like yours doesn't just by the fact your battery went flat like that. Look for some additional wiring on your negative clamp on the battery, rather than just one big clamp connected to it.

I'd be inclined to throw the battery on the CTEK and see what happens. It's also got really cold quite quickly - and when I "broke down" and got recovered in the Lakes, I actually worked out it was just some moisture had managed to get between the battery terminals and the connectors - a quick clean up and all has been well since.

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JakeT said:

I've just been in touch with Birds and am in the process of ordering one of their suspension kits to refresh the Birds kit on my car already. This is the last run of springs and dampers they're doing, so I didn't want to get caught out if I snap a spring or ruin a damper. I'll have my dampers re-built by Bilstein UK once they're off of the car, and then keep them as good spares, too.


It's a lot to spend on an old car, but I don't want a new BMW, and the Birds kit is really good.

That's interesting, because I'm in a similar situation - Ihave the birds kit on mine and it was pretty new when I got the car, but I've done north of 40k miles on them now and currently they just look a bit tattier than when they were new but am wary of what to do when they need replacing.... Shame i don't have the case right now otherwise I'd have them setting there ready!


On another note, in personal E91 news, I drove mine for the first time this year yesterday! With lockdown, I've been borrowing my missus dreadful hyundai to pop to the shops for essentials with the state of the roads, but needed to do a longer journey yesterday that warranted the comforts/performance of the N52. I'd almost forgotten just how good and how well/easily it makes progress on the roads, the A14 near me has some 40mph speed limits, childish second gear pull when you hit the national speed limit sign which is on an uphill and it's like you're driving at hyperspeed as you out accelerate everyone in their eco boxes

Edited by zippyonline on Friday 22 January 12:38