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E46 320D (148 BHP) Tuning advice

101K views 25 replies 14 participants last post by  TDI-Tuning  
#1 ·
Hi guys, this is my first thread and i'm a bit of a noob with BMW's so please have patience..

Looking into getting a 320D as at the moment I've got a 306 HDi which I have done a fair bit to but looking to upgrade.

So my questions are:

1) What sort of power will the standard internals take and are there any stronger direct replacements?

2) What sort of turbo's are used for upgrading, is it case of getting one direct fit or 'bodging' one on using an adapter?

3) With my car I've been able to remap it myself using a KWP2000+ and After a bit of reading on here it would appear you can do the same with the 320d? Is there anyone which makes custom maps which they can email to you?

4) Are there any real problems with these cars? I've read about the swirlpot issues on the 30d lumps and wondered if there was any real issues with the 20d lumps

EDIT: I'm referring to the 148bhp 320D

Thanks!
 
#2 · (Edited)
swirlflap are an issue on the 320d aswell as the 330d, but blanking plates readily available from bmw specialists or flea bay. Also blocked turbo breathers which need replacing for a vortex type if it is still using the 'loo roll' type design as they clog up and can kill the turbo. Talking of turbo's it is not unknown for one to blow. IF you get a euro 4 with with the electronic actuator on it it will mean a new turbo if it packs up. Pre supply pumps can also go giving bad starting/ reluctance to rev.

The easist way to up the power is a remap as you say, some have taken them upto around the 200bhp mark but depending on the health of the engine/drivetrain you may start knocking out components such as the dual mass flywheel, propshaft guibo, clutch or a turbo. all Rather alot of money to replace. Specialists do offer hybrid turbos and bigger intercoolers depending on your budget and how far you want to go.
 
#3 ·
The stock lump can take big BHP and torque but the clutch and flywheel can't, if you are to tune beyond 210bhp consider a new clutch setup. Also as you are new to the forum, have you removed the swirl flaps and replaced the engine breather? Two must do things on the M47 engine block as well as the M57 (3 litre)

What is the history/mileage of the car? BMW have stupid service intervals which don't suite turbos, silly really, I just bought a 2005 525d and whilst it has be religiously serviced as the OBC says, in 74k it has only had three oils changes and never had a new air or fuel filter ! mad.

Despite modern longlife oils, these car need new oil every 10k, it is so cheap to do a DIY oil change (ÂŁ32 with a GM Dexos 2 oil which is top spec LL-04 oil and filter) that it does make any sense not to.

Other common issues are worn rear front control bushes (buy powerflex, Meyle HD or Lemforder, anything else will be useless) worn front wishbones and worn rear trailing arm bushes. The propshaft doughnut goes on high mileage cars and rarely the vibration damper on the engine (big pully on front of engine) wears but that is largely it. Pretty reliable car otherwise
 
#4 ·
Thanks for the replies guys, I did think that after a remap the turbo would be pretty much on it's limit (GT1749V?). Any idea what turbo the 330D uses and whether it would be a straight fit?

Clutch wise on my current car there isn't many options about if you want to upgrade so a unsprung paddle clutch is what we would use, does anyone have any info on OEM clutch upgrades? EG. would a 330d clutch fit and if so how much torque roughly are they good for?

Yeah, I've heard a lot about turbo issues, coming from an already tuned turbo diesel means i do have a bit of an idea but trying to get my head around the issues with these as i've been learning/tuning my pug for the last 2 years! It's making my head hurt a bit.
 
#5 ·
Interestingly the 330d and 320d use the same turbo and clutch/flywheel setup, you can squeaze more than 200bhp with a remap but it will be a pig to drive as the power will be in a narrow rev range. The 123d for example is a twin turbo 2.0l at 200bhp and 335d is a twin turbo 3.0 litre but it is telling you can only buy it with an auto box and the map on that limits the torque in 1st,2nd and 3rd gears
 
#6 ·
Hmm.. Are there any other OEM clutches which will hold higher torque? I'm guessing that if not i'd need an uprated paddle clutch the same as my pug

EDIT: As the displacement of this is 2l just like my pug I'm wondering if a GT2052v would do the trick for higher power (Obviously the turbo would need to be mapped in accordingly) I'm not used to this VNT stuff lol
 
#9 ·
Wait is your car an auto - if so you need to be even more careful, the auto box won't handle the increased torque achievable from a simple remap alone, so a custom map designed to take that into account def recommended.

Changing the turbo is the last thing you should consider for power - heaps and heaps of stuff to do before that, the stock turbo (VNT is better than conventional turbos, more efficient, less lag) is more than up to the task of unlocking more power than an auto box or stock DMF/clutch will appreciate. Bigger turbo, especially non VNT, will inevitably mean more lag, I'd seriously consider other options before messing with the turbo option. Switching from the OEM VNT turbo to a non-VNT would also involve a lot of hassle and coding - which at the end of the day is all futile if all the other easier/cheaper/more practical performance increase options aren't satisfied first.

Not sure why you're so keen to hit the turbo first for a performance increase tbh, theres a reason why the newer generations have twin turbos, a small one to spool up faster to reduce turbo lag on the big main turbo. Long winded way of saying stick with the VNT :hihi
 
#8 ·
So my questions are:

1) What sort of power will the standard internals take and are there any stronger direct replacements?

2) What sort of turbo's are used for upgrading, is it case of getting one direct fit or 'bodging' one on using an adapter?

3) With my car I've been able to remap it myself using a KWP2000+ and After a bit of reading on here it would appear you can do the same with the 320d? Is there anyone which makes custom maps which they can email to you?

4) Are there any real problems with these cars? I've read about the swirlpot issues on the 30d lumps and wondered if there was any real issues with the 20d lumps

Thanks!
With regards to 1) ... I personally wouldn't aim higher than 200-210 PS, you could go well above that if you really wanted to, but that's the highest you should go if you want to still have balance between power and reliability. Above that you'd need to start considering a lot more stuff. Bars the problems with the swirls and the breather, the engines are solid and being diesel can take as much boost as its physically able to in theory. Even at 200 horsies, which doesn't sound like a lot of power compared to some cars, the real beauty is the torque, 200 horsies will deliver about 400 to 410nm of torque, which is a fook-load of torque and huge fun. At those levels of torque if you drive it like you want to, then you're going to seriously want to consider getting a stronger flywheel, as the dual mass flywheels will suffer, as will the clutch. You can still have that much torque and not need to change those components but you really need to be considerate in your driving or expect to make the investment in those parts.

While I'm sure you could remap it yourself, I personally think that would be a bad idea unless you're a professional remapper and know exactly what you're doing. There are well established remapping companies on the go (a few on these forums too with tried and proven maps) and their maps are made specifically for each car, so better to trust those than trying to tweak/eyeball it yourself etc.

Bigger turbo, you could stick pretty much any turbo on that you want, as long as the actuator is the same, ie vacuum or electronic as Matt pointed out. If you've got a vacuum actuated turbo currently, it would be a true nightmare to try and adapt it to take an electronic one, more hassle than its worth. Turbo wise I wouldn't be so hasty to consider an improvement, the stock ones are more than able to pump out great power with the right remap.

Best place to start with performance is efficiency, get the swirls blanked if you haven't already, get the breather switched to the vortex style as soon as possible, change oil every 6-7,000 miles, clean the intake manifold, by-pass/disable the EGR system.
 
#10 ·
Hmm.. tbh i would've thought that the stock turbo would be pretty hard pushed even after a basic remap, they're not that big to start with although i guess with VNT it helps to maintain power throughout the RPM's, I just don't want it to run out of puff at 4k.

With tuning on my pug the turbo is the main restriction for more power, only has a baby K03 so after 170bhp they are well out of there efficiency.

If it's VNT then i'll stick with that but if it's actuator then there is plenty of alternate turbo's out there.


Really i'm looking for big power, has anyone on here got very far with them? a link to a project thread would be awesome.
 
#11 ·
The VNT allows pretty much seamless, transitional between boost required versus need to dump, so its smoother than conventional - picture foot off throttle with conventional, wastegate opens, boost dumped, then foot to floor gotta rebuilt the boost which is more lag, the VNT bridges the transitions. They work exactly the same of course, just how to manages boost/dumping out the exhaust. The stock turbos run at something like 32psi at full boost, thats a lot of boost considering a petrol turbo will often desire half that boost for same effect, versus the derv which you can up the boost without paranoia due to the steel construction versus alloy.

In the diesel, keeping in mind how different it is from a petrol in basics, a remap affects a lot more easily, up the fuel flow in a derv and you'll get more power - and more black smoke, so to keep that balanced you want more air in too, the remap can tweak the timings, fueling and actuation of the turbo so they are all in sync with the new settings. The stock turbo is pretty solid and you can unlock substancially more power for a lot less money by starting with the remap option - definately consider that before throwing money at the turbo, you'll get instantly more power and efficiency for a lot less money :thumbsup Thats why a lot of diesels smoke a lot more after a remap - increased fuel related to no balancing increase in air.

Theres a reason these torque monster machines smoke like a fooker, everythings turned up to bugger :rofl


Thinking back to what I personally would do if going for significantly more power, I'd be considering adding a supercharger before I thought about changing the turbo, and would use the supercharger to reduce the lag of the big assed mental turbo I'd be sticking on. But now you're entering the realm of stage 3 tuning, great power but need to expect a consequence in the form of reduction of reliability and endurance of components. Can turn into a serious money pit.
 
#12 ·
Well on my current car i've managed a 60bhp increase in power over stock with nothing more added than a FMIC and a decent map with increased boost, I wouldn't bother thinking about a supercharger when the latest generation VNT's can make plenty of boost at low RPM's.. Boost pressure isn't everything which is why i would prefer a larger turbo but with a lower pressure, causes less stress on the engine but provides more power.

If i'd be running into clutch troubles after a stage 1 remap though that's not sounding very promising, guessing the price for a decent clutch will be a fair whack.
 
#14 ·
To be honest I think you have picked the wrong car to tinker with, the better mapped derv option is the 330d but if you want real power the 330i with a bolt on Atlanta supercharger will be much better, you will need new injectors and a new map for that but it is an awesome setup and can be purchased second hand for the same kind of money as a performance turbo setup on a diesel.

See http://www.bimmerforums.co.uk/forum/f69/new-e46-330ci-acs-supercharged-owner-t107874/ ÂŁ6k for 300bhp
 
#13 ·
BMW clutches are pretty strong. VAG for example do tend to "minimum spec" them meaning that you will often see other stages where a clutch change is needed.
The 32psi mentioned above is absolute pressure (circa 2.2 bar) which is 1.2 bar of boost.

Boost on a diesel works in a different way to petrol engines. A petrol engine has a narrow range of Air:Fuel ratios which is must stick to. If you don't want power (at idle for example) you must limit the air with the throttle.
If the ECU only injects a small amount of fuel, the burning is unsustainable and the engine will misfire.

A diesel doesn't pre-mix the fuel and air, the air is compressed, and the fuel is then injected which burns during the injection period. So whilst you limit the air for power control on a petrol, you limit the fuel on a diesel.

If you increase the boost on a petrol car, the ECU responds by having to inject more fuel to get the right AFR, and you get more power. On a diesel, you can get to a situation where extra boost will sap power out of the engine as the fueling will remain the same but there is a turbo working harder blocking the exit of exhaust gasses.

You may get more power from more boost under some conditions, if the injection quantities were being clipped by the Lambda map (aka. smoke limiter), where there are calculations for a requested injection quantity but it is held back as there isn't enough air about for the engine to burn clean and smoke free, but in general, it is more fuel that makes power on a diesel, not more boost.
 
#16 ·
Cheers for the replies guys, Having been thinking about it quite a lot i don't think i'll bother with the 320d.. Have been spending a fair amount of time looking at the E46 325i's though but don't think they're very good on fuel realistically
 
#17 ·
320td sport, 6 speed manual (I want more than just a remap)

This is a really interesting subject which I am keen to monitor, I had a 320td with just a pipercross Air Filter and a remap it was superb but sold it on for profit and got the 325.
I now have a 2004 320td sport (Compact) and I want extra performance however i don't want to do a remap until I have done other engine performance mods.

All I have heard of is a replacement exhaust flex pipe, pipercross/K&N. I cant seem to find anything else not even a back box.

Any ideas?
Also would a bigger inter-cooler improve performance (then remap!)
 
#19 ·
All I have heard of is a replacement exhaust flex pipe, pipercross/K&N. I cant seem to find anything else not even a back box.

Any ideas?
Also would a bigger inter-cooler improve performance (then remap!)
A straight through pipeis a good addition (if only because the kink in to the cat will affect gas flow) but don't waste you money on a air filter kit, stock is as good as it getes, also no point in a bigger intercooler, it will just introduce more turbo lag for no real gain in power
 
#20 ·
My 320td sport, has Egr removal, swirl flaps done, removed down pipe fitted, custom back box, new vortex filter and pipercross filter. drilled and grooved discs just to make sure it stops
Remapped last week from 152 to 202 bhp and enough torque to light the rears up in 3rd on a wet day....total cost of mods including map and RR ÂŁ600 so dont bother with the new turbo, the standard one is more than adequate
 
#21 ·
I should be picking up my 2003 320D Sport tomorrow, will initially be looking at getting a 'stage 1' to circa 185bhp and 390Nm (common enough numbers) upgrade, having read this thread will certainly look into the swirl flap and breather improvements.
 
#23 ·
FYI the 5 speed version of the 320d has the same clutch and flywheel as the 330D (dont know about the 6 speed though) and i have had mine up to 258 bhp with no issues with the clutch. Single engine modification was modified under piston cooling jets internally. It already has forged pistons so no need to upgrade them. Transmission is pretty much the same as the 330d except the ratios, as is the diff. So you have no worries there either. Trouble is people mod high power cars without replacing worn parts and when they break assume that its because too much power has been developed, with the e46 320d that is not the case. If you dont modify under piston oil cooling jets your pistons will melt at around 225bhp. Engine mounts can be upgraded to M3 ones, as can the gearbox mounts. These cars are built really well and can handle a heck load more power than a ford or vauxhaul crap!

Mods so far..
High flow injector nozzles (Build myself)
600 x 400 x 100 FMIC
Hybrid gt1756 garrat turbo unit (Built myself ÂŁ275)
Modified under piston cooling jets (Made myself)
Power induction pipe with built in EGR blank
Swirl Flaps removed
Cat and DPF removed

This is enough to leave most 300bhp petrol cars (turbo or not) up to around 100mph
it does 56mpg on a run... and its a touring!
 
#25 ·
Don't waste your money on a decat and panel filter
A standard car with just a remap will see 195-200bhp




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