Room for improvement on E39 540 Exhaust?

[vyking56 0]

Likely to have been covered numerous times before I know - but I'd love to get feedback from someone who has done this.

What are the gains like from working a stock exhaust on a E39 540? I'm finding my M62T very flat and dull from 4000RPM onwards. When I'm in "Sport" mode it likes to go off hunting for red-line, and even with my foot burried there's two fifths of bugger all there. I do a lot of "hill driving" and I get better performance if I manually short-shift and ride the <3500rpm torque curve.

So - has anyone either removed the cats or replaced sections of a stock 540 exhaust with positive results? I'm guessing they're very precisely tuned unlike most systems which have a great deal of room for improvement.

Thanks!

Gareth

[1rotty 40]

When I'm in "Sport" mode it likes to go off hunting for red-line, and even with my foot burried there's two fifths of bugger all there. I do a lot of "hill driving" and I get better performance if I manually short-shift and ride the <3500rpm torque curve.

Thanks!

Gareth

You'll never get the same performance from sport mode that you get driving manually.

Get rid of the rear resonator & muffler & replace with a single free flow muffler.

Better response,sounds great & looks sooooooo hot LOL

As I understand it,because of the o2 sensors you can't remove the cats.

You can also replace the monster muffler thingy forward of the rear axle with straight pipe to the existing muffler(but remove the adjoining resonator)

To this

From this

Edited October 23, 2009 by 1rotty

[1rotty 40]

Decent headers and then decent centre and rear section no point in having a drain pipe at the back if its strangled at the front.

$2500-$3000

And ultimately a third pedal and gain all that power you are wasting in that slush box.

$4000-$6000 & thats if you can get one in.

Not really a viable option I wouldn't have thought.

[smiddy 76]

I may be able to help with headers.

PM me.

[BreakMyWindow 1870]

ive removed both rear mufflers, didnt really notice a gain, but has a nice v8 bark now.

You can get your car re-mapped. I suspect a tune could be made to improve top end. Do you have a vanos m62? Based on the dyno graph plottings i've seen the pre-vanos m62's make more power up top.

Ultimatley you'd want a super charger kit, but they are pricey and these days 35 - 40k will get you in to a nice e39 m5.

[vyking56 0]

Unsure if I have a vanos or not, not worked out how to tell yet! It's the second gen 4.4L and the car is a 1999. I'm not interested in hacking out mufflers or making it loud, it was more finding out if there were any large bottle necks, strangling bends or restrictors in the factory system which are known to rob power. Am still undecided about the cat converters, removing those seems a little hit and miss wether it will make the ECU flip out or not.

I've been happy to cruise around until now, but I got left in the wake of a stock (non XR) BA Falcon the other day because the 540 wouldn't exceed 60km going up a hill. Did some more driving over the weekend and it's started throwing up Check Engine Lights and on one occasion it locked itself into 2nd gear and I had to pull over, and kill the ignition before it would come right again. Sooooo what I thought was a strangling exhaust might actually be the car with the ignition backed off. Going to get the codes retreived and go from there.

I would LOVE a supercharger kit or some sort of parrallel turbo setup, but I did get the E39 to stop me throwing money at the WRX and to keep the wife happy.

[vyking56 0]

Dont get me wrong, it will definately do much more than 60k, but at the time I had my foot all of the way up it and it was busy ringing out one of its many gears and very much out of its efficiency range while the falcon was heading for the distance. I probably tend to exagerate about its "sluggishness" coming from a rapid turbo 4WD - but the CEL's have confirmed for me anyway something is not as it should be. I'm really hoping it's running reduced ignition!

[1rotty 40]

while the falcon was heading for the distance.

Oh no !!!!! To the car doctor fast

[BreakMyWindow 1870]

You have the vanos M62 (M6TU).. The only think restricting the exhaust by the sounds, is either the cat's (there are four of them) or the oxygen sensors are giving false readings. Its best that the car is connected to a diagnosis platform while its running i.e in situations where you are giving it herbs.

I recently replaced the plugs in mine, and noticed that its now more 'alive' its more keen to rev, and has nice low end pull. I was quoted $27 + gst per plug from BNT (with discount). Take a look at the plugs, if they look worn out then replace them. You can pick up a full set for $130 from supercheap autos, they are the Bosh F7 plugs that come in a pack of 4, they are a platinum-irridium fused plug. I was a little suss at the beginning being much cheaper then the NGK platinums, but can confrim no issues using them.

Other things to consider are the Cam speed sensors, they are ~$300 each

Air flow sensor $Expensive$ you could try cleaning it with MAF cleaner.

You mention it locked in to 2nd gear.. that sounds like it could be a transmission issue as well. Either way get the car diagnosed.

If your a DIY type of person, go to www.bimmerforums.com look in the DIY section of the e39 forums section, plenty of useful info there.

[jochen 4]

I've been happy to cruise around until now, but I got left in the wake of a stock (non XR) BA Falcon the other day because the 540 wouldn't exceed 60km going up a hill. Did some more driving over the weekend and it's started throwing up Check Engine Lights and on one occasion it locked itself into 2nd gear and I had to pull over, and kill the ignition before it would come right again. Sooooo what I thought was a strangling exhaust might actually be the car with the ignition backed off. Going to get the codes retreived and go from there.

Your performance issues are caused by a fault with the engine - get that fixed!

You may have clogged catalytic converters, this will rob a lot of power and cause O2 problems with the engine

If one is clogged, replace both at the same time.

A scan will reveal the cause

My 540i would leave everything for dust and would attack any hill at >100kmph with power to spare

So forget modifying the exhaust - fix the problem with the engine first.

[darkwolf 0]

This thread brings up an interesting point. What's that second can for on the end of the standard set up? I assume it is to quieten the exhaust?

[vyking56 0]

Your performance issues are caused by a fault with the engine - get that fixed!

You may have clogged catalytic converters, this will rob a lot of power and cause O2 problems with the engine

If one is clogged, replace both at the same time.

A scan will reveal the cause

My 540i would leave everything for dust and would attack any hill at >100kmph with power to spare

So forget modifying the exhaust - fix the problem with the engine first.

Thanks Jochen, I've found the car nice and torquey... but very flat past 3500RPM. Once the new car appeal wore off I was left kind of underwhelmed and looking at ways to improve it. From what people are saying it's clearly been down on power since I bought it.

Booked in for a diagnostic and engine oil / trans fluid change on Monday, so will go from there.

Thanks very much everyone for your input, it's very much appreciated. I'll post up the results from the diagnostic scan when I have them.

[vyking56 0]

This thread brings up an interesting point. What's that second can for on the end of the standard set up? I assume it is to quieten the exhaust?

It's incredibly dense and heavy so its only real function I guess is a silencer.

[BreakMyWindow 1870]

This thread brings up an interesting point. What's that second can for on the end of the standard set up? I assume it is to quieten the exhaust?

I believe it also acts as a kettle. Mine had alot of water in it when i removed it

[Jeddy 0]

Was just having a troll through Tardme and found this:

http://www.trademe.co.nz/Trade-Me-Motors/C...n-250128131.htm

Could that work?

[vyking56 0]

~~~DIAGNOSTIC RESULTS~~~

Turns out that #6 coil was garked and all 8 plugs were completely shot. I've not picked it up yet, but the garage is claiming it has a truck load MORE power now. I guess the CEL's were caused by the mis-fire it had developed because they were happening almost every time I stuck my foot up it.

Yay

[twisted 45]

Let us know how different it is now

Thought there must be something wrong, because my m60 really gets up and sings past 4k!

[vyking56 0]

It has an absolute truck-load more off the bottom end and through the middle of the rev range... but still feels flat to me above 4500. I guess the ECU is still a little traumatised and has the ignition backed off.

It actually surprised me this morning taking off from a set of lights, I gave it the same amount of throttle I've been giving it since I've owned it and it forgot it was an 1800kg tank and shot off like a bloody rocket! Should be interesting to see the fuel usage now, the inner-nerd in me religiously tracks the fuel consumption of both our cars with an application on my iPhone.

From what I've read it's approx 10:1 compression - so what sort of fuel do fellow 540 drivers use? I've been trying to stay away from BP98 and Mobil/Gull E10 (purely because of availability) and have been running Shell V-Power.

[martyyn 2]

From what youve described I would say your cats are blocked, but thats before reading your post saying the mechanic has found other issues.

I had exactly the same symptoms in my 740, choked engine, no power over 3500 revs, etc. When it happened to mine we got it up on a ramp and could see the exhaust was white hot where it was clogged up. The exhaust gases couldnt get through and they just choked the engine completely.

You have enough power in that car to blow away pretty much everything else on the road and the torque available going up hill at that speed shouldve been immense. Unless your blowing cars into the weeds now, Id still be checking those cats.

Edited November 2, 2009 by Penry

[twisted 45]

IFrom what I've read it's approx 10:1 compression - so what sort of fuel do fellow 540 drivers use? I've been trying to stay away from BP98 and Mobil/Gull E10 (purely because of availability) and have been running Shell V-Power.

I Use BP98 in my 540. I've found i get both the best performance and best economy. Second choice would be V-Power.

I'm not so sure how the m60/62 is on Ethanol fuels.

[*Glenn* 854]

As others have said.. it maybe a cat problem..however I would check MAF readings first with a mobile scanner. Readings should be around 550-600kg under full load. The MAF will often not register a fault code. You must check with live data. If the readings are low, disconnect the MAF and drive it, if operation & performance is better.. its probably the MAF.. if not, its more likely to be the cats. A MAF problem normally throws O2 sensor fault codes though because of lean or rich mixture. If you or your mechanic are unsure about what I'm trying to explain...ring me (09) 2722546

[jochen 4]

~~~DIAGNOSTIC RESULTS~~~

Turns out that #6 coil was garked and all 8 plugs were completely shot. I've not picked it up yet, but the garage is claiming it has a truck load MORE power now. I guess the CEL's were caused by the mis-fire it had developed because they were happening almost every time I stuck my foot up it.

Yay

Hi,

Take the above as a warning sign of no maintenance and go over the rest of the car with a fine tooth comb

A properly maintained car never gets to a state where the plugs are shot - they get religiously replaced well (years) before they get to that point. I have never suffered clogged plugs unless I have air-fuel mixture problems (which I did have on an old VW).

As a start, easy DIY things are:

1. Air filter (you have 3: engine, cabin left and cabin right)

I bet the cabin air filters are clogged! New cabin filters are cheap and make a world of difference to the airflow and smell of the cabin

2. ICV - if the M62 and not M62TU engine, then check and clean the ICV (idle control valve). Makes big difference to idle performance and reliability under changing idle load

Go through the rest of the car - body, interior - and check it and fix all the niggly little broken bits.

Then enjoy the car!

Tip: on my 540i when running perfectly, it used 18 to 20 L/100km around Akld city (start-stop), and 10 to 11 L/100km on a long trip Akld-Rotovegas.

As a mix it was around 16L/100km

Driving on the motorway, at 100kmph, on a flat road, I could use as little as 9.7L/100km

[vyking56 0]

Take the above as a warning sign of no maintenance and go over the rest of the car with a fine tooth comb

A properly maintained car never gets to a state where the plugs are shot - they get religiously replaced well (years) before they get to that point. I have never suffered clogged plugs unless I have air-fuel mixture problems (which I did have on an old VW).

I was very surprised by the garage's findings, especially given the FULL service history it has from Japan (I have these documents) and the $1000 service bill from BMW Wellington the previous owner forked out for less then 10,000km ago - so it annoys me that the basic's were never checked and it even got to a state where it was running rough.

I'll start another thread for the cabin filters, but YES they in a bit of state! The cheapest I've found replacements is for about $150 for the pair.

Broken things to-date is the windscreen washer cleaner / concentrate bottle and pump, rear cup holders and the dash pixel's. Besides that, everything else seems to be in good working order - so it's getting there. I did get it for an absolute steal, so it's a work in progress for now!

[Creaver 55]

Try Gavin @ Euro-Italian (forum sponsor) for the filters, definitely the man to speak to for OEM parts.

[3series 0]

http://www.trademe.co.nz/Trade-Me-Motors/C...n-252777254.htm