E46 M3 Power output lies!

[oakey]

One of my friends owns a e46 M3. He paid top whack for it when he bought it as it seemed v.well looked after and had a few flashy schnitzer extras, and loads of ICE (TVs, 6 subs, all that twatty kind of shit).

Since hes had the car he has fitted a schnitzer exhaust and carbon surround that cost nearly £2k

anyway... he took it for a power run yesterday and it put out a MAXIMUM power of 290bhp thats 50bhp less than it should be. whats that all about?

but by the end of the day after they had remapped the M3 it was putting out 335bhp.- a huge improvement for a remap I thought.

But how can BMW claim a car is 343bhp when in actual fact it is far less?

there has been NO EXPENSE spared by my friend with regards to maintaining this car so it cant be that its fooked.

just thought I'd share that with you lot.

[orangecurry]

aftermarket exhaust lost the power?

[oakey]

aftermarket exhaust lost the power?

Thats what I thought. But he was told by shnitzer that it wouldnt. And i dont see how you could loose 50bhp by changing the exhaust? And he said the car felt like it went a bit better after he fitted the exhaust and I'm sure you would notice a 15% drop in power!

The dude at the rolling road said that the e46 m3s are more than often alot less powerful than BMW state.

The car does have disgusting 20" and 12" wide wheels on the rear I dont know if that will change a R/R reading?

dave

[buster]

maybe the power figure was at the wheels and the bmw power figure is at the flywheel .

[oakey]

maybe the power figure was at the wheels and the bmw power figure is at the flywheel .

No. I assure you this reading is a calculated flywheel figure.

[buster]

Oh ok,just a thought.
Well,yeah ,that is bad

[JungleGus]

calculated flywheel figures are really just an estimate...dynos are really only good for tuning..too much variation that affects accuracy to be a worthwhile comparison. bugger! good chip increase though!

[oakey]

perhaps the rolling road place lied so that they could make it look like they improved the power drastically or something like that?

[oakey]

thats even less powerful than an e36 m3 actually engine isnt it?

[oldroydsr4]

Iv heard alot of M3's being down on the quoted power, i believe its quite common.

[SDM]

the e36 m3 evo never made 321 out of the box...

[munky30]

A car manufacture lying about power figures to sell more cars?

SURELY NOT!

[bigkev]

perhaps the rolling road place lied so that they could make it look like they improved the power drastically or something like that?

I knew a guy that dyno'ed bikes and all he used to do was mess about with the air temp/pressure correction factor on the first run so it looked like the bike was down on power,tell the guy he could 'tune' it and then reset everything as it should be, and run it again to the owners amazement it made loads more power and dug deep into his pocket.Not saying thats what happened but i have heard some stories

[tim_s]

yeah, that. seeing as he was getting a remap, mb its a bit fishy!
plus the remap gaining all those hp mb suggests that there was some prob with the fuel injection - mb the guy ran it on crap fuel so the knock sensors retarded the timing, the S54 has a really high CR. or faulty knock sensors - they can be quite noisy engines and the knock sensors could be picking up lifter noise etc at high rpm rather than knock. If I were him I'd have been much happier to find the missing horsies by finding out what was wrong in the first place rather than remapping.

[oakey]

yeah, that. seeing as he was getting a remap, mb its a bit fishy!
plus the remap gaining all those hp mb suggests that there was some prob with the fuel injection - mb the guy ran it on crap fuel so the knock sensors retarded the timing, the S54 has a really high CR. or faulty knock sensors - they can be quite noisy engines and the knock sensors could be picking up lifter noise etc at high rpm rather than knock. If I were him I'd have been much happier to find the missing horsies by finding out what was wrong in the first place rather than remapping.

I cant remeber the name of the place but it is very well known so I would be surprised if they were scammers, but it is entirely possible.
It could definately be possible that it was running on shit fuel. I'll ask him what fuel was in it.

they didnt tell him there was anything wrong. they said its common that these cars are underpowered.

[tim_s]

did the place explain where the alleged extra remap power came from? did the chap have an AFR curve before and after? figures at the wheels? that amount of extra power (45bhp) doesn't just appear from nowhere, and it makes no sense that BMW would be that conservative on the map on an ///M car that a remap alone could free up that much power.
out of interest, does the chap think the car feels 45bhp faster after the remap?

[pacerpete]

Oakey , your mate and his chariot sound very council , does he wear branded sports wear, lots of tom and have some tasteful body art ?

[oakey]

Oakey , your mate and his chariot sound very council , does he wear branded sports wear, lots of tom and have some tasteful body art ?

It truly is a council masterpiece.
Of course he wears branded sports wear, but I'm not sure if he has any tatoos, but what the feck is "lots of tom"?

Its been featured in PBMW before- they called it "The Ice Rocket".

I personally think he bought the worst example possible

[kam-325i]

Tom.

Tom Foolery - Jewellery......

[JaMMi]

Lol thats quality @ kam

[Andyboy]

the e36 m3 evo never made 321 out of the box...

Yes they do. In perfect condition running 100 octane fuel on an engine dyno. It's a serious breach of German law to overquote power figures and the ADAC randomly test cars with huge fines for manufacturers who try it on.
I've been to enough rolling road days to know how variable cars can be but I can assure you very very best standard E46 M3 using proper fuel will do 340 odd bhp. The same car can deliver wildly different power figures on the same dyno on the same day if the air temperature in the dyno cell is different. 20+ bhp on an M3 isn't unknown.

[stuartgallafant]

S54's are designed to run on high-grade fuel, such as Optimax, BP Ultimate ald all that... using normal unleaded seriously loses power

secondly, MOST people who service these cars, even approved BMW dealerships, dont change the tappets to reset the valve clearances on Inspection II's. this also has a major effect on power.

as big kev has said, i've heard of so many places doing that. i used to look after Jason @ CA Automotive's M3, with tee (zoner). he had had his remapped and the figures didnt change as drastically as that. you could feel the difference in his though

i dont agree with all the shitzer stuff everywhere, esp. those gay wheels. dont really even like E46 M3's to be honest, seen way too many of them!!

[Turbo-Brown]

Air pressure in the RR cell's a good one for changing power figures too, and as it's a percentage effect thing, the more powerful the engine, the wilder the bhp swings brought about by changes in the pressure.

[Royalratch]

I doubt you'd gain 50BHP from higher octane fuel.

Funny thing sis, BMW are usually conservative about top speed and acceleration so why not BHP?

Tim makes a good point, better to get close to the factory figure without ECU tweaks and then see what can be done.

I'd be well pissed off.

[Turbo-Brown]

I doubt you'd gain 50BHP from higher octane fuel.

Ignition timing plays a MASSIVE part in power production and having an ignition system which can adjust itself could perhaps support the arguement that the octane of the fuel could have a large bearing on the power output.

[snoops]

maybe BMW tested the m3 at the north pole

cold air = more power?

[buster]

should i be using super unleaded then ? S50b32

[SDM]

Funny thing sis, BMW are usually conservative about top speed and acceleration so why not BHP?

because for the E36 they wanted to reach 100bhp per litre, 3201cc = 321 bhp

couldn't release the E46 without a bit more could they

[oakey]

should i be using super unleaded then ? S50b32

yes
If it makes a huge difference on my 2.7 I'm sure it will on youre mototr

I'm gonna interogate him about it all today.

To be honest he is a rich little Bstard so I would have thought he would use premium unleaded.

[hubble]

Mornig Dave.

Just a comment, but aren't these rolling road machines supposed to be correctly calibrated?? before use??

[march109]

Mornig Dave.

Just a comment, but aren't these rolling road machines supposed to be correctly calibrated?? before use??

Correctly calibrated how exactly? there is no one steadfast correction algorithm, as as such all RR use different algorithms based on who produces their equipment.

Thats before you even wonder about air pressure, altitude, ambient temperature, RR cooling fan effectivness, which can all not be kept constant because they continually vary.

Then fuel (even fuel supplier!), tyre pressures, and mechanical considerations of the car.

One car could give a reading as much as 20HP out, if tested on two different days, just depending on the weather!

Rolling Roads arn't an exact science, if your that worried bench test the engine in a completley controlled enviroment.

[hubble]

Correctly calibrated how exactly? there is no one steadfast correction algorithm, as as such all RR use different algorithms based on who produces their equipment.

Thats before you even wonder about air pressure, altitude, ambient temperature, RR cooling fan effectivness, which can all not be kept constant because they continually vary.

Then fuel (even fuel supplier!), tyre pressures, and mechanical considerations of the car.

One car could give a reading as much as 20HP out, if tested on two different days, just depending on the weather!

Rolling Roads arn't an exact science, if our that worried bench test the engine in a completel controlled enviroment.

Ok slow down and take a breather. It was just a comment that's all...

[Andyboy]

I doubt you'd gain 50BHP from higher octane fuel.

Ignition timing plays a MASSIVE part in power production and having an ignition system which can adjust itself could perhaps support the arguement that the octane of the fuel could have a large bearing on the power output.

Oh yes indeedy. That's the good thing about cars designed in the last century - detecting crap fuel and retarding the timing to avoid detonation. How to lose 50 bhp from a 343bhp car - shite fuel, tight tappets, incorrect dyno calibration and a dyno cell that's as hot as hell. Easy. A good remap gets these up to well over 350 bhp so I suspect either the dyno isn't a lot of use or there is a problem with the car.

Having said that - a large number of the late M635CSi Highlines were very down on power with some cars down to a 'genuine' 240 bhp. A play with the ECU maps got them bang up to 280-290 bhp. Nobody knows exactly why this was so as BMW bench tested every engine on these and they wouldn't have left the factory like that.

[danny_j]

When i was a wee Boy racer, i put a 1.6 16v Engine into a Nova (Oh yeah baby!)

I went to one rolling road day on the Friday at Regal and my car ran 94bhp (Standard figure for a 1.6 16v engine was 109bhp) I was gutted!

The VERY NEXT DAY i went to another rolling road session and it ran 107bhp... i was alot happier. The car felt exactley the same, the same fuel was used and absoultely no changes were made to the car at all.

The only difference was the weather...

Seems different RRs give out different readings!

[Royalratch]

So what's the deal here?

I was going to take my M42'ed Touring to one of these chooning places to get the last bit of power out but we're saying that they are either all crooked or figures vary so wildly that you cannot confirm whether you actually got a gain?

No?