BMW M52TU 328 engine

[Neil_Bolton]

Hey all,

Just a quickie question - more 'wondering out aloud' stylee really:

What is the rev limit supposed to be on these things? I yesterday accidently revved to 7.5k until the limiter cut in...surely thats rather higher than standard?

Also, I know a lot of people moan about how they get breathless above 5k, however I've been finding that mine revs hard all the way around to 7k quite happily - pulling all the way?

Is there any outward way of finding out whether there is a possibility that mine may have been tinkered with in a previous life, thus explaining the higher rev limit, and remap meaning a better power curve?

Edited to add: Its just been into my local BMW dealer (Lovett, Bristol - cheers chaps ) for an oil service, and it all came out thumbsup - and no mention of anything like this - if it helps?

Edited by Neil_Bolton on Wednesday 18th April 08:41

[Neil_Bolton]

Also am I right in thinking the 328 is speed limited? Is it 155mph?

[bob1179]

I can't remember what the rev limit is set at on the M52 engine, I'm sure it is supposed to be around 6.5k but the BMW straight sixes love revs, plus they sound absolutley awesome when given a bit of right foot.

If the garage are happy with it, I wouldn't worry about it too much, they are great motors.

Edited to ask: Is it a 328i? I think flat out and with the standard 197 bhp (I think) the 328i is good for about 147mph flat out. Though I am doingthis from memory so I may be wrong, so it probably won't have a limiter on it.

Edited by bob1179 on Wednesday 18th April 08:50

[Neil_Bolton]

bob1179 said:

I can't remember what the rev limit is set at on the M52 engine, I'm sure it is supposed to be around 6.5k but the BMW straight sixes love revs, plus they sound absolutley awesome when given a bit of right foot.

If the garage are happy with it, I wouldn't worry about it too much, they are great motors.

Edited to ask: Is it a 328i? I think flat out and with the standard 197 bhp (I think) the 328i is good for about 147mph flat out. Though I am doingthis from memory so I may be wrong, so it probably won't have a limiter on it.

Edited by bob1179 on Wednesday 18th April 08:50

It'll happily go round to 150 leptons on the clock, without fuss, and pulls all the way to it, once there, it struggles a bit to get anymore - probably proving the 147mph bit.

However one morning, in Germany, down a loooong hill, I pointed it downhill and floored it, and found that it wouldn't go off the clock, it was sat just over 155 leptons - it felt like it was being 'held back' - now we didn't know whether this was the aerodynamics, or the way a speed limiter works? Having never driven a car to the max with a speed limiter, I wouldn't know how they work...

To give anyone who knows about these things, it will happily do 100-120 leptons in 20 seconds in either 4th or 5th gear? I don't know whether this is good or bad - people have been muttering that its pretty good for supposedly 193 bhp.

Edited by Neil_Bolton on Wednesday 18th April 08:58

[xm5er]

They are much quicker than their official output would have you believe aren't they. As for the revs, it sounds like you either have a really well screwed together one or more likely someone bunged on a big bore throttle body.

You could check on e36coupe forums to see if anyone knows.

Mine definitely runs out of puff shortly after 6k, it will carry on reving but the urge has gone.

[Dunk76]

6750 is the official limit on the 2.8 engine.

Top speed shouldn't be limited, as the natural aerodynamic barrier at 193bhp is 147mph.

Worth remembering that the heavily restricted engine is well past it's best at that point - peak power is at 5500rpm, peak torque around 4000...

6750 and you're just straining the rods.

Edit: Does sound like yours has been breathed on - getting it up to 7000rpm is a feat in itself, let alone it being willing to do so.

Edited by Dunk76 on Wednesday 18th April 14:28

[Neil_Bolton]

Dunk76 said:

6750 is the official limit on the 2.8 engine.

Top speed shouldn't be limited, as the natural aerodynamic barrier at 193bhp is 147mph.

Worth remembering that the heavily restricted engine is well past it's best at that point - peak power is at 5500rpm, peak torque around 4000...

6750 and you're just straining the rods.

Edit: Does sound like yours has been breathed on - getting it up to 7000rpm is a feat in itself, let alone it being willing to do so.

Edited by Dunk76 on Wednesday 18th April 14:28

Thanks for that

Its a wierd one this, I was driving it for ages based on the above figures - trying to match the gear changes to to rev to 5.5k and then drop to 4k and start again in each gear.

However, on my local autobahn, its obvious that I accelerate quicker through the gears to 150 if I hold onto the revs all the way to 7k. If I don't do this, it still gets there, but not as urgently.

Its also worth noting that there was very little in it between me and a 3.0l M3 on a straight line run, so perhaps like you say, it has been breathed upon.

The only way I suppose is to get her down to a Dyno...

[StuB]

That does sound like it's had the 525 inlet manifold and a chip to me! No visible signs from the ourside though Neil

[Neil_Bolton]

StuB said:

That does sound like it's had the 525 inlet manifold and a chip to me! No visible signs from the ourside though Neil

Bonus then

Stu - if you ever look to flog your Z3 - can you let me know?

Edited by Neil_Bolton on Friday 20th April 22:36

[dazren]

StuB said:

That does sound like it's had the 525 inlet manifold and a chip to me! No visible signs from the ourside though Neil

Could this mod be done to a RHD R reg 528i auto? If so how much extra power?

[Neil_Bolton]

dazren said:

StuB said:

That does sound like it's had the 525 inlet manifold and a chip to me! No visible signs from the ourside though Neil

Could this mod be done to a RHD R reg 528i auto? If so how much extra power?

I understand that it can be, as its essentially the same engine and bits - I have the details and email of the person who you get all this off - I've forwarded it onto you Daz...

[StuB]

Neil_Bolton said:

StuB said:

That does sound like it's had the 525 inlet manifold and a chip to me! No visible signs from the ourside though Neil

Bonus then

Stu - if you ever look to flog your Z3 - can you let me know?

I the very unlikely event, yes, I guess so

[StuB]

dazren said:

StuB said:

That does sound like it's had the 525 inlet manifold and a chip to me! No visible signs from the ourside though Neil

Could this mod be done to a RHD R reg 528i auto? If so how much extra power?

Generally reckoned to make a top end difference of 30-40bhp and a good improvement in torque. I'll try and dig out a picture of how much smaller the 2.8's inlet tracts are, it's about 60% of the size of the 2.5's!

On an old auto????