Area under the graph comparing real world performance of engines

[Anonymous]

There was a thread running on the pros and cons of the 4 pot motors vs the 6 pot motors both turbo'd and NA.

One question asked a few times was how would an E89 30i compare to a re-mapped E89 with a 4 pot N20 engine.

I did some extrapolation work based on other E89 published figures and came up with some predictions.

I kept thinking about this, especially in the light of how my car changed when the flawed Celtic map was replaced by a much better one.

In addition we built up a table of people who had their cars re-mapped and dyno'd to get some data.

All this got me thinking about the whys and wherefores of torque/bhp graphs and another debate as to what was more important, torque or BHP?

I've done a bit of reading and although there's not much out there the primary conclusions are:

1) The more torque and the earlier and wider the torque curve the better the real world acceleration.

2) The more gears that can keep the engine if required between peak torque and peak BHP the better..assuming you can keep the time to change gears to a minimum

To that end the existing BMW generated graph showing the 28i variant of the N20 vs the 30i variant of the N52 engine makes interesting reading..

If you look at the torque curve of one of the re-mapped cars its even stronger than the 'simplified' diagram used by BMW.



So the question I have is, does anyone have an actual E89 N52 Dyno chart?

It would look that a re-mapped N20 would be substantially quicker accelerating in real world situations?

I feel a storm coming..

 

[BTZ461]

That is a massive "fat" gain to the torque curve with the CustomPro STG2 map. We are going try to to broaden the torque curve as you have done with our 3.0si N52 coupe. Slowly adding to the knowledge bank. Now have a friendly dyno man wanting to learn, and an interest in working on a map, from an chap in the US. Not sure if we will do the Milvs, be rude not too. And tossing up about some headers, but given our car is RHD a bit of thought (and stretching of the wallet) may be required.
You car will a have very different personality now, you will be delighted I would be.

 

[Dr. Zed]

Interesting read! I've been reading up up on re-maps etc. with the intention of finally doing some work on my 2.5 E85, but is definitely interesting.

 

[Boltz]

Well, by coincidence I have recently driven a manual 2011 3.0 six pot for sale at a local BMW stealers. So I can now compare it to my 2013 manual Msport 18i which is mapped, de catted etc and put to rest the nagging doubt of whether I made the wrong or right decision to have a 4 pot!!! So my conclusion is that the 6 pot sounds better but that’s it, my 4 pot now accelerates better, the torque feels as good and my car feels much lighter and agile especially in braking and cornering. So for me the modding of a 4 pot was the right way to go and even if you take into consideration the money spent in improvements I am still quids in if I had purchased a 6 pot. The six pot I drove is up for £16k and has 50k miles on the clock and BMW said they would offer £8.5k trade in for mine.

 

[Lazza]

That Celtic S1 map looks a bit rough. Yes you get a big peak to give you the headline figures but it only goes above the stock 18i after 5100 rpm, in other words, you will have less power with general driving and will only benefit from the extra power when you are pushing on!
There is also the big bump at low revs but that drops off quickly so is unlikely to give much benefit.
Is that how they feel on the road? I’d be disappointed with a torque curve that looked like that.

 

[brillomaster]

you are quite right, peak power only tells a very small story, and is only really relevant if you're always using it, like a racecar.

a nice fat torque curve, over a nice wide area, will feel better pretty much everywhere else, all other things (like gear rations, final drive, aerodynamic shape, tyres, etc etc etc) being equal.

So yes, on the simplified graph above, i expect the N20 2.8i to accelerate better than the N52 3.0i. it makes more torque everywhere below 6000rpm, and is only right at the very top end where the N52 betters it.

 

[Anonymous]

That Celtic S1 map looks a bit rough. Yes you get a big peak to give you the headline figures but it only goes above the stock 18i after 5100 rpm, in other words, you will have less power with general driving and will only benefit from the extra power when you are pushing on!
There is also the big bump at low revs but that drops off quickly so is unlikely to give much benefit.
Is that how they feel on the road? I’d be disappointed with a torque curve that looked like that.

Yup that's how it felt..but without a rolling road difficult to tell from the seat of pants or back to back with another E89..

When I went for a drive with Smartbear I noticed his car would always get the initial jump on me ..so that plus a de-cat resulted in me getting it checked out with the above result..

 

[Anonymous]

you are quite right, peak power only tells a very small story, and is only really relevant if you're always using it, like a racecar.

a nice fat torque curve, over a nice wide area, will feel better pretty much everywhere else, all other things (like gear rations, final drive, aerodynamic shape, tyres, etc etc etc) being equal.

So yes, on the simplified graph above, i expect the N20 2.8i to accelerate better than the N52 3.0i. it makes more torque everywhere below 6000rpm, and is only right at the very top end where the N52 betters it.

And the re-mapped N20s put another 50nm on top of the 28i figure plus on average around 20 bhp at about 1000 lower rpm..

 

[Smartbear]

That Celtic S1 map looks a bit rough. Yes you get a big peak to give you the headline figures but it only goes above the stock 18i after 5100 rpm, in other words, you will have less power with general driving and will only benefit from the extra power when you are pushing on!
There is also the big bump at low revs but that drops off quickly so is unlikely to give much benefit.
Is that how they feel on the road? I’d be disappointed with a torque curve that looked like that.

Yup that's how it felt..but without a rolling road difficult to tell from the seat of pants or back to back with another E89..

When I went for a drive with Smartbear I noticed his car would always get the initial jump on me ..so that plus a de-cat resulted in me getting it checked out with the above result..

There’s another factor that i noticed missing in your graphs/pie charts Pete, i have large feet which I’m pretty sure alters the area under the extrapolated line :lol:
Rob

 

[Anonymous]

That Celtic S1 map looks a bit rough. Yes you get a big peak to give you the headline figures but it only goes above the stock 18i after 5100 rpm, in other words, you will have less power with general driving and will only benefit from the extra power when you are pushing on!
There is also the big bump at low revs but that drops off quickly so is unlikely to give much benefit.
Is that how they feel on the road? I’d be disappointed with a torque curve that looked like that.

Yup that's how it felt..but without a rolling road difficult to tell from the seat of pants or back to back with another E89..

When I went for a drive with Smartbear I noticed his car would always get the initial jump on me ..so that plus a de-cat resulted in me getting it checked out with the above result..

There’s another factor that i noticed missing in your graphs/pie charts Pete, i have large feet which I’m pretty sure alters the area under the extrapolated line :lol:
Rob

Mine are 11.5 so I hate to imagine how big your's are!!

 

[Smartbear]

Yup that's how it felt..but without a rolling road difficult to tell from the seat of pants or back to back with another E89..

When I went for a drive with Smartbear I noticed his car would always get the initial jump on me ..so that plus a de-cat resulted in me getting it checked out with the above result..

There’s another factor that i noticed missing in your graphs/pie charts Pete, i have large feet which I’m pretty sure alters the area under the extrapolated line :lol:
Rob

Mine are 11.5 so I hate to imagine how big your's are!!

11.5! Surely you’ve stopped growing by now?
Mine aren’t as long but as you say, it’s the area underneath that counts
Rob

 

[Anonymous]

There’s another factor that i noticed missing in your graphs/pie charts Pete, i have large feet which I’m pretty sure alters the area under the extrapolated line :lol:
Rob

Mine are 11.5 so I hate to imagine how big your's are!!

11.5! Surely you’ve stopped growing by now?
Mine aren’t as long but as you say, it’s the area underneath that counts
Rob

That old line 'its not very long but it is fat' doesn't wash with many!

 

[enuff_zed]

1) The more torque and the earlier and wider the torque curve the better the real world acceleration.

Thanks Pete, that goes some way towards explaining why my car feels so quick to overtake something, even though the peak torque is lower than some other remapped cars, but mine seems a constant line from 1900 to 5000. I assume that defines 'fat'?
Of course, I have nothing similar to compare it too, but it's certainly adequate for my needs.

 

[enuff_zed]

That old line 'its not very long but it is fat' doesn't wash with many!

Of course, I have nothing similar to compare it too, but it's certainly adequate for my needs.

Now there are two posts that shouldn't have ended up so close together!!

 

[Anonymous]

Well Boys n Girls ..Great Uncle Bulgaria has been diligently cranking the numbers for you..
So found and almost pefect spec N52 engine as in exactly the same as in 30i and on European dyno so similar if not perfect apples for apples..

Then extracted PB N20 re-map and N52 data points and plotted..voila..enjoy...I think we can safely say that based on that theory a N20 re-map easily out runs a bog stock 30i..appreciate that's not stock vs stock..

 

[MACK]

Not to mention the N20 cars are lighter too. Not that I'm biased or anything :lol:

Seriously though pre decat and remap the E89 felt a bit gutless next to my E85 3.0i. Now the opposite is true.

 

[Pooltee]

All the graphs and data under the sun won’t change one thing though.....

The 6 pot regardless of power and torque will always sound better than a 4 pot!

I miss the straight 6 sound, and feel the car is always going to be a little less special without it.

 

[Smartbear]

All the graphs and data under the sun won’t change one thing though.....

The 6 pot regardless of power and torque will always sound better than a 4 pot!

I miss the straight 6 sound, and feel the car is always going to be a little less special without it.

The straight six does sound great, but most would place power & torque higher than sound as those things emphatically make the driving experience “special”
Rob

 

[BTZ461]

Well Boys n Girls ..Great Uncle Bulgaria has been diligently cranking the numbers for you..
So found and almost pefect spec N52 engine as in exactly the same as in 30i and on European dyno so similar if not perfect apples for apples..

Then extracted PB N20 re-map and N52 data points and plotted..voila..enjoy...I think we can safely say that based on that theory a N20 re-map easily out runs a bog stock 30i..appreciate that's not stock vs stock..

So to clarify, is that the M54 3 litre or the N52 Si you have used for comparative purpose? As the 3i in N52 is the lesser version of the 3.0Si, from memory the 3i N52 is around 255BHP, and approx 10knm less for the North America market. and 10knm less than the ROW, and Uk spec cars.

 

[Ed Doe]

Aaah I haven't seen a thread like this since my days on the Peugeot forums - the old 1.9Dturbo boys convincing themselves that their stage 1 tuned cars were 'real-world' quicker than the n/a GTi6.

Fwiw that's a pretty odd torque curve you've got there - from experience I'd be far more focused on what celtic have done to cause that, rather than wasting your time trying to work out which car is hypothetically quicker based on arbitrary numbers found on the Internet!