Custom tune to produce more NA-like feel?

[8600RPM]

Would it be possible for a custum tune to better produce a more linear power curve if we were willing to not take as much of a midrange gain? Maybe adding progressively more boost up top without as much down low and in the middle?

Given the wheel spin I am seeing in lower gears, I almost would prefer a tune that tapered off the power a tad down low and in the middle but progressively built it a bit more aggressive up top to give a true NA feel?

Maybe I am alone but could a tuner due this if one were to pay for a custom tune?

Redline raised to 8k perhaps possible or is air flow not happening there?

[ASAP]

Originally Posted by 8600RPM

Would it be possible for a custum tune to better produce a more linear power curve if we were willing to not take as much of a midrange gain? Maybe adding progressively more boost up top without as much down low and in the middle?

Given the wheel spin I am seeing in lower gears, I almost would prefer a tune that tapered off the power a tad down low and in the middle but progressively built it a bit more aggressive up top to give a true NA feel?

Maybe I am alone but could a tuner due this if one were to pay for a custom tune?

Redline raised to 8k perhaps possible or is air flow not happening there?

No... no one can tune the car right now that fine.

Terry, probably can limit boost per gear right now but that is about it.

Also, why would u want the most linear turbo motor to be more linear? No point in having a turbo motor then.

[CanAutM3]

So you are willing to sacrifice performance

[RSXDC5]

There is merit to the OP's stance though. Having a power curve that builds and builds as the revs climb is pretty fun.

That being said, power falls off on a JB4 tuned car SO MUCH after 6k or so (no dyno chart in front of me, sry), that I cant help but think how much more revvy in nature the engine would become if power just climbed and climbed till redline with the JB4.

VTT OEM turbo upgrade anyone? That should solve most of our powerband curve woes!

[JStang]

They can do a more linear throttle map where boost is linear with the pedal position.

[Boss330]

Originally Posted by RSXDC5

There is merit to the OP's stance though. Having a power curve that builds and builds as the revs climb is pretty fun.

That being said, power falls off on a JB4 tuned car SO MUCH after 6k or so (no dyno chart in front of me, sry), that I cant help but think how much more revvy in nature the engine would become if power just climbed and climbed till redline with the JB4.

VTT OEM turbo upgrade anyone? That should solve most of our powerband curve woes!

Exactly!

The JB4 seems to raise boost and max out the turbos. Power falls dramatically after the midrange and keeps falling until redline. Exactly the opposite of traditional BMW M engine characteristics... The Dinan tune has a "boosted" power curve that mimics BMW's power curve.

It should be possible to map boost relative to rpm and get the effect you desire. The car will be slower though... You have to loose a big chunk of that mid range power to reach your goal...

[RSXDC5]

Originally Posted by Boss330

Exactly!

The JB4 seems to raise boost and max out the turbos. Power falls dramatically after the midrange and keeps falling until redline. Exactly the opposite of traditional BMW M engine characteristics... The Dinan tune has a "boosted" power curve that mimics BMW's power curve.

It should be possible to map boost relative to rpm and get the effect you desire. The car will be slower though... You have to loose a big chunk of that mid range power to reach your goal...

Exactly (again)!

The car WILL be slower with the loss in mid range power, but, you would get the power curve you wanted then.

Now, if you were in the market for a turbo upgrade, well then, the above sentence is of no concern to you! Just make as much power as you possibly can and you will probably have a great power curve!

[tom @ eas]

Originally Posted by Boss330

Exactly!

The JB4 seems to raise boost and max out the turbos. Power falls dramatically after the midrange and keeps falling until redline. Exactly the opposite of traditional BMW M engine characteristics... The Dinan tune has a "boosted" power curve that mimics BMW's power curve.

It should be possible to map boost relative to rpm and get the effect you desire. The car will be slower though... You have to loose a big chunk of that mid range power to reach your goal...

MAP3 did pretty well, and still shows a 60whp/80lb-ftTQ gain. from our baseline (not pictured).



There is a new firmware out (v3_4), we have not yet tested. The ability to datalog on the JB4 is a huge plus will only improve maps over time.

[8600RPM]

Can we really say the car would be slower with reduced boost in the low, low-mid range? Traction is a huge issue from everything I am seeing. So to me given at speed and full throttle, you are in the upper end of the rpm band, lower rpm and mid-range drop in boost would allow better hook-up and less wheel spin at lower speeds which is the only place that traction really matters and yet at higher speeds you would be living above mid-range when you wanted to nail it so really what performance loss would you get if you could maximize traction ?

The e92 m3 had no low end grunt and yet put down great times as it had much less traction issue but even that spun through first. The gearing on the f80 cannot handle the level of low end grunt this motor puts out. I personally think lowering the boost down low would lead to better times in all objective categories.

But I am no engineer. On top of all that the feel would be a bit more like an NA car as well

[gmd2003]

Originally Posted by tom @ eas

MAP3 did pretty well, and still shows a 60whp/80lb-ftTQ gain. from our baseline (not pictured).



There is a new firmware out (v3_4), we have not yet tested. The ability to datalog on the JB4 is a huge plus will only improve maps over time.

It's still a peak HP at 4800 rpm then a rapid decline . Nothing special power curve wise and not many's preference . Can't change the fact that at the settings you're using the turbos are maxed put at 4800 rpm .

[Boss330]

Originally Posted by tom @ eas

MAP3 did pretty well, and still shows a 60whp/80lb-ftTQ gain. from our baseline (not pictured).



There is a new firmware out (v3_4), we have not yet tested. The ability to datalog on the JB4 is a huge plus will only improve maps over time.

The car has 559whp (or at least that dyno has measured that number) at around 4800rpm, then it falls to 460-470whp at 7300rpm...

That is a decline of 100whp from 4800-7300rpm...

Quite significant and a distinctive difference from the shape of the power curve of the std engine. That power curve is the exact opposite of what the OP wants...

[CanAutM3]

Originally Posted by 8600RPM

Can we really say the car would be slower with reduced boost in the low, low-mid range? Traction is a huge issue from everything I am seeing. So to me given at speed and full throttle, you are in the upper end of the rpm band, lower rpm and mid-range drop in boost would allow better hook-up and less wheel spin at lower speeds which is the only place that traction really matters and yet at higher speeds you would be living above mid-range when you wanted to nail it so really what performance loss would you get if you could maximize traction ?

The e92 m3 had no low end grunt and yet put down great times as it had much less traction issue but even that spun through first. The gearing on the f80 cannot handle the level of low end grunt this motor puts out. I personally think lowering the boost down low would lead to better times in all objective categories.

But I am no engineer. On top of all that the feel would be a bit more like an NA car as well

The strength of the S55 in stock form is its power plateau from 5500 to 7300rpm. To maximize acceleration, you need to maximize average power. By having this power plateau, the S55 pretty much produces a constant 425hp throughout an acceleration run. If you tune the engine to limit power in the mid range, you will have less average power, hence less performance.

Traction is really only an issue in the lower gears. Once you reach speeds where traction is no longer an issue, might as well benefit from that power plateau .

[FogCityM3]

Doesn't Ferrari tune their new TT engine to give a more N/A power curve and feel?

With regard to what OP is saying could be done for MT but with DCT, would have to change around the shift points for automatic mode. Could involve quite a bit of programming/testing.

[tom @ eas]

Originally Posted by Boss330

The car has 559whp (or at least that dyno has measured that number) at around 4800rpm, then it falls to 460-470whp at 7300rpm...

That is a decline of 100whp from 4800-7300rpm...

Quite significant and a distinctive difference from the shape of the power curve of the std engine. That power curve is the exact opposite of what the OP wants...

I'm referring to MAP3 (green). This holds the power almost evenly to redline.

[tooch]

Originally Posted by 8600RPM

Would it be possible for a custum tune to better produce a more linear power curve if we were willing to not take as much of a midrange gain? Maybe adding progressively more boost up top without as much down low and in the middle?

Given the wheel spin I am seeing in lower gears, I almost would prefer a tune that tapered off the power a tad down low and in the middle but progressively built it a bit more aggressive up top to give a true NA feel?

Maybe I am alone but could a tuner due this if one were to pay for a custom tune?

Redline raised to 8k perhaps possible or is air flow not happening there?

why don't you just use your foot?

[8600RPM]

I think people are making this more complicated. I have no clue why the tranny would matter or shift points etc. I am simply talking about changing the shape of the curve by alterning timing, boost and whatever other parameters go into a piggy back. If the turbos run out of air up top that may be as much top end as the car can put out. I did not mean get rid of mid-range as in get rid of 5500 or above. I meant more of the 5k and below possibly to create a more linear feel. Just a thought I guess. Bigger turbos would be more lag though so I guess always a trade-off

This may be the perfect car if upgraded turbos came with no lag but ability to add power to the top end and rev to 8k rpm making increasing power to redline

[Boss330]

Originally Posted by tom @ eas

I'm referring to MAP3 (green). This holds the power almost evenly to redline.

You are right! I missed that, sorry!!!

[Boss330]

Originally Posted by 8600RPM

I think people are making this more complicated. I have no clue why the tranny would matter or shift points etc. I am simply talking about changing the shape of the curve by alterning timing, boost and whatever other parameters go into a piggy back. If the turbos run out of air up top that may be as much top end as the car can put out. I did not mean get rid of mid-range as in get rid of 5500 or above. I meant more of the 5k and below possibly to create a more linear feel. Just a thought I guess. Bigger turbos would be more lag though so I guess always a trade-off

This may be the perfect car if upgraded turbos came with no lag but ability to add power to the top end and rev to 8k rpm making increasing power to redline

5k and below?

Whats wrong with the shape of the power curve BELOW 5k?

[Mike@N54Tuning.com]

Power rolls off up top because the turbo runs out of airflow up there. If the idea is to maximize power under the curve, add torque to the midrange where you can really use it, then it's perfectly tuned. If you want to limit performance down low to "fool" yourself into thinking it's making peak HP at peak RPM there are a couple ways to do it.

1) Pretend your redline is 5000rpm.
2) Press the gas pedal down more gently going 30% at lower RPM slowly ramping up to 100% at redline.

As far as traction goes BMS is currently working on a boost/traction system for the vehicle to help with launches. Especially from a stop. They may program the car to make less boost than stock in 1st gear, slowly ramping up to full boost in 3rd, or something like that. Whatever it is they will make it fully user adjustable. I'll post more details when I have them.

Mike

[ASAP]

You can also play with the Waste Gate to mimic different feels... I am sure Terry is playing with that consistently.

[MaynardZed]

S65 or S85 swap into your F8x will give you the result you desire.

[Mike@N54Tuning.com]

Looks like enough people have asked for this so BMS is adding a //M map to the JB4 map collection which simulates an NA motor. Low torque with high power at redline.

Mike