Burger Tuning dynos N26 I4 Turbo: Before and after power tune

by Bimmerfest.com Member - Terry @ BMS on November 27, 2012, 4:20 pm
Hey guys,

I had a chance to dyno test an N26 motor today. It's basically the same as the N20 motor (2.0 4 cylinder turbo) but with some minor electronics changes. As far as I know the N26 has replaced the N20.

There had been some rumors that the tuning was detuned or that our Stage1 tune would have problems with it. So I'm pleased to announce it performs basically identically to the N20 motor. While I had it strapped down I did a couple runs on the Stage1 race gas map for kicks. Gains were impressive considering the test car is 100% stock except for the tune.



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35 responses to Burger Tuning dynos N26 I4 Turbo: Before and after power tune

otonimus commented:
November 27, 2012, 4:29 pm

How would we now if our car has the N26?
Terry @ BMS commented:
November 27, 2012, 4:49 pm

Quote:
Originally Posted by otonimus View Post
How would we now if our car has the N26?
The most prominent feature is the electronic wastegate actuator found on the N26 but not the N20.
justinnum1 commented:
November 27, 2012, 4:54 pm

wow
jlukja commented:
November 30, 2012, 2:14 am

Terry, at what % throttle is it remapped? Does one retain the stock tune at low throttle position?
SergioK commented:
November 30, 2012, 2:48 am

Another question, can you specify what kind of race gas was used? Octane Rating? Brand? (VP, Unocal/76, Sunoco, etc...)

Also, I'm assuming no changes in the 'tune' of the piggyback between pump fuel and race fuel? Does this mean the tune can actually modify parameters based on engine feedback/performance?
av98 commented:
November 30, 2012, 7:06 am

+1 on the Wow, thanks for the results Terry. Looks awesome!

Also curious what octane race gas you were using and brand as SergioK's question. 100 octane, 76?

And for pump gas was it 91 or 93 octane? Here in smog nazi land California we get the lowest rated octane in the country 91

Is the N26 on the SULEV models only?
Axxlrod commented:
November 30, 2012, 1:18 pm

I'm not understanding the reasons behind BMW equipping these cars with two different versions of the same engine. Especially since cars made for the state of Kalifornia can be had with either engine.

I would think that BMW would only incur the expense of designing two different versions if they were forced to by strict CA emission standards, and thus would only sell the n26 cars here. But they sell both so what was the point in the first place?
Terry @ BMS commented:
November 30, 2012, 5:55 pm

Quote:
Originally Posted by jlukja View Post
Terry, at what % throttle is it remapped? Does one retain the stock tune at low throttle position?
Low throttle is similar to stock, and heavier throttle progressively gets stronger.
Terry @ BMS commented:
November 30, 2012, 5:55 pm

Quote:
Originally Posted by SergioK View Post
Another question, can you specify what kind of race gas was used? Octane Rating? Brand? (VP, Unocal/76, Sunoco, etc...)

Also, I'm assuming no changes in the 'tune' of the piggyback between pump fuel and race fuel? Does this mean the tune can actually modify parameters based on engine feedback/performance?
100 octane unleaded racing fuel. Maybe 50% mixed with 91. To enable the race gas map you must connect with your laptop and change the map setting.
Terry @ BMS commented:
November 30, 2012, 5:57 pm

Quote:
Originally Posted by Axxlrod View Post
I'm not understanding the reasons behind BMW equipping these cars with two different versions of the same engine. Especially since cars made for the state of Kalifornia can be had with either engine.

I would think that BMW would only incur the expense of designing two different versions if they were forced to by strict CA emission standards, and thus would only sell the n26 cars here. But they sell both so what was the point in the first place?
It seems likely to me they will just drop the N20 but I'm not really in the loop on those decisions.
SergioK commented:
November 30, 2012, 8:20 pm

Quote:
Originally Posted by Terry @ BMS View Post
100 octane unleaded racing fuel. Maybe 50% mixed with 91. To enable the race gas map you must connect with your laptop and change the map setting.
I've bought race fuel both at Buttonwillow and Sears and both times seen huge spikes in lead levels in my Blackstone reports, FWIW.
Terry @ BMS commented:
November 30, 2012, 8:28 pm

Quote:
Originally Posted by SergioK View Post
I've bought race fuel both at Buttonwillow and Sears and both times seen huge spikes in lead levels in my Blackstone reports, FWIW.
BMW's love 100 octane unleaded race fuel. Just avoid the leaded stuff.
SergioK commented:
November 30, 2012, 10:30 pm

Quote:
Originally Posted by Terry @ BMS View Post
BMW's love 100 octane unleaded race fuel. Just avoid the leaded stuff.
Right, it was labeled unleaded. That's my point.
Terry @ BMS commented:
December 1, 2012, 1:30 am

Quote:
Originally Posted by SergioK View Post
Right, it was labeled unleaded. That's my point.
Hmm I dunno. Thousands of us have run 100 unleaded race fuel on N54s for years without issue. Perhaps the lead in your oil had another source? Either way probably not something to worry much about.
White05X3 commented:
December 2, 2012, 11:47 am

Terry - what are the knock counts with the mix of 91 and 100 on the race fuel map? Would you feel comfortable running this combo on a race track (a real one...where you actually turn the steering wheel and a session lasts longer than 15 seconds) in 100 ambient temperatures? What is the minimal safe ratio of 91:100 for use on a race track?
White05X3 commented:
December 2, 2012, 11:53 am

Sergio - welcome to the world of FI! In boosted motors the 100 octane does more good than it did in your e46. Turbo motors generate a ton more heat and are more likely to detonate. So regardless of whether the car is tuned or not, I always run as much 100 as possible during our schools. It is critical to keep these motors away from the threshold of detonation during prolonged WOT sessions. The 100 doesn't add power, it simply helps keep the motor happy and safe.

When you drove my car it was about 2/3 100, 1/3 91.
Terry @ BMS commented:
December 2, 2012, 6:40 pm

Quote:
Originally Posted by White05X3 View Post
Terry - what are the knock counts with the mix of 91 and 100 on the race fuel map? Would you feel comfortable running this combo on a race track (a real one...where you actually turn the steering wheel and a session lasts longer than 15 seconds) in 100 ambient temperatures? What is the minimal safe ratio of 91:100 for use on a race track?
The BMW DME doesn't use knock count system per say. Rather a full adaptive timing system with long term octane trims and shorter term knock trims. The fuel mixture and actual tune settings used depend on your particular objectives. Using the +7psi settings in the dyno above I would suggest at least 97 RM2 octane. Using the default +3psi setting 91-93 octane is acceptable.

For road racing where consistency is king I'd normally suggest using a pump gas map w/ race gas for extra insurance to ensure timing is continuously maxed out for consistent performance.

The race maps are more for those who are interested in drag racing. Which involves runs less than 15 seconds, without turning the wheel, where HP reins supreme. Does not appear to be your thing but appeals to a large segment of the enthusiast base...
SergioK commented:
December 2, 2012, 8:41 pm

Quote:
Originally Posted by White05X3 View Post
Sergio - welcome to the world of FI! In boosted motors the 100 octane does more good than it did in your e46. Turbo motors generate a ton more heat and are more likely to detonate. So regardless of whether the car is tuned or not, I always run as much 100 as possible during our schools. It is critical to keep these motors away from the threshold of detonation during prolonged WOT sessions. The 100 doesn't add power, it simply helps keep the motor happy and safe.

When you drove my car it was about 2/3 100, 1/3 91.
Yeah, my concerns with the lead levels aren't related to the engine itself... but to the emissions system. High lead levels can damage catalytic converters. I don't know if modern cats are more/or less sensitive than those of 15 years ago. FWIW even with the countless track days on my E46 (and almost at 200k on the odo) it still passed emissions so I guess all that 100 octane 'unleaded' didn't do much if any damage, just not sure how sensitive the new cats are to this.
pkim1079 commented:
December 3, 2012, 4:49 am

I dont understand ppl who drag race bmws. Go get a orange dukes of hazzard challenger or the likes lol.
White05X3 commented:
December 3, 2012, 9:48 am

Terry - thanks for that explanation. So what are the long term knock trims? How about the injector duty cycles?
Terry @ BMS commented:
December 3, 2012, 11:02 am

Quote:
Originally Posted by White05X3 View Post
Terry - thanks for that explanation. So what are the long term knock trims? How about the injector duty cycles?
At default the DME thinks it's running say 90 octane instead of 94 octane.
Terry @ BMS commented:
December 3, 2012, 11:12 am

Quote:
Originally Posted by pkim1079 View Post
I dont understand ppl who drag race bmws. Go get a orange dukes of hazzard challenger or the likes lol.
The turbo BMWs are a great drag racing platform.

(My 135i racing a new GTR)

[youtube]z4otaDWehl0[/youtube]
White05X3 commented:
December 4, 2012, 9:44 am

Quote:
Originally Posted by White05X3 View Post
Terry - thanks for that explanation. So what are the long term knock trims? How about the injector duty cycles?
Terry - can you please answer my questions?

Also what happens with your tuner when the car is in Eco Pro mode? What are the afr's in Eco Pro at low RPM, large throttle openings (not WOT, just like 2/3), and high load? Under those conditions does the tuner still raise boost?
floydarogers commented:
December 4, 2012, 10:07 am

Quote:
Originally Posted by Axxlrod View Post
I'm not understanding the reasons behind BMW equipping these cars with two different versions of the same engine. Especially since cars made for the state of Kalifornia can be had with either engine.

I would think that BMW would only incur the expense of designing two different versions if they were forced to by strict CA emission standards, and thus would only sell the n26 cars here. But they sell both so what was the point in the first place?
CARB gives them some sort of credits for the SULEV engines: http://en.wikipedia.org/wiki/SULEV
Terry @ BMS commented:
December 4, 2012, 12:40 pm

Quote:
Originally Posted by White05X3 View Post
Terry - can you please answer my questions?

Also what happens with your tuner when the car is in Eco Pro mode? What are the afr's in Eco Pro at low RPM, large throttle openings (not WOT, just like 2/3), and high load? Under those conditions does the tuner still raise boost?
Answered "knock count" in previous post above. Fuel trims are less than the 34% upper ceiling. This is not a traditional fuel injector, it injects up to 3 times per stroke, so the IPW question does not really apply to this motor. The fuel injectors can probably support around 100whp each.

The ECO mode gives you the same performance characteristics as the SPORT mode from the factory, only they have heavily dampened the gas pedal so you need to push it down further to make the same power output. I've dyno tested all modes and they performed the same at 100% pedal input. So with the tuning in place in ECO mode, the gains also only come under the heavier throttle positions.

Fueling is closed loop full time on all late model BMW turbos including the N20/N26. The OEM AFR targets are in the high 11s and we run the same basic targets only a touch leaner tuned. Since we're running a higher boost target we use the built in lean spool for a few hundred RPM more as seen in the dyno chart to get up to target quickly.
White05X3 commented:
December 4, 2012, 1:01 pm

Terry - Thank you very much.
Jamesonsviggen commented:
December 6, 2012, 11:48 am

I would like to know where the ceiling of the stock turbo is. At a certain point, it's out of it's efficiency range and it's working too hard.

I am thinking 300whp will be no problem with supporting mods(downpipe, intercooler, exhaust, stage 2 tune). But will the stock turbo support 320whp, 340whp?
av98 commented:
December 6, 2012, 1:10 pm

Quote:
Originally Posted by Jamesonsviggen View Post
I would like to know where the ceiling of the stock turbo is. At a certain point, it's out of it's efficiency range and it's working too hard.

I am thinking 300whp will be no problem with supporting mods(downpipe, intercooler, exhaust, stage 2 tune). But will the stock turbo support 320whp, 340whp?
http://www.bimmerboost.com/showthrea...N52-comparison
JoeFromPA commented:
December 6, 2012, 1:34 pm

Quote:
Originally Posted by Jamesonsviggen View Post
I would like to know where the ceiling of the stock turbo is. At a certain point, it's out of it's efficiency range and it's working too hard.

I am thinking 300whp will be no problem with supporting mods(downpipe, intercooler, exhaust, stage 2 tune). But will the stock turbo support 320whp, 340whp?
Why do you think 300whp will be no problem?

300whp is alot of power out of a 2.0 liter engine with a small turbo sized for fast spool. You'll see 300whp out of 2.0 liter engines with larger turbos, sure, but with a turbo that is spooling aggressively below 2000 rpms on this size engine....I'd be worried about it's efficiency profile. It's got to push ALOT of air to achieve that, for it's size.
Jamesonsviggen commented:
December 6, 2012, 1:57 pm

Quote:
Originally Posted by JoeFromPA View Post
Why do you think 300whp will be no problem?

300whp is alot of power out of a 2.0 liter engine with a small turbo sized for fast spool. You'll see 300whp out of 2.0 liter engines with larger turbos, sure, but with a turbo that is spooling aggressively below 2000 rpms on this size engine....I'd be worried about it's efficiency profile. It's got to push ALOT of air to achieve that, for it's size.
You just repeated what I just said about the ceiling of the turbo.

Why 300whp should not be a problem? You see a dyno above showing 283whp with only software. So another 15-20whp from a full exhaust, intercooler and stage 2 tune should be beyond attainable. I saw 7whp just from a catback on a load bearing dyno. That would have you at 290whp right there.
JoeFromPA commented:
December 6, 2012, 2:47 pm

I see a dyno above doing 283whp on race gas. It could probably do even more on e85. I'm talking pump, which I guess I should've specified "without exotic fuel" but whatever. Terry's software tune bumped it up by 30whp on 93 pump gas.

Listen, I drive a car with a 2.5 liter that can JUST hit 300whp on the stock smallish turbo, and the n20/n26 is far more efficient than that car.

However, the turbo in the n20/n26 is a TD04-LR6. I can't find much on the wheel sizes, but this turbo has been around for a long time in it's core form. If you notice Terry isn't shifting the peak later into the powerband - that turbo is capping out at 5500 rpms or so. It is NOT a big turbo. You can find a flow chart on it's efficiency pretty easily.

I'm just challenging the idea that 300whp is going to be easy with bolt-ons on pump gas. I think the turbo and probably fueling requirements are going to cut into the idea of "DP, intercooler, tune" on pump gas.

I could be wrong - I'd love to be - just adding a dose of caution.
Jamesonsviggen commented:
December 6, 2012, 3:34 pm

I agree with everything you just said.

I am just optimistic I guess in the 300whp target.
Terry @ BMS commented:
December 6, 2012, 11:44 pm

I'm sure it can l hit 330rw "some day" on race gas or E85 with higher stages and bolt on mods. Beyond that I'm not sure. On pump I can see 270rw with bolt on mods and more aggressive pump tuning.
Jamesonsviggen commented:
December 7, 2012, 8:51 am

Quote:
Originally Posted by Terry @ BMS View Post
I'm sure it can l hit 330rw "some day" on race gas or E85 with higher stages and bolt on mods. Beyond that I'm not sure. On pump I can see 270rw with bolt on mods and more aggressive pump tuning.
I have already seen 270whp dynos with downpipe and intake added on pump gas.
Terry @ BMS commented:
December 7, 2012, 11:48 am

Quote:
Originally Posted by Jamesonsviggen View Post
I have already seen 270whp dynos with downpipe and intake added on pump gas.
Yes we made 270rw catless on 93 octane. So the potential is there to do that with the OEM cat with a little more aggressive tuning, etc.