N26 dyno testing

Originally Posted by White05X3

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.

Terry - Thank you very much.

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?

Originally Posted by Jamesonsviggen

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

Originally Posted by Jamesonsviggen

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.

Originally Posted by JoeFromPA

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.

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.

I agree with everything you just said.

I am just optimistic I guess in the 300whp target.

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.

Originally Posted by Terry @ BMS

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.

Originally Posted by Jamesonsviggen

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.