09-07-2017, 02:16 AM | #1 |
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N13 vs B38 power
I used to have a 116i with N13 (four cylinder 1.6) engine, and now have a 118i LCI with B38 (three cylinder 1.5) engine. Both engines are rated at 136 hp from BMW. I have had both on dynos to see how strong they actually are, running 95 octane fuel with no engine modifications.
The N13 had 139 hp on the rear hubs, and the B38 had 136 hp on the rear wheels. The dynos are different, the difference being that rolling resistance is included for the B38. Unlike the N13 dyno run, an estimate of the flywheel power was also indicated, at 150 hp @ 4400 RPM. Seems like the power is rather even between the two, and significantly higher than stated by BMW. The B38 seems to be marginally less thirsty than the N13, which is impressive, since the N13 was not thirsty at all. The B38 sounds better (but is overall too quiet), and vibrates a bit more at low (under 1500) RPM. |
09-08-2017, 02:39 AM | #3 |
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Very interesting the comparison, and your experience and credibility makes it even more.
Because its also a comparison of PSA vs BMW block, 3 vs 4 cyl. The performance and the efficiency are key. Another aspect worth commenting is the weight and weight distribution. What I read so long, the N13 is marginally lighter that B38, although very similar. The compactness (longitudinally, vertically) comparision is for me unknown, and how it affects the weight distribution of the car and handling. The performance capabilies of tuning is also worth comparision, to get the most of this f20/21 light engined. And also reliability. |
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09-08-2017, 07:39 AM | #4 |
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It was. But the engine has gotten stronger now, just like the N13 needed some mileage to show the true potential. And I am still running on the original M-Sport wheels with 225/245 runflats. I will replace them with non runflat Michelins before next season.
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09-08-2017, 07:43 AM | #5 |
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The N13 wins easily when it comes to tuning. Seems like most chip tuners can deliver 220+ hp, while the B38 is typically around 170. Not very much, when it seems to have 150 hp running on 95 octane with no modifications....
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09-08-2017, 12:10 PM | #8 |
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The design Bxx block beeing same for diesel and petrol, and for high powers/compression, makes it heavy duty and heavy. The components are also shared with straigth sixs, being therefore overdimensioned for 3cyl.
N13 is a petrol only, light power block design |
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09-08-2017, 12:18 PM | #9 |
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Other difference is N13 has cyl bores with steel sleeves, whether Bxx design include a covering process of steel deposition over aluminium hole (see technical training from bmw) .
How will all this appear when it comes to motor overhaul? |
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09-09-2017, 12:55 PM | #11 |
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09-13-2017, 10:47 AM | #12 | |
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Quote:
But modularity of design Bxx brings drawbacks to some of the range. I think the 6S is the optimized one, being the 4 and 3cyl the less optimal. Performance to weight, in particular. But all in all, I think each times brings its own tech, there has allways been like that. The B38 is a true BMW, slant, upper intake, lower exhaust |
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09-18-2017, 08:16 AM | #13 |
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B38 feels much more improved and stable but as you have said time will tell.
However, N13 feels more powerful. Here is a video I've found (Stage 1 remapped B38 vs Stock N13 136 hp) wonder what's wrong with the tune. it sure does look unstable |
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