Z4 35iS or M135i LCI

SO8 · 06-14-2015, 04:38 AM

OK, so I have an N54 engined Z4 35iS (340ps) and am looking at an auto M135i LCI in the UK which has the N55 engine producing 326ps.

Official 0-62 is 4.8 for my Z4 35iS and 4.9 for the M135i.

How accurate are these figures ? I can't seem to see anyone who has really tested the Z4 35iS in the UK but the M135i seems to be coming in about 4.6 to 60 and under 11 secs to 100mph.

Is the N55 quicker than they are saying ... is it more reliable ? (seems so)

Would the N54 I have ... on a 2013 LCI Z4 35iS actually have the legs on an M135i ? The 35iS has the 7 speed DCT and the M135i the 8 speed auto. I am not going to tune/remap either due to the warranty.

My thinking is they are going to be about the same but I would be interested in peoples view on the performance difference between the two engines and their reliability.

CarAbuser · 06-14-2015, 07:34 AM

This video gives you a good idea of how the two compare: http://e89.zpost.com/forums/showthread.php?t=986117

The Z4 is a 35i but the ESS Stage 1 is a mild tune that brings the car up to if not slightly above the power levels of the 35is.
Race 2/3 both show very little movement between the cars which given the similar power levels is exactly what would be expected.

I would say there's very little in it. If you have no intention of tuning then it seems a waste to own an N54.

The DCT gearbox in the Z4 gives it the edge. I don't think I could live with the 8 speed slushbox in the 1 series. Would have to go for the manual option.

Asbjorn · 06-14-2015, 12:40 PM

Agree with carabuser.

I am adding that the N55 is more reliable, economical and better sounding due to active sound and twin scroll turbo. The N54 sounds less aggressive. Even the S55 does not sound as great as the N55 with the right exhaust. Only problem is, you will never really be able to hear it, because the M135i is not a convertible haha.

Finally the M135i has way more torque below 4000rpm. It is only at higher revs that the 35is starts to compete with the M135i.

If you dont plan to tune it, consider a 6MT with adaptive suspension, nonRFT oem tires and non-variable steering.

nicknaz · 06-14-2015, 04:53 PM

Should be pretty close. 135 additional cooling is an advantage if you are going to hammer it

Hujan · 06-14-2015, 07:52 PM

I think the N54 ultimately has more power potential in the aftermarket but the N55 is probably a more reliable engine. I think it's pretty evident made the switch from the N54 to the N55 in large part because of the reliability concerns with the N54.

Since you don't intend to do much/any aftermarket work on either car, I would sell the 35is and grab the M135i.

06-14-2015, 04:38 AM	#1
SO8 Major 246 Rep 1,206 Posts Drives: BMW G42 M240i xdrive Join Date: Jun 2010 Location: Earth iTrader: (0)	Z4 35iS or M135i LCI - N54 or N55 better ? OK, so I have an N54 engined Z4 35iS (340ps) and am looking at an auto M135i LCI in the UK which has the N55 engine producing 326ps. Official 0-62 is 4.8 for my Z4 35iS and 4.9 for the M135i. How accurate are these figures ? I can't seem to see anyone who has really tested the Z4 35iS in the UK but the M135i seems to be coming in about 4.6 to 60 and under 11 secs to 100mph. Is the N55 quicker than they are saying ... is it more reliable ? (seems so) Would the N54 I have ... on a 2013 LCI Z4 35iS actually have the legs on an M135i ? The 35iS has the 7 speed DCT and the M135i the 8 speed auto. I am not going to tune/remap either due to the warranty. My thinking is they are going to be about the same but I would be interested in peoples view on the performance difference between the two engines and their reliability.
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06-14-2015, 07:34 AM	#2
CarAbuser Lieutenant Colonel 486 Rep 1,550 Posts Drives: Z4 35i DCT / E92 335i DCT Join Date: Jul 2010 Location: United Kingdom iTrader: (0)	This video gives you a good idea of how the two compare: http://e89.zpost.com/forums/showthread.php?t=986117 The Z4 is a 35i but the ESS Stage 1 is a mild tune that brings the car up to if not slightly above the power levels of the 35is. Race 2/3 both show very little movement between the cars which given the similar power levels is exactly what would be expected. I would say there's very little in it. If you have no intention of tuning then it seems a waste to own an N54. The DCT gearbox in the Z4 gives it the edge. I don't think I could live with the 8 speed slushbox in the 1 series. Would have to go for the manual option.
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06-14-2015, 12:40 PM	#3
Asbjorn Captain 93 Rep 833 Posts Drives: Z4 N54 DCT (VTT GC lites) Join Date: Mar 2012 Location: European in China iTrader: (0)	Agree with carabuser. I am adding that the N55 is more reliable, economical and better sounding due to active sound and twin scroll turbo. The N54 sounds less aggressive. Even the S55 does not sound as great as the N55 with the right exhaust. Only problem is, you will never really be able to hear it, because the M135i is not a convertible haha. Finally the M135i has way more torque below 4000rpm. It is only at higher revs that the 35is starts to compete with the M135i. If you dont plan to tune it, consider a 6MT with adaptive suspension, nonRFT oem tires and non-variable steering. Last edited by Asbjorn; 06-14-2015 at 12:45 PM..
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06-14-2015, 04:53 PM	#4
nicknaz Lieutenant General 3194 Rep 10,509 Posts Drives: C6Z Join Date: May 2008 Location: NorCal iTrader: (0)	Should be pretty close. 135 additional cooling is an advantage if you are going to hammer it
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06-14-2015, 07:52 PM	#5
Hujan Brigadier General 576 Rep 3,741 Posts Drives: M3 Join Date: Apr 2013 Location: . iTrader: (16)	I think the N54 ultimately has more power potential in the aftermarket but the N55 is probably a more reliable engine. I think it's pretty evident made the switch from the N54 to the N55 in large part because of the reliability concerns with the N54. Since you don't intend to do much/any aftermarket work on either car, I would sell the 35is and grab the M135i.
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