Why do I want a N55?

[Gizmo135i]

Originally Posted by FrostyDC4

Have you heard of any Dinan flashed N55 cars breaking any of the ancillary parts (fuel pumps, etc)?

Just chargepipes... but those break on stock cars as well so

[iminhell1]

So you want a car that is going to just be used for very occasional use, but want to spend money on a good base in hopes it'll be more reliable?
But then modify it to not be as reliable as stock?

Do I have that correct?


There are thousands and thousands of n54's with hundreds of thousands of miles on them. Look at how many 335's where bought for daily use, miles upon miles piled on them. But on the internet forum world you won't find talk about them, the owners are too buys driving.
The same can start to be said for the N55 cars too.

Just a quick look on cars and there are 413 335's above 100k, all can be had cheap.
Looks like a handful of 135's above 100k also, for cheap.


For a track car that you plan to modify, find the cheapest car you feel comfortable with. There is nothing else to consider. The car is not going to gain value sitting. It is not an investment. It's a moneypit used for enjoyment. Don't think it's ever going to be anything else.


On the N54, use MHD to turn the 'race cooling mode' on for track duty. You won't have any cooling problems. I've done back to back to back 30 min sessions and temps never got out of control; nothing ever above 220*F.

[dleccord]

Originally Posted by Gizmo135i

No but I have driven a lot of cars that have it... again nothing wrong with it, good for what it is.. smooth and stock like, no worries about breaking something, but doesn’t make the same power other options do

if we're comparing torque and not upper end (hp), would the dinan tune be a huge compromise to MHD or Cobb? would you notice the difference if you weren't racing? if dinan stage 2 can output 400 tq, that already sounds a lot for a daily.

[iminhell1]

Originally Posted by dleccord

if we're comparing torque and not upper end (hp), would the dinan tune be a huge compromise to MHD or Cobb? would you notice the difference if you weren't racing? if dinan stage 2 can output 400 tq, that already sounds a lot for a daily.

You go Dinan if you are under warranty. That's the only reason.

All other times MHD, Cobb, JB (in that order). There is no reason to overpay for something that carries no warranty whatsoever. If A Dinan tune blows up your car after install, it's on you. The same holds true for all other tunes too.

And the amount of power has zero bearing on drivability. If you can't modulate your right foot, well maybe you should move to the other seat and watch.

[Gizmo135i]

Originally Posted by iminhell1

You go Dinan if you are under warranty. That's the only reason.

All other times MHD, Cobb, JB (in that order). There is no reason to overpay for something that carries no warranty whatsoever. If A Dinan tune blows up your car after install, it's on you. The same holds true for all other tunes too.

And the amount of power has zero bearing on drivability. If you can't modulate your right foot, well maybe you should move to the other seat and watch.

What I mean by drivability is the car feels stock like except with more power. The Jb4 deffinatly leaves something to be desired in that area, part throttle acceleration is not smooth, power is not consistent. I know the Cobb has always left people with something to be desired... A good tune with mhd is deffiatly the way to go

[bbnks2]

Originally Posted by dleccord

if we're comparing torque and not upper end (hp), would the dinan tune be a huge compromise to MHD or Cobb? would you notice the difference if you weren't racing? if dinan stage 2 can output 400 tq, that already sounds a lot for a daily.

No, Dinan won't be much of a compromise in terms of torque down low (it actually would all depend on which tunes you are comparing...). That is the area where Dinan mainly bumped power in their tuning... low end torque from low rpm boost. Dinan left the upper rev range modest as there isn't much room up top to increase power without over-spinning the turbo and creating heat. They don't really bump up power up top until you get into their stage 3 software... Otherwise, it's comparable to MHD stage 1.

MHD is much more aggressive up top from stage 2 and up, but the gains are marginal.

[AndyW]

I have one of each so can probably speak helpfully on the topic...

First one I got was a 2008 335i N54 A/T E93 with 33K. It is a great car and engine. I dyno'd 384WHP/420WTQ on 92oct pump gas last year. That is with a custom tune by WedgePerformance . I would classify the N54 as "more finicky" but capable of much higher power levels, but that is not my goal. I wanted to stay below the "start to break things" curve as it is my main daily driver.

To start with, on a used N54 I would replace plugs/coils AND injectors if they had not been done in the last 10K...and yes the injectors are expensive. I basically reset everything easily DIY replaceable at around 100K before tuning and it has continued to be a great ride. I now have 140K and no wastegate rattle and, surprisingly, no other turbo issues (crossing fingers). I expect turbo replacement or bearing ledges are my next big jobs, sometime between now and 200K.

Second, because you can't drive a vert in BMW HPDE's, I got a 2012 135i DCT E82 with 73K. It now has 83K. It is also a great car and engine. BMW did a great job refining the N54->N55, but based on what I have read, there is less "margin" to get higher powers like you can with the N54...but again, not my goal. My track car goal is similar to you. 4-5 events a year on a trackable street car. I am also running a WedgePerformance tune on this car. Based on discussions with Wedge, the N55 doesn't have to be FBO to get great performance...he pushed over 500WHP (IIRC) on his N55 135i without catless DP's, for example. So I have only done minimal mods to this one: Wagner FMIC, K&N Filter, ER CP. I had it on the track last year...runs and pulls great.

N54 vs N55 observations/opinions:

Both put out great power and torque stock or with a custom tune. N55 does "run out of breath" a bit at higher RPM due to the single turbo but it is negligible IMO and its other strengths offset this.

N55 requires less attention/parts/refresh/care than the N54 due to the refinements BMW did (a number mentioned in the thread). The only thing BMW can never get a high quality version of is apparently a water pump...

DCT is a key difference between my cars...the A/T with the Alpina flash is no slouch, but the DCT is just amazing (full disclosure: This is my first DCT car so I have no idea if it is better or worse than other DCT's). Whatever car you get...get a DCT for the track unless you just *have* to have a M/T.

HTH. WRT tunability, I hate to sound like an advertisement, but PM Wedge. He has experience with tuning both.

[Apex1.0]

Great post, thanks.

[AndyW]

Originally Posted by Apex1.0

Great post, thanks.

NP. You were helping me in the KW DDC thread, figured I'd return the favor...

I will dyno my 135i on Feb 24th and will post the results. I should have also mentioned that both my custom tunes are stage 2+ level tunes on MHD. I don't think you will need to downtune either engine to be good and reliable on the track. Based on everything I have read, these engines are capable of at least 450WHP before you really start adding real risk, and that requires alternate fueling which I am not planning on doing for two reasons: 1. Risk and 2. Laziness (which is also why I am interested in the DDC... )

[Apex1.0]

I am kind of surprised a catless dp doesn't free up more power on n55 cars. After I read your post, I did some research and found gains are a bit more modest than on n54 cars. The newer engines must have a better factory dp.

So I can live without the massive FBO dyno figures by going n55. Obviously on the street I want the most fun power I can have. But on the track I want some thing that can deliver consistency. I can't work on chassis setup and my driving if the car goes into limp mode or pulls a bunch of power. The more I read the more I am more likely to trade the FBO power of the n54 and go with consistency and reliability of the n55.

At this point the car, condition, mileage, options etc. will trump engine choice, when I buy.

Thanks!

[bbnks2]

Originally Posted by gtjosh

On the subject of power levels the N54 makes more at peak but what about the rest of the time? I think a pair of dyno graphs should be compared between a FBO N54 and a FBO N55 and don’t just look at peak power but the space under the graph. I have never driven a N54 car so I cant say anything about the way they drive or anything like that but I am extremely happy with the power level I am at now and the way the power comes on for both tracking and daily driving. There is still room for improvement for me and I am excited to see more power but for me I want to learn how to use the power I have before I add some more.

N54 twin turbos still win. The restriction at low RPM is fueling from the HPFP and not necessarily the turbo setup on either car. Both cars max out at around 500wtq... There is such a small difference in spool between the twins and the twinscroll that it's hard to measure or see in a dyno graph. N54 might see full boost 100rpm later? There is a bit more lag to the N54 in constant on/off throttle situations though which makes the N55 twinscroll a bit better for track driving if you don't care as much about raw power output. Most track oriented cars run twinscroll EFR turbos for to improve transient response over focusing on increasing peak power.

[kivyee]

Originally Posted by bbnks2

N54 twin turbos still win. The restriction at low RPM is fueling from the HPFP and not necessarily the turbo setup on either car.

I'm curious why that is? Low RPM is when fuel consumption is low, and boost pressure doesnt vary significantly from high rpm. How could there be a hpfp flow(?) restriction at low rpm and not high rpm?

[bbnks2]

Originally Posted by kivyee

I'm curious why that is? Low RPM is when fuel consumption is low, and boost pressure doesnt vary significantly from high rpm. How could there be a hpfp flow(?) restriction at low rpm and not high rpm?

RPM drives flow rate from the HPFP

[FrostyDC4]

Originally Posted by bbnks2

N54 twin turbos still win. The restriction at low RPM is fueling from the HPFP and not necessarily the turbo setup on either car. Both cars max out at around 500wtq... There is such a small difference in spool between the twins and the twinscroll that it's hard to measure or see in a dyno graph. N54 might see full boost 100rpm later? There is a bit more lag to the N54 in constant on/off throttle situations though which makes the N55 twinscroll a bit better for track driving if you don't care as much about raw power output. Most track oriented cars run twinscroll EFR turbos for to improve transient response over focusing on increasing peak power.

500wtq on a stock turbo 1st gen N55 in the E chassis cars?


Skepticalhippo.jpg

[bbnks2]

Originally Posted by FrostyDC4

500wtq on a stock turbo 1st gen N55 in the E chassis cars?

Skepticalhippo.jpg

Yes. 507wtq at 27xxrpms was the highest I saw on my car at a dyno session. I've posted dynos and plenty of 23psi+ logs. Most pulls were around 480wtq PEAK since we began the pulls at around 2700 rpms on the dyno instead of the 1500 rpms of the first few pulls.

[MCandrews]

Originally Posted by Gizmo135i

One thing to think about is that upgrading the turbo on the n55 is considerably less money and simpler to install then the N54.

I know you said fbo, but in the future if you decide you want more power, the pure stage 1 will get you around 400whp for under a grand, a pure stage 2 can produce 450+ Whp on 93 only, or 500+ with meth or e85. It’s around 2500 with the inlet pipe. The ps2 is the way to go... I have it on my Dct car and it is awesome.

Also I think 450whp in N54 is a bit optimistic with stock turbos, it is possible but the turbos won’t last long

Hey, would you tell me if you've experienced any problems with your DCT pushing 400whp? I'm seriously considering Pure stage one with a Cobb pro-tune on my 2011 N55 135i with DCT and I'm worried about the trans. Any info for a fellow like me?

[NonoxX]

Originally Posted by MCandrews

Hey, would you tell me if you've experienced any problems with your DCT pushing 400whp? I'm seriously considering Pure stage one with a Cobb pro-tune on my 2011 N55 135i with DCT and I'm worried about the trans. Any info for a fellow like me?

With Pure stage 1, your DCT should still be OK under max power. At that power point, I've already seen some DCTs slip though.

I would flash this car with a proper backend flash increasing clutch pressure. This would ensure you not to get slippage until muuuch higher power levels.

[Cavpilot2k]

Back to one of the questions from a month or more ago.
I have had the Dinan tune for 50k miles and have not broken anything that wouldn't have broken stock (water pump).
My charge pipe is holding strong as well.
Dinan is on the more conservative side. It gives a great bump in torque, but otherwise is very similar to stock in linear power delivery (whereas JB4 can be "peaky", being generous).
Can't speak to the others, but I went Dinan for their warranty (which wasn't needed) and to get a tune that wouldn't void my factory or CPO warranty.

Plus, my car is my daily driver, not a track car. I don't want a tune or mods that are going to push it to the limits, hoping nothing breaks every time i press the right pedal.

If you are looking for max power, look elsewhere.
If you are looking for good power for daily driveability and reliability, Dinan is a solid option, especially given that the current price is about half of what I paid. years ago.