BMW Misfire Diagnosis and Repair – N54

This is a great blog post from Cobb Tuning and we thought we’d share it out here as well for those interested along with their video.


The N54 powered BMWs respond amazingly well to tuning, but the increased power has caused some owners to experience misfire issues. Trouble shooting and repairing a BMW can seem like a daunting task with things like an advanced electrical system, specialized tools, and intimidating engine covers. But, diagnosing and repairing the typical misfire is fairly straight forward, and COBB Tuning can show you how!

To see our BMW products and custom tuning offerings click here.

PTF N54 Pro Tune with 50/50 (Boost Juice) Meth – single 1.0mm nozzle, full boltons – delta of +153whp +171wtq over stock

Quick update from yesterday.

AR Catted Dp’s
Aquamist HFS-4 System w/ One 1mm nozzle 50/50 boost juice from snow performance
K&N Intake (soon to be bms dci)
ER Charge Pipe w/ Forge Diverter Valves
BMW Performance exhaust (with secondary cats in place)
PTF ProTune

Bone stock baseline showed 264whp/268wtq same day same dyno. Thought I’d throw this up as it was one of the only cars we tuned on a 50/50 meth mixture (usually do north of 80-100% meth mix) and just a SINGLE 1.0mm nozzle. With more meth and/or higher meth concentration more is available through timing. A nice DCI would help another 10-15whp at peak as well but we’re very pleased with a pretty kick ass delta of +153whp +171wtq over stock

ar design, Helix and SPEC Clutch parts now available

We’ve further expanded our website in the last 2-3 months and partnered with a few more quality BMW performance parts manufacturers:

  • ar design for their top notch fabrication/welding work and Line Lock kits
  • Helix for their great FMICs
  • SPEC for their new single mass steel flywheel offering as well as street and drag strip proven 2+ and 3+ clutch kits

Our website conforms to the MAP (Minimum Advertised Pricing) standards set by the manufacturers unless otherwise agreed with them and/or unless there are special promotions currently running. Let us know if you’re interested and we’ll try to do our best to provide you with the best price possible. All parts are shipped from within the US.


P.S. Here’s a pic showing the manufacturers we currently endorse and partner with (minus the Walbro, that’s just there as we’ve catalogued their E85 pump)

Click here to enlarge

PTF Customer Car in the BMW Car Magazine (UK) – February 2013 Issue! – BMW 335i

Marcel is one of our COBB Pro e-Tune customers from Luxembourg. His LCI E90 BMW 335i is simply stunning. It sports all the top shelf bolt-on modifications in both power and suspension departments. It is one of the only cars with properly upgraded air intake and piping that I personally know of (super jealous!), wind tunnel tested Alpina aero and interior modifications and, what every North American can only dream of, access to the Autobahn and the Nürburgring.

So far our tuning with RB turbos on his car has taken the power on the car to 503hp and 719Nm of torque from a with boost hitting 19psi with appropriate calibrated timing, fuel, VANOS maps among others. This was tuned for Euro V-Power 98 RON octane for the moment. Once weather improves and it warms up in Luxembourg we’ll proceed with tuning the car with methanol injection which will allow higher octane and have the car hitting 580+hp and 800+Nm of torque safely and consistently.

Below are the pages from the BMW Car Magazine‘s February 2013 issue, grab yours today!

Marcel, from us at PTF, thank you sir, best of luck at the Nürburgring and we’re looking forward to working with you in the future.




1 step colder plugs for the BMW N54 – NGK 5992 Laser Iridium – ILZKBR7A-8G

If you’ve modified your N54 based BMW extensively pushing well past the stock power levels or you’re just looking to run a different plug than the OEM Bosch ZGR6STE2 for any reason the NGK 5992 (ILZKBR7A-8G) are a great alternative. They can be had for about the same price as the OEM Bosch with some searching, $10.79 from for instance.

Now, I’ve been running them for the last 30,000km, racing, pushing high boost with race tunes with and without meth and these have performed strong as well as set some records without any issues.

Thing to note is that these plugs off the shelf come with a larger gap than we can use on the N54 so just direct swapping them in won’t work and the car will stumble/misfire that way. You MUST have them gapped either to the OEM 0.7mm (0.0275″) or, which I’d recommend, to 0.56mm (0.022″) for high boost. The original gap on the NGK 5992 plugs is 0.8mm (0.031″) so make sure to GAP them before installation!

Some of the reasons I personally like them vs. the OEM Bosch ZGR6STE2 plugs are as follows:

1) Single ground prong vs. 3-prong OEM (makes the NGKs easily gappable when/if required)
2) 1 heat range COLDER than Bosch – standard recommendation is to go 1 heat range colder for every 100hp past stock. I’m at ~300hp above stock at the motor currently so can’t hurt.
3) Iridium center tip
4) They haven’t let me down with literally TONS of very very hard driving on 20+psi boost on RBs, pump+meth. Literally hundreds of 3-4 gear pulls, many drag strip runs and 60-130mph runs.
5) They’ve helped set some records too

Here’s what the NGK 5992 plugs look like and some of its specs:

NGK 5992

Features & Benefits

OE style long life spark plug. Laser welded iridium center electrode and platinum ground electrode, tapered ground electrode to minimize quenching, consistent and stable spark and outstanding acceleration, high fuel efficiency and durability.

Part Number: 5992
Weight: 0.09 lbs
Ngk Part Number: ILZKBR7A-8G
Thread Size: 12 mm.
Resistor: Yes
NGK Heat Range: 7
Center Electrode Material: Iridium
Ground straps: 1
Insulator Type: Ceramic
Ground Electrode Material: Copper core
Thread Reach: 1.043 in. (26.5 mm.)
Seat Type: Gasket

Here’s the BMW N54’s OEM Bosch replacement spark plug and specs for comparison:


Part Number: ZGR6STE2
Weight: 0.12 lbs
Thread Size: 12 mm.
Resistor: Yes
Bosch Heat Range: 6
Center Electrode Material: Copper
Ground Straps 3
Insulator Type Ceramic
Ground Electrode Material Nickel Alloy
Thread Reach: 1.043 in. (26.5 mm.)
Seat Type: Gasket

One thing you may be left wondering about is the heat ranges. These are “manufacturer” heat ranges on the plugs and Bosch and NGK don’t have the same scaling. In fact they go in opposite directions to each other. Once you work it all out though, if you’re up for digging up the info on heat ranges (which is a bit painful by the way), you’ll realize the NGK 5992 are 1 step COLDER than the OEM Bosch.

In the end, nothing wrong with OEMs but there is a solid 1 step colder alternative out there that is easily gap-able.

For information on how to gap plugs and what tool to use see this instructional video from NGK:

PRICING UPDATE: eTune/PRO Tune product bundles, HUGE savings!

Over the last few weeks we’ve established relationships with some of the great names in the N54 scene to be able to offer our customers quality parts along with our custom tuning. Prices have been set LOWER THAN LOW for many of our bundles that include anything from a single part to full bolton with and without Aquamist methanol injection.

Make the long story short, among others, some of the highlights are:

COBB Accessport with a PTF Custom Tune (eTune or Local)
COBB Accessport + Aquamist HFS-4 + 2.2Gal Trunk Mounted Howerton Tank with a PTF Custom Tune
FBO Bundle from cp-E + Aquamist Meth/Tank with a PTF Custom Tune
Aquamist HFS-4 + 2.2Gal Trunk Mounted Howerton Tank with a PTF Custom Tune

For any others you can check directly on our site or PM us here for details. We’re in the process of setting up for products from ER as well so those are not on our website just yet.

Cheers, enjoy the holidays!

BMW 135i 1/4mile – 11.76sec@120.7mph, 1.947 60′ – stock turbo, E40 blend, full weight, street tires, no meth, stock catted midpipes

Sharing some truly awesome results from one of our recent customers. Here’s their review from MIR (Maryland International Raceway) this past weekend.

What’s even more impressive is that 11.7 was done with a 1.94 60′. With DRs, same tune and conditions, this same car can easily see low 11s!!

Very nice working with you Jorge! :)


Incredible times with my 135 thanks to PTF

2009 135
CPE Intercooler
CPE Chargepipe/Tial BOV
CPE Downpipes
Injen DCI
Stock catted mids
Active Autowerke axleback

COBB protuned by PTF

Fuel: E85/93 mix of 40/60

OEM wheels with street tires (Proxes R1Rs)
Weighed car during event at 3340lbs
Temperature for the day 44-51 degrees
Humidity was 55% to 63% during my runs

Total of 5 runs in the 11s
We left immediately after the 11.76 run as I had other commitments. Kind of regret leaving as every pass was faster. The 11.76sec @ 120.7mph pass was the third consecutive pass (no waiting due to very few cars), so car was running great, definitely no kind of heatsoak whatsoever or any other issues for that matter.

Previously ran Dinan Stage 2, 12.98 at 107 mph. Bought the COBB and immediately began using the Stage 2+ aggressive OTS maps with incredible change in power from the Dinan Tune.

Talked to PTF and they immediately were able to set time aside and work with me personally which was a big plus. The results speak for themselves but in addition to that, PTF answered all my questions and exercised much patience with me as I felt that my car “was running slower” after his tune and kept “nagging him” about it.

I think this had to do more with the smoothness of the power which is a testament to his expertise and the driveability of the COBB tune. Not to mention I drove this E85 mix for about 3 weeks, so I probably got used to it as time went by. He advised me to stay with the E85 40/60 mix (originally I was thinking a minimum of 50/50) keeping safety and reliability a priority while still trying to get me MY POWER WHICH I JUST HAD TO HAVE! lol…

It’s great having a local guy that can get in the car with you while you do the pulls, teach you the correct way to datalog, explain the process, etc. etc. However, for folks thinking about etuning, my first time out with PTF was 32 degrees so the car kept breaking traction so we decided to finish my E85 map by corresponding through emails. It worked flawlessly. So don’t hesitate to etune with PTF, they KNOW what they’re doing.

Don’t criticize my video which I gave my son full permission to edit and make it a little fun. He did his best. Had trouble inserting the video, but below is the youtube link. Thanks.


553WHP 631WTQ – N54 TwinTurbo World Record – BMW 335i

Last night I hit the dyno to see what the car can do with the new ported N54 cylinder head, RB turbos, 3.5bar TMAP sensor from the new BMW N20 4cyl motor, FBO (catless), pump 94 octane and meth, stock turbo inlet pipes.

Key thing here, this is with a tune that sees ZERO Timing corrections everywhere on all cylinders and timing that is set right at MBT for this level of boost and this car’s given octane. I’ve run the car on the street with this exact setup this morning, number of pulls, its pretty ridiculous.

553WHP/631WTQ – PUMP GAS (94 Octane) + METH

In terms of the tune, it was running more than 22.5psi in midrange, 19.7psi peak at 6k rpm, 17.5-18psi at redline. Logs of actual boost in midrange aren’t available as I found out that ATP’s datalogging needs to be updated to accomodate the 3.5bar scaling. I was going off my p3 gauge for midrange boost when pushed past the 22.5psi datalogging limit. I don’t recommend this to anyone before ATP is updated for 3.5bar datalog scaling, it just had to be done last night and I decided to push on as I get to do what I feel is best for my car LOL and that’s make some power

No leanouts or fuel issues. LTFTs goes down to zero during the pull, STFTs trend to high negative 20s with meth. The car was running close to if not 100% meth, three 1.0mm nozzles, two of them in the FMIC outlet silicone coupler and another up in the ER charge pipe past the elbow.

I’ll be fine tuning things over the coming days but to be perfectly honest and blunt, last night was about turning things UP and NOT fine tuning. It was to find MBT and push boost as far as it can go while limiting wastegate duty cycle to about 73-74% everywhere especially past 6k rpm. It was also to experiment with various VANOS changes. I experimented with higher wg duty cycles before and RBs didn’t like it. It also introduces too much backpressure into the system even fully catless that the car doesn’t like it.

So, is there more power left here. We’ll see when the intake pipes are swapped for something better flowing. @[U][URL=”″%5DGeorge Smooth[/URL][/U] reported +19whp at his high altitude in South Africa so possibly another 20 in there without any changes. Then there’s mixing race gas or E85 into it to see if there’s anything there in terms of additional power through more timing. All out its very possible this will be a 575-585whp setup once all is said and done, dare I say 600 LOL

Other runs from last night:

By the way, on Smoothing of zero the car made 555WHP :) Nice even number easy to remember

When that torque hits it feels like a big turbo came on!! Swoooooosh!

First BMW DCT N54 (335iS) in the 11s and on stock run-flat tires, no meth!

Congratulations to KC for being the 1st 335iS DCT car to hit 11s in the 1/4 mile especially given this run was his first time at the dragstrip.

The run was done in style with windows down :) OEM Run Flat Tires, FBO, no meth and no DRs!

Simply amazing and good luck KC with your N54, you’ve got a strong runner! It was done at the Maryland International Raceway (MIR) yesterday, October 18, 2012 with weather conditions making for a DA in the mid 800s.

Below is KC’s review of the run from (

Hey guys! Our group, Bimmer Alliance and AAM customers (GTR’s and a turbo 350z) rented out a lane at Maryland International Raceway today from 9am to 5pm with unlimited runs. We all had a great time and and saw some amazing times put down. I wasn’t nearly as fast as those GTR’s, but I still ran a very respectable 11.92 1/4 on RFTs

Details can be found in the Drag Time sticky:…&postcount=279

Not too shabby for my first time! I did however have the windows down on that run, and should have pulled a 11.8x I think, and I’m gonna beat myself up over that one for a while, haha, but I’m very happy with my time! 

Special thanks go to PTF for the tune and special attention. Their AWESOME custom Cobb tunes got me where I am today!

Do I have the record on stock runflat tires, no meth, no upgraded turbos??

Here are my best two slips: