What ECU is the best?

A bit provocative question – and far too broad – in order to give you any simple answers. Basically, the most suitable ECU for your build is the one that suits the most for your preferences, which may vary a lot. Consider an ECU as an investment, where putting more money will get you both more features and quality in return. It is a return of investment. If you will break your engine due to lack of experience towards ECUs, their capability for warning limits and limp modes – it doesn’t matter – if you saved one or two thousand by selecting a cheap ECU in the first place.

The rule of thumb: If you are first timer, you will almost certainly buy a low quality ECU, regardless of all info provided on this blog article. If you are more experienced tuner, you most certainly recognize the importance of knock sensors, data logging, warning limits, extra connectivity and support, which more expensive ECUs will provide for you.

Let’s start with a common aftermarket ECU features. At first hand, these may seem minor issues on your list, but when time goes by, they will grow ever more important:

Checklist when buying an aftermarket ECU:

  1. Configurability of basic parameters (e.g. injector data)
  2. Ability to control IDLE QUALITY with hotter cams
  3. Ease of use and connectivity (e.g. stability, speed, future support)
  4. Longevity of both firmware and program support
  5. Quality and number of support in your country
  6. Number of extra inputs and outputs
  7. Number of knock sensors
  8. VE table configuration (a quite basic nowadays, thankfully)
  9. CAN support
  10. Full sequential support
  11. Warning limits
  12. High quality, wide band closed loop (For handling exceptions and monitoring)
  13. Ability to control up to x number of variable cams for your build
  14. Quality of data logging features: storing, reading and analyzing of data

One good example – actually a bad one – is Miller Warchip. They started with promising livechip feature for 1990’s bimmers, but when years passed on, company struggled to provide necessary support, leading to bad customer experience. If you still want to use Warchip, you are only good with legacy OS with legacy Java on Windows XP. ECU’s support for future upgrades is critical, thus you may have your build for decades. A financially stable company can provide you the best support for software upgrades in future.

How about tuning OEM ECUs? They can be divided into four main categories:

  1. Reprogrammable ECUs
  2. ECUs with add on ‘piggybacks’
  3. ECUs with livechip
  4. ECUs with switchable chip

The newer your OEM ECU, the easier it is to tune. What comes to M6x engines – they are type 2-4 ECUs. Most of us do prefer M60 OBD1 wiring harness and ECU, due to their simplicity for E30 swap. Thus ECU standards were under heavy development in 1990’s, you can face strange oddities in M6x ECU, like frequent EWS updates, or a sudden transition from OBD1 to OBD2. Generally speaking, ’99 model year is the milestone, when M6x engines were fully OBD2 compatible through KCAN interface. Luckily though, most M6x versions support live data logging through program called testo.exe, which I have explained here.

There is some evidence for BOSCH DME 3.3 ECUs having issues on both BMW M60 and Audi S6 engines on ’94 model year ECUs. Some of these, even with fully functioning live or custom chips can face strange oddities, if your build meets one or more criteria:

  • Your engine’s power range is extended to 7000-8000 and/or:
  • You are using bigger injectors, and/or:
  • Your stock MAF is not flowing enough, and/or:
  • You are using hotter cams -> a stock ECU cannot maintain idle -> an engine is stalling at traffic lights

Thus OEM M6x ECUs are somewhat limited for serious builds, it is advisable to turn your eyes on aftermarket ECUs. A bit surprisingly, OEM ECU can handle supercharging better, than building a hot street NA engine.

The problem most first timers lack to understand when selecting an ECU:

  1. ECU’s ability to control idle quality with hotter cams
  2. ECUS’s ability in normal driving conditions: cold start, cruise speed, stopping at traffic lights without stalling
  3. ECU’s ability to prevent a total disaster of your build: Setting up warning limits and limp modes

A list of warning limits any engine builder shall employ in order to trigger a limp mode:

  1. Continuous Oil pressure (OP) and temperature (OT) monitoring
  2. Continuous Fuel pressure (FP) monitoring
  3. Engine coolant temperature (CT) monitoring

In addition, following features must be monitored too:

  1. Knock detection for ignition compensation
  2. Warning limits for boost control (through MAC-valve)

Remember: the easiest part of your engine tune is to setup Wide Open Throttle (WOT) area of the map. It is the graph with nice looking power curve of your build. In reality, the most time consuming part is setting up an idle, cold start and driving quality for cruising conditions. And this is what you pay for.

Think about buying an ECU as an investment. By purchasing high quality parts, you can save big bucks in the long run, possibly avoiding a total disaster of your build.

Building a lightweight BMW M60/M62 engine

Did you know you can save up to 25 kilograms of an engine weight by selecting the lightweight components for your M60/62 build? This reduction can have a crucial effect for your E30 handling. Lighter, the better. Don’t be fooled by excessive weight of modern cars. They still follow the same laws of physics, no matter what marketing department puts us to think. Simply put, all modern BMW’s are too heavy for motorsport. They are not build for motorsport, as was E30 M3 in 1980s. And that is exactly the reason why we are tuning E30s. They are lightweight and offer you a unique driving experience – as if you are a part of a machine – a driving feel any reasonably priced modern car cannot offer for you. There is some lightweight hot hatches, but due to their FWD nature, they are excluded from the equation. Only on the day, when Formula One will switch to FWD, I can admit I was wrong with the amazing driveability, fun and excitiveness of FWDs…

So the weight is you worst enemy, thus your engine must be as light as possible, while providing an instant throttle response and a wide power range. Not so easy task, but doable for full aluminum V8 engine.

Please find below the table about the selection of the lightweight components, and their heavier counterparts:

Selection of lightweight components

Note 1: I excluded lightweight headers from the table, thus stock headers and lightweight custom headers are approx. the same weight, due to 4-1 nature of lightweight headers vs. stock headers with two primary pipes.

Note 2: Example above uses the lightweight hydrobooster from 7 and 8 series instead of a stock brake booster. This will have a double effect for your build:

  • No extra weight is moved forward
  • Hydrobooster is lighter than stock brake booster with a transfer kit

Note 3: Please note you can have further weight savings by:

  • Air condition delete
  • Catalytic converter delete (regulations will vary)
  • Keep windshield washer reservoir empty
  • Change bonnet to carbon fiber (-16kg)

With smart actions for weight saving, you can improve your V8 build’s handling substantially. Of course, there is more aggressive weight distribution tactics, like moving engine backwards, but I consider these too excessive for a street car. You can make your V8 behave like a dream by using the tips mentioned on this blog site. So how fast E30 V8 can be while cornering, if done right, you may ask? Probably faster, than your have the guts to put the pedal to the medal.

Performance tuning 101: Stop the guesswork and start measuring

Did you just click to my blog because you have been wasting hours and hours online, in order to find some crucial metrics for your build ?

My two cents: Stop wasting your time, and start measuring. This is a pretty basic knowledge, if you happen to have an engineering degree. Let’s have an example. You have been thinking if your fuel pump and lines has a sufficient flow for your build. Then you shall do the following:

  1. Attach 14 volts supply to your project cart,
  2. Detach a fuel line from a fuel rail,
  3. Find a bucket with measurement units,
  4. Bypass the fuel pump relay, and feed constant current to the pump,
  5. Measure how much your fuel pump and line will flow gasoline per minute (with 14 volts),
  6. Multiply this by 60,
  7. Done. Now you have the measured information about your fuel pump flow, in liters per hour.

Note: It is important to feed 14 volts to your fuel pump while measuring, thus this will increase the fuel pump flow compared to 12 volts, when your car is turned off.

Now you have the measured data of your fuel pump capacity. How about measuring a fuel consumption per hour in a full throttle then? This is a bit trickier to measure, because you need an access to live or logged data. The parameter we are looking is Engine Load (mg). This number will tell you how much your ECU is putting gasoline trough injectors per stroke.

Example variables for calculating fuel consumption:

  1. Engine load = 826 mg
  2. Revolutions per minute = 5900 rpm
  3. Two revolutions is required for a full power stroke

Calculation:

0,826g *5900rpm / 2 = 2437 grams of gasoline in a minute,

Whereas 1 litre of gasoline weighs 0,75 kilograms,

Thus fuel consumption is 2,437kg / 0,75kg = 3,29 l / minute

Fuel consumption per hour is 3,29 *60min = 197,5 litres per hour.

Now you have the exact, measured data. And we can tell, that your fuel pump shall have at least 200 litre per hour flow capacity + some overhead + reserve for future updates. In this example, 250 l/h pump would be a good choice.

Remember: stop guesswork and start measuring. It can take hours and hours of surfing on the internet, and yet – you have only assumptions – meanwhile you could be measuring e.g. a real capacity of your fuel pump.

My friend gave me a reminder after reading this article: fuel flow is in relation to fuel pressure. There is good charts out there about the correlation, like the one from tanksinc.com. More pressure will decrease a pump flow, so remember to put enough overhead for your calculations.

Stop the guesswork and start measuring. Today.

Performance tuning 101 for a naturally aspirated engine: There is no shortcuts

Lately, there has been a trend among experienced tuners to turn their eyes back to naturally aspirated engines, thanks to their ever challenging and unforgiving nature. Their is just something fascinating in a high revving naturally aspirated engine, especially in a V8.

Let’s admit: If you are interested in maximizing horsepower: buy a turbocharger. It is the easiest way to add power to your engine. But if you are like me, you are not interested in max hp. You may be allergic to turbolag, and interested in faster-than-light throttle response, in order to maximize the traction and driveability. Mate, this is the right blog for you. It is not about maximum hoos pauwo. It is about maximizing your fun, while you are driving along 101 on a west coast, or where ever you are enjoying your E30. In these situations, 300 to 400 engine horsepower and steady 400-500 nm of engine torque is much better than a galaxy exploding power curve. On rear wheels with 4th gear it means approx. 1500-1900nm of torque, if you are using a 5 speed ZF S5D310 and 3.15:1 ratio differential. You can consider 2000nm of rear wheel torque the upper safe limit for twisty (and both dry and clean) roads with 225 semi slicks. Just put the fourth gear on, and start enjoying.

The general idea is, that you may seek for more speed, but you may not be able to put any extra torque to rear wheels, or otherwise you may loose traction. This seems to be pretty tricky for folks to understand. It is the torque on rear tires that makes your driving either fun, or scary and difficult. And that’s why an electric car can be very fast on a track: they are providing steady torque, without any interruptions whatsoever. It means they are easy and logical to drive up to the limit. It is the same reason, why modern BMW diesels have even four turbochargers.

If you are living in the U.S, its pretty straightforward to install a LS engine into your E30, and start enjoying. While in Europe, M6x is popular swap due to a high number of potential engine donors available. And that makes it interesting tuning project for E30. With a basic M6x swap, you can get up to 286 hp for your E30. So your motives to build an engine swap may vary where you live at. M6x is very capable engine, and will response into a tune like any other engine.

Why not M5x then? the V8 has both more displacement and valve area than its little sister – making it the better choice for a NA build. There is no replacement for displacement – the V8 is basically a two four pot 16-valve 318is engines in the same. But if you are going to turbocharge your engine, the six pot can be better starting point, thus its much cheaper to rebuild with forced internals. Turbocharging M6x is more expensive, requires high demand from powertrain, and all these will add tens of kilograms of unnecessary weight on a front axle.

If you are about to keep your engine NA – go for V8 – and keep it as light as possible, thus it is one of the keys for good handling. Even among NA M6x builds, you can save up to 27 kilograms from a front axle, only by making smart decisions for your build. But V8 is still so heavy, you may say. Well, it can be either a true or false. A well built M6x swap is equal in weight to a stock E30 325i. I know this, because I’m a guy with two engineering degrees, and being taught to measure, before start making any hypothesis. In full driving condition, including all fluids and 3/4 of gasoline E30 weights 1180kg with M60 engine. It is in the par with the stock E30 325i. It is a bit of a surprise, but M6x cylinder block is lighter, weighing only 28 kilograms, than a good old four pot M10 block. The name of the game is aluminum.

A good reminder if you are first-timer in performance tuning, please repeat with me: A naturally aspirated engine is as strong as its weakest link. So tuning a NA engine is like drinking a fine vine: there is no shortcuts in the making. Repeat with me: there is no single shortcut. Not only horsepower figures, but also the quality of your build through lightweight parts has to be taken into account. Many times the information from public bimmer forums is limited what comes to NA M6x performance tuning. You must face it: Tuning a naturally aspirated engine is an expensive task. If you have extra penny to spend for performance tuning, then go for it. If you don’t have, it may be advisable to stick with a stock engine.


INPA connection problems explained in layman’s terms

INPA is a great tool for bimmer enthusiast for diagnosing E-series. Thus information is scattered around internet, it can be pretty difficult to understand which version and cable works in which series of a car. Let’s bust the myth, and explain this in layman’s terms.

EDIABAS: The server program needed to establish a connection in between your car and INPA. ISTA+ can utilize EDIABIAS too for E-series, namely E9x.

INPA: Factory level diagnosis tool developed by Bayerische Motoren Werke for E-series bimmers. INPA needs EDIABAS and appropriate cable to work.

ADS Cable: Early data transfer protocol for EDIABAS. Specific rounded ADS cable is needed for late 1980’s cars up to 1995, typically for cars with M50 or M60 engines. One example is a cable called TinyADS.

K-line or KCAN: Data transfer protocol for early OBD1 and OBD2 compliant cars, like late E36, E38 and E46. A modern K/DCAN cable is compatible with both data transfer protocols. Use rounded adapter to connect K/DCAN cable to OBD1 diagnostic plug, like found on E36. E38 model year 1999 has well-hidden OBD2 compliant port in a dash, in front of a gear lever.

DCAN: Faster data transfer protocol for late OBD2 compliant E-series cars, like E9x. Note: DCAN configured INPA (Remember, it is EDIABAS which creates the connection) cannot establish a connection to KCAN compatible car, like E38. The solution is described below.

Common problems and solutions:

  1. You need more tricks than just tapping a switch in a cable in between K and DCAN. You must configure K or D can protocol accordingly for EDIABAS by using a program called D-CAN.exe
  2. C:\Windows\Obd.ini: Com1 port must be set correctly.
  3. C:\EDIABAS\EDIABAS.ini: Interface must be set either INTERFACE =ADS or INTERFACE =STD:OBD
  4. Although Windows may find FTDI drivers for a K/DCAN cable, the version Windows is installing may not be compatible with EDIABAS. Install other FTDI drivers, e.g. these from ftdichip.com
  5. INPA version may be faulty, try a different version.
  6. You bought a faulty cable. E.g. I was wasting a week for configuring INPA for a faulty cable. Very frustrating.

If ADS is not working:

  1. You do not have an ADS compliant cable. The most probable reason is that someone sold you a dummy cable without the circuit inside the rounded end, which is needed for establishing a connection.
  2. ADSsetup must be run from EDIABAS/Hardware/ADS/ADS32 folder. If you do not have this folder, you may have the latest version of INPA/EDIABAS which is not compatible with ADS protocol. Install earlier version of INPA and EDIABAS, containing support for ADS data protocol in the corresponding folder.
  3. IRQ address in COM1 port may be wrong on your laptop. Change IRQ address to 4.
  4. Hardware address in COM1 port may be wrong on your laptop. Change HW address manually to 03F8.
  5. If you cannot change the IRQ address, turn of all unnecessary devices on your laptop, and try again.
  6. If you cannot change the HW address, use program called adsport.exe in order to manipulate EDIABAS configuration file called ads32.dll, and setup HW address according to your laptop.
  7. Enjoy!
Diagnostics information from DME 3.3 module through ADS cable. Tank ventilation error is a typical for engine swaps, thus E30 does not have any sensors for it.

M60 stock crankcase ventilation valve problem: its design fault and insufficiency for performance tuning

There are excellent articles out there about faulty Positive Crankcase Ventilation (PCV) systems, like the one on Timm’s BMW E38 Repairs and information page. PCV or Crankcase Ventilation System (CCV) is basically the same valve with a different name, only acronyms may vary.

This article is from the perspective of performance tuning. If you are about to install hotter cams, raise compression or rev limiter, it is important to understand the design flaw in a stock M60 PCV system. The described mods typically increase engine performance, but also put more stress – and blowby – through the engine. These blow-by gases are the reason, why there is a system called Positive Crankcase Ventilation in the first place. Thus, when you increase stress to your engine by increasing both compression and rpm, you will increase the amount of leaking gases to a crankcase. This will put increased demand to PCV system to do its job.

Unfortunately, the stock M60 CCV design is faulty from the factory. It does not matter if you replace the item with a new one – it is not up to its task, more less when you are doing any performance upgrades.

The main havoc for the stock PCV system is the design: all gases and residue will accumulate in the front of cylinder 8 runner. When there is enough sludge, and you accelerate hard at the same time, the cylinder in question will gulp all the residue into the combustion chamber. The result is pretty obvious: the Pope like white smoke is a testimony of compromised combustion chamber process, with excess oil.

M60 intake cover with Positive Crankcase Valve, PCV. Sludge will build up next to a cylinder 8 runner, and eventually find its way to the cylinder like a big gulp. Hence the occasional white smoke, when accelerating hard to a highway.

Installing an oil catch tank

One option is to bypass the stock PCV valve, and install an oil catch tank for residual gases. This can be done by modifying the stock PCV valve, and rerouting gasses to the tank. Other option is to purchase a new rear plate for intake manifold. The oil catch tank was acquired from BjörkMotorsport.

Rerouting a stock PCV valve for external oil catch tank.

Oil catch tank in place.

M60/M62 tuning: An intake manifold upgrade

The factory has provided at least four different intake manifolds for both M60 and M62 engines. If you have studied anything about airflow, its obvious to select the manifold with the best possible velocity stacks for optimizing the engine performance. Velocity stacks – also called as trumpets or horns – can increase maximum airflow approx 2-4 %, but the benefit may be even higher in mid-range torque due to intake resonance. The science behind trumpets is their ability to smooth out incoming air, maximizing airflow to intake runners.

Source: Wikipedia, Velocity stack detail.gif, credit for user Motorhead.
Picture published under GNU Free Documentation License.

Disclaimer: tuning a naturally aspirated engine is as strong as its weakest link. Cams, valves, cylinder head, headers, collector – and most definitely “the hot air intake system” may be hindering down the power and torque in your build. Thus, the benefit of changing the manifold depends on both level and quality of modifications you have made for your car.

Different intake manifold versions:

M60B30 and M62B35 – These are with smaller runners, so we will forget these.

M60B40 model year 1992 – Large runners with the best velocity stacks

M62B44 Nonvanos – Large runners with minor bends at intake runners

B62B44 Vanos – Version with small runners, so we will forget these too

The best option: Ultra rare M60B40 model year 1992 manifold with proper velocity stacks for maximum air flow.
The second best option: M62B44 Nonvanos intake. Note the pipe in the middle for distributing blowby gasses more evenly to all cylinders. You can read more information about Crankcase ventilation design fault from the other blog article.

There are four hypothesis, why BMW quit developing 1992 version of the manifold so soon:

  1. Factory may have wanted the best possible features and grunt for intimidating the press, when the new M60 V8 engine was introduced.
  2. Guys at the department of finance wanted to cut some costs. We know how expensive these engines are to build. Take for example M60 timing gear with duplex chain. The level of design and robustness is closer to a tank.
  3. Velocity stacks are prone to get loose. Simply put – why bother, if you can cope without them, and avoid any warranty issues.
  4. E34 540i may have been too close in terms of performance to E34 M5. Please check the youtube video about the matter.

Upgrading an improved instrument cluster for E30

A great way to improve your car’s interior, while retaining a stock look is to make retrofittings and OEM style upgrades. These installations are the ones your friend will never know apart from the factory look. One of these upgrades is the instrument cluster. I wanted more sporty interior look, thus I started looking for M3 style instrument cluster, which would be compatible with V8 tacho. Also wanted to upgrade both speedometer and tacho readings up to 280km/h and 8000rpm, respectively.

German company called Maustech was selling a suitable instrument cluster for V8 swaps. It is imitating the stock M3 looks with customizable options to both dials. The cluster is displaying an oil temp instead of fuel consumption. The temperature sensor is included, and can be installed into the oil sump pan. Instrument cluster was a perfect fit, no hassle whatsoever.

Maustech instrument cluster for a V8 engine with 280km/h and 8000rpm readings.
Stock E30 instrument cluster before modifications.
Instrument cluster for E30 with 280km/h speedometer, 8000rpm tacho and oil temp.

Restoring the Driver’s Seat

Ripped Driver’s seat is a typical view on E30 nowadays. Because I wanted to keep the factory look, my first task was to find some new fabric. Stock upholstery for M-technic interior is Anthrazit, code 0269. Orginal BMW number is 8106096. It is also advisable to change the pneumatic cylinders. The corresponding part numbers can be found on bmwfans.info.  Availability may vary.

A typical, worn out E30 driver’s seat.

I just happened to remember an announcement a while back, where other bimmer enthusiast mentioned he had some extra fabric for the sport seats. Luckily I still had his phone number, and gave him a call. It came out he had bought the fabric from New Zealand. Can you believe it? First you manufacture some fabrics in Europe, carry them over to opposite part of the world, and then buy them back to Europe. If communism would have won, we’d just drive along with red colored Ladas, so its better to stick with capitalism, and buy the fabrics while there is some available – nevertheless the price.

The place I ordered the upholstery was Le Mans Autofabrics. They wanted a picture from the old seats, in order to make sure they will send me the right item. Kudos for Kosta at Le Mans Autofabrics for a good service.


M-technic 2 sport seats color code is Anthrazit, code 0269. The new fabric from Le Mans Autofabrics, NZ.
A ripped seat with a sunburn.
The updated interior looks as good as new.

Analyzing the livedata from you bimmer with testo.exe

My friend called me yesterday. His bimmer started displaying the infamous Check Engine Light. The car in question was an E38 with magnificent M62 engine. The program I found very useful for logging livedata is called testo.exe. This program lets you to both display and save livedata to your laptop. Very handy DIY diagnostics tool, indeed. In order to install, you shall have sufficient computer skills, this is not a standalone program! Testo.exe requires a server program called EDIABAS for establishing a connection in between your laptop and OBD port. You need also OBD I and II compliant K+DCAN cable for your bimmer. Download: http://phenoboy.kapsi.fi/testo 

Edit: there is also a standalone version, which does not need EDIABAS: http://phenoboy.kapsi.fi/testo/testo-2016-09-21-standalone.zip
Edit EdiabasLib.config file to change the appropriate COM port.

Testo.exe providing livedata from M62 engine

Fixing the driveability issues, Part 4: The Endgame

Note: if you have not read my previous posts, I suggest you to start with the Part 1.

When I bought the E30, it felt almost undrivable and plain dangerous in higher speeds. Thus, it was quite obvious I had to spent the first driving season to improve its handling. The list below is summing up the modifications I made for the E30 during summer 2015:

  • Correcting the suspension geometry and roll center by installing custom made raiser plates,
  • Raising the car approx. three times,
  • Decreasing negative camber on the front by installing eccentric upper strut mounts,
  • Increasing offset on the front by machining rims,
  • Zeroing toe on the front,
  • Increasing traction by changing tires to Toyo R888R Semi Slicks.

At times I was wondering if the V8 engine is too heavy, and despite of all the changes, non of the above tricks will work. But the engine was not the case. And M60 engine is all aluminum, and with small tricks here and there you can save tens of kilograms. But that’s the other story. So what was the end result? I use my daily commuter as the reference point. It is 2009 BMW 335d LCI with factory M-sports aerodynamic kit, M-sport suspension and OEM 18″ alloy wheels. So the reference car is representing a pretty darn good car design from 21st century.

So how does the E30 compare to the 335? Well, I can honestly say – because I own both cars – that the E30 will beat mighty 335 in EVERY aspect of driving. The E30 is more agile, has better feel for road and – what’s most important – is more fun to drive. I cannot say that the 335 is a bad car to drive. No way. I was driving through Norway with the 335 in summer 2018, and it was a great pleasure to drive with a ton of torque in twisty serpentine roads. Of course, there is some features the 335 is missing like limited slip differential, which actually makes a huge favor for the E30. I know, it is a bit unfair comparison, due to the E30 has a custom built race differential in it.

The reference car was 335d with OEM 18″ rims and ContiSportContact 5 tyres, 225/255 in size.

So the E30 is more fun to drive on twisty roads. OK, we can accept that, because it is around 400 kilograms lighter than the 335. But how about high speed stability after the mods? I got an opportunity to test both cars on a airstrip, and oh boy, that was a great fun! It was a windy day, and I was a bit frightened to try the E30, because I had no idea if it will either start flying off from the airstrip, or keep going like it should be. The result was, that in 250km/h speed I did not notice any wind or unbalance when I was driving the E30. Actually I was watching the speedometer and using only one hand on a steering wheel. While on the 335 I noticed the wind, and had to put both hands on a steering wheel. Do you believe it? A 30 years old Bayerische Motoren Werke is beating 20 years and three generations newer 335 in high speed stability too. The handling in my E30 seems to be working. Amen.

This picture is a good example of well designed front spoiler, preventing the air to go underside of the car. The end result is increased downforce and high speed stability.

Fixing the driveability issues, Part 3: Tires and Rim Offset

Note: if you have not read my previous posts, I suggest you to start with the Part 1.

On the first and the second part of “Fixing the driveability issues” I was concentrating my efforts to correct erroneous suspension geometry. Now, when the suspension geometry was set up correctly, I shifted my focus to both tires and rim offset.

Part one and two were just the basic stuff. Most of us do understand the importance of fixing camber and toe. But for some reason, most of use are neglecting the importance of tires and rim offset.

If you think about what single component is responsible in between your car and road, it should be quite obvious that optimizing the tire quality will give you the best bang for the buck. I mean seriously. The best possible performance upgrade for your car is not 20 000 euros suspension kit. It is tires. Period. The quality of rubber compound makes the most difference. It does not matter how wide your rear tires are either, if their compound is not up to the task. Good semi slicks in 225 size will beat any budget tires in 275 size. Anytime. The difference of tire compound quality is huge. You just don’t believe it – until you will try it out.

Toyo R888R Semi slick tires in 225/45/16 size.

In order to improve handling characteristics even more, I decided to change the rim offset a bit. The rims are very rare and good looking RIAL mesh style in 8×16″ size for front and 9×16″ for rear. The front ET was 13, and it made the steering a bit nervous, thus I ended up machining 2 millimeters from the rim center. So the front ET was increased to approx. 15. Believe me or not, it made the difference. The rear ET was also increased to 15, due to a clearance issue with Toyo Semis. This issues was present with rolled fenders. Rears in 225/45/16 size with 9″ rims and ET15 are pretty tight fit for stock E30.

Toyo R888R 195/50/16 tires on 8″ Rial Mesh rims, ET15, made in West Germany.

Fixing the driveability issues, Part 2: Camber and Toe

Note: if you have not read my previous post, I suggest you start with the Part 1.

Because This was my third E30, I already knew how challenging this small boxy bimmer can be with both suspension and tire setups. On part one, I was able to correct some of the suspension geometry challenges by installing custom made raiser plates.

There was still too much negative camber on front tires, though raising fixed the issue on rear axle. The solution for front tires was to move upper strut outwards. Typically you have two options: either install an adjustable uniball strut mounts or select a fixed one. The advantage of uniball mounts is adjustability, but on the downside it will transfer more load and road irregularities to chassis. Uniball is great for a track use, but not so great idea for bumpy countryside roads. So I wanted rubber strut mounts that were able to adjust camber. The Solution was OEM BMW upper strut mounts with +/- 0,5 degrees of Camber Correction. These are more sturdy than OEM mounts, and raises your car a bit too. That was only welcomed feature for my E30, described on previous blog post. OEM part number for the rubber mounts is 31 33 1 139 484. Note: These OEM rubber mounts are actually more expensive than Uniball strut mounts.

Eccentric upper strut mounts for E30, OEM number: 31 33 1 139 484

Actually, I never took my car into any car service for toe adjustment. Instead, I adjusted the toe manually. I set up a string in between pair of Jacks, and aligned them as close as possible to both rear and front wheels. Then measuring the toe was easy task by using a vernier caliper. I put toe to zero. It is a good compromise in between cornering and high speed stability. Using a string is quite simple method, and surprisingly accurate. Don’t laugh. They use this same trick for WRC cars too.

Take home points:

  • Looking cool is not equal to going faster.
  • Do not add too much negative camber for street use, it will only make your car unpredictable and dangerous.
  • Adjusting toe is surprisingly easy at home garage with pair of jacks, a string and a vernier caliper.
  • Choose upper strut mounts based on the usage. Rubber mounts can be better for street use, uniballs for track. Choose wisely.

Fixing the driveability issues, Part 1: Suspension Geometry

When I bought the car, I really loved the sound and responsiveness of the V8 engine. But the handling was plain awful. I spent the first driving season by fixing and optimizing the driveability. The main reason for bad handling was obvious: the suspension was set too low, causing multiple issues in suspension geometry. At times, I was blaming the V8 engine to be too heavy for E30 chassis. This was to be proven wrong hypothesis.

Effects of lowering E30 too much can result into following:

Front:

Increased (static) negative camber,

Control arms in wrong position 1: roll center gets worse,

Control arms in wrong position 2: decreased (dynamic) negative camber while cornering,

Rear:

Fixed semi-trailing arms in the rear axle will increase both negative camber and toe in.

The suspension appeared to be designed for a stance car, although it was high quality components from KW, full Variante 1 kit. All bushings had been changed to Powerflex, thus those were not the problem either. Even on its highest setting the car was too low, resulting into wrong suspension arm geometry. The strut threading allowed you to set the car from low to below the ground. That was ridiculous.

The fix: I had to add custom made raiser plates made of nylon in order to extend the springs.

Custom made raiser plates made of nylon.
KW Variante 1 coilovers with a raiser plate attached to an eccentric upper strut mount. Note the markings in the coil stands for linear race spring (70N/mm), 140 is the height in mm. Helper spring is placed above the main spring. Its only function is to keep the main spring attached, while car is lifted. Helper is 20-60-80, meaning 20N/mm, 60mm inner diameter and 80mm of height. 

Oh Mighty V8, my New Black

Thanks to climate change and ever tightening CO emissions, almost every new car has a turbocharger of some sort. Well, this is understandable, thus car factories must improve engine efficiency, reduce fuel consumption and co-emissions. Turbocharger is a well suited component for any combustion engine, a pure necessity to tackle CO emissions and climate change. And that’s a great thing for our friend earth.

I was very interested in to build turbocharged engines in year 2000, 19 years ago. It was a time, when turbocharging an engine was an accomplishment. It was something that was not common, or standard. There was a lack of information, the first affordable aftermarket ECU’s were just about to roll out soon. Noways – it is just too easy to turbocharge any modern 4-cylinder valve engine. People don’t get interested anymore, if you start turbocharging an M50 or M52 BMW engine. It is just another turbo build on a discussion forum. 400, 500 or 600 hp – nobody cares.

My daily commuter has two turbochargers, too. It should provide enough excitement. But like other modern cars, it is heavy and sterile, although being one of the best rear wheel drive BMW diesels ever built, a mighty 335d. But still, it doesn’t quite have that immediate feel of road. A good car for commuting, but not for a car enthusiast.

In 2015, after having three cabriolets as my summer cars, it was a time to get back to 2D saloon. I just lost my interest in cabriolets. This time I shall find something new and exciting, so I started looking for E30 saloons. Oh boy, it was an immediate love at first sight, when I saw an advertisement of Alpine White 325i M-tech with V8 engine. The idea of V8 in E30 was something sexy, as was turbocharging and cabriolets before, a taste of exclusivity. Again a purchase I could not reason, a decision based solely to my feelings. You know, this bimmer was one of those must-have investments. Have not been regretting it, since the prices of good individuals have increased in past four years approx. 30-50%

325i M-technic 2 with M60 V8 engine.

Prologue: Once upon a time there was a turbocharged engine…

Turbocharged M10 engine in 2003

Actually my ambition for engines started a way before the engine in the picture was built. Back in 1996, the first engine was a naturally aspirated BMW M10 2,0 engine with hotter cams, 4-2-1 headers and Solex four barrel carburetors. So it was a pretty standard tune, around 150-160hp. Afterwards, it was a good school to understand the basics of engine building. And a good reminder, how demanding it is to increase power in a naturally aspirated engine for a daily driver.

In 2000, I built my first turbocharged BMW E30 with M10 engine. Initial version was a 1,8 litre M10 without intercooler, just a basic built with a better clutch. Back in the days, there was a lack for both modern and budget friendly engine management systems, thus I ended up using a modified Turbo Saab K-jetronic injection.

Second evolution turbo engine was 1,8 litre M10 with intercooler and water/methanol injection, and a turbo from 4WD Sierra Cosworth. K-jetronic got also a companion from Haltech piggyback. After wasting one cylinder head with knocking, I decided to improve the engine management system with a knock detection system. It was also from Saab, a system called APC, Automatic Power Control. Well, it was the analog system back in the days, but I was able to find one from a scrapyard, with little to no cost. I just upgraded the box (with soldering and changing resistors) with Turbo Saab’s track settings, making it a very budget friendly purchase. It was able to read knock signal from the M10 block and adjust the boost pressure according to knock level, and a potentiometer in a dasboard. Pretty cool system back in 2001.

The Third and the final evolution of the turbocharged engine, in the picture, was stroked M10 engine with 2054cc displacement, better headers, ported head, increased compression ratio and a hotter cam. The cylinder head I ended up using was from the naturally aspirated engine in 1996-1999. At the time, it had the most modern turbocharger (at least the price was very high, remember it being around 1200 euros), custom built hybrid Garrett TB03/04. What started as a modest, low budget engine ended up having the engine with a really nice torque and power band. For some reason, I have been always very allergic for any turbo lag, the phenomena I always wanted to get rid of. This engine version developed 0,2 bar boost on 2000 rpm, had 1 bar of boost in 3000 rpm, while maximum boost being 1,2 bar. The engine revved up happily to 6600rpm redline. It was very drivable engine for twisty roads with no turbolag, a fast enough in a car weighing only 1030 kilograms.

Take Home points:

  • Use knock detection and automatic boost control for gasoline engines,
  • Use wideband lambda for AFR measurement,
  • Use exhaust gas temperature, EGT measuring for optimal power,
  • Don’t forget Intake Air Temperature, IAT measuring,
  • Avoid too low compression ratio,
  • Aim for bast burning characteristics,
  • Use proper oil cooling solutions for both engine and differential,
  • Remember the importance of Engine Management Systems: Aim for easy tuning and data logging.