BMW E34 Tuning

"Thank you for reading this BMW E34 tuning tips."

BMW E34 is the 3^rd generation of BMW 5 Series, Which was manufactured from 2^nd November 1987 until 1996. It was launched as a sedan in January 1988, the E34 also saw a “Touring” station wagon body style added in September 1992 and it remained until June 1996.

As many of our site visitors have asked about the E34 and recommendations on how to modify one, so we've created this how to guide to go over what we feel are the primary areas which make for improvement and tuning success on this engine.

The E34 is a good project car to have and the M5 shows what this chassis is capable of. The key to E34 tuning is balancing power and reliability you can waste loads of money if you do it wrong. In this article, we shall give a limited introduction to the best performance parts for your car, but we'd encourage you to spend some time on the site looking into the details of each type of performance part.

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E34 Power mods.

Please watch our video which covers the 5 principles of tuning your E34. Be sure to keep up with our latest YouTube content and subscribe.

Best mods for your E34

1. Turbo upgrades - A New Turbo is the most dramatic method to increase your intakes air supply, allowing you to burn more fuel and make higher power. It is one of the most expensive upgrades it offers big gains.
2. Intake Mods and Exhaust Upgrades - Please note that on their own these mods will NOT ADD POWER in most cases, but they can help enhance power after other mods by lessening the restriction.
3. E34 Handling Mods (suspension) - Fitting a more sporty Suspension kit radically improves your E34 handling Coilovers and Bushings are the usual go to mods
4. Internal engine mods - crank, pistons, conrods & compression ratio including balancing and blueprinting
5. Flywheel lightening - a lower weight flywheel will improve the engines rev changes. But not always suitable for all E34 engines.
6. Fast road Camshafts are generally the biggest mechanical mod upgrade, but they must be installed by someone who knows what they are doing and tracking one down may be hard but you might have a local firm to regrind a stock cam for you.
7. Braking Mods - Improve your ability to stop ought to be near the top of your Mods list.
8. Remaps - A tune/remap ensures the most advantage compared to cost, replacement ECUs, and piggyback ECUs are all alternatives.

E34 Tuning Stages

Typical stage 1 mods often include: Alloy wheels, Lighter flywheel, Suspension upgrade (drop 28mm - 35 mm.), Engine Tunes/Remapping, Panel air filter, Sports exhaust.

Typical stage 2 mods often include: high flow fuel injector, Power/Sport clutch, fuel pump upgrades, Fast road cam, Ported and polished head.

Typical stage 3 mods often include: Engine balancing, Competition cam, Adding or upgrading forced induction (turbo/supercharger), Internal engine upgrades (pistons/head/valves), Sports gearbox.

Our goal when modding the engine should be a wide torque curve. You want to avoid sending all the power to be at the top end unless you are creating a competition car.

E34 Handling/Suspension upgrades

Many E34 owners uprate the handling of their cars with modified suspension parts as a priority, this will certainly increase your enjoyment of the car.

If you set the toe out to 0.9 to 1.5 degrees on the front, and add a little negative camber then cornering will often improve.

Running our vehicle on stock height is very good if it is used by the family but if you are also a car enthusiast and you love modifying your car so you should probably go for MSport Suspension which can easily drop up to 20mm to 25mm and stiffens things up.

The suspension improves traction and handling pretty much. Extremely lowering our car can cause the suspension to contact other things around it or rub with the car's body or with speed bumps, Which can damage the vehicle from beneath or make the oil tank leak if it is rubbed roughly.

These are a few lowering suspension kits available:D2 Racing, Belltech, MaxTrac Suspension, AST Suspension, Tein, Bilstein

The three primary types of suspension are Lowering Suspension kits (harder shorter springs and firmer dampers), Coilovers (these can allow fine tuning of ride height and spring characteristics and would be our recommendation for your E34, and finally Air & Hydraulic Suspension kits that allow the ride height to be adjusted from inside the car.

The latter is suitable for "show cars" where you want to hide the tops of the wheels in the arches, but still need to drive the car to the show over speed bumps and potholes. The ride is generally much softer and there is often more bodyroll with these kits though, so we wouldn't be recommending it as a performance mod.

We suggest that you fit modified suspension and lower the car by 28mm - 35 mm. Larger drops require arch work - especially on models already equipped with motorsport suspension.

E34 Brake upgrades

The brake we install on our car has a great influence on how the car handles and brakes at the right point. When we are looking into gaining more horsepower the brakes should be our priority and they should be upgraded as soon as possible. Safety should be seen first without any hesitation and we should not compromise on a performance car.

For sharper enhanced stopping put better performance pads and match this with larger brake discs.

Bear in mind that motorsport pads will be noisy and will have to be hot before they bite.

On your regular commute to work the brakes are occasionally used so will not stop you as well so source friction pads that have a low working temperature.

Top end torque should be your overall aim with a nice fat wide peak torque band.

There are many types of brake’s available in our market, Which is specially built for a performance car.

• Brembo calipers
•  Hawk motorsport BBK
•  ATE brake disc
•  Stop tech calipers ST60(Race brake set)

Your choice of disk size is limited by your alloy size, with the 16" wheels just about coping with 324mm and the 17" are good for the 345mm.

A few E34 owners have used the E31, E32 and E34 brakes with the M series brakes giving much better performance. It would appear that E38 and E39 brakes will not fit the E34, due to the rotor posts and carrier mounting holes being relocated.

But watch your rotor sizes and choose your pads carefully. Raybestos, EBC Greenstuff and Pagid pads are all rated and recommended for street use, but for the track you might want to go to EBC Yellowsuff or Hawk HT10 (neither of which we recommend for road use due to their high operating temperatures.

Smaller engines do not provide much of a return in terms of power so start with a bigger engine. Engine swaps are a good option if you have a small engine size.

E34 engine tuning mods.

This list of the stages and parts are usually fitted by our members, decide how far you want to push your car before you get started.

We have forked this page out with some engine specific guides as the approach to tuning does vary between them, we will continue with general E34 tuning suggestion on this page though, and we welcome your feedback and tips so we can improve this article for your fellow E34 owners.

E34 Petrol:

• 1.8 L M40/M43 I4
• 2.0-3.8 L M20/M50/M30/wI6
• 3.0-4.0 L M60 V8

E34 Diesel (turbocharged):

• 2.4-2.5 L M21/M51 I6

Getting the best performance mods for your planned usage of the car is vital. Stage 3 motor sport parts just won't work well on the road difficult in stop start traffic. Power ranges from 101hp to 305hp, and shows how flexible the E34 platform is.

E34 remaps

Remaps offer significant power gains on all turbo charged cars. On NA (naturally aspirated) engines the benefits are doubtful. However a tune/remap on a NA (naturally aspirated) engine will help unleash the potential if you have done a lot of mods.

On a stock car with no other mods we would expect dyno tuning can give an easy 10-20 horsepower although this will depend on the engine you have in your E34.

On an E34 with other mods tunes or remaps and dyno tuning can give an additional 50 horsepower, it really does help unlock the power from all those mods you have done.

Fast road cams offer one of the biggest bhp gains for your money as far as a stand alone performance parts goes on a NA (naturally aspirated) engine.

E34 fuelling upgrades

Don't forget to pay attention to the fuelling when you are increasing the power - it makes the car more thirsty.

Most power losses, flat spots and erratic idling after mods are done can usually be traced to timing or fuelling issues. Improving the injectors is another beneficial modification and will deliver sufficient fuel.

Fuel pressure regulator improvements can improve the throttle response and in some cases can improve fuel supply and delivery through the injectors, but it won't add much power on it's own it does improve the characteristics of your E34.

Uprate the fuel pump to cope with the extra fuel requirements of your tuned E34's uprated injectors.

E34 Intake and Exhaust Mods.

Breathing mods are usually next up. The exhaust and intake flow play a large part in your cars power band, but be careful here, getting this wrong can upset the idle and make the car hard to drive in traffic. You'd need to follow a cam upgrade with other mods and finish with a reflashed ECU to fully release the power gain.

Getting air into the engine and expelling the exhaust gases are often sites for bottlenecks and restrictions.

Getting a professionally gas flowed head with larger valves can fully release the engines power. A good triple plate fast road performance clutch will help to keep that power going where it should. Never cut corners or assume a standard OEM clutch to cope. The best mods we would do for your E34 are remaps, sports camshafts and induction improvements.

So don't think of intake or exhaust mods as adding power, they merely remove a restriction, and in some cases these mods on their own can actually lose you power, particularly at the bottom end of your RPM range.

Please note that WE DO NOT FEEL YOU GET POWER GAINS FROM INDUCTION KITS, unless you have tuned your car massively and are finding that the standard air intake has become the bottleneck.

Derestricting the airflow into the engine is the primary part of performance tuning so get a freer flowing air filter if you find that the car is running lean. Induction kits can sound sporty but due to the warm air in the engine bay they will not do much to increase power and more often than not rob you of power on most cars.

Forced induction is a good way to make lots of extra power, but adding a turbocharger can be quite a complex project, please see the engine guides listed above for more specifics on each engine block used on the E34.

We've also seen some tuners toying with twincharging conversions and making some very high power gains.

Despite the large cost involved adding forced induction to a NA (naturally aspirated) engine will give large power gains. Turbos are generally harder to add than a supercharger. Turbos increase power in increasing proportion to the engine speed and this can make mapping difficult.

The nice steady boost and rpm characteristics of the supercharger make them more straightforward to map. Adding forced induction will often require a lower compression ratio or water injection.

Sports exhausts balance the flow of air through the engine. But if the exhaust is too big, ie: it's over 2.5 inches bore, you will lose a great deal of your flow rate and end up sapping power and torque.

Installing an aftermarket header helps us gain some power from which each “Runner”(Tube) is attached to it, Which helps us reduce noise from it.

An exhaust system help gases escape from the combustion chamber. The bigger the airflow the more power it will create. There are a few brands that crop up with E34 owners, but there are many others out there depending on your region and where you source parts from.

Generally speaking you should avoid the cheaper budget systems, you will get what you pay for when it comes to performance exhausts.

• Gibson
• JBA
• Magnaflow
• Gibson

Benefits from a performance exhaust system.

So what benefits do we get when we improve the flow through the exhaust and are there any drawbacks?

• Increases horsepower and torque, by removing the restriction in the airflow
• Larger diameter pipes with few bends and seams improves air flow
• Improved throttle response.
• Backpressure is minimized, but this can be a bad thing in some cases, losing power due to less exhaust scavenging
• Restore full torque (remember we are removing  a restriction, rather than adding power.

E34 Alloy wheel upgrades.

Due to the fact that alloys are lighter they improve performance and they will help to cool the brake disks. Don't forget that your choice of rubber greatly affects your cars grip and handling. It is not worth compromising performance with cheap tyres when you can buy track legal slick performance tires.

The downside to large alloy wheels on your E34 is that you're adding weight, and altering your effective final drive ratio so this will have a negative effect on acceleration.

The 16's are best suited to the early models, and many argue you get a better ride and improved handling characteristics on these, primarily due to the tire sizes you'll be using and the lower unsprung weight.

Due to this, endeavor to keep the overall rolling diameter of the wheel the same as supplied from the factory. In all cases avoid going over 17 inches. Typically the 18" alloy rims wheels are shod with 265/40zr18s and you have a wide selection of tread patterns and compounds to choose from so for track work we would probably stick a set of 18's on it.

Here in the Uk we would recommend an all season tire, as wet grip is quite important so we would probably go with 17's and use Michelins, Continentals or Pirelli.

For more information on Tuning your car please join us in our friendly forum where you can discuss E34 options in more detail with our E34 owners. It would also be worth reading our unbiased BMW tuning articles to get a full grasp of the benefits and drawbacks of each modification.

Please help us improve these tips by sending us your feedback in the comments box below.

We love to hear what our visitors have got up to and which mods work best for them on each model of car. We use your comments and feedback to improve the accuracy of these tuning guides which get regular updates and revisions.

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This article is flagged for an update, so please pass on specific tips below that I can include. All articles, and content was written by me, Waynne Smith TorqueCars founder. Some outlines are just too general so I appreciate your feedback and suggestions. This entry was filed under BMW. You can leave a response below or join our forum to discuss this article and car modification in detail with our members.

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