E34 Performance Upgrades

I recently bought a 1990 525i, the car is high mileage but great condition. I just put in a new timing belt and a bunch of gaskets. What are some relatively inexpensive upgrades I could put in it? Anything that would have a direct impact on horsepower and torque. I've been thinking about a chip but they seem to be pretty expensive for not a whole lot of benefit.

Originally Posted by Microtesties

I recently bought a 1990 525i, the car is high mileage but great condition. I just put in a new timing belt and a bunch of gaskets. What are some relatively inexpensive upgrades I could put in it? Anything that would have a direct impact on horsepower and torque. I've been thinking about a chip but they seem to be pretty expensive for not a whole lot of benefit.

If a chip is expensive, dont bother wasting your money on anything. M20s are not built for power gains. You can get an exhaust for some sporty sound to pretend like youre going faster but there isnt much to do for it...

I heard that an a lightened camshaft pulley made of aluminium and with timing adjustments would be a great way to decrease load on the engine and advance timing (or is it retard timing?) to experience more power in the engine using regular fuel alone.

Originally Posted by robertobaggio20

I heard that an a lightened camshaft pulley made of aluminium and with timing adjustments would be a great way to decrease load on the engine and advance timing (or is it retard timing?) to experience more power in the engine using regular fuel alone.

link to source?

Also, that'd be as much as a chip, and with way less performance gain.

Originally Posted by 95 E34

link to source?

Also, that'd be as much as a chip, and with way less performance gain.

Well no link to sources, just rumours backed up by logic. Lightened anything results in less load on the engine. And the m20 E34s, being more than 20 years old and without the ability to detect the quality of fuel being pumped in, would have been set by bmw to run without problems on the lowest grade gasoline in common use in that era....hence the timing improvements helping things.

But changing the timing via an adjustable camshaft pulley requires more expertise than a chip....a chip would be the best option imo.

Free flow exhaust and tidy up the suspension. Not slowing down for corners is like fast.

Originally Posted by Microtesties

I recently bought a 1990 525i, the car is high mileage but great condition. I just put in a new timing belt and a bunch of gaskets. What are some relatively inexpensive upgrades I could put in it? Anything that would have a direct impact on horsepower and torque. I've been thinking about a chip but they seem to be pretty expensive for not a whole lot of benefit.

One thing you could do would be to change as many of your engine pulleys to the thermoplastic equivalents, where available. These pulleys are 50% lighter than the aluminium versions and that helps a tad. Your old pulleys are probably dented or less than perfect in some way anyway, after 20 years, so this may be a good idea for that reason as well.

Secondly, remove the clutch fan and replace it with an electric fan. The clutch fan is only useful in slow traffic and jams. When the car is in motion, the onrushing air does a sufficient job of cooling it down. An electric fan shuts off at this point and stops its load on the alternator, which reduces its load on the engine. However, a clutch fan merely free spins a little....and still gives you more engine drag than the electric fan.

This has the additional benefit of reducing stress on the water pump (the water pump is connected to the clutch fan), which increases its service life and reduces the possibility of catastrophic wear (generally unlikely anyway).

You can also elect to do away with the clutch fan entirely without replacing it with an engine fan, if you change the resistor on your aux fan to a modern solid-state resistor, you check if your aux fan works at both speed settings (check the bentley manual for instructions) you can confirm that your coolant temperature sensor connected to the aux fan is working fine, and your fuses are in good shape (use the old hard plastic rather than the soft transparent plastic version).

All those pulley and fan mods must be good for 3hp (if that)? Exhaust mods and premium fuel would give more HP and mileage IMO? The car is only a 2.5, not 3.5 or 4. IT WILL NEVER BE QUICK NO MATTER WHAT YOU DO. Also it is old. Extra stress on old drive line not good.

Originally Posted by BMWFatherFigure

Free flow exhaust and tidy up the suspension. Not slowing down for corners is like fast.

This

If you want to play with the engine, do an M50/M52 conversion and then go from there. the M20 doesnt have a lot of good upgrade potential like the twin cam engines do

Originally Posted by _Ethrty-Andy_

This

If you want to play with the engine, do an M50/M52 conversion and then go from there. the M20 doesnt have a lot of good upgrade potential like the twin cam engines do

I have been thinking about doing an engine swap actually. My only concern with that is I assume I would need to get a new transmission also, unless they happen to fit together? Which I doubt. If you had to estimate a price on an m50 or m52 engine, transmission, harness, whatever else I'd need? Just a general estimate is good if you can.

Originally Posted by Microtesties

I have been thinking about doing an engine swap actually. My only concern with that is I assume I would need to get a new transmission also, unless they happen to fit together? Which I doubt. If you had to estimate a price on an m50 or m52 engine, transmission, harness, whatever else I'd need? Just a general estimate is good if you can.

more than a chip

and lots of time

Originally Posted by 95 E34

more than a chip

Obviously... I'm not going to drop $300 for a chip that doesn't do much. I would be willing to spend a lot more for a whole "new" engine.

Originally Posted by BMWFatherFigure

and lots of time

I know it'll take a while, but I love working on my car, and I have others I can drive in the meantime.

You just got a car, did engine maintenance asking for inexpensive upgrades then all of a sudden you don't mind putting in new engine.

Originally Posted by 1995i540

You just got a car, did engine maintenance asking for inexpensive upgrades then all of a sudden you don't mind putting in new engine.

Frustrating, isnt it?

Originally Posted by 95 E34

Frustrating, isnt it?

Start then followed by then finish with

Lol my buddy has a well maintained with exhaust and intake on his 525. My tired old BG eating 535 will dump on that thing even with an auto.
If I was nuts about the 525, a. Cam, port&polish, bigger valves and supporting parts, maybe shaved head, advanced timing I guess, intake, exhaust, injectors, kick ace coil. But really It's useless. The gains aren't that great. With that you maybe hit 250hp

A 5 series is never really going to feel like a quick car. My E34 was keeping pace with a stock E46 M3, but if it wasnt for the time i wouldnt know. Id suggest if you want a quicker car getting an E30 and starting from there. if you want to do an M50 E34, your be better off selling your car and getting an M50 version, BMW offered the conversion you want to do from the factory, why wouldn't you?

Swap in a S85, it's easy. Bolts right in

Or buy another car. I'm about to get a VR6 Jetta, it would no doubt doubt punish a 525, would probably beat mine too. I've had the chance to ride in Radian's 535 which is argueably the best 535 here and it didn't feel fast. It was quick not fast.

E39 540i m sport is a very quick ride. That was fast. One hundred came very easily in it. Look for another car, if you don't get a hard on for taking curves in a your car now, then It's probably not for you.

Originally Posted by _Ethrty-Andy_

A 5 series is never really going to feel like a quick car. My E34 was keeping pace with a stock E46 M3, but if it wasnt for the time i wouldnt know. Id suggest if you want a quicker car getting an E30 and starting from there. if you want to do an M50 E34, your be better off selling your car and getting an M50 version, BMW offered the conversion you want to do from the factory, why wouldn't you?

I miss my E30, my stripped out E30 325is was MUCH more fun than 540I. Shopping cart FTW

Don't get me wrong I never said it was more fun. It just had the balls that no 6 cylinder matched. That V8 just roared, It's hard to stay out of throttle when it talks like a V8.

Does anyone know if headers for an E36 work with an E34?

Originally Posted by gorillaguru

Does anyone know if headers for an E36 work with an E34?

shorties would.

Just go S52 headers and plug the OBII holes.