Helloslice masters, I recently acquired an 84 533i and I'm quite fond of the car. However, I'm considering ways to increase its horsepower. I'm particularly interested in a low boost, non-intercooled stock Motronic setup. While I intend to upgrade the head studs and injectors, I have a few questions:
1. What is the maximum boost that the Motronic system can handle effectively?
2. What size injectors would be suitable for this setup?
3. Should I position the airflow meter (AFM) in front of the turbo (pull-through) or after the turbo (blow-through)?
4. Do I need a fuel pressure regulator for this setup?
I would greatly appreciate any additional information or advice that anyone may have regarding these modifications. Thank you in advance!
How to increase horsepower of 84 533i
Re: How to increase horsepower of 84 533i
Motronic can handle 5-6 psi at most with proper enrichment. Even that is not assured. Without the ability to retard ignition timing you will live constantly on the edge of detonation. The only way to try to work around this is to find a suitable open element IAT sensor and relocate it to the compressor outlet, where it will read boost temperature at it's highest. This may get you to 7-8 psi.
Injectors depends on a lot of other things. With a rising rate regulator, you don't need to go huge. Without a custom tune, you can't go huge. 24lb/hr may work with low boost and a considerable rate of gain on the RRFPR. Problem here is that the BEGI regulators went out of fashion at least 20 years ago and are extremely scarce these days. Vortech makes one but it uses fixed rates of gain and it is more difficult to tune.
I blew through the AFM with my original setup. This works best with the RRFPR and negates many feet of metered intake plumbing. The AFM doesn't know anything about air density so it works as normal and the RRFPR is solely responsible for enrichment. With a draw through you would have to be very careful about sealing up all of the plumbing downstream and a recirculated blow off valve is required as well. As far as the tune goes, I doubt the stock software would be suitable.
A rising rate regulator is an absolute must if you can't make your own motronic chips and don't have standalone injection. Standalone such as megasquirt is a big step but a far superior option in the end. Especially on a 533i, MS would require a lot of supporting modifications just to run. Once you get it there you would never look back though. Motronic kind of sucks. Back in the 80's it was good enough for a stock engine. Trying to get it to work with boost is likely to blow up/break shit. I've been down that road.
Intercooling is also strongly recommended. It makes more power at any given boost level and improves your safety margins in terms of ignition timing and fuel quality. Detonation is the number one killer with forced induction. Detonation is caused by heat, generated by compression, exacerbated by elevated intake temps. Turbo stuff isn't fun at all if your shit just blows up all the time. It doesn't have to be that way, you have to do it right.
Injectors depends on a lot of other things. With a rising rate regulator, you don't need to go huge. Without a custom tune, you can't go huge. 24lb/hr may work with low boost and a considerable rate of gain on the RRFPR. Problem here is that the BEGI regulators went out of fashion at least 20 years ago and are extremely scarce these days. Vortech makes one but it uses fixed rates of gain and it is more difficult to tune.
I blew through the AFM with my original setup. This works best with the RRFPR and negates many feet of metered intake plumbing. The AFM doesn't know anything about air density so it works as normal and the RRFPR is solely responsible for enrichment. With a draw through you would have to be very careful about sealing up all of the plumbing downstream and a recirculated blow off valve is required as well. As far as the tune goes, I doubt the stock software would be suitable.
A rising rate regulator is an absolute must if you can't make your own motronic chips and don't have standalone injection. Standalone such as megasquirt is a big step but a far superior option in the end. Especially on a 533i, MS would require a lot of supporting modifications just to run. Once you get it there you would never look back though. Motronic kind of sucks. Back in the 80's it was good enough for a stock engine. Trying to get it to work with boost is likely to blow up/break shit. I've been down that road.
Intercooling is also strongly recommended. It makes more power at any given boost level and improves your safety margins in terms of ignition timing and fuel quality. Detonation is the number one killer with forced induction. Detonation is caused by heat, generated by compression, exacerbated by elevated intake temps. Turbo stuff isn't fun at all if your shit just blows up all the time. It doesn't have to be that way, you have to do it right.
Re: How to increase horsepower of 84 533i
JamesWare wrote: May 11, 2024 3:21 AM Helloslice masters, I recently acquired an 84 533i and I'm quite fond of the car. However, I'm considering ways to increase its horsepower. I'm particularly interested in a low boost, non-intercooled stock Motronic setup. While I intend to upgrade the head studs and injectors, I have a few questions:
1. What is the maximum boost that the Motronic system can handle effectively?
2. What size injectors would be suitable for this setup?
3. Should I position the airflow meter (AFM) in front of the turbo (pull-through) or after the turbo (blow-through)?
4. Do I need a fuel pressure regulator for this setup?
I would greatly appreciate any additional information or advice that anyone may have regarding these modifications. Thank you in advance!
Funny enough this is just what i did with my 535i. I have a chip for my ecu for timing. i have a vortech fmu 10:1 24 pounders and im at 10 psi on wot throttle i get High 11s low 12s For afr been about 2 months on this setup. will i go to a megasquirt or some other standalone maybe long in the future but i love it right now how it is.
Re: How to increase horsepower of 84 533i
I have a TCD timing chip inside an ECU if you were interested. Allows reversible modifications and serves as a backup ECU...
I ran motronic for 3000 miles or so and it ran OK. Good enough to make some track days at the road course and some good power, though the biggest improvement with megasquirt was in regards to the immediate throttle response and of course the ability to make other modifications like timing and injector changes.
I ran motronic for 3000 miles or so and it ran OK. Good enough to make some track days at the road course and some good power, though the biggest improvement with megasquirt was in regards to the immediate throttle response and of course the ability to make other modifications like timing and injector changes.
Re: How to increase horsepower of 84 533i
Won't be compatible with the 533 DME, different hardware versions.