M52/2.8 tuning.
Discussion
My e21 has just been fitted with an M52/2.8 and I wanted to try and optimize it's performance. I am about to fit a 2.5 inlet manifold and Pipercross induction kit but would there be any benefit in buying a big bore throttle body? I have been offered one for £100.
I am also fitting a Dastek Unichip ''piggy back'' ECU and having it mapped by Paul Sheppard down @ Circuit Motors. He seems to have an excellent reputation and I know he has mapped a fair few Dasteks on e30 M3's etc. Am I right in thinking that the Dastek will mean I no longer need to find a way of fitting a speed sensor for the ECU, as without one I am limited to a 5000rpm limit in limp home mode. I can actually limp home quite quickly but obviously I want to be able to rev to the redline.
I have read that US spec M3 camshafts work well in the M52/2.8 but to be honest, I can't really afford to buy and fit them. I have read that with the cams 240bhp is possible but what is the most I am likely to get on standard cams? I have listed my engine spec below.
Any help and/or advice would be much appreciated please.
1996 M52/2.8
Standard BMW tubular exhaust manifold & 50mm mandrel bent 323 style twin pipe exhaust with free flow silencers
Pipercross cone filter
Big Bore throttle body & 2.5 inlet manifold
Dastek Unichip ''piggy back'' ECU
This was when we first dropped the engine in. It's a lot tidier now.
The exhaust is pretty much straight 50mm pipe through to a pair of small free flow silencers. It does sound quite nice.
I am also fitting a Dastek Unichip ''piggy back'' ECU and having it mapped by Paul Sheppard down @ Circuit Motors. He seems to have an excellent reputation and I know he has mapped a fair few Dasteks on e30 M3's etc. Am I right in thinking that the Dastek will mean I no longer need to find a way of fitting a speed sensor for the ECU, as without one I am limited to a 5000rpm limit in limp home mode. I can actually limp home quite quickly but obviously I want to be able to rev to the redline.
I have read that US spec M3 camshafts work well in the M52/2.8 but to be honest, I can't really afford to buy and fit them. I have read that with the cams 240bhp is possible but what is the most I am likely to get on standard cams? I have listed my engine spec below.
Any help and/or advice would be much appreciated please.
1996 M52/2.8
Standard BMW tubular exhaust manifold & 50mm mandrel bent 323 style twin pipe exhaust with free flow silencers
Pipercross cone filter
Big Bore throttle body & 2.5 inlet manifold
Dastek Unichip ''piggy back'' ECU
This was when we first dropped the engine in. It's a lot tidier now.
The exhaust is pretty much straight 50mm pipe through to a pair of small free flow silencers. It does sound quite nice.
I can't really help I'm afraid. This forum tends to focus on much newer cars. Id try an e36 forum, or bimmerforums, for your query. Your reckoning on power is about right. Without cams you're looking at about 220 bhp I believe but much more consistent power delivery to the red line. I have the m52 in my 328i sport and its unmodified. I would see how you get on with just the m50 manifold and remap. If you subsequently fit cams you'll need another remap.
Finally I love your car! My other car, an e24, is the same colour (henna?). Swapping the m52 into an e21 is something i would love to do if the engine outlives the car. Was your car at gaydon, parked behind the alpinas?
Edited to overcome the inadequacies of posting on my phone...
Finally I love your car! My other car, an e24, is the same colour (henna?). Swapping the m52 into an e21 is something i would love to do if the engine outlives the car. Was your car at gaydon, parked behind the alpinas?
Edited to overcome the inadequacies of posting on my phone...
Edited by griffter on Tuesday 6th September 13:01
Sorry can't help either even as an ex E21 owner. A great project all the same. Love the colour too. The one thing I would be doing is trying to get as much weight moved to the rear, I'd even consider using a bag of cement as ballast. Also consider getting the car corner weighted. Keep us posted on your progress.
Thanks guys.
I had the corner weights done at Northampton motorsport when the old 2.7/m20 was fitted. There's actually very little weight difference between the m20 & m52 so handling remains pretty much unchanged. It's on coilovers, with uprated Whiteline ARB's & adjustable top mounts, so I have about as much adjustment as you can give an e21 without major re engineering I guess.
I'm aiming for 220bhp per ton so, with the mods I'm doing, I think it should finally give me the performance I want along with better MPG and an nicer overall driving experience. This is my daily driver too, so reliability is also important. I regularly shoot down to Cornwall in it and the ability to overtake quickly and safely is a real bonus. It's great to see the looks on peoples faces. Another thing I do like about the m52 is the way it sounds. I've always thought BMW sixes ranked among the best out there.
The colour often gets mistaken for Henna red. It's actually a VW colour though.
Thanks again and I'll keep you posted about how the mapping goes.
http://www.youtube.com/watch?v=Hl51c7Ew9a0&fea...
I had the corner weights done at Northampton motorsport when the old 2.7/m20 was fitted. There's actually very little weight difference between the m20 & m52 so handling remains pretty much unchanged. It's on coilovers, with uprated Whiteline ARB's & adjustable top mounts, so I have about as much adjustment as you can give an e21 without major re engineering I guess.
I'm aiming for 220bhp per ton so, with the mods I'm doing, I think it should finally give me the performance I want along with better MPG and an nicer overall driving experience. This is my daily driver too, so reliability is also important. I regularly shoot down to Cornwall in it and the ability to overtake quickly and safely is a real bonus. It's great to see the looks on peoples faces. Another thing I do like about the m52 is the way it sounds. I've always thought BMW sixes ranked among the best out there.
The colour often gets mistaken for Henna red. It's actually a VW colour though.
Thanks again and I'll keep you posted about how the mapping goes.
http://www.youtube.com/watch?v=Hl51c7Ew9a0&fea...
The M50 inlet conversion will make a big difference, really stops the "strangled" feeling you get past 4.5k on the standard 2.8 - recently done the switch on my wifes 328i and the difference is like night and day.
If you're flowing so much more air from the inlet it seems daft not to maximise it by fitting a big bore throttle body.
I bought a complete conversion kit from Alpina527 - really good quality with no Heath Robinson work evident at all
If you're flowing so much more air from the inlet it seems daft not to maximise it by fitting a big bore throttle body.
I bought a complete conversion kit from Alpina527 - really good quality with no Heath Robinson work evident at all
Have you bought a standard 2.5 manifold, or one that has been modified to fit? It's not a direct bolt on IIRC.
With the manifold, BBTB and a decent remap you should be in the region of 210-220bhp (although not sure what effect your exhaust will have).
The Uni-Q is a decent enough bit of kit for the money - had one on my M3 - so should be all you need.
You typically lose a little low-down torque with the manifold conversion, but I'd imagine a decent mapper will map that out to some extent.
Let us know how you get on!
With the manifold, BBTB and a decent remap you should be in the region of 210-220bhp (although not sure what effect your exhaust will have).
The Uni-Q is a decent enough bit of kit for the money - had one on my M3 - so should be all you need.
You typically lose a little low-down torque with the manifold conversion, but I'd imagine a decent mapper will map that out to some extent.
Let us know how you get on!
Yes, I have the 2.5 manifold but am just waiting on the BBTB & kit to fit it. I got the Dastek for a mere £40 as it wasn't listed correctly. I did offer the guy £100 the day before the auction ended but he knocked me back preferring to wait.
The mapping is going to be done by a chap called Paul Sheppard and he has an excellent reputation. I'll be sure to post the results & copies of the dyno sheets before & after.
The mapping is going to be done by a chap called Paul Sheppard and he has an excellent reputation. I'll be sure to post the results & copies of the dyno sheets before & after.
Nice looking project there, I like it.
Firstly, the M50 manifold can be a direct bolt on without mods if you don't mind some mild jury rigging, and ditching some parts.
The M52 temp sensor can be screwed in with the M50 hole tapped then an O ring to seal. The idle control valve can be plugged directly into the grey grommet in the big hole facing the throttle plate. You'll need to make a supporting bracket and a hose to connect it to the intake elbow feed.
Various vacuum ports connect in the same fashion, but we binned the fuel tank evap system which is the enormous activated carbon can under the MAF sensor and all its associated piping.
You'll need to do some bending of fuel rail spigots to clear the wider intake tracts too, but not too severe.
A BBTB will help, but it's not crucial.
Also, you don't absolutely need a remap. BMW mapped the M50 and 52 very generously, there's a huge amount of room above normal airflow values in the fuel maps. The MAF sensor detects the amount of air going in, and injects to suit. Generally the limit is found when you hit the upper output of the MAF sensor, which is 5v at just under 300hp. So, fitting the manifold alone won't cause any leaning out, or poor fuelling. This goes for fancy induction kits and any other breathing changes.
The greatest benefit you can have from a remap, is ignition advance. BMW was conservative, presumably to allow running on 92 octane horse piss fuel. Gains here are dependent on curve quality and the other work done on the engine.
As for what else you can do, M3 headers are a nice addition but have different joint locations compared to the M52 headers, so fabrication will be needed. After that, it's USM3 cams, or crank and rods from a 330, fan deletion, or maybe underdriven pulleys.
Good luck, it looks like fun!
Firstly, the M50 manifold can be a direct bolt on without mods if you don't mind some mild jury rigging, and ditching some parts.
The M52 temp sensor can be screwed in with the M50 hole tapped then an O ring to seal. The idle control valve can be plugged directly into the grey grommet in the big hole facing the throttle plate. You'll need to make a supporting bracket and a hose to connect it to the intake elbow feed.
Various vacuum ports connect in the same fashion, but we binned the fuel tank evap system which is the enormous activated carbon can under the MAF sensor and all its associated piping.
You'll need to do some bending of fuel rail spigots to clear the wider intake tracts too, but not too severe.
A BBTB will help, but it's not crucial.
Also, you don't absolutely need a remap. BMW mapped the M50 and 52 very generously, there's a huge amount of room above normal airflow values in the fuel maps. The MAF sensor detects the amount of air going in, and injects to suit. Generally the limit is found when you hit the upper output of the MAF sensor, which is 5v at just under 300hp. So, fitting the manifold alone won't cause any leaning out, or poor fuelling. This goes for fancy induction kits and any other breathing changes.
The greatest benefit you can have from a remap, is ignition advance. BMW was conservative, presumably to allow running on 92 octane horse piss fuel. Gains here are dependent on curve quality and the other work done on the engine.
As for what else you can do, M3 headers are a nice addition but have different joint locations compared to the M52 headers, so fabrication will be needed. After that, it's USM3 cams, or crank and rods from a 330, fan deletion, or maybe underdriven pulleys.
Good luck, it looks like fun!
Thanks, that's interesting to know and should make fitting the new manifold a bit easier.
The main reason I am going for a re map, with the Dastek unichip, is that I have no speed sensor (e21's don't have them) and it means I can lose the need for one to get out of the 5000rpm limit in limp home mode. Also, every now and then, the idle will rise and fall like a pulse. I have been told it is because the engine and ECU came from an automatic car and it gets sort of confused, now it's sat in a manual. I am no mechanic so if that's rubbish excuse my ignorance. Whatever the reason, it certainly seems ECU related. Anyway, I figured that using the piggy back ECU would mean it would finally be mapped for my specific car with the added bonus of being optimized for the minor mods I have made.
With regard to limp home mode and the 5000 rpm rev limit, I took a feed from the tacho to the ECU, in an effort to fool it into thinking there is a speed sensor. As far as I could see from the e21 wiring diagram this feed should supply a 5v pulse? (I am trying to learn as I go here so please bear with me) Do you think the feed from the tacho will fool the ECU? Also, do I need to clear any ECU fault codes to get out of limp mode?
In order to get the engine in, I had to slightly modify the stock exhaust manifold but are they worth replacing with a more free flowing 6 branch manifold?
What benefits are there from fitting rods & pistons from a 330? Will this up capacity?
The main reason I am going for a re map, with the Dastek unichip, is that I have no speed sensor (e21's don't have them) and it means I can lose the need for one to get out of the 5000rpm limit in limp home mode. Also, every now and then, the idle will rise and fall like a pulse. I have been told it is because the engine and ECU came from an automatic car and it gets sort of confused, now it's sat in a manual. I am no mechanic so if that's rubbish excuse my ignorance. Whatever the reason, it certainly seems ECU related. Anyway, I figured that using the piggy back ECU would mean it would finally be mapped for my specific car with the added bonus of being optimized for the minor mods I have made.
With regard to limp home mode and the 5000 rpm rev limit, I took a feed from the tacho to the ECU, in an effort to fool it into thinking there is a speed sensor. As far as I could see from the e21 wiring diagram this feed should supply a 5v pulse? (I am trying to learn as I go here so please bear with me) Do you think the feed from the tacho will fool the ECU? Also, do I need to clear any ECU fault codes to get out of limp mode?
In order to get the engine in, I had to slightly modify the stock exhaust manifold but are they worth replacing with a more free flowing 6 branch manifold?
What benefits are there from fitting rods & pistons from a 330? Will this up capacity?
Try is possibly a speed limiter in the ECU as well, they quite often sat in there dormant, so try the tacho pulse and see what happens, but if it starts acting odd, that's what it will be.
The speed signal is 9 pulses per wheel revolution, so about 7200 pulses per mile.
The tacho pulse is either 3 or 6 pulses per engine rev (you can see that if you use 4cyl clocks on a 6 cyl engine, the revs are out by 50%)
I guess any sort of slow pulse, even if it doesn't change and lets the car think it is over a few mph will rid you of the limiter, or it could be switched off in the ECU.
The speed signal is 9 pulses per wheel revolution, so about 7200 pulses per mile.
The tacho pulse is either 3 or 6 pulses per engine rev (you can see that if you use 4cyl clocks on a 6 cyl engine, the revs are out by 50%)
I guess any sort of slow pulse, even if it doesn't change and lets the car think it is over a few mph will rid you of the limiter, or it could be switched off in the ECU.
It should be easy enough, the original sensors would look like a wine cork, with a cut halfway down like you were making a slot for a screwdriver.
Inside this slot passes the chopper which is a metal disc with 9 equally spaced arms / teeth, so you could try and mount a wheel like that anywhere.
Another idea would be taking a feed from the cam sensor.
Considering the max rpm is 6500, the cam sensor would give out pulses up to a maximum of 3250 per minute which would be something like 90mph at a guess (it would be reading like 1.5 miles a minute)
Inside this slot passes the chopper which is a metal disc with 9 equally spaced arms / teeth, so you could try and mount a wheel like that anywhere.
Another idea would be taking a feed from the cam sensor.
Considering the max rpm is 6500, the cam sensor would give out pulses up to a maximum of 3250 per minute which would be something like 90mph at a guess (it would be reading like 1.5 miles a minute)
e21Mark said:
In order to get the engine in, I had to slightly modify the stock exhaust manifold but are they worth replacing with a more free flowing 6 branch manifold?
What benefits are there from fitting rods & pistons from a 330? Will this up capacity?
The usual route is a 3.0 M3 manifold set, but if you're struggling to fit the normal set it most likely will give you the same problems, which means a bespoke part will be needed. 3.2 M3 headers can be made to fit, but they're not a bolt on part. I would certainly assume that a bespoke manifold will increase output, but I would guess it'll be fairly eye watering money to have made.What benefits are there from fitting rods & pistons from a 330? Will this up capacity?
Yep, capacity is increased. The M50 and 52 2.5, 2.8 and m54 3.0 had common bore centres and bore diameters, a 3.0 set is effectively a 'stroker' kit. It is only 200cc though, and it'll involve a lot of disassembly and will likely involve re-honing of your Nikasil/Alusil bores to get rid of any step at BDC.
I can't help much on the electronics. Although I have a switch in line with the speed sensor to de-activate it on track, and no ill effects occur but I'm now running with a cast iron cased M50 2.5 which has a more rudimentary control system.
excellent project!
3.2 Evo manifolds are a direct bolt on if you are fitting the rest of the 3.2 system as well.
they are a different bore size to the standard exhaust.
however, your car won't require cats so i would fit the M3 Evo manifolds and then custom from there back, shouldn't be too expensive.
i would fully recommend fitting the manifold before you put the engine...it is a proper ballache of a job.
some people say that the manifold fouls the block of a 328 so what i did was get some 5mm spacers cut to go between the block and manifold, this cleared the block nicely. no need to change studs as there is just enough thread to do this.
alternatively you could use a hammer and adjust the manifold accordingly.
with the M50 manifold, BBTB (both supplied by Alpina527), a DaveF induction kit, full M3 Evo exhaust and a remap at Evolve, my 328 made 242bhp, 233 torques...
but then at another rolling sesh it made 213bhp...either way, she pops along very nicely.
fitting the inlet, etc does not lose torque, it moves it up the rev range a little.
she is perfectly docile below 3500rpm but then comes alive and headbutts the redline
3.2 Evo manifolds are a direct bolt on if you are fitting the rest of the 3.2 system as well.
they are a different bore size to the standard exhaust.
however, your car won't require cats so i would fit the M3 Evo manifolds and then custom from there back, shouldn't be too expensive.
i would fully recommend fitting the manifold before you put the engine...it is a proper ballache of a job.
some people say that the manifold fouls the block of a 328 so what i did was get some 5mm spacers cut to go between the block and manifold, this cleared the block nicely. no need to change studs as there is just enough thread to do this.
alternatively you could use a hammer and adjust the manifold accordingly.
with the M50 manifold, BBTB (both supplied by Alpina527), a DaveF induction kit, full M3 Evo exhaust and a remap at Evolve, my 328 made 242bhp, 233 torques...
but then at another rolling sesh it made 213bhp...either way, she pops along very nicely.
fitting the inlet, etc does not lose torque, it moves it up the rev range a little.
she is perfectly docile below 3500rpm but then comes alive and headbutts the redline
Thanks guys.
Certainly lots to consider. As you can imagine, space is at a premium in an e21 engine bay and not only did we have to modify the OE exhaust manifold, but we also had a steering link fabricated that mean we could lose the large joint the OE one has. I'm guessing that I would need to go with a bespoke item in order to get something more free flowing but that's just too much expensive for my budget. If I can just optimize the current set-up and make a genuine 200 plus, I'll be happy. I just need to chase up the BBTB & inlet fitting.
Certainly lots to consider. As you can imagine, space is at a premium in an e21 engine bay and not only did we have to modify the OE exhaust manifold, but we also had a steering link fabricated that mean we could lose the large joint the OE one has. I'm guessing that I would need to go with a bespoke item in order to get something more free flowing but that's just too much expensive for my budget. If I can just optimize the current set-up and make a genuine 200 plus, I'll be happy. I just need to chase up the BBTB & inlet fitting.
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