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Ocallen

E39 523i manifold/throttle body/ intake upgrades?

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Hi, I'm sorry to have to bring this old subject up again but I'm just about to do this upgrade to my car and I want to get it right first time and not be buying bits that turn out to be the wrong ones. I know just about every forum has posts about the subject but I'd like, if possible, to get my advice all in one go.

 

Firstly, for what it's worth, I've fitted a K&N cotton air filter. Is that better than the standard paper filter, a foam one or an induction kit?

 

I've seen mention of replacing the rubber elbow pipe but what's that ?

 

I've replaced throttle bodies for larger ones on my previous Saabs and latterly my e36 320i (which had a 325 one fitted) which have made improvements.

 

So which manifold do I need ? Does it need to be for a larger engined car such as a 2.8 or 3.0 ? I've read on some US forums that e36 M3 bits can be used. 

 

Has anyone fitted a stainless exhust manifold to get rid of gases quicker ? 

 

Any assistance will be appreciated.

 

 

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K&N filter's are good; but they have their doubters and their fans

 

I run one, but that's because I already had it and the car came to me with a filthy air filter; so just swapped it out.

 

The 'elbow' part they're talking about is the intake boot from MAF to the throttle body section; there's a resonator on it that folk, like me replace, but I think the 523i intakes are smaller than the 3.0; so not sure if the parts would fit

 

Re the TB; I think the 525i one can be used; I know folk do the M50 mani intake mod on the 528i engines (I think it's those) for better air intake and response etc

 

Re exhaust manifolds; you'd be talking big £££ for not a lot of gains really. I'd leave it be and either go for a sports cat and stainless exhaust back; or, save your time & money, save £££, sell the 523i and buy a 530i or 540i...

 

There's no replacement for displacement etc

Edited by d_a_n1979

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On the 3/523i the perceived wisdom was an M50 325i TB,  inlet manifold & a remap if I remember rightly the 23i is actually a 2.5 and strangled so as not to compete with the 28i.

 

The rest I'd leave alone

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Thanks guys, advice always appreciated.

 

At one stage in my life I would have gone with the idea of a larger engine in my car. This 523i though is sometimes a daily driver and as much as I like it, it's not a car that I pamper. I often go onto building sites so there's lots of brick dust in the air, careless dumper/lorry drivers and tight parking. I regularly do journeys of 50 miles each way in heavy traffic so a 2.5 /6 cylinder engine is better suited than a V8.

 

But as has been said, the 523 is a 2.5 but a bit strangled so I'm just looking to have inlets and outlets more efficient. Total BMW ran a 523i as a project car a while ago and just by making the engine more efficient by manifold changes took the power to 207 bhp. I'm more than happy to be around the 200bhp for the driving that I do.

 

Is there anyone around these days who remaps/chips these cars?

 

Is the throttle body on a 528 bigger than a 523?

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I wouldn't even bother with a remap; NA engines and remaps are generally a waste of £££ unless the engine has been built etc. But, your call.

 

The 2.5/2.8 TB is bigger IIRC (you can always cross ref the part numbers on RealOEM)

 

But better breathing and a better exhaust will release some ponies easy enough; all down to how much you want to spend etc 

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I've just been asked if my throttle body is cable or electric? I don't know off the top of my head and I'm not back at the car till tomorrow.

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4 hours ago, Ocallen said:

I've just been asked if my throttle body is cable or electric? I don't know off the top of my head and I'm not back at the car till tomorrow.

 

Cable IIRC

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Is it possible to fit onto my 523i the exhaust manifold from a 2.8/3.0  m50/s50 or any other BMW engine ?

 

I appreciate that many things are possible by spending time and money but do any of the exhaust manifolds I've mentioned fit reasonably easy and give any gains to my strangled engine ?

 

all of the stainless ones I've found on the internet at reasonable prices are for lhd cars so presumably something on our rhd cars gets in the way. 

 

 

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4 minutes ago, Ocallen said:

Is it possible to fit onto my 523i the exhaust manifold from a 2.8/3.0  m50/s50 or any other BMW engine ?

 

I appreciate that many things are possible by spending time and money but do any of the exhaust manifolds I've mentioned fit reasonably easy and give any gains to my strangled engine ?

 

all of the stainless ones I've found on the internet at reasonable prices are for lhd cars so presumably something on our rhd cars gets in the way. 

 

 

 

Sort of. If you look in Schmiedmann, they say that a small debt needs to be made to clear the steering rack, I think. Worth looking on there. 

 

But, to repeat myself, you're wasting your money and you may as well just leave it be and look to buy a bigger engined E39. 

 

It's your car & your money I know, but for what you could spend, you'll really not get that much of a gain. 

 

If you really wanted to make it faster, rip out the interior as it weighs a Lot, but then that itself renders the car nigh in useless... 

 

If I were to do it, I'd go 200CEL sports cat, stainless exhaust with less restrictive middle box and back box, OEM air intake to a wider TB (if possible), a full plugs, fluids, sensors and oil service, uprated 530/540i brake calipers, discs and more aggressive pads (EBC Yellowstuff or Ferodo DS2500 pads), 17" Style 66s with decent tyres all round, OEM Sachs Sport shocks with Eibach Pro kit springs and leave it at that 

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At last I found the Total BMW magazine with the manifold article , December 2008, that ran the articles over a few months on a Project E39 523i and the various upgrades they made. They sing the praises of the conversion as do car owners who've done it years ago. The only negatives I hear are from guys who say "get a bigger engined car" and have no experience of either the 523 or this conversion. I'm very happy with my car, it's in incredible condition and I've already done quite a lot to it. 

 

They recommended buying a complete kit for this conversion unless you are a trained mechanic because of the alterations that had to be made to these components. Unfortunately Alpina527 who had a brilliant reputation on the e36 and M3 forums for various complete kits, including these,  died in late 2019 .  I can't find anyone else for these conversions but if anyone can advise me I will be grateful.

 

Alternatively can anyone advise me of a BMW specialist in Southern England who does more than just regular servicing, possibly someone who prepares race cars or does engine swaps ? They are likely to know how to do this conversion and not turn their nose up at something that isn't taught in dealer workshops.

 

All help is appreciated.

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On 08/07/2020 at 19:49, d_a_n1979 said:

 

Sort of. If you look in Schmiedmann, they say that a small debt needs to be made to clear the steering rack, I think. Worth looking on there. 

 

But, to repeat myself, you're wasting your money and you may as well just leave it be and look to buy a bigger engined E39. 

 

It's your car & your money I know, but for what you could spend, you'll really not get that much of a gain. 

 

If you really wanted to make it faster, rip out the interior as it weighs a Lot, but then that itself renders the car nigh in useless... 

 

If I were to do it, I'd go 200CEL sports cat, stainless exhaust with less restrictive middle box and back box, OEM air intake to a wider TB (if possible), a full plugs, fluids, sensors and oil service, uprated 530/540i brake calipers, discs and more aggressive pads (EBC Yellowstuff or Ferodo DS2500 pads), 17" Style 66s with decent tyres all round, OEM Sachs Sport shocks with Eibach Pro kit springs and leave it at that 

Fitting bigger brakes on relatively weak engined car is last thing you want. Bigger rotors will increase rotating mass, which doesn't help with picking up speed. Smallest E39 brake setup is already good enough, it will be even better just with good quality pads to improve stopping. 

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I wouldn't increase the size of the brakes. Just fit braided hoses, change the fluid, fit good quality, original size, discs and pads. It's a road car, not track car,  that I sometimes use for work so on my longer journeys to the Brighton, Oxford or Bristol areas. 

As far as increasing the performance is concerned, I'm just trying to get rid of the "strangled" feel the 323/523 engines have compared to their 325/525 siblings. I've driven BMW 6cylinder engines for 45 years now and a free flowing 6cylinder is a great car, no matter the displacement.

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If you can find the parts i'd definitely consider the TB work. The 523i was held back so as not to compete with the 528i which itself was held back.

 

IIRC the M50 3/525i made 192bhp and the M52 3/528i 193bhp despite the capacity hike and the 3/523i 170bhp.

 

The later M54 525i is back up around 190 i think so there is definitely a worthwhile gain to be had which isn't always the case with NA tuning but i'd take 20bhp B)

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