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e39 523i Tuning Options Advice!

12K views 15 replies 4 participants last post by  cheezy88 
#1 ·
Just purchased a e39 523i tourer and love the car on the motorway picks up really well but low down it is piss poor so sluggish although i have posted on another thread i may have an air leak so may be causing this

just want to know what mod's to do to these engines, its 99 model

service, filter or dave f filter, BBTB aplina 527 i think it is? and a remap? is that about it without spending 1000's?

if all done what rough bhp would i be looking at just under 200bhp?

advice appreciated
 
#9 ·
In that case I'd recommend the following...



Total of £325 and your car will handle a lot better.

If your gonna fit all the above then you may as well fit a strut brace while your at it. These vary from £50 - £100 depending on their quality and effect.
 
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#3 ·
With a '99, I think you'll have missed the boat for the M50 manifold conversion, you'll have the M52TU with twin vanos.
A remap will sharpen things up for you, and there is the possibility of using the 330i intake manifold with an adaptor plate but it hasn't really taken off like the E36 tuning has.
 
#5 ·
With a remap by itself, You'd gain about 15-17bhp, but the change in response at lower revs would be more apparent, and would make the car feel better.
The 330i manifold should help just by bolting it on without any changes but there isn't much info on how good the effects are.
It would seem it doesn't give as big as an improvement compared to an M50 onto the earlier M52.
With both together, I reckon you'd get close to 200bhp, but might struggle to break the barrier.
 
#7 ·
You'd need to pick up the manifold from ebay, the adaptor plate would also be something like ebay or USA.
It isn't massive, just the 330i used a different type of throttle and the bolt holes are in different places.
This adaptor bolts on, then you fit your original throttle to it with a slight twist.

M52tu to M54 manifold swap: DONE! Need help though - E46Fanatics

This suggests using the 325 manifold, which I'd actually agree with. Too big, and you could start losing power in the low rev ranges withlittle difference high up.
The 325i M54 version will leave the low rev characteristics the same (your engine isn't being held back at this point, so not a problem) but it'll help in the over 3-4k+ region.

There's some more UK based info here
zroadster.net :: View topic - E46 M54b25 manifold conversion for 2.8 twin-vanos

ignore the second post with the bm conversion's kit, that's an M50/M52 job.
 
#15 ·
I'd also change the shocks too. You can use OEM parts but they'll wear faster.
 
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