Did you do the upgrade to your M52tub 20, if so did you do a write up, would be interested to hear of the results.don't understand all these problems your having?
mine bolted straight on my M52TU with no modifications.
My only issue was that I was originally supplied with the wrong TB adaptor plate. the first one had no o ring groove, and the holes were out of line. one I had the correct one it was straightforward...
Hi gookah it seems we used differant adapter plates plus we may have differant TBs.don't understand all these problems your having?
mine bolted straight on my M52TU with no modifications.
My only issue was that I was originally supplied with the wrong TB adaptor plate. the first one had no o ring groove, and the holes were out of line. one I had the correct one it was straightforward...
,enough said) well the car started after a few cranks, took it out for 34mile run and found that there's no real torque under 4000rpm although by the time I got back it was getting very slightly better and found that it had come down to 3800rpm.
)
Hi gookah, thanks for getting back to me, been back to my lockup today and tested the Disa and although it seems ok I'm of the opinion that's where the problem is likely to be, it's old, used and if not closing would like you say account for the almost total loss of instant torque in the lower rev range. I'm at this moment looking for a new one on the net, may purchase from Germany as some on net are from China and can't afford to put a sub standard replacement on. Been reading up on what and how the DISA works and was astounded at what it actually does and how it does it, worth a read if your not sure what/how it works, most think in layman terms that it shortens/lengthens the air path but in fact it does a lot more than just that, very very clever piece of German engineering, but if it goes wrong can cause havoc with the performance.Hi Roy.
sorry have been away with work
I too noticed a reduction at lower revs but nowhere near as much as you are describing. 4000 rpm onwards is much quicker as you say. which for overtaking is right where I want it, as I drop a cog and it launches.
I knocked 1/2 second off my time at santa pod just by doing this, and there is no way this top end is accounting for a loss as you describe. Car is certainly not boring and I havent had a remap either, I did go into INPA and re do the adaptation though.
the remap apparently gives back the deficit at lower revs and even increases further the upper end.
Car should be giving out over 200hp now so that should certainly not be boring.
MY TB looks the same as yours and I have all 4 bolts fitted, but I was wrong, I did have to do a modification to the TB as below to clear the idle control valve.
Disa valve is a lot bigger on the new manifold. Purpose of the valve is to breathe more air at higher revs, could this be your "breathing too much air" problem at low revs if it is not working/stuck open (or not plugged in
Roy, there are Disa repair kits available which include a new style pin to hold the flap, I did this update to my Disa valve as a preventive measure, IIRC the kit was bought off eBay. I'll have a look for a link if you wish?Hi gookah, thanks for getting back to me, been back to my lockup today and tested the Disa and although it seems ok I'm of the opinion that's where the problem is likely to be, it's old, used and if not closing would like you say account for the almost total loss of instant torque in the lower rev range. I'm at this moment looking for a new one on the net, may purchase from Germany as some on net are from China and can't afford to put a sub standard replacement on. Been reading up on what and how the DISA works and was astounded at what it actually does and how it does it, worth a read if your not sure what/how it works, most think in layman terms that it shortens/lengthens the air path but in fact it does a lot more than just that, very very clever piece of German engineering, but if it goes wrong can cause havoc with the performance.
Roy.
Next step will be to try and find a BBTB to add maybe a little more responce, then altimately a set of reprofiled cams. This is certainly got me excited at what can be done to the 2.8tu. Re-map still on the cards so we can work out just where the gains have been made.
Not boreing any more gookah was a great drive for 123mls but now it's decided to be a pain and in the butt, hard to start, stalling then going like the clappers for a day then next day back to hard to start running badly. Me thinking it's something I've done but then the scanner tells me my inlet cam senser has gone bad, so today ordered a new one and it'll get fitted W/E hopefully. All in a days work when you own an ageing Z3. Fingers crossed its not the start of all the old bits playing up.bet it's not boring now....
.....................should have bought a new Z4.
@t-tony. 
No Tony!!!! inlet sensors can only make you buy a new inlet sensor and pull your hair out.Inlet cam sensors can do funny things Roy, even make you buy a Z4
Tony.
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