as above replaced orifice restrictor in boost pipe after finding out it was missing.
Came from a s reg mine is a v.
Car is overboosting so gonna try drilling the orafice out by .1 of a mm.
is there anything else that could be causing this before i do as its only started happening since brass pill has been in.
thanks in advance.....

 

With the restrictor the boost target will be exceeded then drop back to target boost, If you are hitting fuel cut or exceeding maximum 1.0Bar or 1.2Bar (PPP)of boost at WOT then drill the restrictor out. What boost did you have before?

 

I do not have a boost gauge and I have had the car since october and never knew the restrictor was missing so this was not happening.
I have ordered the drill bits and going to take it out by .1mm at a time and see how it is..

 

What was not happening? What is actually happening that makes you think you have overboost? What mods does the car have?

 

You need a boost gauge if you're going to start messing around trying to achieve boost targets IMO even if you just borrow one.

 

The car has no mods except nur spec.
What is happening.
The car boost then as your going through the revs you can feel the car back off and on I think they its hitting fuel cut maybe.
I know they have a boost limit incase they overboost so i think that is whats happening (overboosting.)
Is it a diy job to fit a boost gauge.?

 

Boost gauge is easy there vis a spre nipple on your inlet manifold that you can connect to, then just run the pipe through the grommet above the clutch pedal.

make sure you have plenty of fuel as quarter tank or less could cause these symptoms at WOT (wide open throttle).

The Nur Spec will cause the boost to ramp up quicker so could be overboosting and even if you get the right restrictor for MY99/00 you may still need to drill it out.

If it was me i think i would fit boost gauge, remove restrictor alltogether and tweak up wastegate actuator until you hit overboost then tweak back. Rule of thumb is 5 mm shortening rod is normally enough without hitting overboost,

On that age of car the lambda and maf normally need replaced, if these havent been replaced within the past two years then they could be faulty.

However as you have reported that car was ok without restrictor we have to assume that higher boost level is the problem. If you have standard ECU then overboost will occur by approx 1.2 bar. (cant remember exactly)

 

not sure if the maf and lambda sensor has been changed. i have had the car since october and have a load of receipts for it non of it mention any of these so i can presume these have not been changed.
I will get these replaced if it is recomended.
I think i will drill out to max 0.9 and if still occuring will remove and adjust w-gate.
Is this difficult?
would a boost controller help? so i could adjust down then?
Thanks a lot for your help... much appreciated.

 

1) Remove orifice completely.
2) Fit boost gauge and record boost pressure.
3) Fit orifice and re-check boost pressure.
4) Drill orifice until you are happy.
5) Adjust wastegate rod by removing heat shield above turbo and shortening rod. Boost will come quicker but boost control by ECU will still be there. Enkoy the extra torque but fuel consumption will suffer.
6) The standard boost controller is all you need, you can fit an aftermarket one but not really necessary unless you plan to upgrade fuel pump and bypass fuel cut and remap etc.

The restrictor slows the air flowing to the map sensor so you get slight overboost before the ECU gets control. If you take the restrictor out then you will still get target boost but the slight overboost will be removed. There really is little noticeable difference on the road, you could also consider a Dawes device instead of the restrictor, do a search.

 

what do you mean by this?
there was a significantly huge difference when the restricter was put in. or would this just be more tourque?
cheers again

 

okay just went and removed the orofice.
put a home made restricter in that was bigger by not that much.....
took car out and all the juddering had gone car was smooth.
one thing is it was not as tourqe-y as it should be.
so am I right in thinking now that this is def the answer to my prob and if I do take the hole out by 0.1 mm at a time untill its not juddering but feels powerful again.
I am looking to get a gauge fitted now also....

 

Well i have had one more thought which is to fit the smaller orifice again and reset the ecu by disconnecting the battery overnight. See if the ECU can learn with the smaller orifice in place. On my MY99 had to reset ECU after any mod.MY00 is same ECU with slightly revised map.

As you mention a significant difference with the orifice installed i would be a bit worried that you may be overboosting a lot.

Really the first thing you need is a boost pressure gauge, otherwise you are working in the dark.

 

Hi beastie
yeah thats my concern
im on the case of getting gauge
gonna wait till then so i know exactly whats happening at the moment,
thanks for your advice.
So if i disconnect the battery over night then put it back on in the morning it should re learn?

 

Yes the ECU will start from default settings and relearn.

 

And is there a need to drive cautiously for a while after ?
cheers again ill leave you alone soon lol.
got gauge coming tomorow.

 

The ECU has to relearn, the normal way is to drive normally for a few miles with decent petrol i.e superplus/Optimax then find a slope that you can go up so that you hit maximum boost in 4th Gear, (you need the slope to get the load and achieve full power.) Once you have hit max boost in this fashion approx 3 times the ECU will have learnt enough info.

If your ECU is standard(which we believe it is ) and you have the boost gauge fitted you should see boost increase to about 1.1 bar before tailing back to 1.0 Bar. This would mean that the orifice is correct. If you hit anything more than 1.15 Bar you need to drill the orifice out.

When you have set this to your satisfaction you can shorten the rod on the waste gate by 5mm (if you want) What this does is keep the wastegate closed for longer and so your boost ramps up quicker and you get a lot more torque lower down the range. Again if you hit overboost cut you have shortened the rod too much.

Overall these small adjustments makes the car very driveable.

 

Thanks a lot ill let you know the outcome.
cheers

 

OKay so now boost gauge is installed took car out and was going to about >1.2 bar.
took orofice out and it was already 0.9mm
drilled it out to 1.0mm
took car out again seemed better then when was properly warm it goes all over the place up to around 1.3 1.4 bar.
any ideas because ive been told not to take it out more than 1.0mm

 

Well you have too much boost simple as that. Try taking some readings without the restrictor to see what boost the car hits.

When you saying the car hits 1.3/1.4 Bar boost is this just momentarily? or does it hold this level of boost. If it is momentarily what does boost settle at going up a hill in 4th?

How stable is the reading on the boost gauge is it fluctuating wildly with the needle vibrating or is it a smooth reading? Often you need to fit a restrictor in line with the boost gauge to smooth out that reading.

Lastly i take it you are not hitting boost cut anymore?

 

okay ill try and see what the reading is without pill in.
the reading is not smooth i read about a restrictor last night actually so gonna look into that.
and yes i am still hitting boost cut
when it goes over 1.2ish it drops then picks up then drops then picks up again
so yes it is still hitting boost cut.

 

result
drilled out to 1.1mm and car is now perfect.cheers for your help

 

Well Done