Low boost td5

[TD50WA]

Td5 d2, alisport intercooler, boost box, Bruce Davis ecu, standard size tyres, auto.

Car goes alright, seems to make plenty of go with no smoke.

Egt max 700ish.

VDO manual boost gauge peaks at 18-19psi
Nannocom instrument reading .91-.93
Nannocom testing shows max 185kp.

Waste gate wound up to only 5 threads left with no apparent effect on readings. WG moves freely when tested.

I thought the boost should be higher than this?

Suggestions?

Cheers all.

[strangy]

Depending on the boost box.
Both TD5 Alive boost boxes fitted to D2s in our family indicated less on the Nanocom, the more the boost was wound up.

You gauge will be a better guide.

[TD50WA]

Cheers, but is 18-19psi at the manifold low, considering I have all but wound up the WG?....I thought it should be around 22 odd?....maybe more?

Kev

[sierrafery]

Hi, when you say "Nannocom instrument reading .91-.93" is that "turbo presure"? cos this means the AAP reading is 92-94 to result 185 absolute pressure which is low(i mean the AAP)... and if the AAP reading is not good(sensor fubar'd) the ECU limits the boost to 1 bar...read ambient pressure on live data

[TD50WA]

My understanding of the nanocom, and I might be wrong here, is that on the instrument reading, the boost pressure is direct from the manifold?

Is that in bar, I guess, so .98 bar, but that's only 14.2 psi and my boost gauge is at 18-19psi...?

But according to previous post, with a boost box , the nanocom readings are suspect.....boost gauge is more reliable, so is 18-19psi at manifold low or ok?

Cheers
Kev

[TD50WA]

Hi, when you say "Nannocom instrument reading .91-.93" is that "turbo presure"? cos this means the AAP reading is 92-94 to result 185 absolute pressure which is low(i mean the AAP)... and if the AAP reading is not good(sensor fubar'd) the ECU limits the boost to 1 bar...read ambient pressure on live data

Which sensor is fubar'd?

[sierrafery]

My understanding of the nanocom, and I might be wrong here, is that on the instrument reading, the boost pressure is direct from the manifold?

Is that in bar, I guess, so .98 bar, but that's only 14.2 psi and my boost gauge is at 18-19psi...?

But according to previous post, with a boost box , the nanocom readings are suspect.....boost gauge is more reliable, so is 18-19psi at manifold low or ok?

Cheers
Kev

so... nanocom reads the MAP output through the ECU which is altered by the boost box, the problem is that nanocom converts the reading into "turbo pressure" by extracting the AAP reading from the MAP reading normally and above all this it converts it in bar too:mad:... the boost box should let the reading up to 240KPa absolute pressure which in reality is the AAP(ambient pressure) + boost (turbo) pressure in KPa

your reading is .98 bar and as the wastegate is shortened it must be more than that unless the fueling it's limited by the ECU and that's a default mode if the ECU "thinks" the AAP sensor is fubar'd...so if the ECU is on that default mode it will manage things as to keep the boost at 1 bar(.98 can be considered so cos it's not 100% accuracy there)

the real 19 psi reading of the gauge = 1.3 bar and this boost is normal for a non-tuned engine but what ever real boost would be there the ECU doesnt know that tdue to the boost box...(you'd get this boost on a standard Td5 without boost box and shortened wastegate rod)

to not complicate things and confuse you cos maybe i can't explain well here's the short story

read fault codes first to see if you dont have an ambient pressure related fault code...if no fault code read ambient pressure on that "testing" or fueling mode where you got that "Nannocom testing shows max 185kp." if you see what i mean

AAP sensor is that sensor in the airbox and according to your readings and the fact that the boost is so low with shortened wastegate rod is very suspect so you must rule out that AAP sensor
Input/Output
Connector C0158 pin 8 of the ECM supplies the AAP sensor with a 5 volt power supply. The pressure output from the
AAP sensor is measured at pin 10 of the ECM connector C0158, the temperature output from the AAP sensor is
measured at pin 31. The earth path is via pin 30 of ECM connector C0158.
The AAP sensor can fail the following ways or supply incorrect signal:
l Sensor open circuit.
l Short circuit to vehicle supply.
l Short circuit to vehicle earth.
l Contaminated sensor element !!!
l Damaged sensor element.
l Resistance in wiring harness.

In the event of an AAP sensor signal failure any of the following symptoms may be observed:
l Altitude compensation inoperative (engine will produce black smoke).
l Active boost control inoperative.
l Turbocharger boost pressure limited to 1 bar (14.5 lbf.in 2/psi ).
l EGR altitude compensation inoperative.
The MIL will not illuminate in an AAP sensor failure, and the ECM will use a fixed default value from its memory.

i hope you understood what i meant cos this situation is very like when your turbo pressure is limited to 1 Bar(.98) by the ECM so the fact that the wastegate is shortened doesnt help much as long as the fueling is reduced.

read "ambient pressure" and report back

[strangy]

Cheers, but is 18-19psi at the manifold low, considering I have all but wound up the WG?....I thought it should be around 22 odd?....maybe more? Kev

You should be able to get those numbers.
Condition/kms on the turbines of the turbo is a consideration.
How is the boost modulator?

[TD50WA]

Depending on the boost box.
Both TD5 Alive boost boxes fitted to D2s in our family indicated less on the Nanocom, the more the boost was wound up.

You gauge will be a better guide.

I'll try to adjust the WG up some more.

This is what mine is doing as it was reading .98, then I wound the WG up a bit and the reading went down to .92, the boost gauge went up slightly.

So can any of the readings on the nanocom be trusted due to the bbox?

The boost modulator indicates it's working - readings on nanocom increase as throttle increases?

I have removed the egr, the car has just under 200k on it, the exhaust manifold is possibly leaking a tiny bit as some sooting can be seen, my egt probe also leaks a bit around wire, not thread, so I guess these issues will also effect final boost attainable?

[sierrafery]

nanocom reads exactly what the ECM gets from MAP... the reading is altered by the boost box but the engine management is based on that input...
IMO from that point of view you can trust nanocom, it doesnt take readings from the sky...it shows you what the ECM gets and the fueling calculations/estimation of air mass in the cylinders is in relation with it if you see what i mean.... i just wanted to help you but if you insist to neglect the AAP thing your choice... the wastegate is a simple port where the extra boost goes to the exhaust if it opens so even if you clog it completely or weld it as long as the engine/turbo doesnt deliver enough boost due to the management you'll not get more boost at the inlet and tha't's what you see on that gauge... i'm trying hard to tell something in english but that's the best i can, just be convinced that i want to help :)

[strangy]

Leaking exhaust can affect your boost The Nanocom reading with the boost box connected is not trustworthy. You could disconnect the boost box and confirm a baseline for MAP and AAP sensors if you wanted to confirm your external boost gauge vs MAP sensor. If the modulator is leaking or the hoses leaking, you will lose boost here also.
Try bypassing it and see if this changes anything. A Nanocom test of the modulator will only confirm solenoid operation, it cannot confirm the integrity/sealing of the valve.
Sierrafery has posted the info to check with sensors, though is struggling with the delivery:)

[sierrafery]

:BigThumb: good point:D

[TD50WA]

nanocom reads exactly what the ECM gets from MAP... the reading is altered by the boost box but the engine management is based on that input...
IMO from that point of view you can trust nanocom, it doesnt take readings from the sky...it shows you what the ECM gets and the fueling calculations/estimation of air mass in the cylinders is in relation with it if you see what i mean.... i just wanted to help you but if you insist to neglect the AAP thing your choice... the wastegate is a simple port where the extra boost goes to the exhaust if it opens so even if you clog it completely or weld it as long as the engine/turbo doesnt deliver enough boost due to the management you'll not get more boost at the inlet and tha't's what you see on that gauge... i'm trying hard to tell something in english but that's the best i can, just be convinced that i want to help :)

Hey cheers mate, I appreciate all the help here and I am simply responding to what is posted by yourself and others. I wasn't ignoring your advice and have just come back from a test drive where I got the following readings:
Nanocom in diagnostic mode shows aap at about 100, dropping as accelerating, I guess this is due to air intake causing lower pressure in air box, the other reading goes to about 185ish, sometimes a bit more, but not into the 200s.
Air flow reading is 60ish idle to 590ish booting it (maf)?

Back in instrument mode, it shows boost at .98 bar. However my boost gauge shows 19 psi which is 1.3 bar
These readings appear to be max as no alteration of the WG increase it above this.
Thanks again
Kev

[sierrafery]

it seems that your AAP is good then:cool:...i went out to my car to check cos i wanted to make sure about that, unplugged the AAP and went for a test drive with nanocom plugged and set on instrument mode...no matter how hard i floored it the "turbo pressure" varied between .98 and 1.1, which means that default mode for faulty AAP, also got "2.8 ambient pressure circuit" fault code... then plugged hawkeye in and got between 196 and 201 KPa manifold pressure which is normal again....with AAP plugged back i've got between 1.28 - 1.35 nanocom and 225-236 hawkeye at full guts and i dont have boost box.

what's certain is that nanocom shows you exactly what the ECM gets from the MAP sensor through that boost box, it has nothing to do with the REAL pressure, the fact that you dont get more that 19 psi/1.3 bar on the gauge that's the problem and as long as you ruled out the AAP there must be some physical thing IMO and that's above my knowledge, it's normal that the wastegate rod doeasnt affect this cos the boost is too low to open it so no matter how much you force it the result is the same, that wastegate actuator valve has a spring in it which keeps the wastegate closed untill the pressure from the intercooler push it to open but that won't happen with low boost, 1.3(130Kpa) with 100 AAP reading is below the normal setup which afaik is at 240Kpa for MAP(MAP = AAP+ boost) on factory setting, can you move the rod with a mole grips? ... the boost pressure leak seems the best theory now, or fubar'd turbo, or god kbows what... i'm useless from now on in this sorry...

btw, what about fault codes though?

[TD50WA]

3,7 airflow logged high.

[TD50WA]

Is that maf?

[sierrafery]

the fault code is about MAF albeit the readings are Ok.... erase it and read again after some miles maybe it was an old code

[TD50WA]

No it was a new code, I checked yesterday and there was no fault codes.

I've got one of those hi flow mafs, but I don't know if it's any good, I'll just have to chuck it in and see if it works.

Kev

[sierrafery]

replace the cranckase breather valve too if you know it's old

[TD50WA]

I think it's beyond old.........:D

[DiscoDB]

Air flow reading is 60ish idle to 590ish booting it (maf)?


Kev, that max air flow reading looks low. Have you checked your throttle position with the Nanocom to confirm you are getting full throttle? David

[TD50WA]

Yeah sorry, should have been in the 600's...

Put the hi flow maf in and no faults now.

Ok, my manual boost gauge shows 19psi, that's 131kpa. So going by that my reading on the nanocom should be 100 aap and 131 on the other reading, but it only reads 98.(total 198 obviously).

This is with the boost box fitted.

Before I fitted the boost box, I had already wound the WG open and the car was stuttering on big throttle input, going into over boost obviously.

I didn't check readings with the nanocom though.
Fitted allisport intercooler biggest that can fit the auto D2, and the boost box, egt dropped considerably and finally able to boot it properly with no cut out occurring.
The boost box controls the information the ecu gets in relation to boost, so in my mind, the low readings on the nanocom are logical?

The car appears to be actually boosting to 231kpa (aap+boost) which is all but in line with others.

I do appear to have some exhaust leaks, next thing to be fixed....could be losing a little bit here....

Egt is below 700 in 95% of driving including spirited stuff! only at high revs at wide open throttle when really giving it does it go to 750 to 800 and this drops with just the slightest of lift off. I am running the Bruce Davis ECU as well.

I hear some others are getting 22psi boost, so I appear to be down a bit, but how much error is there in different boost gauges?
Looking at a new turbo soon anyway, vnt type, so if my turbo is a bit suspect, then this should fix that anyway.

Kev

[DiscoDB]

I would remove the boost box and then compare Nanocom and boost gauge readings. This may enable you to confirm the accuracy of the boost gauge.

[TD50WA]

At 19psi, won't this trigger the cut out anyway and therefore not able to be reached without the boost box.
How could I then verify that reading?

Willing to try though

[DiscoDB]

Aim here is just to confirm if the boost gauge is accurate first. You should be able to hold the throttle at a point with out the over boost kicking in and compare readings. Even if the over boost does kick in, just confirm what the max was on the boost gauge and compare with the Nanocom.

If you have a problem getting full boost as you suspect, then you won't be able to get an over boost. Either you have no problem and your boost gauge is reading lower than the real value, or you are not getting the boost you expect.

Should give some more info either way.

[TD50WA]

True, worth a try, my gauge is a mechanical vdo gauge, so I would expect a reasonably accurate measurement.

Cheers for the comments.

Kev

[DiscoDB]

Plus I am thinking if you find it easy to again hit over boost with less than full throttle then you must be getting over 20psi with the boost box connected.

[TD50WA]

Disconnected the boost box this morning, went for a drive and saw 242kpa for a second before cutout, then 237 cutout etc etc, so it appears the boost box does cause the nanocom to show low readings.....this is logical:p

That means my vdo boost gauge is at least 2psi low:o

I bought a reasonable quality one and expected better, so as predicted, I must be getting at least 20-21 + ........

Time for a new gauge.......

Cheers all
Kev

[blackapache]

Hey Kev - howd you make out with all this in the end? Im only asking cause I'm having similar woes. Im running allisport intercooler, aluminium radiator, TD5 Inside boost box, Uprated ECU and tune and their VNT style turbo too, yet my VDO mechanical gauge is only reading 16-17psi max at full boot...

I'd love to hear what the final washup was for you if you get a second.

cheers, Jesse