Lower than expected boost on a cold day.

[Wobbly Dave]

I took Justin out in Betsy just after we finished at the WM Xmas meeting. Betsy did OK but I was showing J the TORQUE Android App. I have recently fitted a new MAP sensor (manifold air pressure), which I believe is what is read & shown on the app. However I only made 15psi - (1 bar) on 3 to 4 degree ambient, where on tests a month earlier with 10 degree ambient I was making about 21psi. So later this evening - I went out again & reproduced the same results.

Do you think there is a cold limit thing here? Is Betsy showing me up? Is the TORQUE app wildly inaccurate? Or do I just have a boost leak somewhere?

Hopefully find out from a seondary source as I am off to HLM tomorrow on a hunt for a heater matrix amongst other small maintenance issues.

Humph.

[M-R-P]

Might be worth chucking the old map sensor back in to see if it goes back to normal. You'd know if your new one is shot then. Next would be boost leak i suppose.

[Wobbly Dave]

hmm - my internal thinking goes back to the fact that the usual healthy hiss from the recirc valve seems a lot quieter.

In fact on play back - you can bearly hear it

Edit - I think my mind is playing tricks - it is there but it is very difficult to quantify.

[M-R-P]

Which would imply lower boost, which would, in turn, imply the map sensor could be ok.
What about the vac pipe to the recirc?... No, you'd hear it hissing as soon as the compressor spoils up.
Hmmmm...
Map playing up? Can it?
Leaky i/c? Didn't damage it when you sat on it did you? Lol
http://i1100.photobucket.com/albums/g413/martinrpeachey/DSCF7096.jpg

[Wobbly Dave]

Even my arse isnt that big - lol

[Wobbly Dave]

Come to think of it - I did loosen the bottom clip for the FMIC when I put the new coolant hoses on. I swear that I retighted it. Oh god - I am gonna loose sleep thinking about the ridicule if I forgot.

It is unlikely to be the new MAP sensor - as I tested it after fitting & everything was fine.

[M-R-P]

Pmsl. Maby Hamish will have an idea.
My knowledge is limited to the things I have to fix on my own car and the few substantiated snippits of info I learn here.
Hope you get her sorted mate.

[M-R-P]

Ooh.. charge air hose? Mine go pop when I forget to tighten it. ;)
By map playing up I meant ecu map, don't know if they can play up?

[Wobbly Dave]

Gutted really after been blow away by the ferocity of the RS4 - Betsy did not do herself justice.

[Wobbly Dave]

Ooh.. charge air hose? Mine go pop when I forget to tighten it. ;)
By map playing up I meant ecu map, don't know if they can play up?
That's why I was wondering if such a thing as a cold weather protection jumps in - but that doesn't seem logical or probable.

[M-R-P]

RS4 is in a different league mate, twice the cc and 4wd. Don't beat yourself up over it. There are some things a T5 won't beat ;)

[smithy]

but a 940 might have a chance lol

[Wobbly Dave]

Well I will have to resign myself to the fact that I am not going out at this time to jack up Betsy to check a jubilee clip. Too cold - too dark & too tired. I am going off to bed & will face it tomorrow.

I shall have to console myself that Betsy still makes 300 on 1 bar - even if the torque is slightly down she is still rapid.

[M-R-P]

That's a drag race I'd like to watch ;)

[Dangerous Dave]

Theres lots of parameters the ecu takes into account, intake air temps affect how the ecu determines 'mass of air absorbed' so I'm guessing that the ecu will perhaps adjust the turbo output.

I have read somewhere about some ME7 principles, but they didn't go into too much depth.

Also this on wiki
http://s4wiki.com/wiki/Tuning#IAT_effect_on_requested_boost

[smithy]

my car works on the colder it get the faster the car goes lol

[Wobbly Dave]

That is what is bothering me.

[smithy]

That's a drag race I'd like to watch ;)

1 day you never know lets see how the old girl goes in the new season mate

[smithy]

That is what is bothering me.

i think your boost pipe is loose mate

[Justin]

but a 940 might have a chance lol

Everything has a chance smithy, one mistake by me and the race is yours lol.


Gutted really after been blow away by the ferocity of the RS4 - Betsy did not do herself justice.

I was quite impressed with yours Dave, it pulls hard and felt good to be back in an oblob.

[smithy]

Everything has a chance smithy, one mistake by me and the race is yours lol.



I was quite impressed with yours Dave, it pulls hard and felt good to be back in an oblob.

you never know mate you might not need to make a mistake and i might still beat you lol,but when its finished and back on the road i will pop round the shop and give you the keys i think you may be surprised at how the old girl goes now .she is quick at 17 psi cannot wait to turn the old girl up to 28 psi thats when i will give you the keys,so you can get the full benefit.can you still take rwd now you are a 4wd junky lol

[M-R-P]

I was quite impressed with yours Dave, it pulls hard and felt good to be back in an oblob.

I went out in Dave's while she was running full boost... a very rapid run up the M1, preceded by a short, windows down tunnel run.
Very impressed ;) (although, I may have left a little brown mark on the seat lol!) :hilarious

[Wobbly Dave]

I went out in Dave's while she was running full boost... a very rapid run up the M1, preceded by a short, windows down tunnel run.
Very impressed ;) (although, I may have left a little brown mark on the seat lol!) :hilarious
Obviously within the bounds of the legal speed limit.

I have been trying to track down the funny smell for weeks?!!! Boost leak with follow-through?

[Dangerous Dave]

Boost leak with follow-through?
You can shorten that to "crap boost"

[M-R-P]

Obviously within the bounds of the legal speed limit.

I have been trying to track down the funny smell for weeks?!!! Boost leak with follow-through?

Lol, congestion wouldn't allow any more than a brisk run up to match the speed of the traffic :)

Propper funny when you asked if I was watching the the Torque app and I replied "No, I was looking for something to hold on to!"

[Wobbly Dave]

Sure made me smile ;)

[wegal]

Now fess up.. was it the speed and acceleration... or wobbles driving ?

After all hes called wobbly for a reason.. and it aint anything to do with his weight !!

[M-R-P]

Tee-hee, not sayin ;)

[Justin]

you never know mate you might not need to make a mistake and i might still beat you lol,but when its finished and back on the road i will pop round the shop and give you the keys i think you may be surprised at how the old girl goes now .she is quick at 17 psi cannot wait to turn the old girl up to 28 psi thats when i will give you the keys,so you can get the full benefit.can you still take rwd now you are a 4wd junky lol

Haha, mate if its got a wheel in each corner i can drive it, always have been able to :) RWD @ 28psi, that makes me go all warm and fuzzy inside :)

[smithy]

Haha, mate if its got a wheel in each corner i can drive it, always have been able to :) RWD @ 28psi, that makes me go all warm and fuzzy inside :)

lol

[Wobbly Dave]

Time to 'fess up. We ran Betsy with the calibrated boost gauge & the reading were under - so ultimately no fault or boost leak found - however I am now frustrated by the underread & overread from the same application - hence effing useless. Darn it.

I haven't entirely given up on the application. I have tried both MAF reading the boost too - but the results are still under.

Annoying as the mid November readings were a little bit over.

So Justin - that was her running properly - but the Application not.

[M-R-P]

At least she's running right mate. And you hadn't left the clip loose on the ic hose ;)

[smithy]

Time to 'fess up. We ran Betsy with the calibrated boost gauge & the reading were under - so ultimately no fault or boost leak found - however I am now frustrated by the underread & overread from the same application - hence effing useless. Darn it.

I haven't entirely given up on the application. I have tried both MAF reading the boost too - but the results are still under.

Annoying as the mid November readings were a little bit over.

So Justin - that was her running properly - but the Application not.
so are u saying that electronic gismo is crap in ur car t
hen it looked nice and shiny though and ur car is quick mate ps u still looking at uping the torque on ur car and bhp

[M-R-P]

so are u saying that electronic gismo is crap in ur car t
hen it looked nice and shiny though and ur car is quick mate ps u still looking at uping the torque on ur car and bhp

I think the software could have issues updating all the overlayed displays. That's a lot of info for a blutooth system to cope with and it may be suffering some sort of lag.
Dave, try reducing the number of dials on screen and see if it becomes more reliable. ;)

[Wobbly Dave]

so are u saying that electronic gismo is crap in ur car t
hen it looked nice and shiny though and ur car is quick mate ps u still looking at uping the torque on ur car and bhp
I am not saying it is crap - I think it needs work & is not a straight forward as I thought. I presumed (presumption being the mother of all ££££ups) that it read from the MAP sensor. Perhaps Martin is correct - I am running too many PIDs.

I still prefer it to the boost pod gauge horrible things.

I will find a way to make it work.

And yes Smithy - I am still looking at a shed based engine DIY build. I am not planning something OTT to start with just in case it all goes wrong. I think forged rods & volvo pistons to keep the budget down.

Once the bathroom & nusery are finished - I will start looking for a suitable donor engine.

[smithy]

I am not saying it is crap - I think it needs work & is not a straight forward as I thought. I presumed (presumption being the mother of all ££££ups) that it read from the MAP sensor. Perhaps Martin is correct - I am running too many PIDs.

I still prefer it to the boost pod gauge horrible things.

I will find a way to make it work.

And yes Smithy - I am still looking at a shed based engine DIY build. I am not planning something OTT to start with just in case it all goes wrong. I think forged rods & volvo pistons to keep the budget down.

Once the bathroom & nusery are finished - I will start looking for a suitable donor engine.

the system looks nice though hope it work mate and the standard volvo piston only go .4 oversize so make sure u get a good block with hardly any wear on it or u will have no choice to go for aftermarket piston witch go to 82m
m bore .i went 97mm bore on the 940 with wisco forged pistons .volvo pistons are good for 400 bhp though aslong as the map is good witch will be with hlm doing it

[Wobbly Dave]

I am still undecided about wiseco pistons or volvo oem - as this will be my first rebuild. I may just leave the original pistons in & just drop in some rods - then when it all goes wrong I will be not crying so much.

Hamish was talking about a possible trip to Sweden - to get it remapped.

[M-R-P]

I am still undecided about wiseco pistons or volvo oem - as this will be my first rebuild. I may just leave the original pistons in & just drop in some rods - then when it all goes wrong I will be not crying so much.

Hamish was talking about a possible trip to Sweden - to get it remapped.

Cooorrr Blimey! and there I was, working out how much it would cost in fuel to get to Bromsgrove! lol :eek:

[M-R-P]

I just thought about something else... Are you using the app under the same circumstances? i.e. start the app with the car off, or start the engine then start the app or even start the app when moving? there may be a calibration problem if the software looks for differences in readings, rather than calculating the physical value of the reading.
I think I made sense ;)

[Wobbly Dave]

I have been doing some reading around & there is a way to make the boost readings more accurate in TORQUE.

You can make subtle adjustments for the MAP sensor in the car profile. I have been trying to also find a good value for the volumetric efficiency. I was using the standard value.

I am hoping that Adam will call me soon - as I need to finalise things like the baud rate from the ME7 ecu & see if there are subtle differences in the PIDs that Volvo ECU is reading vs what the app is trying to use.

I think with a bit of final tweaking I can get this right. I don't know if the ECU makes allowances for changes in barometric pressure. This may go so way to explaining the changes due to temp & height above sea level.