Rolling Road Blow Out ???

[gsb876]

Right as some may have read went on the rolling road trip today and all was running well until @ 6100rpm the boost cut off suddenly.

Now been thinking of possible reasons for this, the first reason i could think of was a fail safe programmed into the ECU to shut off boost if the Air intake is too high ? is this possible  

After giving more thought to it, it occured to me that the current "new" boost controller is set at a 10 second burst of boost, now on the rolling road the dude was accelerating quite slowly making me think this could be the reason for the boost cut off, does this sound feesible

Alittle disappointed as wanted to see what we got @ 1bar before we go higher to maybe 1.4bar next year, also any other ideas on this here problem

The fuelling and Boost were very consistent so no problems there either

Thanks for any input

Gurj

Heres the graph, apologies for the poor quality pic

[scooby_si]

stupid question why is is set for only 10 sex of boost?
Si

[gsb876]

Only just seen it when i was checking the unit.

[sadgoth]

Gurj, what were your AFR readings at the peak? If they were low and the running on the safe side of performance it could also be the cause?

[antnicuk]

I Cant see the figures in the piccy,  what were they?

if you have a profec A style boost controller, they use an "OTB"  Overtake Button,  you set boost to a certain level and when you want your higher level you hit the button and it will run high boost for a predetermained period,  normally between 1 and 30 seconds.

That could be why your boost dropped off,  also,  as Mark said,  if its too rich it will kill the spark,  no spark = no explosion, no explosion = no force on the turbine side of the turbo = no boost.
My FD did this on the stock apexi fuel map,  sounded like a big fart and all power went.  

One last thing,  you dont have a pop off valve somewhere thats set to the boost limit,  you will find on the rolling road, they do 4th gear runs from low down in the rev range,  this creates more boost lower down the revs to make sure that you are tuned properly .  Which means you may have seen more boost on the rollers than you would normally see on the road,  this method ensures that there are no parts of the fuel map that are not tuned.

As far as i am aware. the Apexi wont boost cut.  Assuming of course you have an Apexi.

[gsb876]

At peak the AFR was just under 10

Power figure was 321.8bhp @ 6100 rpm
Torque was 282.2 @ 6100 rpm
Boost held steady @ 13 PSI
AFR was 12 at start of run then down to just under 10 at 6100rpm.

Waiting to get a fuel regulator anyhow so that may sort out the running rich side of things

[FD3UK]

The PFC WILL boost cut, if the pfc see\'s .25 bar over what its set to. As you have a seperate boost controller you need to make sure PFC is set higher than the maximum boost you intend to run on the boost controller.


Kev

[Tintin]

Might well be the fueling mate , mine started off at 13 and dropped down to just over 10 by 3500 revs , the geezer told me it was running way too rich and I was losing power because of it

[20B_boy]

Gurj - do u have a clearer picture u can post?

[gsb876]

Canna get the pic any clearer have tried matey

[scooby_si]

here you go i\'ve cleared it up a bit for you ya technical numpty:












































http://www.smileycentral.com/?partner=ZSzeb008_ZNxdm46052GB\' target=\'_blank\'>http://smileys.smileycentral.com/cat/3/3_4_10v.gif\' border=0> pmsl
Si (AKA the helpful one...do you have a fax or owt you can send it to me at work if so & i\'ll scan it?)

[Wav]

Just had a thought; I think it could have been wheelspin. Happened to me a couple of years ago in the five, v. similar plot with it all dropping much lower than it should have done, the operator didn\'t notice it then either:rolleyes:

Paul

[scooby_si]

what with a sub the size of a small country in boot & not much power i doubt it
Si (runs for cover......)

[jonyb]

Gurj,

when we talked on Saturday im sure we mentioned that you had gone higher through the revs on the way there......so if you can do it on the road, sounds strange why not on the rollers.

Bet the rollers iced up in the cold;)  

J.

[gsb876]

Nah the roller cant be to blame as Babz car did 344? so alittle higher than mine and that was ok.

Had a quick blast last night in 4th and seemed fine so dont know, i\'m gonna book myself in with the Skyline dudes when they next go and get a figure @ the hubs.

I thought Nobles could have been more helpful, i asked them to run it in 3rd and they made some dodgy excuse up :rolleyes: