Mazda Rotary Club

General => General Technical => Anything Engine/Performance/Tuning related => Topic started by: gsb876 on March 05, 2005, 08:47:28 PM

Title: Rolling Road Blow Out ???
Post by: gsb876 on March 05, 2005, 08:47:28 PM
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 :(
Title: Rolling Road Blow Out ???
Post by: scooby_si on March 05, 2005, 11:59:36 PM
stupid question why is is set for only 10 sex of boost?
Si
Title: Rolling Road Blow Out ???
Post by: gsb876 on March 06, 2005, 10:31:26 AM
Only just seen it when i was checking the unit.
Title: Rolling Road Blow Out ???
Post by: sadgoth on March 06, 2005, 11:27:00 AM
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?
Title: Rolling Road Blow Out ???
Post by: antnicuk on March 06, 2005, 11:44:13 AM
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.
Title: Rolling Road Blow Out ???
Post by: gsb876 on March 06, 2005, 01:04:23 PM
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 ???
Title: Rolling Road Blow Out ???
Post by: FD3UK on March 06, 2005, 07:42:46 PM
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
Title: Rolling Road Blow Out ???
Post by: Tintin on March 06, 2005, 07:54:12 PM
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
Title: Rolling Road Blow Out ???
Post by: 20B_boy on March 07, 2005, 06:21:16 PM
Gurj - do u have a clearer picture u can post?
Title: Rolling Road Blow Out ???
Post by: gsb876 on March 07, 2005, 06:28:21 PM
Canna get the pic any clearer have tried matey :(
Title: Rolling Road Blow Out ???
Post by: scooby_si on March 07, 2005, 06:30:54 PM
here you go i\'ve cleared it up a bit for you ya technical numpty:












































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?)
Title: Rolling Road Blow Out ???
Post by: Wav on March 07, 2005, 06:31:34 PM
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
Title: Rolling Road Blow Out ???
Post by: scooby_si on March 07, 2005, 06:36:54 PM
what with a sub the size of a small country in boot & not much power i doubt it ;)
Si (runs for cover......)
Title: Rolling Road Blow Out ???
Post by: jonyb on March 08, 2005, 09:55:49 AM
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.
Title: Rolling Road Blow Out ???
Post by: gsb876 on March 08, 2005, 12:01:41 PM
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:
Title: Rolling Road Blow Out ???
Post by: jonyb on March 08, 2005, 01:43:44 PM
If its any use the Northants gang have a RR day at Thor booked for the 2nd April......some spaces left if your interested.

Going to give mine a run see how it sorted against Geff\'s figures.

J.
Title: Rolling Road Blow Out ???
Post by: scooby_si on March 08, 2005, 06:01:24 PM
er didnt we already discover your controller was killing it after 10 seconds thou dont see how anything else needs looking at if that\'s case get a proper controller you grinder wananbee :rollin pmsl
Si
Title: Rolling Road Blow Out ???
Post by: gsb876 on March 09, 2005, 07:01:54 AM
QuoteOriginally posted by scooby_si
er didnt we already discover your controller was killing it after 10 seconds thou dont see how anything else needs looking at if that\'s case get a proper controller you grinder wananbee :rollin pmsl
Si

Why you got one for free ???? :rollin :rollin :rollin