i need to get one of these but am unsure what i need.
basically i have a boost problem but i cant seem to find the fault!!
my ecu is set to run at 1.15bar but at the moment it goes to .8bar.
so can i just get a cheap bleed valve off ebay for £20 and that will do the job?
like this
http://cgi.ebay.co.uk/MECHANICAL-BOO...item35ac8edade

thanks

 

You say your ECU is 'set to run', are you talking factory values or have you had it remapped?


What MY car are we talking about and what mods have you got?


I would only ever use a MBC to lower/cap the boost, never to raise it.

 

its got a chip on it which has been mapped to run at 1.15bar
its a 1993 wrx with a decat, dv and panel filter.

 

Is that one of Major_S's chips is it??

You have the same set up as me, '93 import, chipped, full decat and KnN panel. Mine over boosts and hits fuel/boost cut. I use a Dawes Device to cap it below cut.

I would suggest that your chip is a fault as you should be hitting 1.1bar (16psi). If you are not hitting the 'advertised' boost limit, how can you be sure that the rest of the map is doing as 'you have been told' it would?? If the fuelling on the chip is as far out as the boost then you could easily be getting knock/det, especially if you manually increase the boost.

I would highly recommend you get the car looked at to ascertain the AFR's if nothing else.

As a side, you have cut the J1 haven't you??

 

yes it is, he assures me the chip is 100% but have been thinking of asking to try another on my car just to be sure.

yes i have cut the j1..
the chip is definately working.

 

It obviously is not 100% or you would not be at the stage you are. How are you so sure the chip is 'definitly' working?

1.The boost is not making its target, therefor,

2.You don't know if the cut has been raised.

3.Unless you have a KS, wideband AFR meter or datalogging s/w you can't tell if it runs ok on NUL or in fact if it's runnnig ok on V-Power for that matter.

That's with out thinking 'is the turbo is spooling any quicker?'

The only thing that is definite is, that the chip has a map on it, but what map that is.............

I have ran a PolarPerformance chip for around 2 years now with no ill effects, however, i did have the car on the rollers very shortly after fitting to check all was as it should be. In total, my chip cost me around £200, but i have peace of mind that all is well.


Also, if you do go down the MBC route and up the boost to 1.15bar, you will be increasing the boost by c.30%. Bare in mind that the fuelling will need to be matched to achive the correct AFR's. As the map is not performing as it should in one area, then it may not be performing correctly in other areas (ie.fuelling). This would result in det/knock, and we all know what that gets you.

 

has this been resolved yet? i noticed your no further on in your not boosting thread either. tried the restrictor in the bottom pipe of bcs to see if it's actually there?

 

Just out of interest, you have installed the chip properly havent you? And cut the Resistor?

Sounds to me like your still running the standard map...

 

If the 'pill' is missing then you will get boost creep/overboost on a 3 port BCS. The 'pill' in the 2 port work the opposite way round. Not a bad call though, as if the 'pill' is blocked then it could reduce boost, so worth a look.

You say in your other thread (keep them together, it helps people to help) you have a full decat fitted. When i fitted my decat it caused overboost!