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Old 18-03-2019, 02:37 PM
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Scott.T Scott.T is offline
Admin, Meets/Events Organiser.... formerly known as SilverSurfer
 
Join Date: Sep 2008
Location: Hastings, East Sussex
Posts: 9,483
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Hi Stuart, sorry for the late reply it's been a while since I last spoke about one of these.
I think the last one sold was getting on for 10 years ago now.

If you look at the label there should be a code on it along the lines of IMP-ECU-xxxx. From that I should be able to tell you exactly which variant it is.

The map within the chip varied slightly over the years, as thing evolved and more knowledge was gleaned. The basic boost control was modified to run 16.11psi (with corresponding ignition/fuelling changes). If boost was set to run any higher the standard 380cc injectors were running out of juice and the 2.5bar (absolute) MAP sensor was heading towards it's limit.
Tolerance variations with the MAP sensor also meant that running any higher could cause inadvertent activation of the boost/fuel cut safety feature.

People ran these in various guises from just an Exhaust BB through to Full Decat and in some cases FMIC modifications. Some even ran them successfully in national hillclimb events.

Some criticised the 'Generic 'Nature of these tunes (which is a common gripe in the Subaru community, not so much in any other marque). However, the ECU / mapping seemed to cope with all variations quite well and was found to be less fussy than the more complex later ECU (Live tuning of 2001> ECU proved this, as I don't have 2 boost control maps the same between cars I've setup).

The biggest issue for the MY1993-1996 was coil pack failure i.e when increasing the boost cars would start to miss-fire, where they hadn't previously.
The additional boost was blowing out the weak spark.
It took quite a bit of convincing to get the customer to spend £300 on coilpacks (only available through Subaru at the time) in order to run the Polar Performance (and all other variants) chip.
However, once they finally fitted new coil packs they were grinning from ear to ear.

As mentioned above if you can provide the label info I should be able to give you exact details on the tune.
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