In the days before standalone engine management systems really came into their own, piggyback systems were The Big Thing. Marketed as (deep breath) “a plug-in fuel management system designed to supplement and refine the OEM fuel curve to maintain a proper air/fuel mixture when increasing boost pressure in turbocharged applications”, HKS’ F-CON series was one of the more popular choices to come out of Japan during the ’80s and ’90s.

HKS Programed (sic) Fuel Computer.

From what I can gather, the F-CON simply hooked into the standard ECU injector signal and modified it to allow for increased fueling at higher boost levels, not unlike some of the more esoteric “boost enrichment solenoid” DIY kits of the late ’90s. Further fine-tuning of the ‘map’ could be achieved through use of a plug-in hand controller.

This particular F-CON is for the DR30 and US12 FJ20ET, and doesn’t come with the piggyback harness nor boost sensor (which are both necessities given the age of the product). As a result, the start price is an incredulously low 2011 yen.

I could almost be tempted to buy it for squid (for bonus points in the “authentik ’80s mods” category) but without a harness it’s pretty much useless other than for trinket value.

And besides, I’ve already got a Link G4…

DR30 US12 FJ20ET HKS F-CON (body only) for sale on Yahoo! Auctions Japan »