For US$110 delivered i recently got two 28 pin EPROM chips & chipped an already socketed '93-'95 NA8 ECU. You get a stock chip with a 7200rpm rev limit (you pick the rev limit) & a race chip also with 7200rpm rev limit (again you pick the rev limit) mapped for MX5 Mania/ Loch Stewart style Simota CAI, complete Loch Stewart style exhaust system, & Monster Flow style intake crosspipe for a reported 10hp gain with factory timing of 10 degrees BTDC. So this modification doesn't factor in any gain from bumping timing to 14 or so degrees BTDC. Complete socketed ECUs or socketed ECU PCB & components are also available, so it's up to you how you want to approach the modification.
In the US this modification is only suited to the '94-'95 NA8, so read '93-'95 inclusive NA8 here in Australia. It's also applicable to the European '94-'95 1.6, but not the '89-'93 NA6 in any market. US NA6 owners looked at replicating this modification, but decided Megasquirt was best, given hardware & remapping complications.
US '96-'97 NA8 & NB8 owners are also unable to take advantage of this mod due to their OBDII ECUs, but given we didn't get OBDII until the NB8B, there's a chance it might work here even though we got the revised 16 bit ECU. EDIT: After examining our NB8A ECU the modification is not applicable as it doesn't use a 28 or 32 pin EPROM, however have yet to determine if it's applicable to the Australian delivered '96-'97 NA8.
Would greatly appreciate if someone could post a pic of the inside of an Australian delivered '96-'97 NA8 ECU to determine above applicability.Also, bought a cheap eprom reader/ writer & blank chips off ebay, so any map adjustments made can be reburned to a new blank or erased chip.
Here's a couple of pics of an '93-'95 NA8 ECU with the EPROM being the rectangular chip on the left:
2mfynhh stock.jpg
95ecu_002.jpg
Discussion threads:Electronics: "socketing '93-'95 NA8 ECU"
http://mx5cartalk.com/forum/viewtopic.php?f=55&t=38209, &
Engines: "cheap power"
http://mx5cartalk.com/forum/viewtopic.php?f=29&t=38169Both linked back to this page.
Background threads:Good summary in 2nd last post:
http://www.mx5nutz.com/forum/index.php?showtopic=29849Detail:
http://forum.miata.net/vb/showthread.php?t=226162PoC:
http://sccaforums.com/forums/ShowThread ... tID=320931Dyno info:http://forum.miata.net/vb/showthread.ph ... =sts2+dynohttp://forum.miata.net/vb/showthread.ph ... e=13&pp=25
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