dont have my NA 1.6 for some time, decided to write some of my thoughts of modyfying it I still remember, Maybe someone use it
00. dont be afraid of 90HP version.its not much worse than 115HP version. Usually shows 100-105Hp on dyno, while many of 115HP are below 115
0. spark advance adjustment Mandatory for all NA 1.6 users. Instead of stock 10 degrees set 14. Some give even more but it does not work on every engine). Gain is few Nm on low and mid-rpm and 1-2HP. Too much advance can show HP decrease, you have to do your own testing. Many years ago I verified acceleration time on 2nd gear 3000-6500rpm. Worked. Now there are apps for smartphones to do it.
1. intake mods
both versions have AFM device (identical) that limits flow. Heare are measurements and proposed solution:
https://www.autospeed.com/cms/a_110680/article
worth trying
- intake mods, cone air filter
Http://www.solomiata.com/DIYIntakes.html
possible few HP gain on high RPM, if you install it wisely to let COLD air enter intake
- next ster bigger AFM from Mazda RX-7
http://www.solomiata.com/airflowmtr.html
practically not avaliable at this time. But you can but MX-6 or Ford Probe device. Mechanically identical as RX-7, different iside. So you have to install MX-5 electrnics there. Here is how:
https://forum.miata.net/vb/archive/inde … 70157.html
some clever ideas needed to install (does not fit stock airbox), adjustment and works
possible another few HP high-RPM gain
2. exhaust mods Havent done. Maybe someone will write ...
3. cams swapespecially if you have 90HP version
if you have 90HP swap cams from 115HP immediately. Better in all areas.
install plug and play. Few Nm/HP gain, after ECU modification another few
more hardcore mod is using MX6 exhaust cam as intake in MX-5. Exhaust from mx-5 115HP
had for a while, didnt worked for me. No torque below 4500 rpm, going mad from 6000 to 7500 (i was afraid to set limiter higher). Probably i screwed something, lots of guys wrote it worked well for them
https://forum.miata.net/vb/showthread.p … 040&page=6
think its worth considering
4. ECU modifications
115HP ECUs cannot practically be modified. You can only overclock them and raise RPM limiter this way. It also affects spark advance and fueling. Very limited
115HP ECU can be used in 90HP car, after modification. But I recommend 90HP ECU remap, below
90HP ECU - there are few versions - has programmable EPROM and can be modified. I raised RPM limiter (6800->7300), modified spark advance. Gain on dyno was not very big (3Nm 2HP) but car had better throttle response. Pleasant for daily driving. If ECU has immo - remap preserves it
more info in thread
viewtopic.php?f=71&t=31652&view=unread#unread
UPDATE 2023currettly i recommend my ECUs Speeduino PnP NAMuch bigger mods possible: fueling, spark, and many more
5. head shave
potential Nm/HP gain, especially in case of 90HP version with lower compression (9.0 vs 9.4 afaik)
if you are doing head refreshment or headgasket replace - consider it. I personally havent done this
5. lightened flywheel
due to lowering rotating mass we gain faster RPM rise on low gears
worth considering if you are replacing clutch or gearbox for instance
other useful links
http://jasoncuadra.fortunecity.ws/id49.htm
good luck!
