I'm fairly new with my 94 NSX Automatic, but I have some experience with other cars. My 94 has an SOS Throttle Body, Exhaust, and an aftermarket intake. The car is running fantastic but I can't help wonder if the ECU is taking advantage of these upgrades. I understand I have an OBD1 ECU but I'm curious if anyone out there can tell me if I should upgrade my ECU, if its worth it, and who makes them. Also, should I get headers? Thanks for your input. This site is awesome.
ECU Upgrade?
- Thread starter El-Cojonico
- Start date
If you have the 'cojones' and think you can do a better job on an essentially stock engine than the Honda engineers, go here and immerse yourself.
http://www.nsxprime.com/forum/showthread.php/211416-Tuning-the-NSX-3-0L-Using-the-OEM-ECU
The throttle body, intake, header and exhaust are relatively minor modifications that are probably well within the fuel trim limits of the ECU. There might be some small amount of power to be had by altering wide open throttle fuel map settings (either by altering the maps on an OEM ECU or using an aftermarket ECU) if you are prepared to spend the time and $ for dyno testing.
Is it worth it? Depends on your $ / hp value factor. If you like spending money, new headers would probably be a safer bet than heading into the brave territory of messing with the ECU.
http://www.nsxprime.com/forum/showthread.php/211416-Tuning-the-NSX-3-0L-Using-the-OEM-ECU
The throttle body, intake, header and exhaust are relatively minor modifications that are probably well within the fuel trim limits of the ECU. There might be some small amount of power to be had by altering wide open throttle fuel map settings (either by altering the maps on an OEM ECU or using an aftermarket ECU) if you are prepared to spend the time and $ for dyno testing.
Is it worth it? Depends on your $ / hp value factor. If you like spending money, new headers would probably be a safer bet than heading into the brave territory of messing with the ECU.
I can always count on you Old Guy to be a straight shooter. Thanks for the info. Now i'm gonna start doing research on headers and maybe test pipes. Their is no emission testing in Florida, but I really don't want the car to be too loud. As it is, the aftermarket exhaust I have, is on my limits of tolerance.
I recently installed headers on my 1994 and it was the single best performance upgrade I have done. See my post here for the details.
http://www.nsxprime.com/forum/showthread.php/210193-Headers-going-in-this-week
Towards the end of my thread I detail actual performance gains achieved on the race track. I am also running Pride high flow cats. Test pipes are up to you, however I tried them and couldn't stand the stink. YMMV.
Indeed, I remain surprised at what a difference functioning cats make to the odoriferous factor. I have an 1971 car retrofitted with digital EFI. Once warm it idles right around 14. 7 - 14.9 AFR, so definitely no soot coming out the tail pipe; but, man do I notice some strong odors that are totally absent on a modern cat equipped car. Its approaching an 11:1 static compression ratio so definitely not compliant with current NOX limits and I suspect that the odors are from NOX forming nasty things in the exhaust system.
There are a couple of threads including that by [MENTION=32537]mwagner10702[/MENTION] covering the header replacement on early cars. If you go with the later OEM na2 headers you should expect that the incremental noise will be minimal (some thin wall headers can really ring compared to a cast iron header). But, you have to deal with additional items to replace rather than just the header.
I can't really comment on the header value as I have an na2 so no basis for judging the improvement with a header replacement. My only 'value' judgement is to leave the ECU alone unless you are prepared for the 'deep dive'.
I think I will just go with a standard Na1 header install, don't want any headaches. That being said, I see my choices aren't many. Can anyone recommend a brand (OBX, DC...). Also, I guess I will be keeping my Cats but will replace the O2 sensors since I'm already down there. Any advise will be really appreciated. Also, I've been reading that I might have to have an O2 bung added to one of the headers, any truth to this? Thanks guys.
I went with Pride headers and was very pleased, both with fit and quality. However since you have an automatic I would call before ordering to make sure they will fit. Not every header manufacturer makes headers compatible with the automatic transmission equipped car. You may need to source a used NA2 factory exhaust manifold setup.
No need to add an O2 bung to the headers. O2 sensors mount in the OEM location. Only 1995+ cars need the additional bung added to the header as these had OBDII systems which used 4 O2 sensors (one before the cat and one after the cat).
Get the NA2 exhaust manifold gaskets (18115-PBY-J02) as the opening is slightly larger. Also purchase a few manifold studs as you will likely break a couple. Finally I'd recommend getting a full set (12) of NA2 manifold stud nuts (90217-765-000) as they have greater corrosion resistance.
No need to add an O2 bung to the headers. O2 sensors mount in the OEM location. Only 1995+ cars need the additional bung added to the header as these had OBDII systems which used 4 O2 sensors (one before the cat and one after the cat).
Get the NA2 exhaust manifold gaskets (18115-PBY-J02) as the opening is slightly larger. Also purchase a few manifold studs as you will likely break a couple. Finally I'd recommend getting a full set (12) of NA2 manifold stud nuts (90217-765-000) as they have greater corrosion resistance.
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