tuning 95+

[satx]

from the reading I've done it seems that the 95 and newer NSX's cannot be tuned except by a stand alone EMS. Why is this?

 

[liberty1performanc]

oem obd2 ecu's are alot harder to manipulate. it can be done but takes a lot more to do .if you don't want an ems does hondata do any thing for your application? but i would really go with the ems because of all the tunning capabilities to be had!

 

[Semnos_NSX]

I have a ’99 with a bunch of go fast goodies, one of which being a CTSC. I don’t have an EMS, but I do have a VAFC. Recently, I wanted to get it tuned so I started making some calls to reputable Southern California NSX shops to find who I wanted to tune it. One of the shops I called said that having a VAFC was worthless and that I needed to get an EMS because the 99’ has a learning computer and if you tweak the air/fuel ratio while still using the stock computer, it will just revert back to stock settings (no gains will be found) . I then called another shop and asked them if they could tune it using the VAFC and they said sure. I explained to them what the previous shop stated and they said they could make it work. I decided to give it a try and take it to them. After the tuning, I was amazed to find that the VAFC made an extra 15 RWHP:biggrin: . To make sure the computer is not reverting back to stock settings; the shop owner asked me to drive the car for about a month then bring it back so they can make sure the fuel curve is the same. So far the car feels great and I will be taking it back to them shortly to make sure everything is fine. If everything goes well and my fuel curve does not change, I would definitely say tuning can be done with out having an EMS, although I would love to have one.:biggrin:

 

[02#154]

One of the shops I called said that having a VAFC was worthless and that I needed to get an EMS because the 99’ has a learning computer and if you tweak the air/fuel ratio while still using the stock computer, it will just revert back to stock settings (no gains will be found) .

To make sure the computer is not reverting back to stock settings; the shop owner asked me to drive the car for about a month then bring it back so they can make sure the fuel curve is the same.

The stock ECU isn't in closed loop at WOT, is it? I thought that at WOT, the ECU goes into open loop and doesn't use any of it's "learned" data to fire injectors (or advance/retard timing). It has a WOT table and that's what's used. The VAFC makes changes to the outputs of that table, so the settings on it should make a difference.

(This post is not meant to indicate whether tuning with a VAFC is a good idea or not.)

J

 

[Semnos_NSX]

The stock ECU isn't in closed loop at WOT, is it? I thought that at WOT, the ECU goes into open loop and doesn't use any of it's "learned" data to fire injectors (or advance/retard timing). It has a WOT table and that's what's used. The VAFC makes changes to the outputs of that table, so the settings on it should make a difference.

(This post is not meant to indicate whether tuning with a VAFC is a good idea or not.)

J

Apparently, one of the shops I called agreed with your logic and the other did not. I took it to the shop that did and so far it seems that you are right.

I never meant for this post to indicate whether tuning with a VAFC is a good idea or not. The original question was asking why can’t 95 and newer NSX’s be tuned with out an EMS. I was simply stating through experience that they can be tuned without spending $4000 on an EMS.