Sorry looks like I am a little late to the party.
You have a few options and some of the information posted in the above posts do not take into account the OBD2 OEM ECU in your car. To clear a few things up and get you going I have tried to sum up your options but I have a question for you as well.
1. Do you have a plug in emissions test in your area?
OK, since you have an OBD2 NSX and most likely have a plug in emissions test you will have to pass you have two real choices, Keep the CTSC fuel system and improve it a little or add a piggy back and improve it a lot. If you have no emissions testing to worry about then you are free to consider a stand-a-lone ECU like the AEM Series 2 ECU or Infinity ECU.
The Comptech fuel system is really a bit of a bandaid but it works for what it is, what it does is trick the car into thinking it is a WOT with no boost any time the car is really in boost. It does this using a voltage clamp on the MAP sensor, CT calls this an ESM. This is needed to keep the OEM ECU from seeing any boost as it will go into limp mode without the voltage clamp. Once the ECU is prevented from going into limp mode and thinks the car is running at WOT without boost you have to have a way of increasing the fuel being added to the combustion process to account for the added air from the boost. The CT fuel system does this without changing the injectors by increasing fuel pressure while the car is in boost relative to the boost pressure. CT does this by replacing the stock fuel pressure regulator with an adjustable unit they call an FMU. The FMU will allow the fuel pressure to be increased to as much as 100-110 PSI from the stock fuel pressures of 50-60 PSI. Since the OEM ECU is no longer calculating the amount of fuel needed for boost (remember the ESM has told the ECU the car is running at WOT and there is no boost) the injectors are injecting at a fixed pulse width, so the only way to get more fuel into the engine from an injector that is operating at a fixed injector pulse is to increase the pressure of the fuel being sprayed. The problem is that the stock fuel pump operating at stock voltage can not deliver 100-110 PSI without some help. CT added a Boost-a-pump (BAP) or voltage doubler to take the normal 13.8vdc being feed into the fuel pump and kick it up to about 16vdc while the car is in boost. The increased voltage causes the pump to turn faster and pump more fuel. The added fuel being pumped combined with the adjustable FMU allows the injector rail pressure to jump to 100 PSI and push more fuel through the injectors.
If you decide to keep the CT fuel system, then the best thing you can do to improve that system is make sure the fuel system is working as well as possible:
1. Clean Injectors
2. New Fuel Filter
3. New Fuel Pump
4. Tune - not much to tune, you just adjust the base fuel pressure to allow for the proper peak pressure and AFR while in boost
5. I would recommend a wide band with logging options to monitor, Boost, fuel pressure, AFR, RPM, and Throttle position. A single ZT-2 with a few extra sensors will do all this.
If you decide to run a piggy back the most common one used with the OBD2 cars is the AEM F/IC. If you run the F/IC you can get rid of the BAP, ESM, and the FMU but you will be required to change the injectors to larger ones and the fuel pump will also need to be replaced. The advantage of the F/IC is we will have better control of the fuel system, we can now control the injector while the car is in boost, we can run stock fuel pressures, we can retard timing while in boost, and we get rid of the BAP that can over stress a fuel pump and cause it to fail earlier than normal.
If you decide to run the AEM F/IC you will need:
1. New injectors 440-550cc are recommended (I think it is best to run an injector that is similar in design and latency to the OEM injector so I do not recommend running the RDX injector with the F/IC)
2. New Fuel Filter
3. New Fuel Pump
4. AEM F/IC
5. Plug N Play Harness for OBD2 Car and F/IC
6. Tune - You will need to tune the car on a dyno with a tuner that understands the F/IC
7. I would recommend a wide band with logging options to monitor, Boost, fuel pressure, AFR, RPM, and Throttle position. A single ZT-2 with a few extra sensors will do all this. However if you only add an AFR Sensor you can connect the sensor to the F/IC and log within the AEM F/IC software but it will require you to have a laptop connected to the F/IC to do the logging. I would still choose the ZT-2 and wire its AFR output to the F/IC. If you want additional data the ZT-2 can log those sensors as well.
The other option if emissions are not an issue is to add an after marker ECU to run the engine, the AEM Series2 ECU or Infinity ECU are both used with the NSX and are supported to varying degrees by a few different vendors. If you go this route you have a lot more to think about and your tune and tuner will be critical to your success. There are other options in aftermarket ECUs but the AEM will be the easiest path.
If you plan to track a low boost CTSC keeping the Intake Air Temps in check are the most important and most difficult thing to do because of the CTSC design. If you do not control the IATs you will not make the power you want and you will loose power lap after lap as the temps increase. The power loss is something you will feel while on track and will likely feel on the street as well. A 3.2l CTSC with the standard pulley will have no problem making 340-350 whp and can make more. The following Dyno sheet is from a 3.2l with a CTSC Whipple, 6lb pulley, RC550cc Injectors, Walbro 255 fuel pump and AEM F/IC using the OEM fuel pressure regulator.
One other thing we need to clarify, if you have AEM serial gauges they will only work with the AEM Series2 ECU as they require a data stream from an AEM ECU to function, they will not work with the AEM F/IC or as stand alone gauges so make sure what you have is what you need. If you go with the ZT-2 for your AFR and logging they make all kinds of gauges and data displays to show the collected data in gauge form.
Dave
Better safe than sorry.
