haltec in nb8a.. alternator not happy?

[irwin83r]

hey all

looking at installing an E8 stand alone in my car. i hear there are problems with the standard alternator in the 99 model?? anyone know more and or whats needed to fit?

[Matty]

The NB ECU does the voltage regulation, hence removing the ECU is bad.

If you swap in an NA8 alternator, it has the regulator on the alt.

Or just run the Haltech piggybacked (but fully controlling fuel and spark)

[irwin83r]

the na8 alternator a straight swap?

[Okibi]

I think so, ask MX52NV he's done it on an SE.

[mx52nv]

the na8 alternator a straight swap?

Yes.

[blackster]

I was under the impression that Haltech sorted out the alternator field control issue with the E8 on an NB8B/C. Perhaps msg CT and see what he worked out for his racey.

Or just run the Haltech piggybacked (but fully controlling fuel and spark)

.

If thats the case then you may as well as run interceptor and save yourself 1k in the process, providing you didnt want to raise the rev limiter.

[Boyracer]

Why not save all the hassles of doing a stand alone and go for the Adaptronic from Mania...it's a proven bit of gear and is a piggy back that does pretty much all you can do with a stand alone, but save a lot of hassles like having to control the alternator....can raise the rev limit which you can't do with the Inteceptor.

[Hellmun]

He already has the Haltech E8 which he picked up cheap a fair while ago.

[CT]

Seeing as my car was the test turbo car for Haltech and the E8, allow me to explain .......

The alternators in the NB8B and many late model cars use field control via the ECU to control the voltage. My race car used the E8 to control the alternator for 18 months. The only issue occured when the alternator voltage spiked and the failsafe circuit in the E8 would trip and fail. The solution, which is pretty simple, is to either fit a non field control alternator (as Matty suggests, although the NA will require a pulley change), as I have done, a 2 litre 626 alternator requiring simply one wire on the alternator to be disconnected. Haltech are fully aware and were involved in cause and effect studies about this issue.

For the record, all the cars using Motec, Autronic and Haltech have exactly the same issue. None of them have been terribly successful with field control. As for using a piggyback instead as has been suggested, that's fine if you are happy with partial control over the tune. Having a total choice over where your torque arrives is my preference and hence the E8 is the ECU I am very happy with - as are another 30 or so race cars north of the border proving it's reliability for many, many years.

Andrew, if you have any more questions, just drop me a note.

[greenMachine]

Yes, that's what I did for my E8, but don't ask me now what alternator was used. IIRC, it needed a wire to the instrument panel from the Haltech (alternator warning light?), or perhaps that was for something else.

[irwin83r]

cheers all.

[greenMachine]

Seeing as my car was the test turbo car for Haltech and the E8, allow me to explain .......

The alternators in the NB8B and many late model cars use field control via the ECU to control the voltage. My race car used the E8 to control the alternator for 18 months. The only issue occured when the alternator voltage spiked and the failsafe circuit in the E8 would trip and fail. The solution, which is pretty simple, is to either fit a non field control alternator (as Matty suggests, although the NA will require a pulley change), as I have done, a 2 litre 626 alternator requiring simply one wire on the alternator to be disconnected. Haltech are fully aware and were involved in cause and effect studies about this issue.

For the record, all the cars using Motec, Autronic and Haltech have exactly the same issue. None of them have been terribly successful with field control. As for using a piggyback instead as has been suggested, that's fine if you are happy with partial control over the tune. Having a total choice over where your torque arrives is my preference and hence the E8 is the ECU I am very happy with - as are another 30 or so race cars north of the border proving it's reliability for many, many years.

Andrew, if you have any more questions, just drop me a note.

FWIW, from the E8 manual Version 2.0 - 4 August, 2008

Alternator Control (Mazda)
Some Mazda alternators require a PWM actuated signal to maintain a steady output voltage. This feature allows the ECU to control the PWM output to achieve the desired alternator output voltage.
Actual alternator control values from a NB Mazda Miata MX5:
Figure 49 (won't paste - see p54)
· Frequency – The frequency required to control the given alternator.
· Start Duty Cycle – This duty cycle will be run when the engine is cranking, this is also the duty cycle that the controller starts the control process at.
· Gain – Controls the sensitivity of the control system, the larger the gain the larger the change in duty when there is an error between the actual battery voltage and the desired battery voltage.
· Target Voltage – Sets the target output voltage of the system.
· Min Duty – The minimum duty cycle the control system will output.
· Max Duty - The minimum duty cycle the control system will output.

[Okibi]

How did you go?

From the Haltec forum:

The base settings are always a starting point for tuning, and should always be checked for your particular installation. Please take some care here since setting this up wrong can over-voltage your car quite considerably, possibly damaging other electronics.

Now that that's out of the way, the frequency was measured off an MX5 (Miata). The Start Duty should approximately correspond to the duty required to achieve the target voltage. The more accurate this duty, the less work the controller has to do. Change this slowly until the voltage error is minimized.

Min and Max duty's are set to allow full range of operation.

The Gain has been set to minimize any error in voltage when electrical load changes. If this is set too high, you may get a slight fluctuation in voltage, if you set this too low, then the voltage may drift with varying electrical load. E.g. If you have headlights off, you might get exactly 14.7V, but with headlights on, you get 14V. Typically, I used to see around 0.2V to 0.3V error from min electrical load to max electrical load when the alternator control was working acceptably.

The target voltage depends on you battery type. The MX5 tested here showed up to 15V when charging, but a more conservative 14.7V was chosen for the base map.

The Output Inverted option is active in the case where a Haltech patch harness is used. The patch harness uses a circuit to drive the alternator control signal high when the ECU output is GND'ed. This is why this output is inverted. The patch harness has this circuit so that in the event of a worst case failure scenario (such as a wire or connection failure), the alternator is set to minimum charge.

If you wire this output direct with a pull up resistor, then do not use the inverted option, but keep in mind that if the harness fails, depending on where your pull up resistor is, then you might end up with 16V+ coming out of your alternator.

The base settings are listed below so people can follow this discussion without opening a base map:
Frequency: 250Hz
Start Duty: 75%
Minimum Duty 0%
Max Duty 100%
Gain 100
Target Voltage 14.7
Output Inverted

This output function is provided for convenience to Mazda owners and to enable the proper operation when used with a Haltech Patch Loom kit.

Please use a spare PWM output to the charge wire of the Alternator.
Use a 470ohm pull up to 12v on the chosen PWM output.
Please use the software settings previously mentioned.
Remember to check to voltage at each RPM site before racing!

Would you recommend me running one of the new haltec units in my NB8A?

They don't list a plug and play loom on their website, I left a message on their website but haven't received a reply yet.

[CT]

Contact them directly. We have proven how reliable these things are now for many years. The E8 is by far the most cost effective real ECU for the MX5. My car has their first patch loom which was built a few years ago too. My tuner loves it too!

[RobH]

Hi Okobi,

I am in the middle of replacing my ECU as well and the alternator was one of the main hurdles we came accross. We ended up replacing the alternator with a TX5 (Ford Telstra) one which was pretty much a straight swap.

We are still to do proper tuning so I am currently running the standard ecu. Hopefully this will be changed in the next couple of weeks.

Rob