Rev Limiter
- Thread starter SVT Fun
- Start date
6250
x2
and it cuts fuel NOT spark.
Not only cuts fuel, it actually cuts ALL the fuel to every other cylinder, effectively making them a dead cylinder (not a lean cylinder)...
93Cobra#2771 said:
I recently had my autologic chip reburned from Byron Reynolds at Race Systems and here is what he did to my X3Z ECU. I'm still using the factory MAF, intake & airbox, exhaust mods and pullies. TPS set at .99 volts. Crisp throttle response and it runs like a Banshee up to redline. Have not had it to the dyno yet.
The changes made were:
- Remove tip-in power-delay timer present in X3Z
- Remove top-end speed limiter present in X3Z
- Remove lean accelerator pump function present in X3Z
- Complete injector timing table (X3Z fixes injection timing at 300deg of crank; looks like they never tuned it.)
- Remove half-fuel rpm limiter; substitute cut-fuel rpm limiter (stops lean condition at top end).
- +2deg part-throttle spark-adder
- Reshape WOT spark curve completely. 30deg total advance based on 10deg base. Set base timing to 10. (I have mine set at 12 degrees right now running 93 octane BP fuel)
- Trimmed injector slope at idle to help idle stability.
- Reshape part-throttle fuel and spark tables. X3Z is lean in the mid-band and too advanced in the mid-band (I think he mis-stated something here)
Essentially, your calibration looks more like an A3M1 box now than an X3Z...with improvements above and beyond what A3M1 has to offer.
Last edited:
Byron is THE MAN. I had one of his chips at one time, till I got my tweecer. He went above and beyond with his customer service, and did several different tunes for me trying to fix my drivability issues (bucking/trailer hitching at light throttle).
I always recommend him to others for a mail order chip.
I always recommend him to others for a mail order chip.
93Cobra#2771 said:
Yes, I totally agree on the customer service comment. I have never met ANYBODY more CS oriented than Byron. Props to him.
As usual, informative responses, gentlemen.
The X3Z has several areas in need of improvement.
From a performance standpoint, adapting these areas is imperative.
jspalmer (or anyone with the knowledge), could an elaboration be posited about the following:
1) top end speed limiter ?
2) lean accelerator pump function ?
3) tip-in power-delay timer ?
Any additional, more detailed information concerning the above 3 falls under the "greatly appreciated" category.
The X3Z has several areas in need of improvement.
From a performance standpoint, adapting these areas is imperative.
jspalmer (or anyone with the knowledge), could an elaboration be posited about the following:
1) top end speed limiter ?
2) lean accelerator pump function ?
3) tip-in power-delay timer ?
Any additional, more detailed information concerning the above 3 falls under the "greatly appreciated" category.
SVT Fun said:
FUN,
I am not an EEC IV tuning subject matter expert so I won't pretend to be :-D Byron is a REALLY, REALLY nice guy. I bet if you gave him a call he could explain exactly what he did and why. www.racesystems.com
1. Not a set "mph" type of speed limiter. It actually richens the a/f at WOT, and reduces timing, thus reducing HP and speed.
2. When the car is sitting still, in neutral, and you rev it, ever notice the hesitation it has compared to an A9L car? That's what it is.
3. Just guessing, but I think he is referring to the delay it takes for the transition from closed loop to open loop during high load/non WOT conditions. Basically, when teh eec sees a certain amount of load for a certain number of seconds, it will shift into open loop and command WOT fuel and timing tables. The delay for an A9L is 2 seconds, and the delay for an X3Z is 8 seconds. It's mainly a fuel economy thing, but can make a difference at times. Most tuners will set it to 0 seconds for instantaneous response times...
2. When the car is sitting still, in neutral, and you rev it, ever notice the hesitation it has compared to an A9L car? That's what it is.
3. Just guessing, but I think he is referring to the delay it takes for the transition from closed loop to open loop during high load/non WOT conditions. Basically, when teh eec sees a certain amount of load for a certain number of seconds, it will shift into open loop and command WOT fuel and timing tables. The delay for an A9L is 2 seconds, and the delay for an X3Z is 8 seconds. It's mainly a fuel economy thing, but can make a difference at times. Most tuners will set it to 0 seconds for instantaneous response times...
93Cobra#2771 said:
As Richard said.....
they are on ebay all the time
Users who are viewing this thread
