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Old Jul 2, 2008 | 09:38 PM
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From: NNJ
Patch for Failsafes on stock ECU

I was thinking that since we now have the ability to log boost with the stock ECU and also feed wideband AFR into the ECU we can setup some failsafes. I am talking about failsafes the way the zietronix does it.

For those who don't know, the zeitronix can look at Boost, RPM, TPS, AFR, and EGT. The zietronix then allows you to set parameters that will trigger a warning light. An example parameter could be boost>20psi & RPM>3000 & TPS>80% & AFR>12.5

The stock ECU can see all of these except EGT. In theory I think it would be possible to have the stock ECU do this function. I'm not sure that it is really needed with a knock patch but some people might want it.

I personally have the Zeitronix and use it with the parameters shown above but I was thinking why use that if the stock ECU can do it.

What do you guys think? Is it worth it? Anyone want to code it (I wish I knew how).
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Old Jul 2, 2008 | 10:15 PM
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What would be the action taken once a condition has been exceeded?

Really (and feel free to correct me) KnockSum is the only thing we are interested in, overboosting will be handled by BoostLimit table.

If we see knock then backing of the GAS is probably the best thing we can do to protect the engine...
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Old Jul 2, 2008 | 11:42 PM
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You could use a second 3 port solenoid to drop boost to WG pressure, but you would need the trigger from an ECU output of course. This would work great as a meth failsafe or overboosting failsafe.
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Old Jul 3, 2008 | 06:47 AM
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From: NNJ
I guess knock is really the only thing we are worried about, I mean if you lean out and don't get knock then technically thats ok I guess.

I was thinking you could cut boost but instead of using an extra output from the ECU I figured you could just reduce the WGDC.

With your existing patch, what happens when knock level 1 is exceeded, what about when knock level 2 is exceeded?

Might be cool to make the CEL light flash for knock level 1, and give the option of having knock level 2 reduce the WGDC or possibly even reduce timing slightly.
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Old Jul 3, 2008 | 09:43 AM
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CEL-flash for warning, "fuel cut"/ignition cut for critical?
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Old Jul 3, 2008 | 10:07 AM
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Originally Posted by logic
CEL-flash for warning, "fuel cut"/ignition cut for critical?
I think thats a little overboard maybe just ignition retarding. You don't want to have the car completely cut out if you are in the middle of a race or need to really get on it for some reason.
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Old Jul 3, 2008 | 10:23 AM
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Might be overboard, but it's effective. When you say "failsafe", I think "last desperate attempt to save the motor". Might just be a question of terminology?
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Old Jul 29, 2008 | 10:38 AM
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Couldn't we use the intercooler sprayer output to trigger a MAC valve to cut boost? Is that output an option?
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Old Jul 29, 2008 | 04:33 PM
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Trouble is you would only cut boost to wastegate... yeah that could be 15psi less, but still..

I think the biggest/best thing someone can do is taking their foot of the gas..

Not saying I wont do a failover, I just want to discuss it first
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Old Jul 29, 2008 | 04:44 PM
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This would make me very happy:

If/and statements, like the zeitronix, for the stock ECU, something like:

if Knock=10 and TPS=100 then WGDC=0 (or whatever you want the WGDC to default to)

On the flipside, engineering something like that into the AltMap trigger would work as a failsafe

if Knock=10 and TPS=100 then switch to AltMap (and you could setup the AltMap to be your failsafe maps)

ECU+ has something like this, with if/and statements that, if triggered, reduce timing and add fuel in whatever percentage you input.
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Old Jul 29, 2008 | 04:55 PM
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Originally Posted by razorlab
This would make me very happy:

If/and statements, like the zeitronix, for the stock ECU, something like:

if Knock=10 and TPS=100 then WGDC=0 (or whatever you want the WGDC to default to)

On the flipside, engineering something like that into the AltMap trigger would work as a failsafe

if Knock=10 and TPS=100 then switch to AltMap (and you could setup the AltMap to be your failsafe maps)

ECU+ has something like this, with if/and statements that, if triggered, reduce timing and add fuel in whatever percentage you input.
Just have to decide how you want to set up the statements. You could have a lot of statements such as knock, tps, rpm, afr, boost, meth flow, etc and then just set them to values you want. If you don't want to use a parameter, just set it to a value that wouldn't apply. For example, if you didn't want to use TPS you could just set the value to 0 so it would always be satisfying that condition.

I think the best way to implement this would be to set it up so that it switches to the alt map when the failsafe is engaged. This would take care of boost if you are controlling that with the ecu, fuel, and timing.

It would be also cool to add in a few parameters that can be used with the spare inputs on the ecu. So we could input the signal to the ecu and use it as part of the failsafe. Wideband and meth flow are just a few ideas that come to mind.
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Old Jul 29, 2008 | 05:08 PM
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Originally Posted by mfr122887

I think the best way to implement this would be to set it up so that it switches to the alt map when the failsafe is engaged. This would take care of boost if you are controlling that with the ecu, fuel, and timing.
I agree too, but it would be limiting for the people that use the altMap mode already for pump/race maps or pump/meth maps.
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Old Jul 29, 2008 | 05:13 PM
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Well as long as their pump gas tunes are safe on pump, there should be no problem if the failsafe kicks. On race you will be running higher octane so the pump gas map would be fine, and with meth you would be running the normal pump anyway. I think that it would be fine as long as their pump gas tunes are conservative and can act as a failsafe.
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Old Jul 29, 2008 | 05:31 PM
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Basically I would need to know
a) the conditions that _all_ must be met
b) the action to take when the conditions are met

it probably wouldn't be too hard - And have something like a safety set of maps, which would basically be 0...
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Old Jul 29, 2008 | 05:36 PM
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Originally Posted by mfr122887
Well as long as their pump gas tunes are safe on pump, there should be no problem if the failsafe kicks. On race you will be running higher octane so the pump gas map would be fine, and with meth you would be running the normal pump anyway. I think that it would be fine as long as their pump gas tunes are conservative and can act as a failsafe.
That wouldn't work for boost as there are a good amount of people running 24 psi or more on pump gas.
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