Any 2nd Gen ECU Mods?

[C. Ludwig]

A GM MAP sensor (which most standalone systems use) has a three pin connector. +5V, GRN, and signal. The GRN and +5V are easy to source. You could easily use one of the connectors for any emissions related item that is not being used (the vacuum rats nest comes to mind) connected to the signal output of the sensor to route the signal back to the box and then reconfigure the wiring inside the box to get the signal to your EMS of choice. Come on Marty, gotta think outside the box.

Mazda actually uses a MAP sensor in the stock system too. It's the "boost sensor". It's mounted on the right hand wheel well.

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Chris Ludwig
08 ITS RX7 CenDiv

[Geo]

Originally posted by C. Ludwig:
A GM MAP sensor (which most standalone systems use) has a three pin connector. +5V, GRN, and signal. The GRN and +5V are easy to source. You could easily use one of the connectors for any emissions related item that is not being used (the vacuum rats nest comes to mind) connected to the signal output of the sensor to route the signal back to the box and then reconfigure the wiring inside the box to get the signal to your EMS of choice. Come on Marty, gotta think outside the box.

How would adding a sensor be legal?


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George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com

[JeffG]

MegaSquirt FAQ:
3) Many different ignition solutions have been spawned from the base MegaSquirt, such as MSnS. The rotary engine ignition requirements, with trailing firing after the leading, has not yet been achieved using MegaSquirt or its derivatives.

Looks like a fun unit if one wants to start from scratch and play, and play, and .......

There's an awful lot of things to worry about when designing and ECU, even if its only required to function primarily at WOT and idle.

[Eagle7]

Originally posted by C. Ludwig:
Come on Marty, gotta think outside the box.

I didn't think that was the right approach in this situation

<font face=\"Verdana, Arial\" size=\"2\">Mazda actually uses a MAP sensor in the stock system too. It's the \"boost sensor\". It's mounted on the right hand wheel well. </font>

Ooh, didn't know that. Very interesting.

Thanks,

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Marty Doane
ITS RX-7 #13
CenDiv WMR

[C. Ludwig]

Originally posted by Geo:
How would adding a sensor be legal?

How would it not be? You can already add all the sensors you want for gauges and datalogging. You've also been able to use resistors inline to alter the values of OEM sensors for some time. The MAP sensor is a variable resistor.

And if that doesn't suit someone's legal needs the MAP sensor could be stored inside the box (at least of a 2nd gen RX-7) and hardwires to the EMS. That is the way the Autronic and Microtech system are setup anyway AFAIK.

[This message has been edited by C. Ludwig (edited December 07, 2004).]

[This message has been edited by C. Ludwig (edited December 07, 2004).]

[C. Ludwig]

Originally posted by Eagle7:

Originally posted by C. Ludwig:
Come on Marty, gotta think outside the box.

I didn't think that was the right approach in this situation

Eh, bad pun...


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Chris Ludwig
08 ITS RX7 CenDiv

[Geo]

Originally posted by C. Ludwig:

How would it not be? You can already add all the sensors you want for gauges and datalogging. You've also been able to use resistors inline to alter the values of OEM sensors for some time. The MAP sensor is a variable resistor.

And if that doesn't suit someone's legal needs the MAP sensor could be stored inside the box (at least of a 2nd gen RX-7) and hardwires to the EMS. That is the way the Autronic and Microtech system are setup anyway AFAIK.

[This message has been edited by C. Ludwig (edited December 07, 2004).]

[This message has been edited by C. Ludwig (edited December 07, 2004).]

ITCS 17.1.4.D.1.a.6:

Fuel injected cars my alter or replace the engine management computer, or ECU, provided that all modifications are done within the original OEM ECU housing. On the stock (unmodified) OEM ECU connection to the wiring harness may be used. The allowance to modify the ECU in no way permits the addition of wiring, sensors, or piggybacked computers outside of the OEM ECU housing. The stock (unmodified) wiring harness must be used. Adjustable fuel pressure regulators are permitted.

OK, so you cannot add sensors for the ECU. Nor can you add wiring for the ECU. And if you put the MAP sensor inside the box, how will you get to the MAP sensor without illegally modifying the OEM ECU housing?


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George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com

[C. Ludwig]

"The allowance to modify the ECU in no way permits the addition of wiring, sensors, or piggybacked computers outside of the OEM ECU housing."

Eh, I forgot about that. I stand corrected on that note. However let me look at an ECU housing long enough and a way to worm a 1/8", hardshell vacuum line through there will appear.

And once again this rule has shown to me that it's a bad idea. The highest end systems ($$$) can be set up to run run with factory sensors. Making only the most expensive systems appropriate. There are relatively low cost alternatives that can not be used because of the wording. I hated to see the rule changed in the first place. But now that the cat is out of the bag the least expensive approach is to throw open the barn door IMO.

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Chris Ludwig
08 ITS RX7 CenDiv

[Eagle7]

Originally posted by C. Ludwig:
...And once again this rule has shown to me that it's a bad idea. The highest end systems ($$$) can be set up to run run with factory sensors. Making only the most expensive systems appropriate. There are relatively low cost alternatives that can not be used because of the wording. I hated to see the rule changed in the first place. But now that the cat is out of the bag the least expensive approach is to throw open the barn door IMO.

Yeah, that's my take on it, too.

BTW, not sure that snaking a vacuum line into the ECU housing would pass muster. More opinions on that?

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Marty Doane
ITS RX-7 #13
CenDiv WMR

[lateapex911]

Sounds like adding a MAP sensor in the box is adding a MAP sensor...or am I confused? Isn't addding sensors illegal?

Now...if you just take one of the larger ECU harness wires, and pull the conductors from within, you could have yourself a nice vacuum line....until vacuum was applied and it collapsed..

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Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]

[Quickshoe]

Doesn't a circuit that "senses" a +5V signal, where that circuit did not exist before, mean that you have added a sensor?

[Geo]

Originally posted by lateapex911:
Now...if you just take one of the larger ECU harness wires, and pull the conductors from within, you could have yourself a nice vacuum line....until vacuum was applied and it collapsed..

It would also no longer be a stock, unmodified wiring harness.

Here's an idea though that I've thought about for a while....

Some folks have mentioned the Unichip, but that it would require a change in the rule. My question is would it? Can the circuit board of the Unichip fit inside a stock ECU box? If so, it should be possible to legally use one. It would require splicing the unichip between the ECU connector and the ECU board. A lot of work, but that's not the question....


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George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com

[C. Ludwig]

You guys have made my head hurt. Tell you what, I'm going to leave my box stock (the way I think it should stay...but that's neither here or there) and save the cash I'd dump on modifying it for the SP car I'd like to have someday. That way I know whatever I do will be legal.

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Chris Ludwig
08 ITS RX7 CenDiv