ECU modification rules

[cherokee]

Why not open up the computer rules all the way...then let the carb guys switch to FI if they want. It would solve everything....right . That would solve everything. We could also let the carb guys run any carb and intake they want. I have a side draft setup I would love to put on the Opel.

[Banzai240]

Originally posted by chipbond:
If we loose the "or replace" verbage in the current ruling, as you favor, we will be forced to spend large sums to reprogram the stock ECU every time an engine rules change affects us. The ease with which changes can be made in an aftermarket ECU help keep racing costs minimal. I think that in both the long and the short term, the aftermarket "replacement" is more adaptable and less costly than the repeated expense of modifications of the OEM ECU.

And as time goes on, the cost of these boards will decrease further, we would expect.

Chip Bond
Caterham 7 America #37 EP
GT Classics

Chip,

Thanks for sharing... Am I understanding you correctly in having a desire to leave the rules alone? Or are you advocating allowing any ECU?

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Darin E. Jordan
SCCA #273080, OR/NW Regions
Renton, WA
ITS '97 240SX

[Banzai240]

Originally posted by Bill Miller:
There you go again Darin, trying to put words in my mouth.

First of all... what words am I trying to put into our mouth??

Second, I'll go ahead and answer my own question, since you aren't up to the challenge...

Changing the resistance values of the sensors that feed the ECU is currently NOT legal... It was in 2002, but in 2003, when the current ECU wording was put in place, this allowance was removed. We have requested that the CRB add it back in under Errors and Omissions, since we don't believe it should have been removed in the first place, and it potentially made many cars who had implemented this change illegal.

You don't have the mechanism, or the capacity to admit when you're wrong.

Oh, quite the contrary... If I am wrong, I'll admit it... But I'm not... Changing the resistance values of the water temp sensor, which is essentially the main one that gets changed, just fools the ECU into thinking the engine needs to be richer. It does that across the board, unless you use a manually variable resistor, in which case you'd be driving with one hand on the wheel and one on the knob to get the kind of on-the-fly adjustability and tuneability that say supply, or that can be tuned into a Weber with different emmulsion tubes, air correctors, idle and main circuits, etc...

If you're going to allowd motec in the stock box, then I agree w/ the people that say you should just allow any system that uses the stock harness and sensors. The way it's written now, it's no different than the old shock rule. Make people spend more money to achieve the same result, thereby putting it out of reach for some. If you leave it the way it is, you're helping perpetuate the performance gap between those that can spend the money, and those that can't.

Guess what, I don't disagree, but it's not up to me to decide. There are many that believe that if this rule is opened up as you suggest, it will make it mandatory to own a MOTEC to be competitive... right now, there are but a few out there who are actually doing this, compared to those that aren't...

As I said before, this is really a no-win situation, because there are issues at every turn... I wouldn't be suprised if nothing at all got changed, as the rule actually works fine the way it is... Doesn't make everyone happy, but nothing will.



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Darin E. Jordan
SCCA #273080, OR/NW Regions
Renton, WA
ITS '97 240SX

[Eric Parham]

I'm one who missed the two different versions of the current rule. My read of the "or replace" version is that we can *currently* modify within the box "or replace" the thing entirely (no need to use the original ECU box at all). Perhaps we should just make the language consistent by adding the "or replace" to the other version, as well as adding back the accidentally omitted sensor resistances part

Edit: Reasoning is that to "alter" is to modify, but to replace is *not* to modify but to replace in its entirety. Therefore, the requirement that alterations be confined within the stock housing *does not* literally mean that a replacement must fit inside the stock housing. The housing is part of the assembly being replaced!

[This message has been edited by Eric Parham (edited November 06, 2004).]

[Banzai240]

Originally posted by Eric Parham:
I'm one who missed the two different versions of the current rule. My read of the "or replace" version is that we can *currently* modify within the box "or replace" the thing entirely (no need to use the original ECU box at all).

Sorry, have to completely disagree... According to the language in the ITCS, there is a distinction between the "engine management computer, or ECU," and the "original OEM ECU housing."

You "may alter or replace the engine management computer, or ECU, provided that all modifications are done within the original OEM ECU housing."

Context counts... You can't just take one or two words and mix and match them to your liking... You have to use the entire rule...

Even if you "replace the engine management computer"... it must be replaced "within the original OEM ECU housing."

Perhaps I'm daft, but I don't see any other way to read that...

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Darin E. Jordan
SCCA #273080, OR/NW Regions
Renton, WA
ITS '97 240SX


[This message has been edited by Banzai240 (edited November 07, 2004).]

[Bill Miller]

Darin,

You can say that picking a set of parameters and applying them provides on-the-fly adjustability all you want, but that doesn't make it the case.

And if the current ECU rule works fine, then the old shock rule was fine. You can't possibly believe that. How can a rule the requires people to spend more money, and jump through hoops to achieve a legal state (ala the old shock rule) be 'working fine'? BTW, which is it, there are a bunch of people's investments that you have to protect, or only a few who have stuffed a Motec into a stock housing?

And why would people have to buy a Motec? Why couldn't they use one of the many, less expensive alternatives (e.g. Megasquirt, etc.)?

Eric may be onto something. What's the logic behind requiring a replacement ECU to fit inside the stock housing? Make people spend more money because of some variable (and meaningless) size constraint?

<font face=\"Verdana, Arial\" size=\"2\">Originally posted by Banzai240:Again, this is 2004... We're moving forward and looking to the future, not dwelling on what was done in the past... Not EVERYONE (heck, not even a majority from what I can tell...) thinks that the ECU rules are a mistake, or that it was a mistake to open them up.</font>

So, it's gone from opening it up becaus they couldn't police software to "moving forward and looking to the future". Ladies and gentelemen, I give you rules creep at its finest!!

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MARRS #25 ITB Rabbit GTI (sold) | MARRS #25 HProd Rabbit
SCCA 279608

[John Herman]

(As I wrote this, I realized I should clarify that I am talking about computers circa 1990 and newer.)Changing resistance values of sensors feeding the computer does not necessarily allow richening AND leaning the fuel curves or advancing AND retarding of timing curves. At WOT, the computer is only looking at a discrete number (magnitude of 100, not 1000 for ALL atmosperic conditions) of tables to determine fuel and timing, not using a formula to calculate an infintite number of values for the fuel and timing. It uses the values from the sensors to determine which table to look at, NOT plug into a formula. If the computer is all ready in the leanest, most advanced table, it doesn't matter what you do to the sensors, you're not going to lean out the fuel or advance the timing anymore (my car does not use a distributer, so there is no mechanical means to adjust). Vice versa, if the computer is all ready in the richest fuel table, I don't care what you do to the sensors, you're not going to richen it anymore anymore. It will interpolate the value needed if the sensors determine the engine is operating between two points in the table, but it won't magically change the overall values used in the tables (e.g. If operating exactly between two points, the "value" above the point is 10, and the value below the point is 8, the answer is 9. If the "value" above the point is 10, and the value below the point is 10, the answer is still going to be 10. There is NO way to get 11.). Additionally, current OE systems have various "self preservation" modes. Under certain extreme conditions (long periods of WOT under heavy loads for one), if the OE computer determines the driver is going to "melt down" their engine or catalytic converter, it decides, rightly or not, to "save itself." It begins to richen the mixture and retard the timing to cool the engine/converter. So now you don't have improved performance (or consistent for that matter) throughout the race, but just the opposite. I've been told (by a software engineer at Delphi) most OE software is designed to run the engines a bit rich and slightly retarded vs. ideal to protect the catalytic converters. Given the 100k warranty and the $$$ involved in emissions recall, this makes a lot of sense for the car industry to do. But, this explains why tuning the computer for racing can yeild some improvements. The amount of those improvements depend on how conservative the original software engineer was. I also asked him about systems like MOTEC. He stated that IF you can tune the OE system (and we're not talking adding resistors into wires, or those stupid rotary knob things you buy on ebay which we laughed about), there is no benefit to using a system like that. And the "IF" now brings us full circle.

BTW, people talk about choosing their weapon when topics like this come up. I choose the car I did because I worked with the group that did the original engineering work at GM and I "liked" it. I didn't do a detailed engineering analysis of the pros and cons of every single modification vs the potential impact on my car vs the $ impact, vs cars currently competing vs potential new cars being classed vs tracks I was going to run......it was a car that I "thought" could win. Rightly or wrongly. Many custom parts and lots of research later, I am still having a lot of fun. It has been a long, frustrating, but rewarding experience. So when people make comments like, "Yeah, they should have known that piston return springs weren't available, so too bad to them" kind of bother me. When I started this racing stuff 10 years ago, I didn't know how to get a license or how to register for an event. I've liked the IT scene, and , for the most part I like how its going. I like the fact that Darin et. al. are doing their best to please most people. To grow this sport and club, we will need to adapt to the newer cars and technologies. As much as I hate to admit it sometimes, this computer technology is not a matter of IF anymore. My $0.02.

[Knestis]

...and THAT, folks is what a useful contribution to a discussion looks like. Read it again.

K

[chipbond]

Darin, Responding to your question regarding my preference for an open ECU rule or the existing wording, I think I would choose the existing wording, or some variation of it that allows ECU replacement while retaining the stock ECU connector.

As it stands now, selection of a replacement ECU must consider the factory sensor resistance curves, injector resistance, the connector interface and most daunting, the ability to physically fit in the OEM enclosure. The cards we are using are just 3" x 5" but it is suprising how little room is left within the Ford enclosure after installation and wiring. We have to mill parts of the interior to get sufficient room now.

In fairness to all, and recognizing that some enclosures may be too small to fit even a card this small, than perhaps some variation of the existing rule that requires the stock ECU connector BUT allows modification of the enclosure may be the best approach.

Seems that the connector is key in retaining the stock harness and sensors, all big parts of IT class philosophy.

Chip Bond