Of Dinosaurs and ECUs

alfadriver said:

In reply to Knurled. :

I wouldn't say nothing.  Not much, but not nothing. For the later cars, virtually all of them run too rich at wot, and there *might* be some more spark left in addition to the rpm limit. 
 

Buth the spark does require better fuel, especially if it is leaned out a little. 
 

is it worth it?  Depends on the original one. I'd wager there would not be much left in something like a neon acr. 

Youd be shocked. The acr pcm to mopar performance (1st gen acr) gets roughly 15hp and A LOT under the curve. Whole different beast. 

In reply to alfadriver :

I'd venture that if you're not drag racing, there's no benefit to leaning the WOT mixture.  GM seems to like around .8-.83 lambda for power enrichment, which isn't too bad, and I wouldn't want to go much leaner on an engine I want to lean on for more than a handful of seconds at a time.  They're pretty aggressive with ignition timing too.

L5wolvesf said:

RacingComputers said:

Pick up a replacement EDU at a local Pick a Part

See if it runs any better or worse

The pick-a-part ECU option brought a few other questions to mind. I generally avoid electrical parts from parts yards. How reliable is a parts yard ECU? Are they sensitive to being jostled? For instance a car in traffic accident and the battery, or other component, shorts.

 

Also, do I have to, or is it recommended to, take the cable(s)?

Most yards I work with give an implied warranty. I'm sure it varies but if you get something that is defective, they will take it back and give you another.  
Now plenty have been handed a defective ECU by a dishonest person so they may have policies to protect themselves.  
   How do you protect yourself from those you race against having cheater units?  Draw a tag for a given unit from a hat Sort of deal?  

In reply to Knurled. :

Power enrichment will be almost perfect, as that will be very dyno timed. 
 

Beyond that, the component protection is where there are gains, as that will run down to .65 lambda to keep things cool. For drag racing, that will happen at the very end of the run. 

Keith Tanner said:

All they can look for is physical alterations to the circuit board - a socketed chip or a new crystal for the rev counter. That's dinosaur level modification these days, but may be the only option for a car 15 years old. Just look at the ECU and see if there are any items that don't look like they were mass-produced. 

I would expect this to be the most likely sort of enforcement you'd see at a circle track. The problem is that some mods can be very subtle - for example, with many Hondas, the only thing that would have to be done is soldering a couple extra chips into locations that look like they're meant to take a chip. A tech inspector MIGHT have a picture of how this ECU is supposed to look inside, but probably won't unless they get a lot of Hondas. Others are a bit more obvious. This Nissan ECU has a circuit board that looks a bit out of place.

Then sometimes you find a race ECU circuit board has been pulled out of its original packaging and stuffed in a stock ECU case.

And, as has already been pointed out, some of the ECUs don't contain any visual giveaways at all. Pretty much any OBD2 ECU - 1996 or later - would fall into this category. So do a lot of GM ECUs before 1995 - they contain their tune in an easily removed chip that you can swap out for another identical-looking chip.

My guess is that if you don't see something blatantly non-factory-looking stuffed inside the case, the tech inspector will let it through.

Can they not tell if it's been altered if the CVN is different?

The gains from a tune may be small if on a stock setup, but once you change the intake, go to a better than stock exhaust setup and run some quality fuel the gains from a  tune will  be significant for the application.

frenchyd said:

L5wolvesf said:

RacingComputers said:

Pick up a replacement EDU at a local Pick a Part

See if it runs any better or worse

The pick-a-part ECU option brought a few other questions to mind. I generally avoid electrical parts from parts yards. How reliable is a parts yard ECU? Are they sensitive to being jostled? For instance a car in traffic accident and the battery, or other component, shorts.

 

Also, do I have to, or is it recommended to, take the cable(s)?

Most yards I work with give an implied warranty. I'm sure it varies but if you get something that is defective, they will take it back and give you another.  
Now plenty have been handed a defective ECU by a dishonest person so they may have policies to protect themselves.  
   How do you protect yourself from those you race against having cheater units?  Draw a tag for a given unit from a hat Sort of deal?  

The 2 yards here, which are 45 miles 1 way, have warranties, but I’ll have to check if it applies to electrical. I have not plan to be dishonest with them they are pretty friendly and a potential sponsor.

IMCA has been known to “surprise inspect” various parts on their own. I imagine people could be protested. I have a gut feeling that is how the series leader got DQ’d last year. IMCA has, or is getting, a rep for keeping a fairly tight leash on this division.

In reply to MadScientistMatt :

Your guess fits with what others here are saying. And, now I understand why a lot of cars are advertised as having “tuned ECUs” a.k.a. cheating – the rule may not be enforceable an any practical way.

FWIW, many/most Hondas are not allowed (no VVT) and the Honda CRX is specifically not allowed.

Peabody said:

Can they not tell if it's been altered if the CVN is different?

The gains from a tune may be small if on a stock setup, but once you change the intake, go to a better than stock exhaust setup and run some quality fuel the gains from a  tune will  be significant for the application.

OK, what is a CVN?

IMCA, and similar, rules don’t “allow” intake changes, and only exhaust change allowed is a 2” pipe.

L5wolvesf said:

In reply to MadScientistMatt :

Your guess fits with what others here are saying. And, now I understand why a lot of cars are advertised as having “tuned ECUs” a.k.a. cheating – the rule may not be enforceable an any practical way.

FWIW, many/most Hondas are not allowed (no VVT) and the Honda CRX is specifically not allowed.

This thread has made me rethink why some racing classes had rules along the lines of "Tuning the stock ECU is limited to software and/or hardware modifications inside the stock ECU case."  It's a terrible rule in terms of the number of Smokey Yunick level tortured interpretations somebody might come up with. But it was, at least, a rule that could be enforced.

L5wolvesf said:

OK, what is a CVN?

IMCA, and similar, rules don’t “allow” intake changes, and only exhaust change allowed is a 2” pipe.

Calibration verification number.

If you're going to be successful in limited class racing you're going to have to read the rules. Intake changes are allowed, and an open 2" exhaust will be better than stock in most cases. A tune in this respect will make a big difference. Enough so that if the other cars aren't doing it, it will likely be noticeable.

Knurled. said:

There are ways to tell,  but it would require a vast library of stock tunes to compare from and lots of time to read and compare them all. Such a library does not exist.  From my position here that looks like an unenforceable rule.  The benefits are too low to justify the expenses in enforcement.

Such a library does exist. California has the most comprehensive list as they use it to check that ECU's match for smog. Not sure how you would get access though.

Apparently some publish it, others it's a paid subscription. That's the purpose of the CVN

I knew it was a thing, but had to ask my buddy who does it for a living and he explained what it was. He also told me that some ECU's can be fooled to provide the correct (or incorrect if you prefer) numbers

Peabody said:

L5wolvesf said:

OK, what is a CVN?

IMCA, and similar, rules don’t “allow” intake changes, and only exhaust change allowed is a 2” pipe.

Calibration verification number.

If you're going to be successful in limited class racing you're going to have to read the rules. Intake changes are allowed, and an open 2" exhaust will be better than stock in most cases. A tune in this respect will make a big difference. Enough so that if the other cars aren't doing it, it will likely be noticeable.

Thanks on the CVN.

To clarify, my intake comment refers to intake manifolds not to "cold air intakes". Updating or backdating intake manifolds is talked about but is not legal. "All engine components must be unaltered OEM for year, make and model of car used, must match
V.I.N."

Dusterbd13-michael said:

alfadriver said:

In reply to Knurled. :

I wouldn't say nothing.  Not much, but not nothing. For the later cars, virtually all of them run too rich at wot, and there *might* be some more spark left in addition to the rpm limit. 
 

Buth the spark does require better fuel, especially if it is leaned out a little. 
 

is it worth it?  Depends on the original one. I'd wager there would not be much left in something like a neon acr. 

Youd be shocked. The acr pcm to mopar performance (1st gen acr) gets roughly 15hp and A LOT under the curve. Whole different beast. 

I can vouch going from a stock pcm, to acr pcm to a Mopar performance pcm is 3 good steps different.