Chevy Gen III small block in CMC2 question

[jeffburch]

I recently tried to sell some o2 sims on ebay I had left over from a 2000 C5 street car. Ebay nixed the ad saying they were illegal.

News to me.

It seems the only way to remove cats from these and f bodies is to turn them off in the computer.

Since reprogramming ecu's is disallowed in our rule set, does this mean LSx cars in CMC2 are running a catalytic converter?

 

Please, PLEASE!, no stupid friggin cat pics!!!!!!!!!!!!

thx,

jb

[snakebit]

Still an outsider looking in here...and not meaning to highjack your thread. But if rejetting of carbs and timing adjustments are allowed on older cars, why not allow computer tunes? Instead of a screwdriver and a 9/16 wrench...we'd be using the obd port and a laptop. The end result would be the same...and no cockpit adjustability.

 

I understand the simplicity of the rules set, That is one reason why I'm choosing to build a car for this series, but....I'd like to have the option of adjusting timing and/or air/fuel ratio to meet hp/weight requirements instead of a restrictor plate. I think (key word think) that I would have better torque numbers. The little 281 under my hood is lacking in that department.

 

John

Always causing trouble

[Glenn]

ebay likely nix'ed the add due to federal emission regulations.

i see no reason they cant be used in CMC. these are for the post cat O2 and those in no way affect the way the car performs. they only verify the cats are working.

now, if these were connected to the front O2's, i'de have issue w/ that.

far as i'm concerned, O2 sims for the rear are legal.

 

also realize the its not just the LSX based F-bodies that this affects. all 96-97 LT1 cars also had rear O2's that could use these sims.

 

for what its worth...... a no limits build will result in a LT1/LS1 car w/ the SES light on. the cats missing from the car w/out sims in place of the rear O2's will not make it shine any brighter. total waiste of money for the sims on a race car if you ask me.

put them up on one of the C5 forums.

 

i have sims on my 98 Z street car. the computer has not had the rear's turned off. if you do, it results in an 18XX code that will fail your state inspection (yes, w/ just this code). its better to use the sims.

 

as for the computer programing........... its been hashed out many times. i feel we should be able to turn off emissions type codes but nothing else.

start a new thread on that if you really want to know why.

[jeffburch]

Since they're no longer available, sims should be a hot commodity if you want to be legal in cmc2 running without a converter.

Contact me if you're interested in my set.

 

jb

[Glenn]

i'm not sure why you think they are needed to be legal?

[Dave Schotz]

Yup... SES light on this LS1 car as well... although I do wonder about some interpretatoins of this rule... I'll get to that in a minute.

 

I have no cats... and rear o2 sims... and still have a light, but that could be due to the other smog stuff off the car?

 

But... even if you didn't have sims... and didn't have smog... GM cars throw a light... but don't pull any power. So... it's merely their to annoy you... you don't need the sims, or the programming, to have 100% of the power available on a GM product. Can't speak for a Ford...

 

Ok... back to the computer reprogramming side of things:

 

So... while we all know you can't 'tune' the ecu for CMC or CMC2... what is your interpretation of this ruling:

 

8.21. Smog Equipment

All smog equipment may be removed, including the catalytic converter(s). Any smog equipment not removed must either be disabled or left to function as originally intended by the manufacturer. All disconnected ports and holes must be sealed.

 

My question specifically is that it says the smog stuff can be disabled. So, technically wouldn't this mean you can 'disable' them in the computer?

 

Thanks,

Dave

[jeffburch]

i'm not sure why you think they are needed to be legal?

 

Uhhh, it's a sims vs reprogram and reprogram is not allowed.

Not sure why you are confused by that.

I wouldnt run a car with a SES light, period.

Too half assed for me.

 

 

jb

[Dave Schotz]

Hi Jeff, how do we run without an SES light on the 3rd Gen? Didn't you remove your smog on that car too?

 

Thanks,

Dave

[Glenn]

my point was that if you've removed the cats, you've also likely removed the air pump, evap, egr and other stuff. so far of that list, the rear O2's are the only ones your gonna be able to solve the SES light for. the other will still cause it. if its just the cats you've removed, then i guess SIMS are worth the money.

my car has a SES, and there is no legal way to prevent it.

in fact, i've never enen checked for codes w/ my car. the SESis in the glove box where i cant see it.

[bsim]

I'm with Jeff - no light for me either. Sims x2...

[powerslide91]

I'd like to be able to reprogram. These are modern cars and it has become the norm for street cars already.

 

Just data; my 3rd gen has the light on for the EGR. Turns out it ended up masking another failure the car developed last race or two. If I would have been able to reprogram out the emissions stuff which I can legally remove, I would have know my car was having a real fault can could have fixed it faster. Also really like to be able to reprogram out the VATS but so far that one has not bit me.

 

Jeff

[Keith]

FWIW, you can make power and weight in CMC with an LT1 without an SES light and I have to believe the same is true with an LSx in CMC2. You just can't make the same mods as guys with other motors...

[jeffburch]

Hi Jeff, how do we run without an SES light on the 3rd Gen? Didn't you remove your smog on that car too?

 

Geez DS I dunno. Yes, removed. I got an EGR code once. I cleared it and it never occured again. I have a 6 ohm resistor hanging from the harness for the VATS so......

 

jb

[Dave Schotz]

[quote name="jeffburch"

 

Geez DS I dunno. Yes' date=' removed. I got an EGR code once. I cleared it and it never occured again. I have a 6 ohm resistor hanging from the harness for the VATS so......

 

jb[/quote]

 

Well geez JB you must have one dem special 'stock' computers! Where it only looks for smog once and then you 'clear' the code and it never looks for it again! I gotta get me one of dem!

 

Sorry guys I'm with Glenn on this one. If your ecu is untouched and you have all smog removed you shoul have a light.

 

And I'm also for tuning the ecu's under 2 condition:

 

1. If we aren't monitoring it today by pulling down current competitors ecu flashes.

 

2. And since we have dyno readings verifying rwhp.

 

Peace

Dave

[AllZWay]

On my 93 LT1...without tuning you get a ses light evertime it is cleared. It is always smog related.

 

I understand the fear of the slippery slope of programming and excpept...but I do wish I could tune smog and vats crap out.

 

I figure that vats bypass will one day cost me a weekend it fails.

[AllZWay]

On my 93 LT1...without tuning you get a ses light evertime it is cleared. It is always smog related.

 

I understand the fear of the slippery slope of programming and excpept...but I do wish I could tune smog and vats crap out.

 

I figure that vats bypass will one day cost me a weekend it fails.

[jeffburch]

Well geez JB you must have one dem special 'stock' computers! Where it only looks for smog once and then you 'clear' the code and it never looks for it again! I gotta get me one of dem!

Peace

Dave

 

Dave, not sure what you're implying so let me educate you a bit on my '91 stock oem ecu.

 

Of the 4 solenoids related to the emissions (1 Canister Purge Solenoid, 2 EGR Solenoid, 3 Air Converter Solenoid, 4 Air Port Solenoid) only one (EGR) is monitored by the ecu. Code 32, and it's only a marginal monitor looking for a short. (factory manual page 6E3-A-41).

 

Ony one code related to removed emissions!

 

What code are you getting?

Maybe I'll help you get rid of them.

 

Yup, the whole car is Special.

Word up

Peace

 

jb

[mitchntx1548534714]

I've had an SES light since day one. Codes all pointed to emissions related issues.

 

Important engine systems are monitored via Autometer gauges.

 

The only issue I have that the computer controls using the OBD monioring system is A/F ratio.

 

Without ECU fuel trim tuning, A/F ratio is uncontrollable. So, an SES light is inevitable ...

 

So, I change plugs once a year and change my oil more often.

 

A liftetime ago, I lobbied for a single tuner, like PCMs for Less, and NASA enter into an agreement and alow OBD1 and OBD2 ECU's be allowed to be altered (not tuned) to shut off emissions and security related attributes in the ECUs firmware.

 

The pat answer I got was that there is no way to monitor it. Like mointoring a distributor's position or carb jetting is easy or even done.

 

Maybe with more and more cars coming into the series with this issue, this can be revisited.

[Adam Ginsberg]

Like mointoring a distributor's position or carb jetting is easy or even done.

 

Checking the distributor is easy, and it's been done. Carb jetting can be done as well, but only a handful of cars still run old skool.

 

As for touching the program in a factory ECU - no f'n way in hell, regardless of VATS, emissions, etc.

 

We're already sliding down the slippery slope. Let's not add more slickery shit to it.....

[King Matt1548534716]

The pat answer I got was that there is no way to monitor it. Like mointoring a distributor's position or carb jetting is easy or even done.

Checking timing with a light or pulling jets is about as easy as it gets when it comes to teching a car, and infinitely easier than policing reflashed computers. Whether or not it's done is no different than any other tech issue.

[Dave Schotz]

My only challenge... is we say 'ECU Tuning' is a slippery slope... but what are doing today to ensure no one is tuning?

 

If we don't have people (NASA/CMC Officials) with Flash tools to ensure ecu's aren't being tuned... it's not different than saying tuning is or isn't allowed?

 

I'd like to be able to shut off the emissons/vats crap as well... as for 'performance' enhancing... all that would mean is I'd have to run an even smaller restrictor to limit my power in the cmc-2 car.

 

Peace,

Dave

[Glenn]

since no region i know of including Nats has no way of checking it, there is no way of policing it.

 

isn't that the very reason max camber was removed from the rules?

 

 

I'm w/ Dave on this one. removal of emissions should include the disabling those items in the PCM.

 

allot of our rules rely on the honor system. there is a certain amount of faith placed on fellow racers that none of us have billet cranks, H beam rods, forged pistons, so on and so on. there is also faith that guys like me haven't reprogrammed their PCM's. so the same faith can be placed upon me that's already there that i will only disable the emissions in the PCM and not alter the fuel/timing maps.

[mitchntx1548534714]

Adam/Matt ...

 

Timing can be checked with timing light. requires the use of a timing light.

Jets ... requires a tear down of the carb ... no teardown rule.

 

ECM altering ... no SES light and a piece of paper from PCMs for less stating what has been done.

 

Now, which is easier?

[King Matt1548534716]

How do you verify what's on the paper? And we don't have a no teardown rule. Read rule 7.7:

 

"NASA tech inspectors and CMC Officials shall have the right to request disassembly or any other procedure required to verify vehicle compliance with these rules including a dynamometer re-certification, or running of monitoring equipment."

 

That certainly covers pulling float bowls to check jets.

[Glenn]

you cant even verify timing on an LT1/LS1/4.6 mod motor and a few other CMC/CMC-2 legal cars w/out something like a TechII. i know the LT1/LSX cars do not have a timing pointer or a balancer available w/ timing marks.