Anyone tried a stock tune on a big motor?

Cali HP Addict

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Hey all,
Stuck in Cali here and I have been running a custom tune on a N/A big bore stroker (322ci) forever. Now, I have to put a stock tune in it to pass the smog requirement. Has anyone done this?
By my rudimentary calculations the displacement is approx 15% greater than stock. I also run ported big valve heads and fairly mild Comp 127-301-9 cams.
I would:
- swap my cobra 39# injectors for the stock 24#
- re install the cmcv's under the intake
- re install the stock air cleaner box
- already run the stock fuel pump system

How much can the stock tune add to compensate for the larger, more efficient motor?
I only need it to run decent enough to put 50 easy miles on it and take it in for the test.
Any wisdom from this group is greatly appreciated. Thanks
 

07 Boss

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It's gonna be hit or miss. I would think more like a miss. Now I would think fueling wouldnt be too much af an issue if you put the stock injectors in there. Your MAF should read any extra air coming into the motor and adjust accordingly, I think. As far as everything else working together I highly doubt it. Cam and ignition timing may be off. It may run rich or lean or misfire. And even though it may run it may not run well or efficient enough to get your computer to pass the readiness part of it. It may throw some random codes and then it definetely won't pass. Worth a whirl though. Be sure to update this so us curious folks can see what happens.

How were you passing smog before?
 

GlassTop09

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It's gonna be hit or miss. I would think more like a miss. Now I would think fueling wouldnt be too much af an issue if you put the stock injectors in there. Your MAF should read any extra air coming into the motor and adjust accordingly, I think. As far as everything else working together I highly doubt it. Cam and ignition timing may be off. It may run rich or lean or misfire. And even though it may run it may not run well or efficient enough to get your computer to pass the readiness part of it. It may throw some random codes and then it definetely won't pass. Worth a whirl though. Be sure to update this so us curious folks can see what happens.

How were you passing smog before?
+1 here.

As 07 Boss posted........I'd also be curious to see what happens as well.

Good luck!
 

Juice

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Do not run it full throttle, WOT fueling is very likely going to be lean.
50 miles may not set emission monitors.
Is that big cam emissions legal for street use?
 

JC SSP

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We used to have emission is FL and my little coupe had a hell of time passing (Very similar to you... big cam & heads, high compression and over-bore, etc.) thank GOD we go rid of that years ago.

If your too rich you will fail emissions and too lean (I am guessing this is where you will be at) you might damage something especially if they run it on rollers up top speed...

Have you reached out to the tuning gurus and ask if they can develop an emission tune with your existing combination?
 

Juice

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JC brings up a good point:
Did it fail because monitors were disabled in the tune?
Or fail because it has a tune (but emissions are left intact)?
 

07 Boss

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JC brings up a good point:
Did it fail because monitors were disabled in the tune?
Or fail because it has a tune (but emissions are left intact)?

I'm thinking he has to have the stock tune in there. California is transitioning to new machines that can tell if the programming is stock or has been altered. It's not longer just an OBD readiness test.
 

Jwood562

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exactly right, we (CA) are switching to some new testing method where they can tell if there is a tune present.

I have two vehicles (toyota tundra and my s197) that I smog and keep registered. when I took my tundra in this year to the same smog guy I always go to, he remembered I have a mustang and he asked me if I had a "computer chip" in it because a new testing regulation would show and it will fail.
 

Jwood562

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but sorry OP, I have basic bolt ons and a tune so I cant help with trying a factory tune on an built motor like yours, good luck
 

cgornowich

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I've played the emissions game when I lived in Maryland, where they have annual emissions testing. I had a tuner write two tunes, one to pass emissions and a second for the rest of the year. Worked well and was not too big of a deal. Just had to take it nice and easy with the emissions tune..... Too lean is too bad...
 

07 Boss

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I've played the emissions game when I lived in Maryland, where they have annual emissions testing. I had a tuner write two tunes, one to pass emissions and a second for the rest of the year. Worked well and was not too big of a deal. Just had to take it nice and easy with the emissions tune..... Too lean is too bad...

Can't do that with the new smog machines. Any aftermarket tune without a CARB# will get flagged and not pass.
 

Dino Dino Bambino

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Is that big cam emissions legal for street use?

They're the CompCams VSR Stage 2 so as 3V cams go, they're pretty mild in a 281ci motor and they'll be even more tame in a 322ci stroker.

exactly right, we (CA) are switching to some new testing method where they can tell if there is a tune present.

CA is taking smog Nazism to the extreme. Having your car with performance mods/tune potentially fail an emissions test even though the exhaust gases could actually be cleaner than stock is totally dumb, and that's because the inspection stations don't even perform tailpipe tests anymore to determine the real world emissions. This proves that the testing isn't about improving air quality but is really just a campaign to shut down the aftermarket performance industry.
 

Juice

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They're the CompCams VSR Stage 2 so as 3V cams go, they're pretty mild in a 281ci motor and they'll be even more tame in a 322ci stroker.



CA is taking smog Nazism to the extreme. Having your car with performance mods/tune potentially fail an emissions test even though the exhaust gases could actually be cleaner than stock is totally dumb, and that's because the inspection stations don't even perform tailpipe tests anymore to determine the real world emissions. This proves that the testing isn't about improving air quality but is really just a campaign to shut down the aftermarket performance industry.
Do you know how many inspection stations still have a working gas analyzer? Very, very few. And the ones that still do, wont as soon as the machine breaks.

As far as not letting a tuned car pass, the real answer is simple. They dont feel like policing tuning. We all know a tune can be made to complete monitors. Im not going to post what I have observed tuning my own car, but can confirm that statement is true.
Also keep in mind, even with a factory calibration, regardless of monitors completing just fine, any Non-CARB approved part still fails the visual inspection.
 
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Flapjack

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I don't have a clear answer, but I do have two thoughts:

1) I'm going to guess running the stock tune won't work on a Ford. I remember putting a 6.0L in my old 2002 Chevy Avalanche (originally a 5.3L). I didn't expect it to run, but it ran great. When I asked a tuner, they said it had something to do with how GM calculates (infers) displacement based on the crankshaft sensor signal. I do know that the displacement field in the S197 PCM does absolutely nothing. When I was doing my own tuning, I changed it just due to OCD... but I don't believe it actually did anything.

2) Has anyone in CA actually restored a stock tune and had it pass? The reason I ask is that stock tunes are going to change. Unless CA has a way to read the actual bytes of the tune itself and run a hash on it, then compare it to ALL the hashes for each dealer's PCM revision, it doesn't make a lot of sense. My guess is that they have simply required all 50-state legal PCMs to have the "e-fuse" we've been seeing. I know GM and Ford have had them for a while, as well as Volkswagen and others. An e-fuse is just a cryptographic algorithm that is set at the time it's initially flashed. If you flash anything with an aftermarket tuner, you would not have the private key used for digitally-signing the tune. If the signature is not derived from the auto maker's root private, the e-fuse is considered "tripped". If that is the case, restoring the stock tune with an aftermarket programmer wouldn't really help. This would be a lot easier to implement for the state.
 

Juice

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I don't have a clear answer, but I do have two thoughts:

1) I'm going to guess running the stock tune won't work on a Ford. I remember putting a 6.0L in my old 2002 Chevy Avalanche (originally a 5.3L). I didn't expect it to run, but it ran great. When I asked a tuner, they said it had something to do with how GM calculates (infers) displacement based on the crankshaft sensor signal. I do know that the displacement field in the S197 PCM does absolutely nothing. When I was doing my own tuning, I changed it just due to OCD... but I don't believe it actually did anything.

2) Has anyone in CA actually restored a stock tune and had it pass? The reason I ask is that stock tunes are going to change. Unless CA has a way to read the actual bytes of the tune itself and run a hash on it, then compare it to ALL the hashes for each dealer's PCM revision, it doesn't make a lot of sense. My guess is that they have simply required all 50-state legal PCMs to have the "e-fuse" we've been seeing. I know GM and Ford have had them for a while, as well as Volkswagen and others. An e-fuse is just a cryptographic algorithm that is set at the time it's initially flashed. If you flash anything with an aftermarket tuner, you would not have the private key used for digitally-signing the tune. If the signature is not derived from the auto maker's root private, the e-fuse is considered "tripped". If that is the case, restoring the stock tune with an aftermarket programmer wouldn't really help. This would be a lot easier to implement for the state.

And #2 is the reason the pcm will need to be restored by a Ford dealer.
Thanks for explaining why a restore to stock from a handheld does not fully restore the pcm.
 

JC SSP

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Flapjack you are correct! Never knew it was called e-fuse.

I have heard some people use a "piggy-back" interface tune (i.e., Neuspeed, DINAN, JB4 Berger Tuning, etc.) while a vehicle is under warranty because any uploaded tune would automatically trigger a change in the system, even when you would download it back to stock before going to get dealer servicing, the dealer knew the car was altered.
 

Laga

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They're the CompCams VSR Stage 2 so as 3V cams go, they're pretty mild in a 281ci motor and they'll be even more tame in a 322ci stroker.



CA is taking smog Nazism to the extreme. Having your car with performance mods/tune potentially fail an emissions test even though the exhaust gases could actually be cleaner than stock is totally dumb, and that's because the inspection stations don't even perform tailpipe tests anymore to determine the real world emissions. This proves that the testing isn't about improving air quality but is really just a campaign to shut down the aftermarket performance industry.
You can thank the diesel tuner community for that backlash. They totally ignored any EPA guidelines and blatantly put out tunes that were no where near compliant. They were daring the government to do something, and they did.
https://www.thetruthaboutcars.com/2020/03/diesel-brothers-fined-850000-for-rolling-coal/#
[URL]https://www.roadandtrack.com/news/a41104777/epa-hits-two-more-diesel-tuners-with-dollar10-million-fine-for-defeat-devices/[/URL]

 

JC SSP

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I remember VW did the same thing... cost them Billions $$$

Oh on the diesel topic... my buddy retired in 2021 and bought a brand new 2022 F250 and matching 30' travel trailer. He spent close to $150K on everything! OUCH! But he never knew he had to add Urea to the separate tank when he refueled. He was pissed!
 

Juice

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You can thank the diesel tuner community for that backlash. They totally ignored any EPA guidelines and blatantly put out tunes that were no where near compliant. They were daring the government to do something, and they did.
https://www.thetruthaboutcars.com/2020/03/diesel-brothers-fined-850000-for-rolling-coal/#
https://www.roadandtrack.com/news/a...ith-dollar10-million-fine-for-defeat-devices/
https://www.thetruthaboutcars.com/2020/03/diesel-brothers-fined-850000-for-rolling-coal/#
And Im sure the "must remove my cat converter" crowd had no impact on the wrath of the EPA.
 

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