California emissions vs federal emissions

Doubeleive said:

except for me, I burn thru cat's like there going out of style. Vehicle runs perfectly.

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One of the issues with aftermarket tunes, you make more power when they richen up your fuel curve and increase your timing curve. If they get it right you get more power with no downsides. IF they get it wrong you are burning up Cats that should have lived longer.

My son is very good at providing quality tunes, he does mostly Audi and Porsche but also has a 1,000 HP Corvette that has twin turbo's on it.

He keeps asking me why I have not let him tune my engines. My answer is always: Because they are working just fine as is.

I absolutely know he could offer me more response and more HP and Torque. On my twin turbo Porsche he could bump the power 300 HP no problem.

Working 40 years in the industry with 30 years as an engine specialist I have seen thousands of broken and damaged pistons. Tunes were involved in many of those failed parts. So some tunes are all good and some are not. Choose carefully.
When you burn a piston the turners always get to hide behind the waver sheet that says they are modifying your engine for higher performance, Modified engines have no warranty. If they break you are on the hook, not the tuner.

Doubeleive said:

I burn them up, it happens when you drive a vehicle like it's a F1 car
THEN what happened in my case is the regular front cat's blew so much crap out it clogged up the 3rd non-monitored cat, so had to have that hollowed out
that's what was causing this problem, was fine if you drive like gramma but try to do anything , pass someone, accelerate, etc and it just caused massive backpressure
skip to about 1:39

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What software are you using for the gauges and the table data? It/they look quite useful!

Picture says EFILive.

West 1 said:

One of the issues with aftermarket tunes, you make more power when they richen up your fuel curve ...

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This is a bit of an oversimplification. On a 4.8L 5.3L & some 6.0L with under 10.1 scr, Power Enrichment may be on a bit of a delay.
Simply reducing that delay to 0.0sec will 'richen the fuel curve'.
(Reducing the permissible TPS% and TPS% delta can get Power Enrichment to come on even sooner; this was referred to as 'pump shot' for carburettors.)

However, GM is also known for Power Enrichment AFRs that are a bit richer than necessary for peak torque and peak power on most engines (not just V8s).
In other words, SLIGHTLY leaning out Power Enrichment AFRs makes more power than GM intended - one of the many benefits of a tune, donchaknow?
(still richer than .9 Lambda, it also changes with RpM and RpM delta). Mail order tunes still tend to do better than GM, they get these pretty close.
However for better results, send some data back to your tuner so they can further refine the initial tune.

And then there is CAT OverTemp Enrichment (don't know if that's what GM still calls it today), which is independent of, but tends to run richer than Power Enrichment.
Don't think the catalytic converters have dedicated temp sensors, so converter temp is inferred. If the ecm thinks the converters are hot enough,
there are (at least) three stages of CAT OverTemp where the AFR goes richer than Power Enrichment.
CAT OverTemp always happens after a few seconds of sustained WOT; it can ALSO happen occasionally even when putzing along.

Scrappycrow said:

What software are you using for the gauges and the table data? It/they look quite useful!

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efi live it's free to download & plat around with, but it only works with a flashscan or autocal
loading a tune requires a vin license.

Doubeleive said:

efi live it's free to download & plat around with, but it only works with a flashscan or autocal
loading a tune requires a vin license.

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Thanks!