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Old 10-07-2022, 12:40 PM   #1
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2021 L9 360HP Upgrade HP & Torque

Have seen many older discussions regarding L9 400 HP upgrade to 450. Does anyone have experience in upgrading a 2021 or 2022 L9 360HP to 380HP under warranty? If so, is it worth the cost?
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Old 10-07-2022, 07:46 PM   #2
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The only reliable source of information is to jot down your engine serial number and call Cummins customer service.

Also part of the answer depends upon the transmission make/model, you should also have that information when calling.
Just being an ISL/L9 engine does not mean your engine may be safely uprated.
Last I read, Cummins was charging approx. $750 for an uprate with warranty.
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Old 10-08-2022, 05:12 AM   #3
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Ray is absolutely correct.

Cummins will research your engine number and see if your CPL (Critical Parts List) from the original engine/tranny configuration specs permit a horsepower increase.

On my ISC 8.3L it wasn't.

If yours is available for an upgrade and your still under warranty, I'd make certain the work is done at a Cummins Service Center only.

Just my 3 cents.
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Old 10-08-2022, 11:34 AM   #4
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Thank you guys for your replies.

My engine can be upgraded to 380HP and 1250 Ft Lbs. torque with an ECM Flash/Update. I have received a quote from Cummins and have been quoted $750 - $800 for the ECM Update and $3,200 for Cummins to update the warranty.
My question to the forum is: Has anyone done this on this 360HP engine and in their opinion, was it worth it.

Thanks Scott
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Old 10-08-2022, 11:48 AM   #5
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20hp for $4 grand. Only you can decide if it's worth the cost of upgrading at $200 per pony. Personally I wouldn't do it until she's broken in and you're out of warranty.
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Old 10-13-2022, 03:49 PM   #6
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The L9 360hp engine is a different CPL than the 380/1250 rating and includes a different piston and turbocharger. If you have been quoted only a calibration flash, that is incorrect.
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