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Larger turbo, same boost always needs more fuel.
Larger turbo, more boost needs a lot more fuel.
I'm curious what the cam alone will do to AFR.
 

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Larger turbo, same boost always needs more fuel.
Larger turbo, more boost needs a lot more fuel.
I'm curious what the cam alone will do to AFR.
I cannot say for certain because it was installed at the same time as the UMP. But the cam on stock turbo needed more fuel. It was running rough, a little on the warm side, went back to the Dyno and they said they needed to add fuel. I'm still not logging because I haven't installed a wideband yet so I do not know specifics.

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What tune was on it when you changed the cam?
KMS e85, id1080x, big wastegate, stock intake, AP intercooler, not sure on stage. 3 maybe 4? I do not know how they rate them but I think they're a little conservative. They said I made the same power as their pump gas and clutch tune

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KMS e85, id1080x, big wastegate, stock intake, AP intercooler, not sure on stage. 3 maybe 4? I do not know how they rate them but I think they're a little conservative. They said I made the same power as their pump gas and clutch tune

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I should add (I think I may have on a previous post) KMS wanted the part number of the cam because they were impressed with the increase.

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KMS e85, id1080x, big wastegate, stock intake, AP intercooler, not sure on stage. 3 maybe 4? I do not know how they rate them but I think they're a little conservative. They said I made the same power as their pump gas and clutch tune

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This is with E85, and the new cams?
 

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This is with E85, and the new cams?
Before cams it was e85, id1080x, wastegate, intercooler, cat delete, exhaust dump. Tuned pretty good but was starved for air.
Cam and UMP was installed and car needed more fuel. Went back in the Dyno and retuned. 201.68 dynojet at 4500'. Comment was made by MTS (Dyno is at MTS and KMS remotes in) that I was making same power as KMS pump gas and clutch tune (maybe intake too, I don't recall) If this is true I figured they left some power on the table. Either they want their staged package to be King or the guy was mistaken that said it was making same power. I have no idea on power, it was just there to get it running safe on A/R and be faster than it was before.

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I'm curious what the cam alone will do to AFR.
I don't know for sure, but a cam change shouldn't need a A/F ratio change. A intake or exhaust change yes, you're changing the air in,, air out, that determines the A/F... Just a big air pump. Change in cam, valves, compression, stroke or bore don't change the A/F ratio, just the A/F volume.
 

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I don't know for sure, but a cam change shouldn't need a A/F ratio change. A intake or exhaust change yes, you're changing the air in,, air out, that determines the A/F... Just a big air pump. Change in cam, valves, compression, stroke or bore don't change the A/F ratio, just the A/F volume.
More air flow needs more fuel. Anything that causes the engine to flow more air will require fuel to be added to maintain the same AFR.
 

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A cam change on a closed loop fuel injection system can effect Afr. The only time our machines run an open loop is during idle but at speed the fuel is predetermined by the tuner . A cam that allows more air to enter the combustion chamber with the already predetermined amount of fuel will result in a different afr.
 

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A cam change on a closed loop fuel injection system can effect Afr. The only time our machines run an open loop is during idle but at speed the fuel is predetermined by the tuner . A cam that allows more air to enter the combustion chamber with the already predetermined amount of fuel will result in a different afr.
Actually, it's the other way around. We have a narrow band O2 sensor that is only accurate at stoick (14.7). That is waaay to lean at full throttle, and even leaner under boost. Full throttle should be around 13.5 -13.8. Under boost, it should typically 11.5 - 12 to 1. This is why it goes to open loop mode and gets it's fueling data from a predetermined lookup table. That table was generated based on a certain amount of airflow. Any deviation from that upsets the AFR apple cart.
 

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Cales, I just reread your post and realized that we are saying the same thing. You just have open and closed loop modes backwards.
 

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I don't know for sure, but a cam change shouldn't need a A/F ratio change. A intake or exhaust change yes, you're changing the air in,, air out, that determines the A/F... Just a big air pump. Change in cam, valves, compression, stroke or bore don't change the A/F ratio, just the A/F volume.
Sorry, but big facepalm here. 🤦‍♂️
 
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