Load Logging max @ 1.4

Tuning discussion specific to 2006-2008 NC1 Miata MX-5 vehicles
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sigratton
Posts: 6
Joined: January 31st, 2025, 4:32 am

Load Logging max @ 1.4

Post by sigratton »

Hi, I am logging from my NC1 mx5 that is turbo'd. I have got the tune into a reasonable place running 7.5psi. I have noticed that the Load value is flat lining at about 1.4-1.41 absolute load, even though the MAF values are increasing. The load did not go over 1.416 even when I accidently put 18psi through the engine because of a waste gate issue.

Do you know if this is a logging limitation or is there something else I am missing because the absolute load log line is 100% flat from about 4000-6500 on WOT pulls.

Looking at WOT pulls before I turbo'd the car actually has similar behaviour, is there something in the load calculation that makes it tend to a constant value?

Any help is appreciated.
sigratton
Posts: 6
Joined: January 31st, 2025, 4:32 am

Re: Load Logging max @ 1.4

Post by sigratton »

Although it is a bit odd, it is actually not an issue, because I can tune the Volumetric Efficiency Load Multiplier table through the rev range to get the correct AFRs. Would still be good to understand.
xbrandino
Posts: 32
Joined: August 15th, 2023, 1:08 pm

Re: Load Logging max @ 1.4

Post by xbrandino »

It is possible to have a flat curve with load during WOT depending on your airflow, however I haven't seen this before on a set boost. Either way, best thing you can do is to provide a log and see what is happening with the car.

On another note, there is no need to change your Volumetric Efficiency on your car if you are still stock internals, cams etc. You should really only be changing your MAF calibration to correct your AFRs. If your AFRs go richer during the WOT, this can provide incorrect values for your load and make it stay higher than it is, hence why I recommend sending through a log so others can check what is happening.
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