AFR Sanity check

Hey, this is my first time tuning a car. I have a MX5 NB1 (1.8L) with a T28 turbo from an s15.

Im looking to eventually push it to around 10 psi.

Can anyone check my work for me as a starting point for my AFR table. Iv leaned the AFR at 100kpa as the base tune was for a naturally aspirated engine then gradually richened as i move into boosted areas + tapered off towards higher rpm.

i think this looks good but would love somone with experience to take a quick look to make sure im going down the right path.

[img="blob:https://www.hpacademy.com/6069ed9b-f991-4439-9359-87877fb69276" alt="" alt="" ]

I think you could be richer sooner as why have 1 until 80kpa? you are missing power by keeping it so lean

I'd richen it up a bit then bring it back down and see what difference it makes later on.

Other than idle area and low rpm I'd be wanting 0.95 then 0.92 then 0.9 at 100kpa then even richer.

My advice is to just make sure the ignition isn't too far advanced and then take it easy before going WOT

I tune it with the turbo off first anyway. At least you can get some decent data without the turbo boosting as you end up missing the 80 to 100kpa area

While almost everyone who sees this might come up with different values, what you have looks like a reasonable starting point, and of course you'll end up adjusting as you go. Happy tuning!

As Mike said, different people will look at it differently.

My starting point - I'd probably be looking at 1.1 for the part throttle ranges for economy and clean running, and transit through 1.0 around 1 bar, up to 1.2 for maximum manifold pressures, and working around what the engine actually wants from there.