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-   -   now here's why I think fuel is important too (https://www.miataturbo.net/diy-turbo-discussion-14/now-heres-why-i-think-fuel-important-too-9843/)

Braineack 05-14-2007 08:19 PM

now here's why I think fuel is important too
 
https://www.miataturbo.net/braineack...nd/fueling.jpg

the run with more power was run at 1 psi less. however you can see it held flat at 12.5:1 (that's what I logged), untill the stock ecu dumped in the extra fuel.

if you look where my new AFR plot crosses at 5.6K (11.1:1) my hp/tq finally makes more than before...I attribute most of this to fuel tuning. Since I had no onboard WBo2 to log against, and this was my 9th dyno run (heh heh) i had to leave it where it was after getting my spark worked out.

I can't wait to see what it plots with optimal fuel and spark. Al's fuel map has proved useful, you can see how flat the curve is...just needs less fuel throughout, with no other changes.

Ben 05-14-2007 09:01 PM

I am going to know a ton more about tuning when I take my car to the load dyno and a professional tuner. But from what I understand now, you leave it pig rich and push the timing advance first. Then once you've advanced timing such that you're just under the knock threshold and/or you're just under the limit to where advancing results in no additional power, you start to trim fuel.

Fuel looks like the easy part. Timing, I'm sure is tricky.

What's interesting about your plot is you go 10:1 rich and you're still making more power than at 11.5:1 with less pressure. I'm sure that has a lot to do with removing the AFM. You also made less power under 3500 rpm. That's because you didn't have any fuel.

Add some fuel in before 3500 and remove some after 5600 & I'd put money on the exact set up going peak 205 rwhp and peak 185 rwtq holding 180 flat until redline. Get your timing map tweaked out, and I'd put money on close to 200 rwtq w/o touching the mbc.

Braineack 05-14-2007 09:20 PM

other way around...red line is bipes/fmu @ 11psi blue is MS @ 12psi.

timing should be good, just needs less fuel...what im saying is when i finally crossed the fuel, the power made around the same....if I lean it up throughout I suspect lots more power.

Al Hounos 05-14-2007 10:24 PM

I think your exhaust may be a big problem, bottling up your VE, flowing less air, which means my map runs richer on your car. It would be interesting to see if you just removed everything from the downpipe back and took a log.

Braineack 05-14-2007 10:34 PM

bet your right. I go from 2.5" to 2.75" on the DP; 2.5" on the cat; 2.25" on the catback; (2) 2" rear exits.

Your fuel map is perfect...just needs to be scaled down thats all...i love the flatness and the tad bit richness up top.


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