sr20det intake manifold swap

sr20truck · Post by **sr20truck** » Sat May 30, 2009 3:06 pm

red top sr20det in a 240sx has fmic, 3 inch turbo back exhaust, AEM wideband mounted in the test pipe, otherwise stock.

I got the greddy knockoff plenum onto the car just lately, seems I lost a pound of vacuum. It was at 8.4 and now is 7.3 at idle. This caused the A/F ratio to be at 18.0 at idle. I messed around with many values like my K constant up to 26475 from 21475 stock and got results but made the rest of the power band very rich. I put that back to normal and got a result of 14.9 A/F ratio from changing only the lower left block on the fuel map to 11.00

This works fine but does it sound crazy to you? It makes the 3D graph go underneath itself in that spot. Should I really wait till the supporting mods like the z32 mafs, gt2871r turbo, and larger injectors are fitted?

Rich S · Post by **Rich S** » Wed Jun 17, 2009 2:52 am

this may be too late but... since you are changing injectors and everything else.... What I did was use the injector latency to setup idle A/F. then your k constant to get the off idle map roughed in before I started changing numbers in the cells.

Then when I was done, I turned on the O2 and knock feedback switches.

sr20truck · Post by **sr20truck** » Fri Jun 26, 2009 5:15 am

the problem was the air filter (apexi) was dirty and even after cleaning it, it still was garbage. I bought a new one and I have no issues. another silly move on my part. I have the z32 but I am thinking why even bother installing it because the turbo is still stock T25.

I did figure out my vacuum problem. Also I am going to have the intake mounting surfaces refinished, the people who sold it to me chromed every last part of the manifold except the inside of it.