This page is about experimental PWM nitrous control by VEMS v3

My setup is a dry kit using WON nitrous solenoid which supports pwm-ing by nature. Tests were made with 1.1.56 and 1.1.57 firmware, using alternate boost pwm logic.

None of the existing nitrous features of vems firmware involved, I made my base maps to nitrous-friendly values.

This is my desk setup:

As you might see, this solenoid responds well to PWM-ing all over the duty-range.

I used an injector output to drive the solenoid, which in my case was a IRF640N FET (instead of default ones installed from webshop). Although my tests were made with 10A fuse which held on well, with higher supply voltages current can be up to 15A(?) with this solenoid which might be too much.

As it can be seen on video, solenoid inside temp was above 50 deg C, and hot-melt glue (used for FETs miserably) has also started to melt.

Regarding to pwm-control, there are two minor flaws;

Car setup:


The NOS-branded solenoid is for purge only


As the purpose of this setup is spool-up, I used a ref table like this:


On the road it was annoying that "turn off valve below" value simply didn't work and it resulted nitrous to come up even slightly above 80kpa -which is normal cruising.

All in all, it worked well, I needed to use a #100 jet to get a good spool to my HX-50 turbo on 3.5L engine -and stay inside traction limit in 2nd gear.

Sorting the minor issues mentioned above, and a similar new pwm-table and output in firmware would be really fine!