Howto: Boost Gauge that shows boost/vac on GEN-IV LS scanner

[ArthurJGuy]

I have tried this with the HPTuners 2 Bar OS and it seems to work perfectly.

On the 2/3 Bar OS for GEN-IV vehicles (LS2 specifically) there is no specific 2 or 3 bar PID, that is because the standard Manifold Absolute Pressure (SAE) PID reads into boost.

What I have done is created a custom parameter that takes the Manifold Absolute Pressure and subtracts your exact Baro giving you boost for your elevation and conditions in +/- PSI.

This parameter then multiplies itself by 1 if a positive value is read, or 2.04 (2.036 rounded up) if a negative value is read.

The final output is 0.00 at key on, negative numbers are vacuum in in/HG, and positive numbers are boost in PSI.

I setup a gauge for display with a range of -30 to 30 and it works great for me. Try it out for yourself and let me know if it works for you.

([PID.11.IMP]-[PID.51.IMP])*(([PID.11.IMP]<[PID.51.IMP])+1+(([PID.11.IMP]<[PID.51.IMP])*.04))

[5_Liter_Eater]

Wow, and I thought I was good with PIDs. <hat tip> I didn't even know the relational and conditional operations existed when defining a user defined PID. I've only used them in filter functions.

One thing I'll say is I got flack for using the baro sensor PID to determine atmospheric, but that was on my car which doesn't have a real baro sensor. Unless you're at high altitude I find it OK to SWAG atmospheric as 14.7 PSI/101.3 kPa to save on the bytes.

I'll have to try this out.

[ArthurJGuy]

Gracias. You wouldn't believe me when I said that was the first custom PID I created.

I read the post where you were getting flack but I decided to go with the Baro because my DA can go anywhere from 1,000 feet to 6,000 feet depending on the weather here.

I'm not sure if it was DA or Altitude that changed the calculation so I went with the Baro to be safe.

[5_Liter_Eater]

So do you see your baro change with the weather?

[ArthurJGuy]

I JUST got HPT last week and it was rainy and the Baro was 13.64 when I checked it.

I will check it tomorrow when the weather clears up and I will report back on that.

[DSteck]

I pretty much always use barometric as the reference for my boost PID.

[IDRIVEAG8GT]

Robbie like this thread.

[littless]

just a question to the wizards. can this be done for the GEN 3 motors. i followed the write up for doing it on there but i can't get it to read above 2psi it read neg without a problem and almost matches the gauge. i am just curious if it can be done this is what i have right now. thanks for the help or suggestions

[5_Liter_Eater]

I dont think so. The 4th gens can change the MAP linear and offset for whatever MAP we install. I believe the 3rd gens do some fiddling with custom PIDs or something to that effect.

[littless]

damn ok i will keep searching thanks

[IDRIVEAG8GT]

How would you convert this over for the stock O/S with 105 KPA Map? Or is it possible?

[5_Liter_Eater]

No, you need a multi bar MAP.

[IDRIVEAG8GT]

Dats too bad

[camaro1]

i tried this pid today and i must have something messed up because the pid was reading like 7psi boost and i was only at 103kpa,, i was just messin around in the garage and revved the engine a few times,,

2010 ls3 with a zr1 map(with correct map data), baro and map reading 99kpa at key on

[camaro1]

anyone else try this pid yet?,,, i did a little test drive today and it seems to be way off

[cvccbum]

99 KPA is a 1 bar sensor I think? Need 2+ bar for this to work

[camaro1]

99 KPA is a 1 bar sensor I think? Need 2+ bar for this to work

i do,, i have a zr1 map with the correct data, im seeing 98-99 kpa with key on(baro), and under boost im seeing 120+kpa, but the boost pid is showing really high numbers

[carlrx7]

not working for me.

[cvccbum]

ah gotcha, yeah I just tested this with a 2bar cobalt map sensor. 05 LS2, reading is way high (50+ at idle)

[ArthurJGuy]

Boost (135kpa) - Baro (110kpa) = 25 kpa.

25 kpa = 3.6 PSI.

It looks like you have some things hayware in your setup (7.8:1 commanded AFR?) so how do you have the MAP sensor configured?




I need to know far more about your vehicle setup(s) and the way you have the PID configured to help.