I've been dumping NepTune logs into Megalog Viewer for a while now, allowing me some more options for analysis/math channels.

I'm thinking about adding a couple of sensors to my setup this fall, finally putting the additional inputs on my NepTune setup to use.

Mostly I'm concerned with what to do about the EGT. Does anyone have experience with the PLX box? I like that I can daisy chain it to my gauge since I'm already running an SM-AFR and DM-6. I don't like that it appears to come with a closed element thermocouple. That's easily remedied at work though, I can just grab one there for cost. If I choose not to go the PLX route, I can get a $12 board from Adafruit that will do the job just fine and will fit onto the interface board I plan to make for the other sensors anyway. Anyone have any other recommendations, EGT-wise?

Other sensors I plan to add are

- Fuel pressure: Already have a sensor. I really want to be able to do the math and reference (rail pressure - MAP). This will allow me to see injector tip pressure and check the linearity of my FPR. It's also the first step to me finally starting to experiment with higher fuel pressures & calculating fuel consumption more accurately.

- Cooling system pressure: Mostly just because I can. Really I can put any pressure here, but currently I'm interested in the behavior of the cooling system.

- Crankcase pressure: I have a handful of sensors I scavenged off of scrap blocks at work (we have an impressively expensive scrap heap). I've always wanted to log it and start really playing with different methods of crankcase evacuation, here's my chance.

- Intake temperature: I want to run both the GM and Honda sensors, to get a feel of what's really going on

The way I intend to build my board, it would simply be a matter of swapping some pins around to change sensor types. The EGT (if included) would be the only one fixed.

Hope I'm not nerdin' out on this too much for some folks. I'm looking for small projects to keep me busy for a bit during the off season since I don't have my whole shop out here with me yet.

 

I have a few PLX units, what are you wanting to know exactly? Some of the newer stuff seems to be lasting but the older boxes would burn out after about a year or so. I definitely have a love hate relationship with PLX LOL!!!

Personally I had to run a snubber on my fuel pressure sensor. Given, it's on the rail, but I have all AEM stuff and not a external FPR. Without it the fuel pressure was all over the place and definitely not consistent enough for your intended use.

Crankcase pressure will need both vacuum and pressure if you want to really see what's going on.

Depending on how you are sourcing your GM stuff, I may have a better solution for you. Also, you can strip the tip of the Honda IAT for an exposed element sensor if you are looking for faster feedback.

Coolant system pressure? Cool, I guess... well not really (for me). I mean it shouldn't ever build more pressure than your radiator cap rating assuming it's in working order. As temperature increases - pressure increases. Simple stuff really... however I am not saying I wouldn't read a detailed report from you on it.

 

Thanks man, that's really what I'm looking for. Mostly someone with hands-on experience with the PLX box. I'm leaning more toward making a DIY solution, honestly... Mostly debating the value of having EGT right on the dash. Aside from maybe wanting to play around with lean cruise, I'm not sure there is a ton of value in having it displayed real-time.

I'd expect to have to run some sort of pulse damping to make fuel worthwhile. I log FP at work and it's a mess half of the time. I can run a smoothing function on it there though, not really an option with the hobby-grade software I use at home.

I have access to pCC sensors at work and the cal curves for them. They measure absolute pressure... same as a MAP, just in a different form factor. So not an issue. The sensors are designed specifically for this task but there is a place right on the side of the race blocks for them. They are right at the rear of the block and protrude into the crankcase on those. I could do some minor modification to an oil galley plug and have the perfect port for this.

I don't have any concerns or need to modify the stock sensor. I just want to compare it to the values in the intake tube. Nothing exciting/exotic planned there. I have no need for anything fancy on my NA DD non-vtec beater. The stock sensor/location is more than adequate. In fact, I think that (in my case) a faster responding IAT would do nothing but make life harder when calibrating IAT offsets.

Cooling system is just for an experiment and for my own enrichment. There isn't really any point in logging it aside from monitoring cooling system health. I recently had a minor cooling system snafu that turned out to be a tired radiator cap, but it just made me think "hey, I want to log this and see how it behaves." It should be noted that I did cooling system design for my FSAE team in college. I tend to think about it a lot more than a normal person.

In the last two cases, I can log any pressure and temperature I want. Learned what I wanted to learn from watching cooling system pressure and Intake temps? Cool... I just add sensors wherever else I want them (say oil temp and pressure), move the plugs over, and enter new values into the cal tables. No need to run any extra wires or anything. I'm thinking a simple loom through the firewall with five plugs on it that I just plug in whatever I feel like logging that day.

 

I run EGT in my N/A and Turbo cars. I can count on one hand how many times I look had looked at it on my last B20/V build. It just doesn't change like a turbo car. I know you are all techy, so if I were in your shoes I would just build my own. If you are feeling lazy or like the idea of plug and play and not needing another gauge then PLX it is. You can get the EGT boxes for under $100 or so.

Do you hage a catch can? For crankcase MAP I just pull out the breather tube (it's longer than you'd think LOL) and drill and / or tap that depending on the size you need for the sensor. The block would be more ideal, but that's too much like work.

That's actually a sweet idea about logging what you want and switching stuff around. I am a freaking nut when it comes to having sensors and data logging. That's my biggest complaint with Hondata and NepTune... I want MOAR!!! I have a S300 v3 and the 8 analog and 8 digital just isn't enough... Whenever I finally get my CRV back on the road with my next turbo setup I have 4 O2 (PLX), 4 EGT (PLX), Ethanol content, fuel temp, fuel pressure, oil pressure, oil temp, KnockSense, Exhaust Back pressure, and I have to decide between pre-intercooler IAT and crankcase pressure. Sucks!!! OR I guess I could get rid of fuel temp... decisions, decisions...

On my supercharged GMC I just have two PLX O2's and one PLX vac/boost gauge. Each one has it's own DM-6 actually and rather pointless, I know. I hate that you can't just buy the box itself anymore. So after about one week one of the SM-AFR (Gen 4) boxes stopped putting out to the digital display but the Christmas tree lights still worked on the DM-6. Swapped them all around and it's only that box. Called about getting it fixed and was told it would be on me... pissed me off.