02sierraz71_5.3

iTrader: (2)

I currently have the NA 1bar setup for HPT. Has anyone tuned an engine with a 2 bar map using 1bar software setup in speed density?

Im thinking it will cut the ve table in half so if it says 50 kpa its actually at 100kpa.

Has anyone ever done this?

MNC5

I've done it with EFI Flashscan. It worked very nicely with my Radix 427. I'm now using EFI's custom OS which is a dream on my turbo truck. But it did work well for me, I'm not sure if the loss of resolution hurt anything from what I could tell. Seemed that most of the normal driving occurs in the same MAP columns.

I posted a how to on efilive.com just search my posts.

Good luck

greentahoe

iTrader: (2)

I would like to know as well.
02sierraz71_5.3 are you going mafless? Where did you get your 2 bar from? How much?

MNC5

If you search my posts on Silverado SS.com or Efilive.com I think I posted the part # for the MAP I used.

Dennis

02sierraz71_5.3

iTrader: (2)

Im tuning someone elses big block whipple truck. Im still NA

Ive got him looking into swapping in the 3.8SC 2bar map from the GTP's. If all goes well should find one that is a direct plug and play.
Here's my post over on tech about it
https://ls1tech.com/forums/showthrea...12#post4277512
those guys think the resolution of the ve being cut in half will hurt so instead of having 1cell/400rpm/5kpa it will be 1cell/400rpm/10kpa.
I posted my thoughts over there on ve table resolution as it seems course anyway with the stock values Im hoping polynomial smoothing 1x10^-5 will make up for lack of resolution.

This is all speculation though if HPT doesnt respond they way I think it will, I just dont see why I should pay 200 bucks to read an extra 100kpa from one sensor.

02sierraz71_5.3

iTrader: (2)

so did it actually cut the map readings in half?

MNC5

The pcm is only capable of reading 0-5 volts And you can't change the kpa column headings in the program. So by changing the reference voltage you can actually use a 2bar map. Because the PCM sees only voltage just think of the KPA values in voltages instead of KPA for the 1bar vs. 2bar and you'll understand how it works.

Stock 1 bar 0kpa O volts 105kpa 5 volts (for example only)

2 bar map 0kpa 0 volts 105kpa 2.5 volts 210kpa 5 volts

So the 2bar map scales the voltage differently to the pcm. Which is why you need to change the values by 1/2 in the VE table.

Sorry if thats clear as mud...

02sierraz71_5.3

iTrader: (2)

makes sense Im just wondering if the histogram will relate. So the 2bar map sees 100kpa and spits out 2.5v, which with a 1bar OS it will appear as 50kpa. Is this what you see with your setup?

MNC5

With EFI live you could do it either way. I've never used HPT. But I'm sure you can set it up either way. You'll just have to think in Volts vs KPA. I had one gauge on the dash board read actual boost and the other KPA.

In the (Logging MAP) used the regular PID for auto tuning the VE.

TurboBerserker

iTrader: (1)

Without a true 2 bar custom OS, you will see the MAP values as 1/2 * actual. This also means that every single MAP calibration value will need to be 1/2'd in the tune if you use a 2bar sensor in a 1bar tune. You then just get adept at autodoubling when you look at your MAP

I ran this way for a while and it seems like a decent solution. I like the actual 2 bar os much better however (it's smoother).