Handling more than stock boost ?

[someguy]

How are people handling boost levels higher than stock ?

Lets say that I install a turbocharger system that generates 60 PSI of boost. And lets say that I want to use a fuel limiter that works right up to full boost, ie 60 PSI. How would you set this up, sensor wise and EFI Live wise ?

I'm guessing that you would replace the stock sensor with something that went to 60 PSI.

I'm guessing that you would change the mapping of the sensor in EFI Live so that voltage output profile of the sensor matches the pressure its sensing.

I'm guessing that the boost dependent tables would get an axis change from 0 to stock boost to 0 to 60 PSI, 400 KPA or whatever it is.

Is this right ? I never hear of anyone doing this. So how do people deal with boost levels higher than stock ?

Thanks !

[THEFERMANATOR]

If you don't want the ECM to cut fuel due to boost, the simplest way I know of is to rescale your boost sensor so that it will only read so high. This way when it goes higher, the ECM doesn't really knoiw it due to the boost sensor scale change.

[someguy]

At what pressure does the ECM kick out an over boost signal on a 6.7 ? And can this be changed in EFI Live or does EFILive just turn off the CEL for all overboost ?

Lets say that the ECM is registering an overboost error for 30 PSI. Lets say the stock sensor is good to 40 PSI. You are saying that one would rescale the sensor so that it reads 30 PSI when the boost is really 40 PSI ? If so, I get that. I understand that its a way around letting the ECM defuel the engine.

But lets say I want to make 60 PSI and I want to use the boost defuelling table to control smoke and EGTs. I want different fuel delivery at 20, 30, 40, 50, and 60 PSI of boost. What is the best way to set that up ?

Thanks

[4NEATR]

I'd like to know this too, my compounds will put out about 70psi

[2007 5.9]

Cummins are 3-bar sensors. To read higher you'd need a higher bar sensor and rescale it.

[4NEATR]

Ok so I find a 5bar sensor, my 6.7L EFI doesn't have the Axis define table to re-calibrate the map sensor like the 5.9's does. And the 6.7 boost parameter in the EFI limit only goes to 58psi, where the 5.9 goes up to 100psi? Will this be a fix in the new updates or how will this work with my turbo system as it sits now?

[someguy]

I'd like to know this too. I'm going to run twins on my 6.7 and I'll need to rescale as well. 4NEATR, where did you get your sensor from ?

[4NEATR]

I haven't picked one up yet as EFI can't rescale the sensor for the 6.7 yet anyway. I am still learning about EFI, so still running my XRT in the truck, just doing some logging and seeing what is going on. There must be some way to do it with EFI as the H&S program is working fine. I logged a run and my gauge says that I peaked out at 61psi, but the EFI log says the max MAP sensor reading was 39.9 psi, and no de-fueling what so ever.

[ScarabEpic22]

Does the log say the max MAP was 39.9, or does the dash say the max MAP was 39.9? You might need to rescale the dash to accurately display higher-than-stock values.

[4NEATR]

The log shows that the MAP max reading was 255Kpa, so actually about 36.984psi. I was keeping an eye on the ISSPRO boost gauge on that run, and it maxed out just over 60psi. I don't look at the dashboard when i'm doing a run, but I just pulled up the log and the dash maxes out at 110Kpa, lol, so it is pinned.

[ScarabEpic22]

Ok, that answers my question if the log actually maxxed or if you just needed to rescale the dash. Interesting to know about the max pressure, most gas guys never push more than 255kPa!

[4NEATR]

Wow, all the turbo cars i know don't even hit 100Kpa! My turbo set up will push a little over 515Kpa, so I would like to have a sensor that goes up to 600 at least so I'm only using 80% of the gauge.

[someguy]

Twins will make 70 PSIG or ~85 PSIA.

[4NEATR]

AEM makes a 7bar (100psi) map sensor at 0.5v to 4.5v, the only thing that would confuse the ECM would be the limiter of 58psi on my truck compared to the 5.9's at 100psi. Is there any way to tell what the hard limiter is on a 6.7L? The EFI soft limit seems to be 58psi.

[someguy]

Digikey has Honeywell 7 bar absolute pressure sensors for $90. Way better than those plastic things.

http://search.digikey.com/scripts/DkSearch/dksus.dll?wt.z_cid=ref_hearst_0211_buynow&site=us&mpart=PX2AN1XX100PAAAX&v=480

I don't think there is a hard limiter. The ECM supplies 5V and takes in whatever voltage the sensor gives back, 0 to 5V. Rescale and let it rip ?