Sarg

iTrader: (6)

I was just curious which route to take on tuning a 3 bar os with 15-20 psi. It seems like it would make sense to have it reference the PE table and have a single target of 13-12.5 any time the engine was out of boost and then add in the additional fuel with the boost enrichment (be) table for when it is in boost. Is there any disadvantages to doing it this way as opposed to doing it all through PE or a blend of the two? This is my first time tuning a turbo LS with HP Tuner. I have owned and tuned multiple turbo cars but they have all been other platforms or used a stand alone ecu.

James@ShorTuning

That's the way you would think it should be however on HPTuners custom OS the BE table isn't referenced quick enough to enrich when the condition occurs. I had a car that delayed nearly 2 full seconds in boost before BE finally kicked in. PE is instantaneous so with that said I never use BE anymore. Sucks cause who wants 11's AFR out of boost but under load? I know I don't.

Sarg

iTrader: (6)

So be is effectively useless?

MontecarloDrag

iTrader: (3)

I have used both without problems.
BE is very useful with root supercharged cars because they can enter into boosted areas at low throttle and low RPM conditions. PE can't deal with those situations without getting rich AFR at low RPM (bad for mileage).

I use PE without MAP or RPM delays, only with TPS as an enabler
I use BE to start around N/A WOT MAP values.

It takes a little adjusting to make it right. Every setup is different and even some turbo setups can give surprises and make boost without the prope enrichment so you need to be careful and test all driving conditions, not only WOT

Sarg

iTrader: (6)

See that is what I was hoping BE could be used for....if it makes boost in an unexpected area of the map then the BE could take over. But a 2 second delay could be fatal to the motor! I don't expect to have the quickest spooling turbo in the world with a large t6 on my little 5.3, but once it starts spooling it should be over fairly quickly.

James@ShorTuning

The delay is really setup dependent. A corvette has a longer delay then a fbody would just simply because there isn't as much stuff for the PCM's processor to compute. It can be functional however the delay kills it for me. I still setup the BE table to fuel like it would be used but I keep my PE at desired commanded lambda as well to make sure fuel is there. I normally set the tps fairly low and use the map enable to kick PE in.

The main thing is to try different settings on your particular application to verify and make sure it's enriching the fuel under boost.

Sarg

iTrader: (6)

So how bad is the delay with a 2000 Z28 ecu? I guess I could put the values in there anyway as a safety precaution. I guess it just uses whichever one is richer correct?

soundengineer

iTrader: (16)

I don't know what delay you are talking about as I have not experienced this ever...
The 3 bar os will use the richer of the 2 tables... PE vs BE

There are quite a few tables that affect pe/be operations.

If I was at home, I'd tell you to post the tune where you are having this issue and we could step through it to see why it is repsonding that way.


The way the pe/be works, is that it will command pe up to the BE Map value...then the BE will take over...
It still follows the rpm and time delay settings of the PE table.
The BE hysthesis determines when it will exit BE and go back to normal PE tables, and it still follows the same rules for exiting PE and going back into closed loop operation.

NicD

iTrader: (7)

The BE delay is very real and it varies depending on different conditions, on gen3 PCMs anyways. I usually setup the PE table to start to go richer in the higher RPMs just like i would set the BE to go richer as boost goes up. That way it kind of covers all the bases and leaves the bottom RPM area not super rich yet still forces it to be richer at the higher RPMs where you would most likely be into it all the way anyways.

James@ShorTuning

http://www.hptuners.com/forum/showthread.php?p=232014

Here is a post from a while ago I made on HPTuners forum about it and my findings were confirmed by Chris@HPTuners

Sarg

iTrader: (6)

Good read. It seems they say that BE is only a failsafe, but it would be a pretty poor failsafe if it takes a long time to react

James@ShorTuning

I'm wondering if EFILives custom OS's have this similar issue? I don't have EFILive currently but am looking into buying it so that I can use a roadrunner PCM with it eventually. Plus I like some of the features for custom nitrous fuel and timing adjustments.

Sarg

iTrader: (6)

If I can't get it to work well enough on the stock pcm I will go stand alone...either Megasquirt or Holley or maybe even AEM.

06X6spdGTO

iTrader: (6)

Agreed to the EFI Live!!! HPtuners is good software but the ability to expand for radical builds is, well to say the least... POOR!!

COS5 in EFI Live AWESOME option for Nitrous guys...

James@ShorTuning

Yeah that's what I've seen as well. Really sucks to not have some specialty stuff designed around the 0411pcm. With the EGR control etc it wouldn't be a huge task to build a custom OS that used that PWM circuitry for a boost control solenoid. I'm no programmer but coming from the old chip based Hondas there are guys that have turned that function on those old dinosaur ecus to control boost vs gear or speed.

I don't have efilive but plan on adding it to my arsenal... How does efi work with 2/3bar upgrades? What function is added to control commanded fueling vs boost? Just curious what the actual operating system differences are compared to the 2/3bar HPTuners OS.

joecar

EFILive:

COS's are available for some of the OS's that run on the 411 PCM;

they have tables for boost VE and spark;

COS5 additionally has a TP VE (alpha-N) which can be blended into the normal VE.

edcmat-l1

iTrader: (10)

I think the biggest bene to EFIlive is the COSs are free. Both have their pros and cons though. I've found plenty of stuff in HPtuners that's not in EFIlive, and vice versa.

Sarg

iTrader: (6)

Are they not free with hptuners? Or are you talking about things like speed density?

edcmat-l1

iTrader: (10)

Custom OSs are not free with HPtuners. Their licensing structure is less expensive though, so kind of a trade off.

joecar

EFILive: more info (COS5 shown):