Just when you think you have all the plans laid out something new bites you on the butt. I have the 749 and all the necessary parts to create the adapter harness (thanks again Mike). I bought the TDF from TunerCat and a Helms Wiring book (which I have to return because it doesn't even have the SyTy ECM wiring). Anyhow - without even thinking about it I ***umed that the VE tables went from 20kPa to 200kPa. Nope. No such luck. The VE tables only go to 100kPa. You can't REALLY tune past 100kPa. According to TunerCat (thanks TC!) ...
"the BPW is then doubled if a 2 bar sensor is being used."

... ouch. I like the way the aftermarket does it.

Tim

 

Tim,

could you clarify this;

Anyhow - without even thinking about it I assumed that the VE tables went from 20kPa to 200kPa. Nope. No such luck. The VE tables only go to 100kPa. You can't REALLY tune past 100kPa. According to TunerCat (thanks TC!) ...
"the BPW is then doubled if a 2 bar sensor is being used."

... ouch. I like the way the aftermarket does it.

Are you telling us that we need the VE tables to go up to 200kpa to read boost?

 

Just when you think you have all the plans laid out something new bites you on the butt. I have the 749 and all the necessary parts to create the adapter harness (thanks again Mike). I bought the TDF from TunerCat and a Helms Wiring book (which I have to return because it doesn't even have the SyTy ECM wiring). Anyhow - without even thinking about it I assumed that the VE tables went from 20kPa to 200kPa.

Tables go from 30 kpa to 190kpa although this may not be what tunercat shows

Nope. No such luck. The VE tables only go to 100kPa. You can't REALLY tune past 100kPa.

Of course you can. By installing a 2 bar map you roughly half the voltage per kpa. The computer doesn’t care about actual pressure only voltage.

According to TunerCat (thanks TC!) ... "the BPW is then doubled if a 2 bar sensor is being used."

The multiply by two is a scaling factor for compensation of halfing the map voltage. The right of the table still corresponds to 5V only with the 2 bar sensor 5v = 190 kpa instead of 100 kpa

This is the output that ... ouch. I like the way the aftermarket does it.

No comment


John

 

Yes, the spark tables DO allow you to set the advance from 30 to 190 Kpa, but there doesn't appear to be a direct VE table that corresponds.

A funny thing, the VE values in the "basic" VE table is extremely low (much lower than a 7730). Possibly this is the result of "halfing" values.

I don't have a "hack" of the $58, so I cannot tell if TC is just showing it "differently" or whether the 7749 handles fuel much differently than a 7730. On the 749, you select the AFR you want in PE and there is a much more detailed "Boost vs. MAP vs %TPS" table than the simple "PE RPM vs %TPS" in the 7730.

But the fact TC does have MAP values from 30 to 190 on the Spark Tables would make me think TC has not goofed on the fuel. I just think that the 7749 handles things differently than the 7730 and you need to "forget" 7730 and learn 7749. Sure would be nice to find a hack for the 7749 though.

 

ok..got a idea..I have everything to run a '749 on my Malibu but it would have to be N/A for now. I should have the exhaust done this weekend and the wiring in a couple weeks. I would like to help "hacking" the $58 code and document what changes were/are needed to run it with a V8. I know this can and has been done with success and is of much discussion on the diy mail list. Now for the disclaimer...had some code and microprocessor class back in school, been a while, and a bit rusty, but have all my books and all the lit that Glenn posted in the source code thread. Also new to "tuning" by chip, I have a burner, 20 odd 27C256 chips, a couple 29C256's that wont work with my burner, :-( and a cable/laptop/software ready to go. If you all would like to take a crack at the $58 code I am willing to help and use the Bu. Interested? cheers, Bob

 

Bob, Glenn, and Tim....and anyone else i may have left out;

PM me with your email addresses. I have a good friend who works in Research and Development for Intel. He is a guru when it comes to code! I can then send you his email address and we can get him to help us "crack the code"

 

Isn't there an option flag for 1 or 2 bar?.

 

hehe..yes there is. thanks Grumpy

 

Yes, the spark tables DO allow you to set the advance from 30 to 190 Kpa, but there doesn't appear to be a direct VE table that corresponds.

Rechecked notes and I changed byte d4f1 from 3b to 3e. This changed the scaling map value from 20-100 kpa to 30-190kpa.



I don't have a "hack" of the $58, so I cannot tell if TC is just showing it "differently" or whether the 7749 handles fuel much differently than a 7730. On the 749, you select the AFR you want in PE and there is a much more detailed "Boost vs. MAP vs %TPS" table than the simple "PE RPM vs %TPS" in the 7730.

Where would you like me to post it?

John

 

Nevermind I will attach it here.

HTH

John

 

Thanks!

 

I'm kinda under the same impression as Tim. There was a few major things that turned me off from running $58. One of them was, it does infact appear the spark tables scale to 190kpa, but the VE table does _NOT_. It appears to have a multiplier for BPW vs map (boost).

Is this _true_?

-- Joe

 

for tunning fuel above 110kpa the ecm uses a BPW multiplier. it works well.

it takes the value from 100kpa BPW x BPW multiplier goes from 110-190kpa. then it uses the rpm.

so it grab the approiate celle from the 100kpa colum. and the correct rpm. BPW multiplier = output PW.

not that hard to tune really.

have fun. and the spark table work fine in 2 bar mode they are correct. if you need a $58 hack toss me an email. i have a publically avaiable on3.

 

Well the question at that point is, why wouldnt you just import that logic into $8D..

-- Joe

 

The code I've been running lately uses a boost multiplier table, and it's more then just adequate. And for timing when in boost, just an adder table works out very well also.

The thing is that there are a number of signifigant details needed when running T/C S/C applications that aren't big issues in the N/A stuff. MATs being one of them.

In the case of T/C engines, there is even more details to look at since it's EGT that runs the show.

 

Your email is bouncing.
I'm at BPLECAN@woh.RR.com