Full Open loop tuning on the dynojet with wideband
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TECH Senior Member
Joined: Nov 2001
Posts: 10,341
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Full Open loop tuning on the dynojet with wideband Here is my combo:
385 stroker with S3 heads (327cfm at .600 lift) 11.8:1 comp
236/242 110LSA 11ICL cam
37# lucas injectors
racetronix pump
Stock descreened MAF
LS6 intake
LS1 motorsports lid
stepped headers with merge collectors and offroad Ypipe
My car made ~466RWHP and ~440RWHP at 6000rpm
My WOT tuning is fine but my part throttle tuning needs work. My merge collectors have a few leaks, my O2s are old and my LTRIMS/STRIMS are out of whack.
I wanted to know a good starting point for full open loop part throttle tuning on a dynojet
I am planning on removing the MAF and turning off the O2's altogether
Ideally I'd like to hear what you think are good starting points for IFR with the 37# lucas injectors and also VE and PE/RPM values for safe part throttle fueling. (Say starting at 13.5:1)
The WOT fueling we can take care of easily.
I basically drive the car to the track and race and also head out to a couple of cruise nights.
Any suggestions welcome
I know the dynojet doesnt load as well as the street/eddy current dyno but I think I can get pretty close. (Maybe richen it up 3-4% to account for the extra load on the street)
385 stroker with S3 heads (327cfm at .600 lift) 11.8:1 comp
236/242 110LSA 11ICL cam
37# lucas injectors
racetronix pump
Stock descreened MAF
LS6 intake
LS1 motorsports lid
stepped headers with merge collectors and offroad Ypipe
My car made ~466RWHP and ~440RWHP at 6000rpm
My WOT tuning is fine but my part throttle tuning needs work. My merge collectors have a few leaks, my O2s are old and my LTRIMS/STRIMS are out of whack.
I wanted to know a good starting point for full open loop part throttle tuning on a dynojet
I am planning on removing the MAF and turning off the O2's altogether
Ideally I'd like to hear what you think are good starting points for IFR with the 37# lucas injectors and also VE and PE/RPM values for safe part throttle fueling. (Say starting at 13.5:1)
The WOT fueling we can take care of easily.
I basically drive the car to the track and race and also head out to a couple of cruise nights.
Any suggestions welcome
I know the dynojet doesnt load as well as the street/eddy current dyno but I think I can get pretty close. (Maybe richen it up 3-4% to account for the extra load on the street)
What tuning package do you have???
13:0 (1.13 in your Open Loop F/a table) is a good starting point for AFR
With the amount of time it MAY take to dial in the PT tune on the dyno you may as well buy you own WB and tune on the steet
13:0 (1.13 in your Open Loop F/a table) is a good starting point for AFR
With the amount of time it MAY take to dial in the PT tune on the dyno you may as well buy you own WB and tune on the steet
If you have HPTuners there is a conversion tool under the ools menu that will calculate your IFR value at 0 kpa what i did was divide the new number by the old number and scalled the whole table by that value to come up with my new IFR table ie 36.95/26.41=1.3990912533131389625141991669822 this is what i scaled the whole table by.....
If you could somehow use the throttle and the brakes on the dyno to hit as many cells as you can then i can see you dialing in PT. Just use the WB output to your HPTuners cable to log the AFR and you will be fine.
If you set the open loop Fuel air table to 1.13 all the way across the board you are commanding the PCM to run an AFR of 13:1. Using the WB output and your HPTUnerds cable you will get a AFR in the scanner tool in ve table format. Take this AFR ie 15.5 and divide it by the constant 13:1 and you will see how far off you are on the ve table
eg
map=20
rpm =3400
ve value = 49
15.5/13.0=1.1923076923076923076923076923077
15.5 is 20% leaner than 13.0
then you would take
49 * 1.1923076923076923076923076923077=58.4230769230769 23076923076923077 (new ve value)
If you could somehow use the throttle and the brakes on the dyno to hit as many cells as you can then i can see you dialing in PT. Just use the WB output to your HPTuners cable to log the AFR and you will be fine.
If you set the open loop Fuel air table to 1.13 all the way across the board you are commanding the PCM to run an AFR of 13:1. Using the WB output and your HPTUnerds cable you will get a AFR in the scanner tool in ve table format. Take this AFR ie 15.5 and divide it by the constant 13:1 and you will see how far off you are on the ve table
eg
map=20
rpm =3400
ve value = 49
15.5/13.0=1.1923076923076923076923076923077
15.5 is 20% leaner than 13.0
then you would take
49 * 1.1923076923076923076923076923077=58.4230769230769 23076923076923077 (new ve value)
Teching In
Joined: Jun 2003
Posts: 16
Likes: 0
From: Boostingham, AL
Originally Posted by HumpinSS
With the amount of time it MAY take to dial in the PT tune on the dyno you may as well buy you own WB and tune on the steet
If you own the dyno, you can try to start around a 50% throttle and see if you can distinguish timing changes, if you can, you can probably get it to work. Then try 25% and 75%, etc.
