The Official Overboosted Overlords Club
MAF volts would be ~4.7x at ~380 g/sec on PDXHAK's calibration.
As noted elsewhere, the "baseline" for this dyno (on that day under those conditions) would be the bone-stock '09 car.
The AFR differential between the OE WB and the dyno WB (about a full point) required some hair-splitting, but as I've pointed out many times before, there is not enough power differential between 11.2:1 and 11.9:1 on these FI engines with relatively small turbos to justify the risk (which is substantial).
Also, to add fuel to the fire:
1) PDX's car made more power as I pulled timing
2) PDX's MAF was showing a bit less airflow on the higher power dyno pulls at the same AFR than the lower power pulls
3) PDX's MAF curve is, essentially, the OE MAF curve extended out to 5v.
4) At the power peak, PDX's car is flowing (according to the MAF) ~175% at a Pr that is 170% while producing 170% more power than the NA example.
As noted elsewhere, the "baseline" for this dyno (on that day under those conditions) would be the bone-stock '09 car.
The AFR differential between the OE WB and the dyno WB (about a full point) required some hair-splitting, but as I've pointed out many times before, there is not enough power differential between 11.2:1 and 11.9:1 on these FI engines with relatively small turbos to justify the risk (which is substantial).
Also, to add fuel to the fire:
1) PDX's car made more power as I pulled timing
2) PDX's MAF was showing a bit less airflow on the higher power dyno pulls at the same AFR than the lower power pulls
3) PDX's MAF curve is, essentially, the OE MAF curve extended out to 5v.
4) At the power peak, PDX's car is flowing (according to the MAF) ~175% at a Pr that is 170% while producing 170% more power than the NA example.
Last edited by MazdaManiac; Dec 19, 2010 at 04:31 AM.
Like an exact opposite of the MAF curve in the tune.....
each volt change up top corresponds to an exponentially large change in airflow, so logged the other way, the volts should spike then flatten out.
each volt change up top corresponds to an exponentially large change in airflow, so logged the other way, the volts should spike then flatten out.
So - are you saying that there does seem to be a setup problem ?
As for number 2) off the cuff I would say more timing and less fuel at a lower calc-ed load... but if your pulling timing already to make more power, then I dunno.
^ I know what is going on exactly. I'm just adding input for discussion.
Also, note my edit - I added 2 more points for contention.
No - I am saying that his car produced exactly the right number at the right numbers for that dyno on that day and there is nothing "wrong" here at all, other than the need to work the boost controller a bit.
9 PSI (175% of ambient pressure) on that turbo produced 170% of the NA result with 170% of the NA airflow..
Also, note my edit - I added 2 more points for contention.
No - I am saying that his car produced exactly the right number at the right numbers for that dyno on that day and there is nothing "wrong" here at all, other than the need to work the boost controller a bit.
9 PSI (175% of ambient pressure) on that turbo produced 170% of the NA result with 170% of the NA airflow..
Last edited by MazdaManiac; Dec 19, 2010 at 04:37 AM.
Looking back at J Cab's BNR, he made 290 WHP at about 4.65 Volts on his dyno day.
His timing was more aggressive at 16 BTDC but had a 15D split, and a gigantic boost leak.
So, if I had to guess, for fun. His AFR's were the same, and the airflow was lower, either the temp changed making his load lower, since his IAT is pre turbo and intercooler, or the spit changed?
His timing was more aggressive at 16 BTDC but had a 15D split, and a gigantic boost leak.
So, if I had to guess, for fun. His AFR's were the same, and the airflow was lower, either the temp changed making his load lower, since his IAT is pre turbo and intercooler, or the spit changed?
^ I know what is going on exactly. I'm just adding input for discussion.
Also, note my edit - I added 2 more points for contention.
No - I am saying that his car produced exactly the right number at the right numbers for that dyno on that day and there is nothing "wrong" here at all, other than the need to work the boost controller a bit.
9 PSI (175% of ambient pressure) on that turbo produced 170% of the NA result with 170% of the NA airflow..
Also, note my edit - I added 2 more points for contention.
No - I am saying that his car produced exactly the right number at the right numbers for that dyno on that day and there is nothing "wrong" here at all, other than the need to work the boost controller a bit.
9 PSI (175% of ambient pressure) on that turbo produced 170% of the NA result with 170% of the NA airflow..
Power!!
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As I read it the intent was to figure out if the dyno was reporting low numbers relative to the anecdotal norms or if there was something mechanically wrong with the car.
And Jeff pointed out that the increase in air was proportionally equivalent to the increase in power showing that the overall efficiency of the engine did not drop vs. the NA baseline. Thus we can conclude that setup is mechanically sound.
That is assuming that turbos don't somehow break the 3rd law of Thermodynamics as a rule.
And Jeff pointed out that the increase in air was proportionally equivalent to the increase in power showing that the overall efficiency of the engine did not drop vs. the NA baseline. Thus we can conclude that setup is mechanically sound.
That is assuming that turbos don't somehow break the 3rd law of Thermodynamics as a rule.
As I read it the intent was to figure out if the dyno was reporting low numbers relative to the anecdotal norms or if there was something mechanically wrong with the car.
And Jeff pointed out that the increase in air was proportionally equivalent to the increase in power showing that the overall efficiency of the engine did not drop vs. the NA baseline. Thus we can conclude that setup is mechanically sound.
That is assuming that turbos don't somehow break the 3rd law of Thermodynamics as a rule.
And Jeff pointed out that the increase in air was proportionally equivalent to the increase in power showing that the overall efficiency of the engine did not drop vs. the NA baseline. Thus we can conclude that setup is mechanically sound.
That is assuming that turbos don't somehow break the 3rd law of Thermodynamics as a rule.
Is two yards better than a fathom?
The dyno is just a fancy vernier caliper. The numbers are (to me at least) meaningless by themselves.
It's nice to be able to say "It made X power!" for the customer's sake.
But when I'm tuning, I only look at the target A/F numbers and the torque shape.
The dyno is just a fancy vernier caliper. The numbers are (to me at least) meaningless by themselves.
It's nice to be able to say "It made X power!" for the customer's sake.
But when I'm tuning, I only look at the target A/F numbers and the torque shape.
