Boost controller on a nDBW T-28
06-11-2004, 07:17 PM
#11
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load is definately MAF/RPM
in essence, load is the theoretical injection value to obtain a 14.7:1 A/F ratio.
3ms is a pretty big change, so I doubt you're going over any limit just by changing the cat.
One theory is that the high flow cat is less pressure on the turbine outlet, so for a given wastegate opening, there is a higher pressure difference, so more exhaust gas will escape, leading to lower boost
3ms is a pretty big change, so I doubt you're going over any limit just by changing the cat.
One theory is that the high flow cat is less pressure on the turbine outlet, so for a given wastegate opening, there is a higher pressure difference, so more exhaust gas will escape, leading to lower boost
06-11-2004, 08:24 PM
#12
it's a valid theory in my experience... i had the APR high flow cat on my car
and recorded over 230-240g/sec of MAF. Now with a test pipe on, I am having a hard time breaking into the 214+ range.
06-12-2004, 06:24 AM
#13
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I could see lower boost since the turbo isn't working as hard, but lower airmass doesn't make sense
to me. Why would a freer flowing intake/exhaust yield lower airmass?
When a Mark P changed his stock ICs out for the AWE ones (which have less of a pressure drop), he saw a significant increase in airmass. Shouldn't the same be true with removing restrictions in the exhaust (i.e., cats)?
-Dave Pramanik
When a Mark P changed his stock ICs out for the AWE ones (which have less of a pressure drop), he saw a significant increase in airmass. Shouldn't the same be true with removing restrictions in the exhaust (i.e., cats)?
-Dave Pramanik
06-12-2004, 08:28 AM
#14
the ideal turbine assembly would be spooled by the speed of the exhaust flow
and in fact for the same wastegate position, the wastegate and turbine paths are both freed up...so you wont necessarily have the same air in each passage. On non-dbw this can be the issue. On a car with a MAP sensor...i dont know. You and Mark should look at wastegate duty to compare...
06-14-2004, 07:57 AM
#18
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different setups, different problems, different results....
On a nonDBW A4, using the N75 valve, the boost could be lower with a high-flow cat, which would lead to lower MAF readings.
A car running an aftermarket boost controller should see the same (or higher) readings, assuming the boost is the same.
A car running an aftermarket boost controller should see the same (or higher) readings, assuming the boost is the same.
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