air flow question

[DSMeclipse4G63]

I logged my car to have 26.xx lbs/min(didnt see exact amount) at 14.5-15psi on a b16g. Is this normal high or low, mods in profile. Thanks
Andrew

 

[psychlow]

Since the maximum theoretical airflow of the Big 16G compressor is 36lb/min, that seems a bit high to me just taking that fact into consideration, but I'd need to run a log of my own to be sure.

If I get a chance to do so, I will and post my results. Should be able to in a couple of days unless someone else can do so sooner.

 

[DSMeclipse4G63]

I just logged my car after swaping my 2.5in exhaust with my 3in ATR and the results were amzing. ALOT better pull, quicker spool then my 3in downpie 2.5 catcatback setup and better low end. I logged thinking Id get a more accurate reading, and I was suprised....29.18lbs/min at 15psi. thats 3lbs more at the same psi. That and my turbo sounds alot different its not like a vacuum cleaner now its back to the good old high pitch spooling sound...all that from a cat back swap.
Andrew

 

[psychlow]

That's cool... I'm wondering how much air you'd log at 24 or 25PSI....

 

[DSMeclipse4G63]

with that kind of improvement with justa cat back...I can only imagine when I get injectors and safc and boost 18-20 on the street. my guess would be 32lbs or so. I just have to figure out if my throttle is opening all the way...Im getting a 94% on my logger so I may need to adjust it a little and that may help a bit.
Andrew

 

[midnght]

I just logged my car after swaping my 2.5in exhaust with my 3in ATR and the results were amzing. ALOT better pull, quicker spool then my 3in downpie 2.5 catcatback setup and better low end. .
Andrew

You usually lose some low end with the exhaust being enlarged.


How did you log your airflow? That seems odd if 15 is getting you to almost 80% of your flow.

 

[DSMeclipse4G63]

You usually lose some low end with the exhaust being enlarged.


How did you log your airflow? That seems odd if 15 is getting you to almost 80% of your flow.

I logged it with my datalogger, I was using open(no muffler)2.5in and I deffinatley got better low end. I dont know why...but It is supposed to lose some but it didnt . I got 26lbs with the 2.5 and about 14.5-15psi, and now with it flowing more it does haul ass compared to before.
Andrew

 

[psychlow]

Turbo cars usually don't lose any low end due to the fact that scavenging is almost worthless on them.

Having a huge restriction in your exhaust (TURBO) makes pretty much any larger exhaust worthwhile since spooling the turbo is so much easier with less backpressure.

On N/A cars, it's a different ballgame. You have to have an exhaust that's tuned for your desired RPM range. Factory exhausts are usually tuned to scavenge a mid-range RPM for good torque and driveability, so using a aftermarket exhaust changes that scavenging level upward in the RPM range for better top-end, at the cost of some low-end.

 

[DSMeclipse4G63]

I logged it tonight at about the same level and dumb ass me wasnt looking at my boost gauge and I realized I was hitting 19+psi. I then promptly hit fuel cut and sent my gf head first into the windshield.

But I cam across a problem Ive been having when I nailed it driving home the timing retarded like normal back to base timing. But then it went to 3 and then BARELY went up to 5 from 3k to 5.5k-6k. It only happens ever once in a while, and mopst of the time itll retard to like 9-12 degrees then stedily pick up like normal. I am starting to think its my intercooler heat soaking and cause knock therfore pulling my timing. Any ideas would be greatly appreciated. Thanks
Andrew

ps I replaced my coil pack, plugs and wires so they arent the culprit.