what kinda gm/cyl are you seeing
07-18-2005, 11:16 AM
#4
i think the format of this survey should be:
dynair and/or Maf(sae)(and please do not report just fluke spikes, this is about knowledge not a pissing contest), rpms, speed (ram air effect counts too!), map, IAT if possible too, hardware description. this way we can correlate things like weather, height above sea level, effects of hardware at speed, with the real airflow.
dynair and/or Maf(sae)(and please do not report just fluke spikes, this is about knowledge not a pissing contest), rpms, speed (ram air effect counts too!), map, IAT if possible too, hardware description. this way we can correlate things like weather, height above sea level, effects of hardware at speed, with the real airflow.
07-18-2005, 11:33 AM
#7
Using baro = 99 kpa, IAT=110 F
maf/dynair
.63 / .67 @ 3000 rpm
.65 / .70 @ 3500
.64 / .73 @ 4000
.65 / .73 @ 4500
.67 / .74 @ 5000
.67 / .74 @ 5500
.67 / .71 @ 6200
This was done in speed density on the same run. I'm surprised how much the stock maf is off from speed density considering the wideband a/f ratio matched desired a/f ratio almost perfectly (in speed density).
This is with a 222/222 .570/.570? 112 cam with ls6 intake and catted kooks.
maf/dynair
.63 / .67 @ 3000 rpm
.65 / .70 @ 3500
.64 / .73 @ 4000
.65 / .73 @ 4500
.67 / .74 @ 5000
.67 / .74 @ 5500
.67 / .71 @ 6200
This was done in speed density on the same run. I'm surprised how much the stock maf is off from speed density considering the wideband a/f ratio matched desired a/f ratio almost perfectly (in speed density).
This is with a 222/222 .570/.570? 112 cam with ls6 intake and catted kooks.
Last edited by P Mack; 07-18-2005 at 11:53 AM.
Trending Topics
07-18-2005, 11:37 AM
#8
another thing is gearing/speed, for example:
1st gear on the street, 6000rpm:
MAF(SAE)39.82
MAP: 96kPa
2nd gear, same run, 6000rpm
MAF(SAE): 40.61
MAP: 94kPa
are these genuinly different because of speed/gearing, or is it just within the margin of error?
does anyone have any other good 'full' runs with 6000 rpm figures in 4 different gears for example?
1st gear on the street, 6000rpm:
MAF(SAE)39.82
MAP: 96kPa
2nd gear, same run, 6000rpm
MAF(SAE): 40.61
MAP: 94kPa
are these genuinly different because of speed/gearing, or is it just within the margin of error?
does anyone have any other good 'full' runs with 6000 rpm figures in 4 different gears for example?
07-18-2005, 11:43 AM
#9
Moderator
iTrader: (11)
Join Date: Mar 2002
Location: East Central Florida
Posts: 12,605
Likes: 0
Received 6 Likes
on
6 Posts
I routinely see over 0.8 g/cyl (sea level, stock H/C,
worked-over inlet tract). However bear in mind that
I also run with the fattest of the factory truck MAF
tables, because I like the airflow measurement to be
biased on the rich side and this table gave me the
best fidelity (trims / wideband AFR matches commanded).
The g/cyl you read depends on the calibration you use.
g/cyl should be independent of RPM until your VE falls
off. g/cyl should follow your torque curve (or more
properly, vice versa).
The MAF is a slow instrument and will lag true airflow
when RPM is running up fast.
worked-over inlet tract). However bear in mind that
I also run with the fattest of the factory truck MAF
tables, because I like the airflow measurement to be
biased on the rich side and this table gave me the
best fidelity (trims / wideband AFR matches commanded).
The g/cyl you read depends on the calibration you use.
g/cyl should be independent of RPM until your VE falls
off. g/cyl should follow your torque curve (or more
properly, vice versa).
The MAF is a slow instrument and will lag true airflow
when RPM is running up fast.
07-18-2005, 11:51 AM
#12
ill look up my info but i think mine was at about 0.78-0.80 in 3rd gear at 5500 rpm, redline is 6800 though. this was also at a 99 kpa map, and yes i have ram air, i come up with a contraption to seal the hood to the box and i have seen 3-4 kpa increase in my map.
07-18-2005, 11:52 AM
#13
im in SD by the way, f13 cam
just curious, what is your interest in these numbers?
redhardsupra: ive got a 1-3rd gear run up to 5500 and a short bit in 4th, ill put up a compairison to them. i see a max of 98 kpa in 1st and 2nd and 3rd i got up to 99 kpa, im sure 4th with the ram air sealed 100-101 kpa would be reached. im sure with ram air the numbers vary a lot more with speed
just curious, what is your interest in these numbers?
redhardsupra: ive got a 1-3rd gear run up to 5500 and a short bit in 4th, ill put up a compairison to them. i see a max of 98 kpa in 1st and 2nd and 3rd i got up to 99 kpa, im sure 4th with the ram air sealed 100-101 kpa would be reached. im sure with ram air the numbers vary a lot more with speed
Last edited by WS6FirebirdTA00; 07-18-2005 at 11:58 AM.
