Intake restrictions. How to diagnose?
03-11-2009, 03:37 PM
#1
Intake restrictions. How to diagnose? Tuner thinks I might have an intake restriction that is causing MAP KPA to dip a bit lower than it should at WOT. I get 96-98 at low to mid RPM and 92-94 at WOT. Not sure this is even a problem.
I have a stock ported 52mm TB, air diverter, 1LE rubber elbow and Arizona Speed & marine CAI. All components look good and the filter does not look unusually dirty.
I have Scanmaster and Datamaster to log MAP KPA.
I have a stock ported 52mm TB, air diverter, 1LE rubber elbow and Arizona Speed & marine CAI. All components look good and the filter does not look unusually dirty.
I have Scanmaster and Datamaster to log MAP KPA.
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03-11-2009, 07:58 PM
#8
cant remember exactly but i think 1" equals 1% in power. also cant remember what 1" is equivalent to in kPa so not much help. reading kPa from your map sensor will let you know the restriction is in the intake tract and not the manifold. mine pulled the same vacuum with an open maf. disconnect the cai and see if your restriction is gone. if not you only have 3 more things...tb, elbow, and maf.
03-12-2009, 08:59 AM
#10
Here is something I worked up from a Datamaster log while at the strip last year.
Here is some data that I have from a run at the strip last year.
BP= 101.1
3025 RPM = 98.2
4025 RPM = 97.8
4500 RPM = 97.4
4925 RPM = 95.6
5575 RPM = 96.7
6075 RPM = 95.2
6375 RPM = 94.0
So it appear that pressure loss at redline is 7.1 which could potentially = 7% power loss.
Is this about right or excessive?
Here is some data that I have from a run at the strip last year.
BP= 101.1
3025 RPM = 98.2
4025 RPM = 97.8
4500 RPM = 97.4
4925 RPM = 95.6
5575 RPM = 96.7
6075 RPM = 95.2
6375 RPM = 94.0
So it appear that pressure loss at redline is 7.1 which could potentially = 7% power loss.
Is this about right or excessive?
03-12-2009, 10:38 AM
#11
Zero pressure difference is unrealistic. That is not costing you 7%, some maybe, 7% no.
I see vaccum with this setup. Is a f-body MAF and 58mm TB.
http://i120.photobucket.com/albums/o...R/DCP_0549.jpg
I at one point had a single cone with a inverted cone in the end and that actually screwedup MAF readings too close and flow was not even and stable, the dual cone moved the filters away from the MAF a bit stabilizing flow and readings.
I see vaccum with this setup. Is a f-body MAF and 58mm TB.
http://i120.photobucket.com/albums/o...R/DCP_0549.jpg
I at one point had a single cone with a inverted cone in the end and that actually screwedup MAF readings too close and flow was not even and stable, the dual cone moved the filters away from the MAF a bit stabilizing flow and readings.
03-12-2009, 12:07 PM
#13
Look at the link. The dual filters on the 3.5" y-pipe fed to a stock f-body MAF and then the 58mm TB with short rubber couplers between. How much more open could I make it?? Yet it still pulls vaccuum, actually pretty close to the vaccum you are seeing.
03-12-2009, 01:04 PM
#14
i was saying 1 in/hg equals 1% power loss. just looked it up and 1 inch equals 3.386 kPa. is your bp reading actual or are you just plugging in standard bp at sea level?
03-12-2009, 01:10 PM
#15
Datamaster give a BARO reading, probably safe to assume that is what he is telling us.
Someone on another forum told him 1 KPa was 1% HP.
I think the flaw with that theory is to assume that 1% pressure = 1% volume in addition to like I said you wont ever get it down to 0%, If you want to bench race I suppose you could do a functional ramair, BUT those do not simply stick out into the wind and they wont work at legal speeds.
Someone on another forum told him 1 KPa was 1% HP.
I think the flaw with that theory is to assume that 1% pressure = 1% volume in addition to like I said you wont ever get it down to 0%, If you want to bench race I suppose you could do a functional ramair, BUT those do not simply stick out into the wind and they wont work at legal speeds.
03-12-2009, 01:19 PM
#16
i understand asking for a zero loss is a bit much just letting him know 7% is not possible at least from what little ive been told. even with a zero loss that would be ~2% unless im completely wrong. by the way cap my bench is faster than yours 
03-12-2009, 02:13 PM
#18
So throwing out the bogus percentage. Are those numbers out of line. Yes or no.
03-12-2009, 02:58 PM
#19
unless you are trying to get everything out of the motor i wouldnt worry about it. you probably arent going to be able to achieve a zero loss intake tract and if you do its not much gain. like i said just play with it. compare open tb to open elbow to open maf. find out whats causing the vacuum and decide whether you want to open it up.
03-15-2009, 07:21 PM
#20
An update,
I made a run without the CAI and one with. They both had very similar MAP behavior with the run w/o the CAI being maybe a point better at higher RPM's. Obviously no significant improvment. I also noticed that the filter was a little dirty but not overly dirty.
I did notice that on the run w/o the CAI, the AFGS was higher by about several points at higher RPM's.
NON CAI run on the left. CAI run on the right.
I made a run without the CAI and one with. They both had very similar MAP behavior with the run w/o the CAI being maybe a point better at higher RPM's. Obviously no significant improvment. I also noticed that the filter was a little dirty but not overly dirty.
I did notice that on the run w/o the CAI, the AFGS was higher by about several points at higher RPM's.
NON CAI run on the left. CAI run on the right.