Boost Readings (Please Help)

[laloosh]

Ok this is really starting to aggrivate me any im trying to figure out if its the POS prosport boost gauge or if my car has a boost leak.


In gears 4-6 my car will spike to around 18 psi, drop down to 15ish hold it there till about 4k rpm and drop down to 12-13 hold it there till 5800 and drop down to 10 and at 6k it pretty much dies as well all know. AT idle im am sitting on -24, -25 if that matters

Now i hear stories of people holding 15 psi, what rpm are you guys hold 15 psi till? Either you guys are lying or i have a boost leak that i have to find.

Here is my vid. I did a pull in all the gears. Notice how my car doesnt hold anything close to 15 psi in any gear but 6th. And in 6th it holds 14 for like 2 seconds and it goes down to 13.5ish

1st will go to 9-10psi
2nd will spike to 13 and hold 12 before the throttle plate kicks in
3rd will spike to 15 and hold 13 for a little and the go to 12, then the throttle kicks in
4th will spike to 16 and hold 13-14 and once again down to 12, the the throttle kicks in
5th will spike to 18 and hold 13-14 and down to 12 tillt he throttle kicks in
6th will spike to 17-18 hold 14 for a little than goes down to 13
Reverse....well i havnt tried it lol

http://www.youtube.com/watch?v=e2AEZr3YFr8

Does yours do this?

 

[laloosh]

Updated with added video(deadhorse

 

[Nutari]

Now i hear stories of people holding 15 psi, what rpm are you guys hold 15 psi till? Either you guys are lying or i have a boost leak that i have to find.

1. Calling forum members liars is a horrible way to try to get help
2. Boost leak, defective gauge. Could be either one.
3. I thought only ricer honda's hollowed out their cats.

 

[Nutari]

Hm, do you have pictures of where you have your vacuum source t'ed from?

check all vacuum lines for kinks.

if all that is fine, call up prosport and get a new gauge.

Does it sit at 0 when the car is off?

 

[Rotus8]

Hmmm. You say "AT idle im am sitting on -24, -25 if that matters" and that is strange. Atmospheric pressure is 14.69 psi at sea level so how can you have a vacuum of -24 psi?

 

[SharkDiver]

My car idles at about 20-22 InGh.I have a prosport and my car seems to do pretty much the same thing.My car use to hold boost better but not really anymore.I dont know what the problem is either.Did you zip tie you vac line that does into the boost gauge.

 

[jhowey]

When my car is off it sits at 2 vaccum, so I figure that is my zero point, am I wrong in assuming that?

 

[laloosh]

Last night befor emaking that vid i took off the IC, tightened the hoses, zip tied all the vack lines i could find and it pretty much did nothing. I like i asked in my first post. For the memebers holding 15psi, what rpm are you holding it till? My boost guage vacuum source is from the bov just like every1 else. I really starting to think its this pos guage. IT sits at -2 when its turned off, wouldnt that make it off by 2?

 

[Jays07MS3]

Here are a couple of past logs I have of some WOT runs.

1st - spike ~ 12, hold ~ 10-11 psi
2nd - spike ~ 16, hold ~ 13-14 psi
3rd - spike ~ 18, hold ~ 14 psi
4th-6th - spike ~ 20, hold ~ 15 psi

 

[laloosh]

thanks for the reply, but i dont have excel on this computer yet. What rpms are you holding it till before it drops off?

 

[Jays07MS3]

thanks for the reply, but i dont have excel on this computer yet. What rpms are you holding it till before it drops off?

Sorry, but since I'm at work I don't have time to look at the logs right now. Here is an excel viewer you can use.

Excel viewer

 

[tru-boost]

Here are a couple of past logs I have of some WOT runs.

1st - spike ~ 12, hold ~ 10-11 psi
2nd - spike ~ 16, hold ~ 13-14 psi
3rd - spike ~ 18, hold ~ 14 psi
4th-6th - spike ~ 20, hold ~ 15 psi

the boost pressurees you are holding is pretty dead on with what i see.
but my spikes are no nearly as high. i get no spike at all in gears 2-3.
4-6 will spike to 18 and hold 14-15.

 

[laloosh]

I dunno i was going over cobbs website, and their car doesnt hold boost either. They are at 4000ft asl but their max psi is 13 and goes down to about 7 after 6k. My max psi is 15 and goes down to about 9 after 6k.
The drop is is relativly the same. However im only 500-800 feet above sea level. Anyway i am most likly going to the track tomorrow or thursday. The car ran a 13.9 @ 100 before the boost gauge. Im my trap speed becomes lower than 99 i will be worried, if im trapping my usually 99-101 i wont care one bit what this gauge reads.

 

[mazdaspeed32007]

i have an auto-meter carbon fiber series gauge and i hold a steady 16-17 psi until about 5600 then it drops to 15, in almost every gear. with the exception of 1st. i spike at about 20-21. sometimes on a good day ill run a strong 17 psi. if i can get you a video tomorrow i will do so. not sure how im going to hold a cam and steer and shift, but ill give it my best. i can at least show you in each gear anyways. hang tight.

 

[laloosh]

im really starting to peg it ont he gauge being off by 2. If you simply add 2 to all my readings they become waht ever1 sees.

i see -24, -25 at idle, add two and u get -22,-23
I see 18psi spikes that turn into a 13-14psi hold that drops to about 12
add two and u get a 20psi spike that turns into a 15-16psi hold that drops down to 14 around 6k

 

[mazdaspeed32007]

ok...i did it quick tonight. it was wet out so i gave it my all from 2nd through 4th. its quick and amateur at best but you can get a feel for what im getting from about 3000 to redline. my car boosts a bit better when dry and it would be more eminent if i had someone taping for me. it runs 20 vac and 0 psi is straight up going in increments of 5.

EDIT: bad news. you cant see. doh! ill do it tomorrow....oye.

 

[mazdaspeed32007]

ok so heres a quick crappy vid of my boost from 1st to 4th. 1st i got about 10 or 11. 2nd i got spike at about 17 and ran a steady 16. 3rd i got a spike at about 18 and ran a 16-17 then dropped to a 15 at redline. 4th i hit 18 spike and ran a quick 16-17 psi. thats not the best ive gotten. its hard to drive and tape at the same time. usually i spike a 20-21 and run a 17 then drop off around 5800-5900 to 15-16. anyway.....

http://www.youtube.com/watch?v=hnWtPTOv3Cg