[u5g335]

For those of you with boost gauges, what PSI boost do you typically see? I just installed a digital gauge and it has never gone over 6.1PSI. This is at wot to redline through-out the rev range. My car is stock and from what I've been able to find on this forum, pressure should be in the 8.5 psi range. The outside air temperature has been <40 degF during this testing. Would that cause the boost to be on the low end? Is it possible I have a faulty gauge, leak, etc....? Thanks.

[e90AW335i]

Originally Posted by u5g335

The outside air temperature has been <40 degF during this testing. Would that cause the boost to be on the low end? Thanks.

Originally Posted by shiv@vishnu

If outside temperature goes down, so does the boost temperature (as measured by the T-MAP). Immediately, the ECU compensates for the increased air density by lower the boost pressure slightly.

So...Yes, your logic makes sense.....

[u5g335]

From 8.5 to 6 psi is considered slightly? That's like 30%..... Is that what everyone is seeing when it gets cold out? Just want to be sure before I spend time looking for a solution to a problem that doesn't even exist.

[e90AW335i]

Originally Posted by u5g335

From 8.5 to 6 psi is considered slightly? That's like 30%..... Is that what everyone is seeing when it gets cold out? Just want to be sure before I spend time looking for a solution to a problem that doesn't even exist.

Most people on here are running some kind of tune....but the information I gave you was the closest thing that I found that applied. Sorry it didn't help...

[OpenFlash]

Originally Posted by u5g335

From 8.5 to 6 psi is considered slightly? That's like 30%..... Is that what everyone is seeing when it gets cold out? Just want to be sure before I spend time looking for a solution to a problem that doesn't even exist.

Totally normal.

shiv

[u5g335]

Thanks for the responses. What outside air temperature would I have to be driving in to see 8.5psi boost as reported by others?
Also, does this mean when I install PROcede and most people are seeing 12+ psi, I'm going to see 9?
Baseline numbers are always important.

[supertech335]

when my car was stock i hooked up a guage to check it, it was at 8 psi, it was like 85 degrees out when i checked it.

[Edman951]

Your car is just like mine.

I've had a boost guage on my car since week one.

The boost range is all over the place on this car.
This was even when stock before the SSTT that i have since october.

On my gauge in stock trim,it would vary from 6-7 psi. mostly only 5-6psi.

After the SSTT it went to 9-10 psi on the first run.
Then level back to 8-9. And these days to 7ish 8 psi.

I took off the SSTT tonigh before leaving work. Since its hard core winter here, we got 12 inches of snow in the last 36hours.
Boost went down to 5-6 psi.

[Terry335]

The ECU moves boost up and down based on inlet temp, altitude, and who knows what else.

[Edman951]

OK, but from one gear to another it varies alot more then you would expect.

[sambonator]

Where's the best place to tap in for measuring boost? Solenoid vacuum line?

[O-cha]

Originally Posted by sambonator

Where's the best place to tap in for measuring boost? Solenoid vacuum line?

Sure if you want to measure how much vacuum is being applied to the wastegates. You want boost you want the lines to the diverter valves.

[sambonator]

Originally Posted by O-cha

Sure if you want to measure how much vacuum is being applied to the wastegates. You want boost you want the lines to the diverter valves.

Ah got it. Thanks! I had to do some searching to figure out where it was. This is a great picture. I wonder if Terry335 was the one who took this photo?
http://www.e90post.com/forums/showpo...4&postcount=52

[O-cha]

Originally Posted by sambonator

Ah got it. Thanks! I had to do some searching to figure out where it was. This is a great picture. I wonder if Terry335 was the one who took this photo?
http://www.e90post.com/forums/showpo...4&postcount=52

I put a T on the line from the manifold then connected it to the factory T with a short line, that 4 way would make me nervous.

[sambonator]

Originally Posted by O-cha

I put a T on the line from the manifold then connected it to the factory T with a short line, that 4 way would make me nervous.

Short line... meaning to a boost sensor sender unit like this one?
http://www.dakotadigital.com/index.c...rod/prd117.htm

Where did you tap for power?
Thank you!

[O-cha]

Originally Posted by sambonator

Short line... meaning to a boost sensor sender unit like this one?
http://www.dakotadigital.com/index.c...rod/prd117.htm

Where did you tap for power?
Thank you!

No I meant a short line of hose, that way its only "tapped". I'm pretty sure it doesn't make a difference and the 4 way works fine, but in a lot of other applications (water for instance) doing something like that would disrupt things.