[timtech]

I installed a new intercooler a couple weeks ago and would like to validate that I'm not leaking anywhere before heading to the track. I found this post by Shiv and wanted to see if I can get more details.

Originally Posted by shiv@vishnu

Hi guys,
With the Procede, your turbos aren't going to work much harder if you have a boost leak. This is because we limit the authority range of the boost controls system. So the only thing you will notice is that you wont make the desired boost target (which is loggable as "boost setpoint"). If the boost leak gets bad enough, you will be so far below the boost setpoint that you will actually trigger an underboost code.

I'm not getting any codes but just want the information more for validation.

What items should I log and graph out besides the "boost setpoint"?

Danke

[OpenFlash]

Originally Posted by timtech

I installed a new intercooler a couple weeks ago and would like to validate that I'm not leaking anywhere before heading to the track. I found this post by Shiv and wanted to see if I can get more details.



I'm not getting any codes but just want the information more for validation.

What items should I log and graph out besides the "boost setpoint"?

Danke

You an also log boost control DC%. If boost setpoint (target) is consistently higher than actual boost at full throttle (especially at high rpm) and/or boost control DC% is unusually high, then you can be certain that you have a leak. The first criteria is usually easier to work with.

Shiv

[timtech]

Thanks. I think this should be done by everyone after getting a new intercooler just to make sure.

Thanks for the great information and quick turn around.

[dzenno]

Well your boost target won't really follow the actual boost curve at high rpms if you're pushing these turbos higher than about 16.5-17psi...you'll see your actual boost curve dip below setpoint ...they simply can't hold boost higher than that for more than a couple hundred RPM.

[Slidewayz]

Is there a DIY or other post on how/where to check for boost leaks? I've got one, but haven't had time to poke around and find it.

[dzenno]

Check around your DVs or blow off valve, most importantly hoses on the FMIC...

[timtech]

Originally Posted by dzenno

Well your boost target won't really follow the actual boost curve at high rpms if you're pushing these turbos higher than about 16.5-17psi...you'll see your actual boost curve dip below setpoint ...they simply can't hold boost higher than that for more than a couple hundred RPM.

Great info to know. Luckily for me autotune sees between 12.8 and 14.8 so far.

Thanks for the info!

[interpol]

If what Shiv says is true (turbos are not stressed if there is a boost leak), is it normal for me to see Boost Control DC spiking up to 100? I possibly might have a boost leak at the turbo side of my AMS IC, but have never received a code. The other comments here made it seem like boost should not reach the boost setpoint if there is a major leak, and my logs show the exact opposite (boost > setpoint).

I took these logs about 1 month ago and the car is sitting in an airport parking lot while I'm out of the country for several weeks. Any comments are appreciated.

thanks.

[OpenFlash]

Originally Posted by interpol

If what Shiv says is true (turbos are not stressed if there is a boost leak), is it normal for me to see Boost Control DC spiking up to 100?

That is completely normal for any PID based closed loop system. What you are seeing is a large proportional correction that gets induced when boost is well under the boost target. As boost error gets smaller, so does the proportional correction.

Also, it looks like your boost setpoint display and boost display (which are on the same graph) are NOT sharing the same scaling. Which is why boost looks higher than the setpoint.

shiv

[Doug007]

Originally Posted by dzenno

Well your boost target won't really follow the actual boost curve at high rpms if you're pushing these turbos higher than about 16.5-17psi...you'll see your actual boost curve dip below setpoint ...they simply can't hold boost higher than that for more than a couple hundred RPM.

Huh? The turbos can't push higher than 17psi for more than a few hundred rpm?

I beg to differ...http://www.e90post.com/forums/showthread.php?t=436001

[M3 Eater]

For boost leaks..... I have heard to listen for a hissing noise from the hoses and DV's, charge pipe. Will you actually hear this if the car is in park and the system is under vacuum? It woudn't be blowing air, but sucking it right? I just bumped up my tune 1 psi and got a 30 FF code. Everything looks tight, and there are no visual holes in the FMIC piping either. I did take out the fmic pipe and reset it with the clip, is there any procedure to reinforce that connection by the stock clip to address maybe some wear in that area from removing and replacing charge pipe and elbow for meth hardware adjustments.

[Jeff@TopGearSolutions]

Originally Posted by dzenno

Check around your DVs or blow off valve, most importantly hoses on the FMIC...

Originally Posted by Doug007

Huh? The turbos can't push higher than 17psi for more than a few hundred rpm?

I beg to differ...http://www.e90post.com/forums/showthread.php?t=436001

Ya I have no problem holding 18 PSI actually, and thats stock intercooler