Jump to content
LegacyGT.com

Not hitting full boost?


Recommended Posts

Well my car decided to stop hitting full boost, and I'm trying to figure out why.

 

Stage 2 e tune, stock intercooler and bpv, vf40 (new) and invidia catted dp.

 

Just checked the turbo, it's perfect. Replaced it 7k ago, so it's still healthy. Also checked all the vaccum lines and they all seem to be connected.

 

Could it be the stock intercooler or bpv? My usual boost under full throttle is right around 17.5, and I'm hitting max of around 14.5.

 

Thanks in advance!

 

 

Sent from my iPhone using Tapatalk

Link to comment
Share on other sites

I just went for another ride, and did notice that there was a way bigger "wooooosh" sound when boosting, and a louder almost blow off valve like sound after letting off the throttle.

 

 

Sent from my iPhone using Tapatalk

Link to comment
Share on other sites

You have an e-tune. So I assume you know how to make logs. AP or tactrix/vagcom?

 

If Tactrix/vagcom, log these and also pull a LearningView.

A/F Learning #1 (2-byte)** (%)

A/F Sensor #1 (2-byte)** (estimated AFR)

Boost Error* (psi)Engine Load (4-Byte)* (g/rev)

Engine Speed (rpm)

Feedback Knock Correction (1-byte)** (degrees)

Fine Learning Knock Correction (1-byte)** (degrees)

Gear (Calculated)* (position)

IAM (1-byte)** (multiplier)

Ignition Total Timing (degrees)

Intake Air Temperature (F)

Knock Sum* (count)

Manifold Relative Pressure (4-byte)* (psi relative)

Mass Airflow (g/s)

Primary Wastegate Duty Cycle (%)

Target Boost (4-byte)* (psi relative sea level)

Throttle Opening Angle (%)

Turbo Dynamics Integral (4-byte)* (absolute %)

Turbo Dynamics Proportional (4-byte)* (absolute %)

 

 

If AP, log these instead:

RPM

Boost Target

Boost

Knock Sum

FBKC

FLKC

Mass Air Flow (NOT voltage)

Ignition Total Timing

Intake Air Temperature

Turbo Dynamics Proportional

Turbo Dynamics Integral

Primary WGDC

Engine Load

 

And do a WOT pull in 3rd from 2K to redline.

Link to comment
Share on other sites

Okay. Now a quick log that doesn't require driving. Just hop in, turn the key to on (no need to start the engine) and pull these parameters:

AF Learning 1 A

AF Learning 1 B

AF Learning 1 C

AF Learning 1 D

Dynamic Advance Multiplier

 

5 seconds or so will do.

 

My initial suspicion, however, is you have an enormous leak somewhere.

Link to comment
Share on other sites

Check the intercooler. Is there any residue on the plastic towards the front on the passenger side?

 

 

Yeah there is. It's kinda like a black soot type of stuff. What's that mean?

 

 

Sent from my iPhone using Tapatalk

Link to comment
Share on other sites

  • Moderators
Get a used one. Or a aftermarket unit.

Intercooler can be welded but it doesn't make sense. It would leak eventually.

Happened to me already

 

Sent from my GT-P3110 using Tapatalk

 

Unfortunately, the stock TMIC can't be welded--not welding metal to plastic!

 

It can be reinforced though (see my signature).

 

PM BarManBean for an intercooler reinforcement kit. Should prevent this problem from happening in the future.

 

You rang? :p As above, see my signature for more info on reinforcing your stock TMIC.

"Bullet-proof" your OEM TMIC! <<Buy your kit here>>

 

Not currently in stock :(

Link to comment
Share on other sites

  • 6 months later...

Hi, resurrecting an old thread to help with boost leak.

 

I've built a boost leak tester using a 4" rubber plumbing cap, and in testing found that the stock hose was not just loose but torn. Replaced with a Mishimoto hose, but am still only hitting 13.5psi on a half-completed Cryo tune (thanks to Dave, who has been very patient with me while I sort out my car!)

 

The stock TMIC has been bulletproofed, and the only mod is an invidia uppipe.

 

The hoses at the blue T are ziptied and in place, and the boost leak tester doesn't find anything else at the 15psi I checked with.

 

What other locations could be leaking (besides TMIC, inlet hose, blue T) and what else oculd be causing this?

Link to comment
Share on other sites

Is it possible for a boost leak to be occurring underneath the intake manifold?

 

I've checked to 20psi now, and soap/water doesn't show any leaks at the turbo/TMIC junction, the TMIC, or the inlet hose. The tester isn't perfectly sealed so there's a hissing from the tester/intake, but I may be hearing one underneath it as well.

 

So, with the throttle body closed it is possible to get a leak underneat the manifold, or am I just hearing an echo?

Link to comment
Share on other sites

Is it possible for a boost leak to be occurring underneath the intake manifold?

 

I've checked to 20psi now, and soap/water doesn't show any leaks at the turbo/TMIC junction, the TMIC, or the inlet hose. The tester isn't perfectly sealed so there's a hissing from the tester/intake, but I may be hearing one underneath it as well.

 

So, with the throttle body closed it is possible to get a leak underneat the manifold, or am I just hearing an echo?

 

Yes, there is the possibility of a leak under the manifolds.I just found one today from a line that comes off of the turbo inlet. It was a massive leak though.

Link to comment
Share on other sites

Hm, doing the boost leak test again and I don't think it's the manifold after all.

 

To think about this another way, is there a way to figure out the problem with an AP? I tried again today to make boost and only got 13.9psi when I should be at 15.

 

Checking AF learning it read a high of 7, which seems low for a boost leak.

 

Is there any other reason I'm not making full boost?

Link to comment
Share on other sites

  • 4 weeks later...

FWIW it took forever to get this sorted out, and I'm pretty sure the car ate about a square foot of skin...

 

My issues here were the clamps themselves. I had worm drive (screw) type clamps, and even though they were the better options off the shelf I guess they weren't enough. The worm drive clamps will wreck the "threads" on the stamped part of the clamp under suprisingly low preesure. Went with T bolt clamps from Mcmaster.com and all of a sudden no leak.

 

If ever taking the IC off, I would just plan on swapping these clamps into place to prevent future issues.

 

The other bit of advice is if using the Mishimoto hose, try and get the "MO" part of the label facing straight up (and towards the back of the car obviously)

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.



×
×
  • Create New...

Important Information

Terms of Use