No boost at launch!

[phocusd]

I am sure that this has been covered before, but I recently went to the track and have a problem building any boost on the line, this resulted in a terrible 2.23 60ft time and a 13.27 et. However my mph was 111.4 mph which should corelate to a 12.0 or even 11.99 et. I sat at the line for several seconds and could not even get one pound of boost. I am running a TA-49 turbo with the stock torque converter, as well as 50# injectors with the correct chip for them.
Can someone tell me the possible causes for this lack of low end power and inability to get a decent launch? I even tried doing a burnout on the street and cannot get tires to start spinning while holding the brakes and giving it gas.

Thank you

 

[UNGN]

The most minor of pre-turbo exhaust leaks will prevent a TA49 from spooling with the stock converter.

First, use a scan tool to Check the RPM of your car at stall.

If its 2300+ and the turbo isn't spooling, look for an exhaust leak or make sure you aren't running too much fuel pressure (If you are adding base FP to reduce top end knock, add octane next time and leave the FP alone).

I took the headers, crossover, turbo, etc, off and inspected every inch for cracks, leaks and warped flanges, then had the cracks welded and warps filed flat so I was sure there was no leakage. I even had to replace my crossover with a good one.

If you are not seeing at least 2300 RPM on the scan tool, look for a converter problem.

 

[phocusd]

Reply

Yes, the exhaust leak might be possible however the car only has 8,000 miles on it. I am only running 38# of fuel pressure with the vacuum line off, so I don't think that is too high.

 

[salvageV6]

THDP puck leaking over the turbo hole in the ex. housing.

 

[phocusd]

How can that be fixed?

 

[phocusd]

Fixed the problem. One of the lines on the vacuum block was cracked and I had a huge vacuum leak from the throttle body which was bleeding off boost. The car now launches very well, getting sideways on the street and spiking the boost up to 15 pounds as my Mickey Thompson et drag radials went up in smoke for about 70 feet!