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a 4" pvc pipe cap makes a nice boost leak tester just use a stick or something to help hold it in place when going over 20psi
 

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Discussion Starter · #82 ·
I have 3sx alu adapter for pressure test. Just never knew which hose I have to block during pressure test..... :) Will do it on saturday and will report back.
 

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Don't think I saw it posted. What fuel was being used?

Gain on 0 isn't a bad thing. It's just not saving the block like you mentioned above. As you stated above, you were at full boost by 3500-4000rpm and tq peak looks to be close to 4500rpm. If you were tuning to save parts, you would pull some power out around tq peak or 4000-5000rpm range. Gain only stops or slows boost spikes. If you have limiters on boost, it can cause boost surges as it spikes too fast and corrects over and over. My gain is usually 2-4 depending on weather. Hotter and more humid air gets more gain.

Without a datalog, we can't help you much otherwise unfortunately. My big curiosity is the fuel used. You didn't have meth and if you were on pump gas, I wonder if it was knocking. I could never get pump gas to take more than 17psi reliably on a piggy without knocking. I know you said you pulled timing from 5k up but it's been my experience that once an engine starts knocking, it won't stop until you let the throttle go and you were full boost before tq peak and pulled advance after tq peak. Tuning can maintain a lower count but it doesn't seem to get rid of it if you stay in it.

The boost leak will or should lower manifold pressure below expected or targeted boost but what the manifold is seeing is the power level that should be delivered. Your turbos are just working harder to get there and making more heat doing it. The added heat could start a knock problem. That circles back to the above paragraph of what fuel was used?
 

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Discussion Starter · #84 ·
It was used 100octan EU fuel. I had knock 2-4 count, but when I pulled timing, there was 0 knock.... But what I never saw was, on boost gauge drop from 18psi to 0, and stayed that way. But on Blitz boost gauge it shows up to 21 psi...
 

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Discussion Starter · #85 ·
First I will check for boost leaks, but after that, I have to put my dr arc 2 in....from reading it looks so much easier to tune it. than safc.
Well my fuel was around 11.2-11.5 A/F, but on top was round 10.5.
 

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Other thing with this, did the turbos go into surge? I can't start a dyno pull in 3rd below 4000rpm. The turbos shoot into surge and power takes a dive. It's also horrible on parts to continue pushing through surge.

Next time you dyno, log your runs.
 

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Discussion Starter · #87 ·
We started on dyno with 1st then 2nd, and 3rd gear was pull, started from 2500rpm...no I had no surge with this turbos, even on street.... on 15g I had little. I am thinking maybe because of boost leak I dont have surge....
 

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We started on dyno with 1st then 2nd, and 3rd gear was pull, started from 2500rpm...no I had no surge with this turbos, even on street.... on 15g I had little. I am thinking maybe because of boost leak I dont have surge....
Yes if you have a boost leak, it will “fix” surge.

I definitely would NOT be doing 3rd gear pulls from 2500 on a td04 car. One because of surge. Two because of how much load you can put on the motor with quick spooling turbos. In real life, you wouldn’t be doing pulls that low either as you should be shifting from 2nd to 3rd at WOT and land in rpm a lot higher rpm. There is no practical reason to ever be that low and fully spooled up. (Unless you drive a diesel).
 
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