I put a turbo on my Lightning the beginning of the yr. I got it in a trade. It's a comp turbo 80mm with a .96A/R. It's got a 2-1/2" crossover and the cold side is 3" from the turbo into the intercooler (A/A) then comes out 3" for a little run then turns up and goes to 4" into the TB. The motor is a built MMR900 5.4 with comp stg 2 cams XE270AH (Duration 270/274....Duration @ .050" Lift 234/238). The heads are stock ported stg2 done by MMR. The downpipe is 3-1/2" The problem I'm having is I can not get this thing to build more then 14lbs. I had a manual controller on it and had few people tell me different ways to run the lines and nothing worked. It had 22lbs springs in the gate. I ended up changing the springs to 25lb springs and ran a line from the compressor housing to the top of the gate and still only makes 14lbs. Any insight on what might be going on as to why it won't build more boost?? Here are a couple pics of the set-up...... Thanks for any help.

I thought I had a newer pic showing the MAF is now right after the coupler as it comes up before the bend into the TB......
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I have since moved the MAF since this pic was taken. Just to show where it switches to 4".......
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What pressure is the turbo making you could hook a boost gauge to the compressor cover to check. Also what/where is the waste gate can you bench test the gate and make sure it is fully working properly and not opening early.

 

By the quality of your other parts, I'm guessing your wastegate isn't a chinese unit? What brand, size, location in exhaust, and is it rerouted back into the DP or dumped to atmosphere?

 

No I haven't tried to put a gauge on the turbo its self. I'll have to try that.
It is a Precision 46mm and it dumps atmosphere. It dumps to the front of the crossover not towards the motor like one of the pic shows. Here are a couple pics showing the location.....

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Here is an updated pic of where the MAF is.

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Placement looks good, I would test pressure at the turbo like mentioned that will let you know if you have a coldside boost leak or not and then bench test the gate.

 

I had to rebuild the crossover when I got it cause he had the gate on one bank so I got it to where it is now. I'll try and get a gauge on it and take it out and see what the turbo makes. So if the turbo is making the boost it should, will it go to say 20+lbs? I'm still learning all this turbo stuff. Lol I got someone that said they would smoke test it for me so I might try and hit them up.

Thanks for the help so far I really appreciate it.

 

Can you hear the wastegate opening when the boost levels out at 14psi ?

 

Yes hook a compressor up to the reference and dial up the pressure to see where its fully open at or leaking etc.

 

Before I changed the springs no I couldn't. After I changed it to the 25lb springs I finally heard it open. I have a video from when I ran it at the track I'll see if I can upload it here and see what you guys think.

Cool. I'll give it a shot this weekend. Thanks again guys least gives me somewhere to start. Lol

 

Hope this works.....

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