Strange loss of power after intercooler install - can't explain
#61
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Well last night I got on it and saw 4psi (no idea on rpm but not redlined) and I backed off because i'm still on stock injectors. It started chirping the tires ![Happy](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_stretch.gif)
Now its time to put in my 42lb greentops and start tuning/datalogging!!
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Now its time to put in my 42lb greentops and start tuning/datalogging!!
#63
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I'm can't say exactly for sure, but I would guess 1-2psi. Once I get started datalogging and ensure I have proper fueling, I'm going to know exact numbers. My eye is more focused on the wideband now, rather than the boost gauge because 24lb inj isn't enough fueling for it.
#72
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"while in the manifold I get max 13psi at 3200rpm dropping to 9psi at 5700."
Have you checked back psi? [Ideally, should be <2X boost]
Could be: @ 3200 the exh volume is producing close to 2x, and at 5700, the ratio is well beyond 2X...
Also: I always check the w/g to see if it's working correctly. I have an adjustable regulator, an accurate gauge and a simple hose setup.
Using shop air, I "run" the w/g to see if it stays seated up to set boost...
Have you checked back psi? [Ideally, should be <2X boost]
Could be: @ 3200 the exh volume is producing close to 2x, and at 5700, the ratio is well beyond 2X...
Also: I always check the w/g to see if it's working correctly. I have an adjustable regulator, an accurate gauge and a simple hose setup.
Using shop air, I "run" the w/g to see if it stays seated up to set boost...
#76
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Excessive back pressure will cause the wastegate to open earlier. I ran a TC76 with a turbosmart 38mm with a 7 lb spring. I could hear the wastegate open really early and it would run 6-7 lbs of boost. I swapped to a PT76 which has a 83mm inducer / 75mm exducer turbine wheel compared to the 68mm exducer of the TC76 and boost would hit 15lbs past 5000 rpm. With the high back pressure of the TC76 it would flow enough volume of air out the wastegate to maintain low boost. Once my back pressure dropped the wastegate no longer could support my turbo.
I bet your back pressure is through the roof with that tiny 68mm turbine wheel on your 383. You need to be in the 87+ mm size.
I bet your back pressure is through the roof with that tiny 68mm turbine wheel on your 383. You need to be in the 87+ mm size.
#77
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Well, turbo specialists recommended me this TC78 for up to 900 crank HP, now I'm not even at 600 and you're saying my turbo is tiny and backpressure is over the roof?
Not sure.
Yesterday did one more test. This time WG signal right on the first pipe coming from IC, and boost gauge directly before IC. Torque curve was much more linear this time.
What's more, I've put differential pressure sensor on both sides of IC piping, and it indicated 6psi difference before pipe blew off at 5000rpm, with only 9psi in manifold. Damn I love testing
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Yesterday did one more test. This time WG signal right on the first pipe coming from IC, and boost gauge directly before IC. Torque curve was much more linear this time.
What's more, I've put differential pressure sensor on both sides of IC piping, and it indicated 6psi difference before pipe blew off at 5000rpm, with only 9psi in manifold. Damn I love testing
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#79
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"and it indicated 6psi difference " DAMN!!
I haven't reviewed the entire thread, so this may have already been posted....
Bypass the IC, and see what happens.
If the 6psi IC pressure drop is accurate, it's time to pull it off and see wtf is going on inside.
I haven't reviewed the entire thread, so this may have already been posted....
Bypass the IC, and see what happens.
If the 6psi IC pressure drop is accurate, it's time to pull it off and see wtf is going on inside.