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Discussion Starter #1
I never even realized this till after I seen my own vids the other day but I have 17lb springs in my wastegate, it usually never goes over 20lbs and I wasnt sure if the gauge was reading wrong but in my one vid I seen it climb to 24lbs. is there a logic explanation for this or is it possible my gauge is wrong, I was always under the impression that it wont go that high above the spring rate especially 7psi above, its 18psi @ 6k rpms and 22 @ 7k rpms 24 @ 7500 only in 3rd, 2nd stays pretty consistent 18-20psi
 

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Discussion Starter #3
Most of the time its not the spring that causes the spike but the wasetgate. It just cant flow enough to slow the turbo down enough.

Im guessing you dont have a boost cut setup?
nah no boost cut, I never experienced this before, but I never had more than 11psi and the guage was always dead on. I just bumped the boost to the 17psi springs 2 months ago and havent drove the car all that much
 

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internal or external wastegate?

set up boost cut, it will save your motor
 

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Can you datalog to verify that the gauge is on point? If so the only real thing i can think of is the wastegate just no bypassing enough exhuast. The 11psi setup was tuned and probably had no problem bypassing and slowing the turbo down because it wasnt spinning as fast but the 17pis spring is letting the turbo spin faster so when it opens it has a harder time slowing it down.

Makes sense to me. Kinda like driving 40 miles and breaking vs driving 80 and breaking.
 

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Discussion Starter #8
Can you datalog to verify that the gauge is on point? If so the only real thing i can think of is the wastegate just no bypassing enough exhuast. The 11psi setup was tuned and probably had no problem bypassing and slowing the turbo down because it wasnt spinning as fast but the 17pis spring is letting the turbo spin faster so when it opens it has a harder time slowing it down.

Makes sense to me. Kinda like driving 40 miles and breaking vs driving 80 and breaking.
no I cant datalog, I seen it very from 22-24spi from 7-7500rpms in different vids
 

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what turbo are you running?
 

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Where is the wastegate getting it's vacuum/boost signal from?

From the compressor housing? Pre-intercooler? Post-intercooler?

Move it to after the intercooler if it's sourced from anywhere else.
 

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Discussion Starter #12
Where is the wastegate getting it's vacuum/boost signal from?

From the compressor housing? Pre-intercooler? Post-intercooler?

Move it to after the intercooler if it's sourced from anywhere else.
compressor housing, does the hot air from the turbo make a difference?
 

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No but is a less accurate source

It does not account for pressure loss do to all the piping and intercooler....

Where are you getting you gauge reading from
 

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What you are explaining is actually boost creep.

Your wastegate can't keep up with the exhaust gas from the extra power you're making.

You should probably get a bigger (and better brand) wastegate.

Or you could tune it for the boost and hope it doesn't blow up.

Or you could put the old wastegate spring back in.

Or you could intentionally make your exhaust system more restrictive so that the engine will make less power on the same boost, thus feeding your turbine less air to deal with.

etc etc.
 

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Discussion Starter #16
Its probably your gauge. What gauge are you running, and what EMS? You need to find a way to hook up a laptop, and datalog. I have had two gauges that did great at 10psi, but on 18-19 psi, the needle just kept going. Hell, even at 15psi, it was showing 20 or so. But through Smanager, that wasnt the case. Gate held fine.

And I have used both the intake manifold, and the compressor housing as a boost source for my wastegate. Never had an issue with either, but liked having less hose from the compressor housing, so I left that.
I tuned it crome with a P28, gauge is a digital glowshift, coming rite off intake mani with a short vac line to the electrical sending unit, I figured that would be most accurate, and I can hook up a laptop I do all the tuning myself, but when I tried soldering it the latch for datalogging one of the little holes wouldnt take solder and had a hell of a time getting the old solder out, id have to get another ecu
 

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Mine was reading 16psi on a 60 trim T3 on a bone stock y8...turned out the sender for my boost gauge was getting jostled in boost because my mounts suck, causing it to read high
 

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Discussion Starter #18
Mine was reading 16psi on a 60 trim T3 on a bone stock y8...turned out the sender for my boost gauge was getting jostled in boost because my mounts suck, causing it to read high
thats good to know, I set the boost cut to 19.9psi, I'll see if I can take it for a drive tonight and see what happens
 
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