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Uni Stage 2 Boost Peaking at 15-17 PSI?

Prescription_Bandit

Passed Driver's Ed
Recently had a New South Boost Gauge installed; I'm admittedly a total noob at reading the gauge, but it looks like its peaking at anywhere from 15-17 psi when I go WOT(assuming 3rd gear around 3.5K RPM)

I was under the impression Unitronic's stage 2 tune was set to 20 psi. Maybe I'm reading the boost gauge incorrectly? I don't think it's a boost leak as I'm not throwing a CEL or noticing any difference in power or behavior(I got the car dynoed in April and it was putting out numbers that a stage 2 tune should).

Can anyone shed some light on this?
 

jay745

track sl00t
The actual psi will vary depending on weather. Cold weather you will read less psi because the air is more dense and it doesn't need as much pressure to achieve the same results.
 

MmmmmBoost

Ready to race!
Yep, what Jay745 said, temps around Collingwood are 0°C - 10°C so it makes sense that the boost is down, I have the same thing up here in Canada, I'll peak around 17ish and hold between 14-16
 

csumt76

Go Kart Champion
That's why it's called a boost "target" Your elevation and weather will influence what your actual manifold pressure is. Temperature/density/volume are used by the ecu to calculate how the turbo is used. Expect to lose about 3% of your HP per 1000ft of elevation.
 

kyoo

Ready to race!
Did you read the thread?
verifying cuz i've never heard of this - evo hits 25psi hot cold or anything in between

i guess though it would depend on the tune and where the boost is measuring, if it's just measuring by amount of air that gets in i guess that would make sense
 
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csumt76

Go Kart Champion
verifying cuz i've never heard of this - evo hits 25psi hot cold or anything in between

i guess though it would depend on the tune and where the boost is measuring, if it's just measuring by amount of air that gets in i guess that would make sense
Could be different setup I guess. There is a sticky talking about IHI and turbo efficiency. I had a Cobb stg 1 on my 2016 STI. The gauge hood in the dash would store the max boost pressure. IIRC it made about 20 but most of the time was 17-19psi max. They had a low/high waste gate OTS map if you weren't hitting target boost.
 

kyoo

Ready to race!
unitronic reiterated that this tune should not be seeing low psi based on temps. the mk7s yes, but not the mk6r's?
 

GolNat

Go Kart Champion
Oh. I only see target boost on hot days with my Uni tune (GTI though). As far as I know tunes are torque target as this is how the OEM system is setup but if Unitronic is saying otherwise then maybe you have a problem.

Time to do some boost logs to compare requested boost vs actual. Boost leak test also.
 

kyoo

Ready to race!
Oh. I only see target boost on hot days with my Uni tune (GTI though). As far as I know tunes are torque target as this is how the OEM system is setup but if Unitronic is saying otherwise then maybe you have a problem.

Time to do some boost logs to compare requested boost vs actual. Boost leak test also.
the mk6 gti is e888 which is the same architecture as the mk7r correct?
 

U-20T

Go Kart Champion
the mk6 gti is e888 which is the same architecture as the mk7r correct?

Not even really close, M7r has a different ECU semens vs mk6 bosch. The mk7r also has dual variable cams with valvelift, has a way different head and a turbo good for about 120hp more than an mk6 gti. also the mk6 is a MAF based strategy where as the mk7 is a speed density.
 

kyoo

Ready to race!
Not even really close, M7r has a different ECU semens vs mk6 bosch. The mk7r also has dual variable cams with valvelift, has a way different head and a turbo good for about 120hp more than an mk6 gti. also the mk6 is a MAF based strategy where as the mk7 is a speed density.
thanks, good info there.
 
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