I have an APR v3.0 also I have a boost gauge. before I installed the chip,
03-02-2000, 06:54 AM
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I have an APR v3.0 also I have a boost gauge. before I installed the chip,
if I was on the highway going 80 then pushed it (WOT) the boost would max at
8PSI . from my understanding this is normal. Now I have the apr 1 bar chip. I thought it would max at 14.7 psi, however, if I do the same thing now it will max
at 18psi!!!!!!. Is this normal????? HOLY S*!# the car is fast. I am not complaining, I just want to make sure this is ok.
8PSI . from my understanding this is normal. Now I have the apr 1 bar chip. I thought it would max at 14.7 psi, however, if I do the same thing now it will max
at 18psi!!!!!!. Is this normal????? HOLY S*!# the car is fast. I am not complaining, I just want to make sure this is ok.
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03-02-2000, 07:51 AM
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14.7 psi (1bar) is the "average" boost produced...
In colder weather you will see the turbo put out less boost, and in warmer weather it will put out more. Totally normal. I'm sure Brett/Stephen@APR will respond in detail.
03-02-2000, 08:54 AM
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This is normal and here's why it does that...
As Goku posted below, max average boost pressure will vary with ambient temperature.
However, there is another phenomenom at play here. On the non-Drive-By-Wire cars (97-99.5 A4/Passat 1.8T) boost pressure will vary depending on the gear the car is in. With the APR V3.0 chip, you will see a max average boost pressure of 15psi. If you put the car in 5th and lug the engine, the maximum boost pressure will rise slightly above the average max boost pressure because of the way the engine is loaded when in higher gears. I believe that if you check the maximum boost pressures in other gears they should be close to ~15psi. The drive-by-wire cars use a different system to regulate boost pressure and do not have as significant a problem with varying boost pressures with gear selection.
As for safety, the boost pressures are tuned to reliably remain safe with the K03 turbocharger. As for the 14psi safety figure that has been thrown around for some time, this is not true. This number stemmed from a published comment several years ago and was nothing other than a 'well-that-sounds-good guestimation' in my opinion. The fact of the matter is that turbochargers are mapped dynamically; compressor efficiency will vary with pressure ratio (boost pressure/ ambient pressure) and mass air flow. As long as you stay within the operating parameters of the turbo without exceeding mechanical constraints (overspinning) you will be fine. Although Triple K does not release much technical information on their turbochargers, safety margins can be determined by carefully monitoring compressor inlet and exit temperature, exhaust gas temperatures, and engine power output (to estimate overall efficiency). All APR chips have been designed to operate safely within the mechanical constraints of the stock hardware.
Brett
APR
However, there is another phenomenom at play here. On the non-Drive-By-Wire cars (97-99.5 A4/Passat 1.8T) boost pressure will vary depending on the gear the car is in. With the APR V3.0 chip, you will see a max average boost pressure of 15psi. If you put the car in 5th and lug the engine, the maximum boost pressure will rise slightly above the average max boost pressure because of the way the engine is loaded when in higher gears. I believe that if you check the maximum boost pressures in other gears they should be close to ~15psi. The drive-by-wire cars use a different system to regulate boost pressure and do not have as significant a problem with varying boost pressures with gear selection.
As for safety, the boost pressures are tuned to reliably remain safe with the K03 turbocharger. As for the 14psi safety figure that has been thrown around for some time, this is not true. This number stemmed from a published comment several years ago and was nothing other than a 'well-that-sounds-good guestimation' in my opinion. The fact of the matter is that turbochargers are mapped dynamically; compressor efficiency will vary with pressure ratio (boost pressure/ ambient pressure) and mass air flow. As long as you stay within the operating parameters of the turbo without exceeding mechanical constraints (overspinning) you will be fine. Although Triple K does not release much technical information on their turbochargers, safety margins can be determined by carefully monitoring compressor inlet and exit temperature, exhaust gas temperatures, and engine power output (to estimate overall efficiency). All APR chips have been designed to operate safely within the mechanical constraints of the stock hardware.
Brett
APR
03-02-2000, 09:58 AM
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That's normal, I sometimes see higher boost with my MTM chip
and I trust them to have tuned their chip to be reliable (considering their relationship with Audi). In fact, from what I've seen posted here and learned in person from other chipped owners, this is pretty typical of practically all 1.0 bar chips. As for reliability, well that remains to be seen, but Rich Q. has over 50,000 chipped (MTM) miles on his A4 and the turbo is still fine (last I heard...Rich you out there?).
Regards,
Rodney
'99 A4 1.8tqms
Regards,
Rodney
'99 A4 1.8tqms
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