Vrdesign Member 42 Member For: 10y 10m 28d Posted 15/12/14 12:48 AM Share Posted 15/12/14 12:48 AM Hi,Ive been logging some boost pressures at different ambient temps, also I hooked up a second boost gauge on the wastegate line out of the turbo to see the pressure drop accros the whole system.14 psi Manifold, 18 psi Turbo @ 30 deg C16 psi Manifold, 20 psi Turbo @ 20 deg C (tune was done at this temp, 340 rwkw)17 psi Manifold, 21 psi Turbo @ 15 deg CAre other people seeing these sorts of numbers? 2 Link to comment Share on other sites More sharing options...
I JET Member 325 Member For: 11y 10m 18d Gender: Male Location: Wollongong Posted 15/12/14 08:42 AM Share Posted 15/12/14 08:42 AM I like data logging.....Maybe someone more knowledgeable could chime in,,,,.....is the variation in boost pressure with the change of temperature the ecu adjusting boost and timing to suit intake air temps when tuned in closed loop??? Link to comment Share on other sites More sharing options...
FiftyOne Bronze Donating Members 1,145 Member For: 11y 4m 25d Gender: Male Posted 15/12/14 09:30 AM Share Posted 15/12/14 09:30 AM Epic thread in progress Link to comment Share on other sites More sharing options...
discostig Manual mode ________________________ All day, erryday Donating Members 13,798 Member For: 17y 2d Gender: Male Location: Probably above atmospheric pressure Posted 15/12/14 09:31 AM Share Posted 15/12/14 09:31 AM (edited) Good question, I imagine if humidity was constant that 15PSI is the same volume of air regardless of temp...so ECU might be allowing more power in colder conditions.The number of years I've been reading here you'd think I'd know by now, hahaha.Also, good to see someone logging it. Edited 15/12/14 09:32 AM by -Stever- Link to comment Share on other sites More sharing options...
Vrdesign Member 42 Member For: 10y 10m 28d Posted 15/12/14 10:47 AM Author Share Posted 15/12/14 10:47 AM It defiantly seems like safety built into the tune as the compressor efficiency seems to change predictably with temp, I'm not sure what else could cause this.Also, Is a 4 psi pressure drop across the system a typical result? 2.5 hot side, plaz1000, 3" cold side into std plenum Link to comment Share on other sites More sharing options...
JVK Silver Donating Members 751 Member For: 18y 11m 8d Gender: Male Location: North West Hot Hell,VIC Posted 15/12/14 07:59 PM Share Posted 15/12/14 07:59 PM Did this quite a few years ago on the stock system and iirc came up with the same results, 4 psi drop across the system. Link to comment Share on other sites More sharing options...
Peppy_t92 Silver Donating Members 748 Member For: 11y 7m 24d Gender: Male Location: Liverpool Posted 16/12/14 07:29 AM Share Posted 16/12/14 07:29 AM There are a few variables when I comes to boost, mainly if it was tuned in closed loop or open loop... Open loop is just like a bleed valve that can be adjusted for a different RPM, this is quite commonly used and you will see variances in boost pressure through the gears, but I didn't really think that IAT came into play... Closed loop is a PI based system where you command a boost level and the pcm will try to target this value all the time 1 Link to comment Share on other sites More sharing options...
ratter Member 6,793 Member For: 18y 5m 30d Gender: Male Location: @ my laptop Posted 16/12/14 08:15 AM Share Posted 16/12/14 08:15 AM and it can also be tuned to vary with intake temperature 1 Link to comment Share on other sites More sharing options...
Vrdesign Member 42 Member For: 10y 10m 28d Posted 16/12/14 08:20 AM Author Share Posted 16/12/14 08:20 AM Thanks, it sounds to me like air temp compensation tables that drive solenoid duty cycles? Probably a question for the tuner Link to comment Share on other sites More sharing options...
gaz097 Bronze Donating Members 1,751 Member For: 13y 4m 5d Posted 16/12/14 08:56 AM Share Posted 16/12/14 08:56 AM How many logs at each temperature did you do? Link to comment Share on other sites More sharing options...
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