Hi guys,

good day - greetings from Australia. What a supercar a tuned 996 turbo is.

I have been checking my boost versus the boost set point and note quite a big variance, see below.

I am not getting the boost my map is asking for. I am peaking at about 1.1 bar, when the map says it can go to ~1.3 bar. Its always been like this since rebuilt engine went back in. perhaps that is why i am still alive

see below is a typical durametric 6 log.

Do you think this is normal - or is boost disappearing ? i have 2 forge dump valves (0.8bar springs) on a silicon f pipe. all pipes tie wrapped. my wastegates could be opening as not enough pressure from the n75 on the actuators ?

yes i probably need to do a leak test ! not done since rebuild to be fair. - but still, have others checked their set point v actuals and seen what sort of variance there is ? i suspect boost should read much closer to the set point ?

I also checked my injector duty and noted it peaked at 70% on my 60 lb injectors running stock fuel pressure but twin 044 pumps in series. this at a lamda of 0.78. she runs great, but is suspect some boost is missing !


rpm iat fueling (ms) lamda 1 lamda 2 boost set point variance 10:26:55.4552212 4078 30.8 12.67 0.82 0.81 1848 2308 460 10:26:55.6452320 4375 30.8 15.25 0.8 0.81 2012 2368 356 10:26:55.8202420 4717 30.8 15.36 0.79 0.79 2144 2324 180 10:26:55.9802512 4924 30.8 16.62 0.79 0.78 2176 2289 113 10:26:56.1492609 5180 30.8 15.69 0.75 0.77 2166 2288 123 10:26:56.3302712 5477 30.8 15.03 0.8 0.8 2192 2315 123 10:26:56.5052812 5761 30.8 14.26 0.78 0.79 2216 2354 138 10:26:56.6962921 6001 30.8 14.08 0.78 0.77 2235 2446 212 10:26:56.8703021 6215 30.8 13.57 0.77 0.76 2223 2518 295 10:26:57.0533126 6454 30.8 13.46 0.77 0.74 2176 2536 360 10:26:57.2483237 6714 31.5 12.93 0.74 0.75 2147 2521 374 10:26:57.4133332 6857 31.5 12.89 0.76 0.77 2142 2369 227 10:26:57.5883432 7116 32.3 12.39 0.77 0.76 2136 2405 269 10:26:57.7763539 7059 32.3 11.35 0.87 0.87 2258 1004 -1254 10:26:57.9383632 6416 32.3 0.9 2.9 3.01 1635 1004 -630 10:26:58.1063728 5742 32.3 0.9 3.97 3.39 1397 1004 -393

 

we cant read what you posted

how about a simple boost leak test to 20 psi for 30 seconds... must hold...
and check your Wgs alos by getitng a hand pump and putting pressure on the actuator to see where it opens and does it hold ?
this is easy your looking way in the wrong direction...

 

sure can check at what pressure the wastegates open, but, the N75 adds pressure to the actuators to keep them closed, and so build boost to the map set point right ?

If this is correct, the N75 (if working and no leaks) will override the point the springs are set to open the waste gates.

come on guys, no one ever looked at their boost variance ?

 

Some advice, just stop....
no one wants to get in this pointless discussion and IM not trying to sound negative...
do a pressure test from the lower two boost hoses of ICs by blocking one off and putting 20 psi for 30 sec in another.. if if hold you have no leaks...
you obviously have no idea why Im asking you to manually put pressure in the actuator... you should... and see if the actuator is holding... inspect them too if they are after market... also while your at it sometimes a bad turbo would cause your symptoms... inspect the compressor wheel.. spin it once and check the shaft...
you want to play tuner let me know..

 

Markski,

with all due respect - that is not a helpful (or friendly) reply. Perhaps can you keep those sort of put down comments to yourself.

Hopefully someone who is interested in sharing technical information can share comments, at the end of the day we are here to help each other.

thanks for your consideration mate and good luck.

 

 

Not trying to be disrespectful but I seriously have no idea what your asking about... and my advice is honest... and always free. So instead of playing tuner, just keep it simple... mind you.. you posted this: can you read it because I cant...

rpm iat fueling (ms) lamda 1 lamda 2 boost set point variance 10:26:55.4552212 4078 30.8 12.67 0.82 0.81 1848 2308 460 10:26:55.6452320 4375 30.8 15.25 0.8 0.81 2012 2368 356 10:26:55.8202420 4717 30.8 15.36 0.79 0.79 2144 2324 180 10:26:55.9802512 4924 30.8 16.62 0.79 0.78 2176 2289 113 10:26:56.1492609 5180 30.8 15.69 0.75 0.77 2166 2288 123 10:26:56.3302712 5477 30.8 15.03 0.8 0.8 2192 2315 123 10:26:56.5052812 5761 30.8 14.26 0.78 0.79 2216 2354 138 10:26:56.6962921 6001 30.8 14.08 0.78 0.77 2235 2446 212 10:26:56.8703021 6215 30.8 13.57 0.77 0.76 2223 2518 295 10:26:57.0533126 6454 30.8 13.46 0.77 0.74 2176 2536 360 10:26:57.2483237 6714 31.5 12.93 0.74 0.75 2147 2521 374 10:26:57.4133332 6857 31.5 12.89 0.76 0.77 2142 2369 227 10:26:57.5883432 7116 32.3 12.39 0.77 0.76 2136 2405 269 10:26:57.7763539 7059 32.3 11.35 0.87 0.87 2258 1004 -1254 10:26:57.9383632 6416 32.3 0.9 2.9 3.01 1635 1004 -630 10:26:58.1063728 5742 32.3 0.9 3.97 3.39 1397 1004 -393

 

Boost leak test and ensure that your waste gates are set properly with a hand pump. I trusted an expert P-car mechanic to set my gates to 15psi and one was set to 8psi and the other to 10psi. It's all the small mechanical things that really negatively effect these turbo cars. One tiny leak or improper mechanical setting and the computer will control (your ECU) will not properly manage your car....hence the weird numbers you are claiming.

 

Also a thought...If you are protomotive tuned...wont they look at your logs for you or help you with that?

I know my tuner answers TONS of questions. Crap, I even asked him what wheels he thought I should buy

 

What boost were you running when they were set at 8/10 psi?? Because if you turned both gates up to 15psi from there,,that is a BIG increase and I hope your tune was adjusted for that...

 

1.47. After I set them to 15psi, I changed some settings on the EBC and turned it up to 1.55. I made 11 passes on the strip yesterday at 1.55 with 104 and meth. No issues and drove it home.

 

With 104 and Meth with that you should be good at that boost level...

 

I have 1 bar springs in the actuators. Thing is, I thought the n75 pressures up the actuators to hold them closed to match the ECU set point....perhaps i got that wrong ?

 

[QUOTE=996tt bandit;4033857]I have 1 bar springs in the actuators. Thing is, I thought the n75 pressures up the actuators to hold them closed to match the ECU set point....perhaps i got that wrong ?[/QUOTE


It all depends on what you tuner says to run /start with that works with his tune.
I have my crack point at 12.5 psi and have a peak of 1.4 frequently in the upper RPMs..

 

Got those nice IWG-75 actuators on brand new turbos.
Proto were great, I just thought my set up was perfect, until recently and they obviously checked the lamdas. And it is not like the power is not already huge.

my last attempt, can anybody actually explain / confirm if the actuators are supposed to keep the wastegate closed, until it is about to hit set point pressure ? A N75 valve is v fast acting, so I would have thought this closed loop control system would only give a very small boost deviation, not like 0.2 bar, as I am seeing unless there is fault/leak. I have a log from when the engine was rebuilt and it is exactly the same as now.