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Discussion Starter · #1 ·
I can only get .8 bar after full decat, yet in TTC mode i get 1.2 bar??

i have checked all the VSVs and they seem fine, and the actuators seem to work as they should, what else is left? any one else had this problem?
 

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I am not sure I understand your question. What is decat? Are you talking about removing the catalytic converters?

1.2bar in TTC is normal and healthy.
 

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Boost, whether in TTC or seq mode, is going to wind-up the same. Are you saying that when doing back-to-back comps (with no cats) that these are the results?
 

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MtFujiSupra said:
Boost, whether in TTC or seq mode, is going to wind-up the same. Are you saying that when doing back-to-back comps (with no cats) that these are the results?
Yes, that is what he is saying. He's from the UK, so decatting there and in Australia means removal of the catalytic converter.

Ken.
 

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Discussion Starter · #5 ·
Sorry guys should have explained it better, decatting = (removing both catalytic converters)
anyway due to the J spec having a small waste gate, decatting results in very high boost, unless a restricter ring is fitted to limit the boost to 1.2 bar,

i have run my car in TTC and sequential mode and it will make the 1.2 bar in TTC mode but will not make the same in sequential mode, any ideas? as i said all VSVs work and the actuators work so i am baffled.
 

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Have you checked the small pressure lines to the two actuator valves on the top of the sequential system? On the upper valvae I once had a popped off hose and after that I could only hit 0.9bar barely.... Check those lines carefully. Maybe this is the culprit.
Gerd
 

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Discussion Starter · #7 ·
I had both turbos off last week so all the pressure/vacume lines were checked, which is why i can't think of a reason for the low boost.
 

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Tricky-Ricky said:
as i said all VSVs work and the actuators work so i am baffled.
How do you know they all work? The only way you will make less boost in sequential mode is if a VSV or actuator is broken. All it takes is one bad/broken vsv or actuator to prevent the whole sequential opertation from performing correctly.

Look specifically at the
EGCV VSV & actuator (Exhaust gas control valve)
IACV VSV & actuator (Intake air control valve)

One of those 4 things is broken.
 

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Is it hitting 1.2bar in TTC and holding it all the way through? Or is it spiking at 1.2 bar and falling back down to what it is peaking at in sequential? Also, how did you do TTC, if you did TTC with the check valves or ETTC rather than wiring the actuators you are still relying on the sequential system so if you are hitting 1.2bar in TTC using checkvalves or ETTC your sequential system could be fine (unless of course somehow in sequential one or more of the actuators was not opening and using the checkvalves allowed the air to be trapped in.

The reason I asked whether or not you were spiking to 1.2 and holding it or dropping is a reason not a lot of people talk about but is very important. If you are on the factory wastegate VSV still (meaning no BC intercepting) and you floor it in TTC around 3k rpms or so (depending on gear and load) you will or should hit peak boost a little sooner than in sequential. This is important because for sequential the factory wastegate vsv is still open at that point (bleeding off air allowing the wastegate to be closed so the number1 can get a good amount of boost) so in effect when you floor it at 3k rpms in TTC and hit peak boost sooner than you would in sequential you are kind of like running it with the wastegate hose pulled for a split second since the vsv is still open and the wastegate is shut, thats why I asked if you were holding that 1.2 all the way, or if it dropped right back down to .8 (at which point it would be dropping back down to .8 because the vsv has closed and the wastegate is opening) If it is hitting 1.2 and holding it all the way then this is not an issue though. I have not seen a lot of people talk about this though, but that is how it was explained to me and I have tested it/monitored the operation of that vsv.
 
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