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Discussion Starter · #1 ·
hi to all. i been having problems with my secondary turbo coming online. i have 1999 gs400 with the aristo vvti swap. i did the manual ttc mod. wired the actuators open instead of relying on the pressure tank or a switch. went for a test drive. no boost at all. double checked everything. everything was fine, drove the car home from a buddy of mines shop. get back to the house. check again everything. take it out on the road again, boost's .15 bar lol. can anyone steer me in the right direction on what is wrong with the car? i opened up the air filter element and revved the car and it feels like there is a back flow of air coming out it. just when i rev it. there is also a resonating sound that is coming from there also. i put everything back to stock and it boosts fine on the first turbo, just the second turbo doesnt kick. it does .75 on the first then the second goes down to .4.

the reason for the ttc mod is to see what if i can get the second turbo to come online....

cliff notes: boosting .75 on first turbo then dwindles to .4 so....
i did the ttc mod and max boost is at .15

any ideas?
 

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You need to have the EGCV & IACV actuators open.

If you did that and it is still not boosting right, then your 2nd turbo might be blown.
 

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Discussion Starter · #5 ·
yea i wired both open and no dice :(. no change in tone really. there was a resonating sound coming out of the air box if that helps
 

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If the second turbo didn't operate properly in stock form there's a pretty good chance you're second turbo is blown.
 

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If the second turbo didn't operate properly in stock form there's a pretty good chance you're second turbo is blown.
There is no way to tell if his second turbo is ok or not as there is a problem with the changeover. For the record, wire open ttc sucks as a diagnostic tool.

Put the car back in stock form, go for a drive and build full boost a couple of times. Quickly pull over and pull the hose off of the IAC or EGC vsv INLET. There should be a good bit of pressure release.

If there is pressure release, go into TTC via vsv bypass (bypass the egc and iac vsv's by plumbing directly to the actuator from the loom). Go for a drive, you should be in ttc.

Even if your ptank valve is blown, vsv bypass ttc should still work.

It sounds like you have more than one problem with your system. Do these diagnostics and report back with the results.
 

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Discussion Starter · #10 ·
still the same thing. sucks. i got a used set of usdm twins so ill be puttin that on. the boost was the same though. no ttc= 10-11 lbs on the first turbo and dwindles down to 5-6 psi. ttc= 0-2 psi of boost. no death wine or anything. just weird. the actuators opened up as there was a change of tone in the exhaust. but still no boost.
 

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still the same thing. sucks. i got a used set of usdm twins so ill be puttin that on. the boost was the same though. no ttc= 10-11 lbs on the first turbo and dwindles down to 5-6 psi. ttc= 0-2 psi of boost. no death wine or anything. just weird. the actuators opened up as there was a change of tone in the exhaust. but still no boost.
Sounds like the #2 is dead then.
 

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Really? With no death whine?
 

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did you take off the pipes on the secondary turbo to see if the turbo spins freely?
Do this first, to be sure. If your exhaust note changes in TTC but the #2 doesnt come online I really cant think of anything else it could be...

yea thats what i thought :(. is it hard to put usdm turbos on an aristo vvti tt motor?
couldnt tell you. There is something nagging in the back of my head about this but I cant put a finger on it. I think the exhaust port layout is the same....
 

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Random, but my 2nd turbo was blown with somewhat of the same symptoms - no noise, no smoke but NO boost at all. The only weird thing was that my pipe going to the fenderwell to the intercooler (I still have the rubber one) was soft and not hot...so nothing was going through there. Tommy at Autobahn tested everything and when he took everything out, #2 was seized. Hope you find another problem though...
 

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after going back to normal seq. mode i was getting the same thing. Then i switched it back to TTC and it hit 18psi, then 15 after another run, and on ttc it was going around 13-15. Switched back to seq. and it was hitting 11 then dropping to 4-5. Parked the car and the next day on seq. it was staying at 11-12.
 

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Discussion Starter · #18 ·
damn it man. i got the fsm on the removal of the turbos. looks like a fun filled weekend coming up! we'll get everything off and report back with the out come. random...how much free play, if at all, should there be on the wheels?
 

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checked my turbo wheels, seems like my motor hardly got used in japan, thing looks damn new, not a bit of shaft play, probably a little tiny bit but i dont see/feel any
 

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Discussion Starter · #20 ·
holy cow. me and my buddy took majority of the turbo system off yesterday. if i ever have to do this again, i will be throwing the stockers in the trash and going single :(
 
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