Boost Creep

[MrMike]

I have just done a few basic mods to my 33.

FMIC

AVCR

SAFCII

3Inch turbo back

Hi flow Cat

Now my problem is the car runs too much boost. i disconected the AVCR and ran a straight line from the IC cold pipe to the turbo wastegate........

All seems ok until WOT where the boost will get upto about .84Bar on the AVCR

All i can think of is the actuator could be screwed (but was fine before the exhaust and CAT)

Or the nipple in the IC piping may be leaking but i dont think so.

Could the splitter pipe on the dump/front pipe be causing this.....

Really run out of ideas....so anything will be helpful.

Thanks Guys

P.S if i use the AVCR i can bring boost on quicker and harder in the lower rev range but up around 4500 it will start to creep

[MrMike]

Anyone>?

[petern]

you may be on the right track that it could be the split dump pipe, as you said it didn't happen before the exhaust was put on.

The reason as explained to me by my tuner. The wastegate is not fully opening, but when it is the flap is opening in the dump pipe itself - therefore restrict flow as keeping some boost.

I got a split dump and was told by my turner to return it and get a bellmouth one. He has seen many Skyline with this boost spike. On one car they even tried enlarging the open, grinding around it to flow better but still spiked - replaced with a bellmount and problem was gone.

BUT.. on the other hand, I have read that many other people has used the spilt dump without any problems

[R33silverS2]

Check the line running to the wastegate doesn't have any cracks in it. Is the nipple in the standard position on the ic pipe? Many people with hybrid kits have issue as they dont come with a nipple and try to get around it.

[R33silverS2]

Also i take it the standard solenoid has been disconnected or reomved? I had the same issue with my car after those mods but just bought a turbotech and left it running on 11psi. now is ok. It may also be the diametre of the hose you are running to the w g. If you have the stock hose try putting that on (it has a brass restrictor inside).

[Ryanrb25]

oops double post

Edited August 15, 2007 by Ryanrb25

[Ryanrb25]

even with a piggy back such as the SAFC II, the standard ecu can introduce that retarded timing bizzo, I found with my old s1 rb25det the ecu would pull the timing way back around 4-5.5k rpm which in turn would allow boost to creep up. i was explained it a while back but thats the gist of it. Mine did this all the time. even with complete stock boost lines, solinoid all hooked back up, different actuator fitted etc. Was a pain in the arse. The only real aid for this problem is a PFC, microtech so on and so forth. By all means check your actuator etc etc...if you have fitted an aftermarket dump pipe make sure its not restricting the wastegate movement.

Edited August 15, 2007 by Ryanrb25

[MrMike]

I am convinced it is the splitter pipe........i saw another post somewhere with a very similar problem

.....i disconected the wastegate linkage and the wastegate opens freely.....which leads me to my next question

Should there be any resistance in the movement of the wastgate? mine feels as if there is nothing connected inside the turbo.......

Thanks for your help

Mick

Edited August 19, 2007 by MrMike

[petern]

there should be no resistant at all, it just opens and closed a flap inside.

-if nothing was there, you would have no boost

-if it was closed, you would have unlimited boost

The good thing is it can open fully and not hit anything, but the actuator wouldn't have that reach so only opening partially.

So i still stand by my comment that the flap opening in the wastegate pipe is affecting flow, as the air is hitting flap and going to the side of the pipe.

[Yme33]

I rang just jap and they told me its the first they have heard of the problem.......they told me to pull it back off and let them see it.......so i will pull it back out in a day or two...and see what they have to say........i disconected the wastegate linkage and the wastegate opens freely.....which leads me to my next question

did this fix the problem I bought an FMIC off them and im running unlimited boost, before hand it was 14 psi which is still to high, now when boost hits it hits, high boost wooooooo rich n retard spikes to 20 psi, noticed it dosnt have the T peice in the inlet pipe so might be the problem even fixed up an Vac leek before this, man sometimes i hate the problems with Skylines.

[MrMike]

Mate got it sorted with a bell mouth dump

Your problem deffinately would be the nipple from the cooler pipe to your controller/solenoid. take off the small pipe next to the cross over pipe buy an aluminium threaded nipple and tap a thread in the pipe screw in your nipple....use some sort of silicone and screw it in........problem solved.

Good luck.

[SevenAngryPenguins]

I installed a split dump and had the same problem what i had to do was modify the heat shield so actuator could move further and die grind the inside of the pipe and still now cant get the boost under 11 psi so i'm going to get a bellmouth

[MrMike]

yeah mate go the bell mouth.............should be able to sell the split dump.....alot of people have no issues with them

[SevenAngryPenguins]

just went and picked it up (bellmouth) actually yeah had no problems with the split until the high flow cat went on

installed bellmouth and it didnt fix the boost problem which is starting to get frustrating

Edited August 23, 2007 by SevenAngryPenguins