Help Fast Please!! Overboosting!

[JDM_s13_Silvia]

i have an sr20det redtop and from the minute i got it its overboosting. i installed a turbosmart boost controller and set it to 0 and it still goes way over! where is the factory boost solonoid located? do i have to play with that? PLEASE HELP!!!:help

[themadscientist]

normally it's on the strut tower next to the turbo, did you harness possibly come with that missing? It's about the size of half a roll of quarters and has a couple of vacuum hoses hooked to it. You could put a nipple in the intercooler pipe close to the turbo and plumb that to the actuator.

[JDM_s13_Silvia]

i got a full front half of a silvia from japan so everything was complete, but isnt there. there is the vacuum hose that goes from wastegate actuator to my intercooler piping and i now have my boost controller between the 2 and thats about it....help!

[GraySilvia]

Sounds like you might have a bad wastegate actuator. Try just running a line from the IC fitting to the actuator and see if you have any boost control then. It should stay around 7psi. If not, you have a bad actuator.

[JDM_s13_Silvia]

ahh christ, thats how it was in the first place, and it was still doing that, so i put the boost controller on hoping it would change it

[GraySilvia]

Yep, sounds like the actuator. Enjuku and Heavythrottle both sell the HKS actuator for ~$60. Give one of 'em a call.

[Cyberkreig]

if i could PLEASE hyjack this thread on a semi related note.. what are you all talking about?? My wastegate is vacumed DIRECTLY to my intake mani..

[GraySilvia]

You can run the actuator off the intake or the IC, doesn't matter, much...All you need is a boost signal to the actuator. The only difference is that 7psi at the intake and 7psi at the turbo outlet are two different things. You might not make as much boost using the IC fitting Versus the Manifold fitting because the turbo will make boost until it see's 7 psi (on the actuator), it doesn't care if that's 7psi at the turbo, or 7psi at the intake after the air has been cooled and lost some boost due to all the intake plumbing...

[Cyberkreig]

Ok, i was just wondering what factory boost sylinoid you were talking about.. themadscientist post made it seem that you really should have it.

[themadscientist]

well some Nissans just run a hose directly from a boost source to the actuator, RBs for instance but the CA and SR have a comuter controlled solenoid that modulates the boost like an aftermarket boost controller. Apparently his is missing but if he has it hooked up as he describes it looks like the actuator is bad.

[JDM_s13_Silvia]

ok, i did my own diagnostic work on it and i have NO IDEA. i dont think its the actuator cause the wastegate still chatters and i hear the wastegate under boost. that means that it isnt stuck closed cause it wouldnt whistle and its not stuck open cause i still boost.....

[MadSideways]

I'm not sure exactly why, but in the past, I've seen disconnected/cracked vacume lines cause overboosting on turbo cars...

I think it prevents the wastegate from functioning properly...

[NEED4BOOST]

From a performance perspective (and assuming you dont have the boost soleniod) is it better to run the vaccum hose from the actuator to the intake manifold or to the IC pipe?

And also if the boost sloeniod is missing is it affecting anything at all or is it more of an emissions unit (to electronically regulate boost via the ECU)? Is it necessary at all?

Seth

[JDM_s13_Silvia]

it really doesnt matter where you run the vacuum line from, cause it gets an accurate reading from both. As for cracked lines, ive checked them countless times and gone over my setup 100x over in my head. There are no leaks, cracks, etc, just a hose from my intercooler piping to my boost controller to my actuator....the wastegate and actuator both work, i tested it. I CANT BELIEVE THIS IS HAPPENING!!!!! AHHHGH

[slw240sx]

ok try this... disconnect the actuator bar.. this will allow the waste gate to open completely leaving you only running stock boost.. when you get a clue as to what might be causing the over boost then hook the arm back up ,and run the wastegate acuator line to the intake compressor side of the turbo ... this is how mine was set up with stock turbo on my CA the compressor housing should have a nipple on it, run a line from it to the wastegate actuator.. insert boost controller inbetween the two when ready to fool with the boost

[martin]

ok try this... disconnect the actuator bar.. this will allow the waste gate to open completely leaving you only running stock boost.. when you get a clue as to what might be causing the over boost then hook the arm back up ,and run the wastegate acuator line to the intake compressor side of the turbo ... this is how mine was set up with stock turbo on my CA the compressor housing should have a nipple on it, run a line from it to the wastegate actuator.. insert boost controller inbetween the two when ready to fool with the boost

I don't follow this logic... Disconnecting the actuator bar will leave the wastegate flopping around, you won't make any boost at all!

-Martin.

[pampadori]

how high is the overboost? maybe you have an aftermarket actuator? the solenoid isn't needed. it's purpose is to make boost come on smooth....yada yada you don't need it. unhook the c clip on the rod to the flap door and see if boost goes away. see just how high the overboost is....if its around 14psi, i would bet you have aftermarket actuator.shaun

[GraySilvia]

Also, with an ECU controlled solenoid, the computer can yank boost if it sees too much knock, like it does on DSM's

[Silvia240sxNiSmO]

welll if the wastegate and the actuator r both working properly then you just might have as pampadori says an aftermarket actuator, but then again that doesn't explain your boot controller not having any effects.

[pampadori]

Also, with an ECU controlled solenoid, the computer can yank boost if it sees too much knock, like it does on DSM's

on the nissan, it can't take boost away. you won't have less then 7psi of boost all thing equal. the solenoid isn't a air pump so it can't "make" the actuator open. only 7psi can make it open.shaun

[pampadori]

welll if the wastegate and the actuator r both working properly then you just might have as pampadori says an aftermarket actuator, but then again that doesn't explain your boot controller not having any effects.

if his actuator has a 14 psi spring in it, the boost controller can't make it boost 10psi. it can make it boost 17 though. but you can't go lower then the spring.shaun

[JDM_s13_Silvia]

thanks alot for all the help guys! you guys are amazing. im gonna try a few things and hopefully we can get this thing going. i never thought of a high boost actuator, but it makes perfect sense seeing as though the motor came from japan on a clip with tein coilovers, hks intake and hks compresser side of the turbo.....:thumbup

[JDM_s13_Silvia]

oh and im not sure how far it overboosts, i seem to hit some sort of fuel cut when it overboosts, but ive seen it as high as about 12lbs. THANKS AGAIN GUYS!!

[GraySilvia]

on the nissan, it can't take boost away.

DOH!! Thanks for the info.

[JDM_s13_Silvia]

I was out tonight with it and it seemed to hit my fuel cut at 6lbs....just another wrench into everyones thoughts....

[GraySilvia]

It'll not boost well and sputter and such very similar to how boost cut feels if there's any kind of significant boost leak....just a thought

[pampadori]

i agree, check your bov and interooler pipes. there isn't going to be any fuel cut at 6 psi. also check your tps connection for a good contact. if its not a good one, above say 50% throttle, the motor will cut out.shaun

[joe3180]

i would have gone with the apex avcr it costs alot but i would say its the best out there