Right, as some of you would know, I have been having overboosting issues on my sequentiol tubbys!! totaly stock tubs, but I\'ve got super custom high flow super shiny pipes with a monster Blitz cooler!! LOL anyway, when I first fitted the set up all was awsome! mapping was done & everything was peaking & holding perfectly, but after a while I started to get this wierd overboost! initialy it happend now and again, then it whent to now every time :(
Anyway, what\'s happening is this: WOT from low RPM, boost comes fast up to the set .85 bar (or what ever I set the boost controller to), @ 4000 it drops (as it should) then at 4500 all hell lets loose & imidiatly she hits fuel cut @ 1.02 - 1.05 bar so I end up running 1/2 -3/4 throttle from 4k just to be safe!
I\'ve re piped the rats nest & checked the solonoids & they all seem to be working as they should (one has a slight presure loss, but not what I would call serious as it is 1psi every 3 seconds!) but it is still the same! so last night I had another look & found the pipe to the presure relief valve was prety mangled along with the actuator pipe, so I have now changed all the pipes from the UIM to what would be the Y pipe. Would you think this could cause an overboost issue when the second turbo comes online, or am I clutching at straws???
Cheers
Jono
Crazy question but are you sure you have repiped all the rats nest. When I took the twins off I found a bad pipe behind the water pump that had been casuing all my headaches. There are quite a few that run down to the turbo packs.
Shaun
i dont know anything about the twins but the actuator pipe could well of been your problem.
let us know how you get on.
Hey Mate, I had big problems with the pipes underneath the intake pipes mine were all brittle. (I doubt you have a blown pipe) Have you checked the one way vales are one way or even anyway for that matter? They caused me all kinds of issues with the 2nd turbo.
Also make sure the actuators down there are moving as they might be stuck open or closed. (not venting boost)
All the actuators on the turbo pack are moving (prespool & wastegate) checked them ages ago when the problem started. Thereis one pipe I haven\'t changed as I didn\'t have the correct size pipe, and a few other amall ones that dissapear in the unknown from the nest! basicaly I have repiped the nest itself and a few others I could get to, but not done eversingle one of them!!
Jono