What causes boost to spike

[4ageturbs]

Why does boost spike with an internal actuator?????????

[EVLGTZ]

rangi bleed valves

[EVLGTZ]

Actually, to expand on this, some internal wastegates and actuators are unable to control boost, especially the mitsi onces from my experience

Bleed valves basically make this worse due to the nature in which they operate.

[MrOizo]

rangi bleed valves

hahaha a biggie ups to the rangi bleed valves

[hazard80]

can someone explain to me what an internal actuator is? do you just mean internal wastegate..


and whats the difference between 'boost creep' and 'boost spike', i know what boost creep is..

[flynboy]

rangi bleed valves

EG mine. haha

[4ageturbs]

Nothing wrong with a bleed valve, apart from when they drop boost, but stil it doesnt answer my question, would a dump pipe help with this or even puting a stronger spring from the wastegate to the actuator, even some externals drop too.(i dont want an external)

[LowRydr]

creep is where teh boost gradually goes u in psi in relation to the speed/revs our doing, so say your car his optimum 7psi at 4000rpm then the gauge keeps going up at a slow buy constant rate till redline, that is boost creep,

boost spike is where your driving along boosting it and you hit optimum boost but then for some reason it spikes to liek say 16psi, i had spikes wen i up rated my fule pump and added a front mount i got hard spikes

[EVLGTZ]

Nothing wrong with a bleed valve, apart from when they drop boost, but stil it doesnt answer my question, would a dump pipe help with this or even puting a stronger spring from the wastegate to the actuator, even some externals drop too.(i dont want an external)

Bleed valves dont actually drop boost, in fact you are most likely returning from a boost spike.

Bleed valves bring boost on in a non linear motion, so feels as if its coming on stronger, but in reality its coming on slightly later later than what it would with a proper gated setup which gives much more linear boost.

Secondly a dump pipe wont cure this. An external wastegate will, well a decent quality one will anyway. Mine goes to my desired boost setting and doesnt move from it until i change go, no creep, no fall away.


One thing ya can do though it get ya std internal wastegate ported. Did this on my old mazda and it helped boost control alot.