Boost Spike Bad

[GOLD_JET]

hey guys just had my turbo rebuilt and the internal gate port welded due to being very laggy. spools up real quick now but as soon as it hits 8psi it jumps straight to like 15-20??? what would be the cause of this. my external gate is only a cheapy and has an 8psi spring would this be the cause or something different. cheers

[GOLD_JET]

anyone?????

[kristafa]

check your plumbing of the external gate.

all i can think of this early in the monring

haha see how i spelled morning..

hmm going to bed now.

[GOLD_JET]

lol. what do you mean? check the hoses. ive checked the lines all ok. the gasket is new and ive sealed with that exhaust stuff so i dont think it leakings? im realle not sure. it has to be gate i think cause i cant control the boost with or without controller. its running unlimited boost. but i donno why it jumps so hard?

[sky_2.0T]

lol. what do you mean? check the hoses. ive checked the lines all ok. the gasket is new and ive sealed with that exhaust stuff so i dont think it leakings? im realle not sure. it has to be gate i think cause i cant control the boost with or without controller. its running unlimited boost. but i donno why it jumps so hard?

if all you did was rebuild the turbo, and it was running fine before that, then what ever was done to the turbo is the problem. sounds like the external waste gate was the problem. Not sure how a welded internal w/g would improve spool time?

Edited August 13, 2007 by sky_2.0T

[GOLD_JET]

na it was really laggy before, wouldnt start spooling until like 4500. had turbo rebuilt and internal gate port welded and it spools up way harder, unbelievable difference. but as soon as it hit like 8pis to 10 it jumps straight to like 15psi to 20 really quick. prob go more but i back off?

[GeeTR]

Hey man,

Nothing seems to be controlling your boost. Pull the boost line from the gate, push 8psi into it, and listen for the "clink" of the valve open, or remove dump and check visually with a torch. Make sure it indeed is opening at the rated spring pressure of 8psi. If so, check the boost line to the gate. Generally they feed the gate from the compressor cover. Some take the source from the plenum. Check the wastegate for how many pressure ports there are. Make sure pressure feed is to the bottom of the diaphragm and the top one is left to vent (or into compressor intake, to make it legal)

[GOLD_JET]

thanks heaps. i will try this tommorrow to see how it goes. cheers

[GOLD_JET]

i have been told i need a larger gate that can by pass enough flow due to the amount of boost spike. a guy told me this off another forum, is this correct?

[sky_2.0T]

i have been told i need a larger gate that can by pass enough flow due to the amount of boost spike. a guy told me this off another forum, is this correct?

could be a good possibility. Get a good w/g that matches ur setup, ie turbo specs, etc. Use what works with everyone else's setup. sometime the cheap stuff sucks!

[7yphon]

If it holds 15 - 20 PSI then your gate is missed matched, If it goes higher sounds like your not getting enough Air to the Valve, if you have anything other then the Gate take it off, Or yes your gate doesnt go with the setup and you need a bigger one but it still should hold some sort of boost because it should level out.