Boost surge / flutter ?

[gtirx2]

I assume the flutter your talking about doesn't happen on boost, the flutter off boost is more than likely air coming back out, "reversion" this can happen if your inlet is to sort and your MAF is to close to the comp inlet. My Z32 was attached to a 3" 70 degree pipe which was only about 12" long, I used to get reversion when I pulled up to stop, the revs would dip to almost stalling then pick up after a few seconds. I extended the 3" inlet pipe another 6" - 8" away so the filter is righ into the corner behind he headlight and the reversion stopped ;-)

Mine is pretty much the same as jonesy, and i am still on the standard inlet pipe and turbo running 1bar-1.2 with ssqv.
Its only if you are say cruising along in 5th on boost and back off just a little bit you get the flutter and the jerk.If you back off enuff to make vacum on the boost gauge its fine as the dump valve opens a little,its just that little bit from backing off from on boost and still making a little boost is when it jerks if you back off enuff to make vacum its fine.
Same still happens if i removed the dump valve, its fine if you back off completly it just when you back off a little and are still making a little boost on the gauge is when it jerks a little.

 

[youngsyp]

Mine is pretty much the same as jonesy, and i am still on the standard inlet pipe and turbo running 1bar-1.2 with ssqv.
Its only if you are say cruising along in 5th on boost and back off just a little bit you get the flutter and the jerk.If you back off enuff to make vacum on the boost gauge its fine as the dump valve opens a little,its just that little bit from backing off from on boost and still making a little boost is when it jerks if you back off enuff to make vacum its fine.
Same still happens if i removed the dump valve, its fine if you back off completly it just when you back off a little and are still making a little boost on the gauge is when it jerks a little.

Can you adjust your BOV ? Might be worth allowing it to open at a lower boost level ?!

 

[Jonesy]

Yes thats exactly the same as mine. Not sure if the bov is adjustable need to have a look.

 

[gtirx2]

Can you adjust your BOV ? Might be worth allowing it to open at a lower boost level ?!

Yep i can adjust it but tbh since i fitted a front mount intercooler it don't seem to make much differnce where i set it.When i was on the top mount i used to be able to screw it in tight and get the flutter on low boost levels but since the front mount it opens all the time even screwed right in tight it will still open on very low boost levels?It sounds likes a rattle snake sometimes:lol:
I don't think thats the problem as the bov won't open unless it reaches vacum anyhow?
Tbh the flutter/jerk is not a problem for me,plus i am proberly taking my white R off the road and putting the engine out of it into a black R that needs some[a lot:doh: ] of work as i rolled it on its side a few years back and may go hill climbing/sprinting with it.