Help in eliminating surge

[20Vcqdriver]

Any brainiacs out there know of possible solutions to eliminate surge (flutter at WOT). Have tried a few things using the eBoost2 I have fitted but as soon as I touch 23psi it starts to be noticed, just... aim for 24psi and its very noticable so presently knocked back to 22.5psi and no surge.
would a restrictive exhaust cause this?
Running similar spec on my 3B as DJones on his ABY with MD357( thats supposedly capable of 32psi). Not aiming that high but would like to get to 26psi....
Also have ported head Wagner exh manifold, ported inlet.
Any ideas

[cooperquattro]

What intercoolers do you have,could be a flow issue....i have same issue with surge

[Error404]

IIRC Darren changed to a .80 hotside and larger turbine wheel though
i am sure PRJ will be along soon to help

[Rusty]

I had the same symptoms with a cracked EM, so could be a leak somewhere. Does it do this at all point in the rev range or just early on?

[20Vcqdriver]

Doesn't happen at low rpm only once past 4500rpm ish and only once you approach 23psi. Running a chargecooler rated to over 600bhp (massive) and with 80mm inlet and outlet sizes and a pretty short route between turbo and throttle body. Basically out of the turbo into 300mm long hose that increase to 80mm and 90degree in chargecooler, out of chargecooler through 90degree hose reducing back to fit pipe that runs over the top of cam cover to throttle valve. (S3 dump valve also on this leg). Car off on 10th March to get a larger system fitted to match the larger downpipe I had made a few months back. No Cat and free flow silencers but it is only a 2.5" system at present and hoping this might be causing the issue at a likely 360bhp at present boost....

[Error404]

I would say 2.5" is not sufficient much above 300hp.

[URquattroGus]

Anti surge compressor housing? Probablt treating the sympton and not the cause though. My Gtx turbo had this.

[20Vcqdriver]

Plenty seem to have suffered with it, but how about solutions.
Once my exhaust changed I am going to have a play with the eboost 2 and see if changing the settings for the wastegate operation and valve frequency settings etc improve things. Let you know what happens after the 10th March

[cooperquattro]

With the eboost2 you can experiment with settings for rpm based boost control,or gear based boost control

[20Vcqdriver]

Exhaust system upgraded today with 3" straight through Silencers too and sounds great but still getting the fluttering at WOT as revs rise though I noticed it is worse on cold outside temps. Tried playing around with the eboost2 sensitivity setting but still this annoying 5Hz flutter if I try and go above about 25psi. All suggestions for a solution welcomed as I'm at a loss....

[Error404]

Be less greedy with boost, bring it in later and more progressively

[martinws]

I don't know if this is even relevant but I get a slight flutter on mapped ABY at WOT at high load when my fuel is running low, I put it down to my external mounted 044 wanting to be fed at pressure. I have an MD357 to fit soon as well but I think I'll retain the N75 and have boost map done to suit

[20Vcqdriver]

I don't know if this is even relevant but I get a slight flutter on mapped ABY at WOT at high load when my fuel is running low, I put it down to my external mounted 044 wanting to be fed at pressure. I have an MD357 to fit soon as well but I think I'll retain the N75 and have boost map done to suit

Be interested to see if you get a similar issue as you pass 23-25psi. Will try a few more things with the eboost2 and see if it makes a difference

[martinws]

It will be a while yet i think as still collecting other parts to support it.

Here is a link to online tutorials that seem reasonably good on the Eboost2

[sailaz]

It will be a while yet i think as still collecting other parts to support it.

Sooo ... Any progress with this ?