HG issues fixed, now external WG dump is setting off knock sensor falsely

[turboglenn]

Well, after getting the head gasket and head stud issues taken care of and working on some other things over the last few weeks while i was changing the HG (one of which was putting a new bend or two in my ext. wastegate dump) now i'm having issues with the gate settong off the KS. Before anyone says "maybe it's real knock" I can tell you it isn't because the J&S sends the voltage out to it's external display in certai frequencies depending on what it's picking up and what cylinder is knocking (it retards each cylinder individually and only the cylinders it detects knock from)

The change i made was moving the external dump away from the passenger fan by pointing it at the down pipe. I also shortened it up a LOT, it use to go outside the engine bay pointing at the ground but when i built the 3" DP i had to cutthe dump shorted because of space issues and it was pointing at the fan and doing minor damage to it, after moving it recently now it points directly at the down pipe about halfway between the outlet of the turbo and the oil pan.

AFter suspecting the gate to be at fault i turned the boost down to 19psi (lowest i can go) and it would go insane with knock each and every time the gate opened as soon as it opened.. then i turned the controller up to 30+psi and boosted into the 25psi range at just enough throttle to not open the gate and guess what, no matter what i did from throwing more timinmg at it to leaning and richening it up there now was no knock, but each and every time the gate opens the knock is there and it's pegging the J&S to pull 10* from one of my jugs

I know it's fake bu this sucks for performance, and now i'm faced with either routing the gate back into the DP ( which i've been planning to do and is why i pointed it in the direction i did) or raouting it back out of the bay and down to poin at the ground

the reason i'm posting is i'm wondering if it's better to go re-routed or if i should go back external dump outside the engine bay by putting more length on the tube again??? I don't want to re-route it if it blowing "into" the pipeis gonna cause this as well because that's a big hole to patch if it does.. but i'd rather not keep it atmospheric dump much longer as i've grown old with the sound.

any input from anyone who's dealt with this before?? I"m sure i'll find a solution i just thought i'd post about my decision i need to make to see if anyone has had this problem and if anyone was able to solve it by simply routing back into the DP

 

[turboglenn]

Just thought i'd post a little update, I just gt done welding up a new dump tube from sme heavy guge SS that exits all the way to the bottom of the oil pan and doesn't turn and fire on the down pipe at any place.

about to go to the pharmacy and the gas station and see how she performs and if the noise of the dump is still being picked up by the KS.

IF it's better i will get a couple of flanges and make the dump route back intothe DP fr the nice quiet ride i've wanted for a while now

And yes, again'st most of your advice i do still plan on putting a chmabered muffler on the car here soon in place of the OEM cat converter

edit:

Sure enough, I put the gate dump outside the engine bay and all false knock was gone.. THe only time isaw dtonation and 3-4* timing pulled was wheni hit 30psi at 12.7-12.91 AFR's

THis was with only 13* timing @ 28+ psi and from 5500 RPM ad up (10 through 12 in the spool areas)

AFter richeing the AFR's to right at 12.2:1 I wasable to increase timing until i saw 16* up top at the sameboosts and still no detonations..

One thing i'll say is althoug i only went up 3* timing through out the curve the power gains were amazing!!

I've set the haltech up to control boost by programming duty cycle and then i have a knob that lts me add or subract a percentage of duty cycle to the table's value, I'ts nice having solid boost control again, especially where i can set a limit to the peak boost and it won't go past it.

well, that's all i have to report for now.. goes to show proof that yourdump being too looud in the bay or pointing at the down pipe can have severe effects on phantom knock!