The valve we're using isn't on there, but that might be worth a shot. We'll raise frequency and see if we can get it to hold more boost on the ethanol setting, once we figure out this boost oscillation.

or maybe it might be time to go 4port bcs+dual port wga, because we're playing with serious boost on this car.

Yea, I thought the high boost canister would be enough, but I'm eyeballing that MAC4port and Turbosmart 2 port now. It just suck if that didn't cure the oscillations, but I'm not opposed to investing to get it running right.

Wish there was real estate for EWG

The dual port would be great for winter mode/low boost or boost toggle ala Aiden? rotary dial

Yeah, but more so for holding high boost. You can do the whole low boost mode by simply adding a switch to the power or ground going to the bcs and de-power it leaving it open for "winter mode"

Haha, 17psi (cracking pressure) winter mode

Obvious observation. It only starts to get choppy at or above 5700-6000RPM

6th gear provided a nice long load until I was speed limited on a public road. But it's under 5k and steady boost at 17.x which is reasonable for wastegate with tons preload. Any lower gear pulls which brings the RPM into a higher regime exhibits the characteristic choppy boost oscillation.

All these logs are running with the EBC unplugged, so effectively wastegate pressure. After talking to Vlad, I hooked the wastegate directly to the boost reference and that's where the "expansion joint" log came from. That was sketchy as hell and the car hopped around a bit.

oops. Still choppy. Thinking if not electric interference on the MAP sensor side, then the wastegate is failaids.

Peeping down at the boost gauge shows no identifiable oscillation. It's also running a 2.5 foot vacuum line and to the Sender, and I don't know how sensitive the stepper is.

Welp, unless someone has any other ideas, I'm thinking we up the smoothing filter on the map signal and move on. Or maybe add an inline filter to the vacuum line to dampen the pulses. I've seen/heard of that before

You have the in manifold AEM map sensor right? Got a part number? Or the post where you installed it?

this is still how your map is setup?
I would suggest mounting the MAP on the chassis and tapping the upper intake plenum for a barbed fitting instead of using the port that only references the #1 runner.

Those ports are known to have turbulent air.

oh wow and here I thought you were referenced at the back of the IM

.......like you should be.

packaging lol. It's tight back there with the fuel stuff. I have to redo the fuel lines and remove a flex sensor that is unused inline and switch the pressure sensor onto the rail. This will free up space as well as changing/relocating catch can off the firewall. Will re-re-relocate. Probably on weekend.


This doesn't answer EO2K's on board MAP oscillations though. Was he referencing from this location as well?

Mount it on the firewall and run a vacuum line to it?

Leave it where it is mounted, and just run the vacuum line to it from a different port?

That works too.

Will tee off from the front IM nipple by vvt solenoid. This should be sufficient right?

Also, what prohibit the car from running north of 28psi with EBC since wastegate is on the order of 17ish and referenced right on the compressor housing? Is the EBC failing/not bypassing the bleed port enough to force the wastegate shut?

Just wondering if it's worth picking up a new replacement EBC, to which point would it be more beneficial to get that MAC 4port versus the pierburg replacement.

@kmo25 still have that efr EBC? Can I test something?

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don't do the front nipple. it also is right after tb. you wanna reference in the middle or in the back. they say "ideally" off the brake booster line

before you go replacing the ebc or wg, I'd test the setup with boost control disconnected and the wg wired shut, ON E85 AND READY TO LET OFF AS SOON AS IT SPIKES PAST 28, if it ever does

basically literally run ALLOFIT and see if it goes past 28psi. no point in replacing parts if your turbo/ic/setup won't allow for more boost. I'd also keep in mind that if you don't start making more power with more boost, you shouldn't even really try to boost it that high anyway

do this at your own risk though, lol

Or set a hard boost cut at 30 with incremental changes?

On a side note, I found a thing happen to vacuum reference on fpr

https://cimg0.ibsrv.net/gimg/www.mia...db516740e8.jpg

Vacuum leak https://cimg8.ibsrv.net/gimg/www.mia...664112d91f.jpg
https://cimg0.ibsrv.net/gimg/www.mia...bdba32f0f6.jpg

china: destroying America 1 cheap rubber fitting at a time.

if that wasn't leaking massively I'll be surprised