The Project Pad

if there is ONE thing that i know, its that fords are better than chevys.

LOL @ Dan for feminine sounding 20VTs

Go big Jared, doing it old school is always fun!

Now just put the 07K in the dodge

So here is the boost issue I am having. Hopefully someone can offer some insight to the issue at hand. It will continue to do this until I fully release the pedal and step on it again.

[youtube]https://www.youtube.com/watch?v=I3F0oFCntZU[/youtube]

Thats real strange. What WG spring do you have in there? The WG must be opening right up to loose that much. I actually dont remember how the 20vt WG defaults when the ecu isnt happy. With the 20vt it just goes to straight spring pressure (6psi), but the 20vt gate is controlled differently. How is your boost control piped? Turbo pressure to bottom of WG with the WGFV and a line to the top?

40v4kq wrote:the 20v has a smoother and more feminine sounding exhaust where as the 20v has a more powerful and masculine sounding pulse

i think prefer the sounds of a screaming female to a grunting man most any day. Its all personal preference I suppose.

dana wrote:Thats real strange. What WG spring do you have in there? The WG must be opening right up to LOSE that much. I actually dont remember how the 20vt WG defaults when the ecu isnt happy. With the 20vt it just goes to straight spring pressure (6psi), but the 20vt gate is controlled differently. How is your boost control piped? Turbo pressure to bottom of WG with the WGFV and a line to the top?

Its a 1.8bar spring with adjustable wg mod (m12 / 19mm) bolt. Yes wgfv line to the top. We have tried unplugging it but no difference. Ive cranked down the bolt all the way but still does the same thing minus the increased boost

is your BPV opening up? Try increasing spring pressure in that? I dont think with that much spring pressure your wg can limit your boost to basically nothing. You would still have some base pressure even if your WGFV stopped working or was cut by ecu.

We tried a new bpv at bbq and same thing. I checked over my 710n and no issues

None of these problems started till we installed the volvo k24. Im wondering if the cis cant keep up and freaks out when too much air is getting sucked in

AngryTaco wrote:We tried a new bpv at bbq and same thing. I checked over my 710n and no issues

None of these problems started till we installed the volvo k24. Im wondering if the cis cant keep up and freaks out when too much air is getting sucked in

yea maybe, hard to believe a boost leak could create this issue. Does it feel like a fuel cut? I dont think your wastegate setup could physically limit the boost to be that low if the motor is still getting fuel and is still under load.

im not sure the computer even has a way to keep track of how much air is actually being pulled in, there isnt limit switches on the fuel plate i dont think? it just knows boost pressure. Maybe you will have to go manual boost controller and try dialing it down just a bit.

Yeah the thing is if I keep it to 13 and under it wont do this. Only above that and over 4000 rpm is boost > 13psi. Its like its an aiflow thing. Never had a problem with 20+ psi on the stock k24

Bizarre. Pretty sure there is no feedback to the ecu about fuel plate location. Have you pressure tested the intake track to see what happens at 15+ psi?

That looks like a massive boost leak. I'd pressure test the intake, and remove the bpv from the equation (a C battery fits perfectly for testing)

EDIGREG wrote:That looks like a massive boost leak. I'd pressure test the intake, and remove the bpv from the equation (a C battery fits perfectly for testing)

X2 there's really no way you can actually be running below spring pressure if you don't have a massive boost or pre turbo/WG exhaust leak. I've had loose hose clamps do that, loose pressure, go back to normal next pull, loose pressure again etc.

I would completely remove the bpv, plug the holes and go for a spin. If that isn't it then I would suspect fuel cut.

Remember, CIS is metering air flow, now boost pressure. 15 PSI on a 7400 is going to be a lot more air than a k24 or k26 at 20psi. I vote fuel cut.

Hank

but can cis cut based on airflow? does computer know the position of the air flow plate? thats the only thing that has me doubting the fuel cut.

the ECM does not measure air flow. It does not know where the fuel plate is. As Hank said I believe this is the total air flow related. Which makes sense because I can hold 13 psy all the way to redline. It will hold 20 psitill about 4200 rpm

yea, that makes sense for sure.....i just want to know HOW the ecu knows total airflow. If it had an MAF, then yes, Im right there with you, but i cant see how the ecu knows the volume of air, so how would it know to cut fuel? Not trying to be a dick, maybe im missing something obvious.

dana wrote:i think prefer the sounds of a screaming female to a grunting man most any day. Its all personal preference I suppose.

All depends on what is making her scream. And I never mentioned grunting men, that's all you buddy lol

dana wrote:yea, that makes sense for sure.....i just want to know HOW the ecu knows total airflow. If it had an MAF, then yes, Im right there with you, but i cant see how the ecu knows the volume of air, so how would it know to cut fuel? Not trying to be a dick, maybe im missing something obvious.

The ecu just sees pressure. Thats it. It doesnt know how efficient the charge is. It has no idea how much fuel is being injected. The mechanical fuel injection is on a circuit all by itself. All the ecm dies is adjuat timing based off pressure and knock

right, this is what i am saying. So i am thinking its not a fuel cut because the ecu would not be cutting at 13 psi, regardless is actual airflow. I like the boost leak theory the most.

if all you are seeing is boost loss and a loss of power then its a boost issue. fuel cut is violent and feels like the car shuts down. if its one thing I know with my 4kqt build on CIS, its fuel cut.

Yeah... you just have a boost leak. Fuel cut is violent, you can't 'drive through it,' ECU can't drop boost below spring pressure.

I've got a pressure tester if you'd like to borrow it, not sure what size the volvo K24 inlet is so you might need a different hose. mine is just setup for the K26. Seems weird though cause I know when mine had a lot of boost leaks it would build boost normally and then top out at the max it could flow and then taper off at redline, never had it drop to 0lb's unless I blew a hose off or something. Either way testing the intake piping is never a bad thing.