Bouncing Boost

[psycho6cyl]

Stock.turbo w rjc 3" thdp. It seems.if I go.into.the car easy or mild the boost will bounce around 10#s but if I llay into her boost will go to about 15#s. Im.using stock.actuator w rjc boost controller. I have eliminated the wastegate cylenoid.. any ideas?

 

[we4Mateo]

What is the SM showing for KR? I've seen boost jump around with knock.

 

[psycho6cyl]

Ill.have knock once in.a blue at close to 10#s but 02s low to mid 800. Which I believe is false. What was contributing to the bouncing boost and knock

 

[we4Mateo]

Who cares what your O2's are when you are having knock? The O2's will be off if there is any knock as the combustion process is disrupted from the norm and the narrowband is a crappy indicator of real air/fuel anyway. Additionally, too much fuel can cause knock and adding crappy gas on top of a tune that is knocking won't make it go away.

I'd be asking, why is it knocking at 10psi at all? Start checking the ignition system. I see you run a TT chip so timing curves should be good. Have you verified fuel pressure rise 1:1 with boost?

 

[Turbo Negro]

The stock boost solenoid, in my experience, worked fine at this level. Make sure you've got proper fueling first, then look into a HD adjustable actuator if you plan to turn it up.

My guess is that you've got the RJC controller set to around 10#'s, so when you reach that psi, it's pulsing the boost signal to the old stock actuator that is opening the wastegate at somewhere less than the original 15lbs, causing the fluctuation you see. Then when you go WOT the boost goes straight through the RJC at 10#'s, allowing the full signal to been seen at the actuator, fully opening the WG and limiting max boost to ~15lbs by design.

You should be able to test this by first eliminating the RJC controller & verifying the stock actuator. If this checks out & you have no KR, you should re-install the controller & turn the adjustment in gradually to achieve your desired boost (approx 1 full turn per #), up to the actuator's verified limit. The RJC controller will then allow you to turn the boost up beyond the actuator's verified pressure to achieve higher boost, up to ~23#'s, which is now limited by the stock turbo.

If you do not intend to exceed the given WG actuator's limiting pressure, then you do not need the controller.

Hope this makes sense.

 

[we4Mateo]

The stock boost solenoid, in my experience, worked fine at this level. Make sure you've got proper fueling first, then look into a HD adjustable actuator if you plan to turn it up.

My guess is that you've got the RJC controller set to around 10#'s, so when you reach that psi, it's pulsing the boost signal to the old stock actuator that is opening the wastegate at somewhere less than the original 15lbs, causing the fluctuation you see. Then when you go WOT the boost goes straight through the RJC at 10#'s, allowing the full signal to been seen at the actuator, fully opening the WG and limiting max boost to ~15lbs by design.

You should be able to test this by first eliminating the RJC controller & verifying the stock actuator. If this checks out & you have no KR, you should re-install the controller & turn the adjustment in gradually to achieve your desired boost (approx 1 full turn per #), up to the actuator's verified limit. The RJC controller will then allow you to turn the boost up beyond the actuator's verified pressure to achieve higher boost, up to ~23#'s, which is now limited by the stock turbo.

If you do not intend to exceed the given WG actuator's limiting pressure, then you do not need the controller.

Hope this makes sense.

There are so many things wrong with this post. The RJC controller, which he doesn't have, he has an RJC downpipe, if set to 10psi, won't allow the car to make more than 10psi so that part makes no sense. It also in no way would cause the boost to flutter at any boost level as it pulses too quickly to cause this. The RJC will have a higher boost limit even with a standard gate than the gate will support hooked up tuner style like you mention. You clearly don't know how the stock wastegate system works with an RJC boost controller in place of the factory solenoid. But this guy isn't even using an RJC controller and most likely is using the stock solenoid which still doesn't explain the rough boost level at 10psi while maintaining ability to take it to 15psi.

 

[we4Mateo]

It should be just as smooth at 10psi if it's able to go to 15psi. You either have KR or a fuel problem or an ignition problem that will probably show as KR.

 

[Turbo Negro]

He does have the RJC controller, & the stock boost solenoid is also by-passed (re-read the OP).

I'm not saying there aren't possibly other issues regarding fuel, ignition, & KR either. These should obviously be addressed FIRST!

If the RJC controller is set to 10#'s it won't allow the actuator to see the boost signal until 10#'s (it blocks the signal until the set boost is achieved, then sends it through to the actuator). In this case, if it takes 15#'s for the actuator to open the WG, he will still boost to 15#'s.

 

[we4Mateo]

He does have the RJC controller, & the stock boost solenoid is also by-passed (re-read the OP).

I'm not saying there aren't possibly other issues regarding fuel, ignition, & KR either. These should obviously be addressed FIRST!

If the RJC controller is set to 10#'s it won't allow the actuator to see the boost signal until 10#'s (it blocks the signal until the set boost is achieved, then sends it through to the actuator). In this case, if it takes 15#'s for the actuator to open the WG, he will still boost to 15#'s.

Got ya. My bad. I just saw the first line stating "stock turbo with rjc 3" thdp" and thought he was referring to the downpipe as a terry houston style but from rjc. And yes, if he has the rod too tight, then it won't matter what the boost controller is set to in that it'll need to get to that point to overcome the spring on the actuator anyway.

I still don't think an actuator set to 15psi with rjc controller set to 10psi could possibly cause this flutter though. If the gate is staying closed until 15psi then no amount of boost from the controller side between 10-15psi will open it and cause the condition noted. It should be smooth at all points under 15psi.

 

[Turbo Negro]

If it were mine, I'd ditch the RJC controller, and use the stock set-up, until trying to exceed the actuator's capability.

The stock solenoid does an excellent job at this level, and keeps the boost steady.

 

[psycho6cyl]

Just installed wideband and im not able to.post a log right now but I hit 14lbs w 5 degrees knock. Wide band read 12.49. Is that too lean?

 

[we4Mateo]

Too much kr, especially for 14psi on a stock turbo and yes that's lean. You should be at 11.5:1 at wot on just gas. Every car is different and kr will cause your afr to read inaccurately. I'd be checking fuel pressure at wot then spark.

 

[psycho6cyl]

Ok thx I.wasnt at wot. I am.checking baseline fp and rise w boost tom.and take from there