Seq. Transition Probs.
 

My mods

BNR Stage3's (1 month old)
Profec B Spec1
PFC
no emissions
simplified seq system
full exhaust
intakes
IC

When the transition occurs I get boost fluctuation in a 5-10-5-10 until 5500-6000rpm. The primary boosts fine and the secondary is fine after it quits fluctuating. It also boost fine as long as the turbos are locked in together from 3000-redline. The vacuum lines are fine I checked them yesterday. What are some other things that could cause this?? Would the lines too/from the solenoid being to large be a problem(I've heard this, but they worked fine on the stock turbos).

BTW the turbos worked fine for 2-3weeks this just started a week or so ago.

How do you have your boost controller plumbed in? Do you still use the precontrol actuator or any pills in the system?

Sometimes too fluctuation is a sign you need to tune the sharpness on the boost controller.

Dale

I can't help with your boost problems (my stock seq setup always worked perfectly) but I would like to hear about your initial impressions of the stage 3s setup sequentially. also, how much boost are you running on them?

I have no pills and I have the precontrol tied in with the other actuator(it really doesn't have a bad transition, when working right). Its version 2 on the other threads. The sharpness is fine on the controller, if anything it is alittle on the low side. I've messed around with it and it does it with it turned down. Like I said it worked perfectly on the stock and the stage 3s up until a week or so ago. I actually was getting about a 10-7-10 pattern, when running normal.

I'm actually running 12-13psi normally, I still have the stock fuel system. I ran 9-10psi on the track this past weekend for safety issues. I only have the stage3's because I took them to BNR to get the wastegate ported on my old ones and we took them apart and the stockers looked like an apex seal had been through the secondary(previous owner), so I just got him to build be a set. I actually bought the set that was on there used because the ones that came on the car blew up, so I've been through some turbos in the past year.

The boost about like the stock ones as far as spool up and everything, they don't seem to have the drop off as much as the stock ones had at higher rpms. I haven't had a chance to dyno them yet but I'll let you know how that goes when I get to. I'm happy with them so far, no problems except for this which I think is something else.

If it worked last week but not this week I'd start looking for popped hoses and any other little gremlins. I'd also detach the charge relief valve from the airbox as a test to make sure it's not venting anything in parallel mode.

I don't have anything more specific to suggest than that.

Dave

Well the hoses looked fine as of last night. How can I tell if the CRV is venting under boost, or am I just suppose to listen for it?? both it and the BOV vent to atm. already, and they don't seem to make any excess noise.

Oh well I guess I'm just going to have to start taking everything apart again and checking everything. I'm tired of messing with my turbos I want to put my bushings in :cursing:

First off, thank you for being (imo) smart and running sequential. Seccondly have you though that it might be a bad solonoid? They are pretty easy to test. So maybe do that and check the condition of the hoses. Good luck man. I'll be rocking this setup as well.

--Hank

Thanks alot, I see no reason to run non-seq. since after one transition they run in non-seq mode until you drop below 3000rpm. If I wanted to go non-seq I would have just got a single.

I have thought about the solenoid, I just haven't had a chance to check and I really don't want my BC solenoid to go bad because that means I have to buy another one, so I'm looking for other stuff first.

By 'testing' the CRV I mean listen to be sure it's not venting above 4500rpm. The CRV should only be open between 3000-4400 (the numbers vary depending on how hard you're accelerating) and never above 4500. The BOV should be silent except when you let off the throttle.

Rather than tear into everything, you can tee your boost gauge into the line between a solenoid and actuator and observe it during boost to see that the solenoid is operating correctly. You might need to pick up a 1/8" tee fitting.

The other possibility is an actuator not moving properly. If you have a Mityvac, you can apply pressure (or vacuum) to the actuators to see that they move smoothly and don't leak. Like the solenoid test I mentioned above, this can be done in-car with very little digging.

Dave

Thanks alot.

As far as the CRV I'm pretty sure all I'm hearing are the turbos. Is it possible to text this in neutral or will the secondary not spool up, since there is only a few psi?? I can always rig something up and run it back into the car to make sure.

If it's vented to atmosphere you should have no trouble hearing it at all. It's unusual for the CRV to not be running into the air filter(s).

I don't think neutral will be helpful to test it. However, that reminds me that another excellent test for the transition components is the KOKO test. (described on www.fd3s.net)

- After checking for pressure and vacuum in the system after a drive, rev it again in neutral to put a few psi of pressure into the pressure tank (or take it on another short drive and make a little boost). Then stop the engine and lift the front of the car so you can see the TCA. Also remove the intake pipe to the secondary turbo to see the CCA clearly. Turn the key on, the actuators should move. Turn the key off, they should move back to their original positions. This should happen several times without funny business - if it doesn't pass this, and the pressure and vacuum tanks are storing properly, you are looking at a hose problem or bad solenoid.

Dave

Here is a follow up, sorta. Basically I've been riding around with this for a while, I pretty much now just wait until after the transition point to floor it most of the time. I've done the KOKO test, and the CCA works fine, the press/vac. tanks work fine, even after 2hrs they have press/vac. The TCA on the other hand doesn't move when I KOKO, or atleast if it does it has moved back before I get around to crawling under and looking at it. I can push the rod in by hand if I put enough pressure on it.

I also today toke the UIM back off and checked everything again, and it is all connected correctly. Another thing is it only seems to fluctuate about 80% of the time, seems more like if I go through it then drop rpms real fast and go back through it doesn't do it as often(whatever that means).

So is it possible the TCA is worn out since it is not moving on the KOKO test?? I'm 99% sure the Boost controller is fine, I've also tried turning the sharness up/dn and all that does if make it spike or not spike, and also do the flutter thing at high rpms. Anyone got anymore ideas??