I decided to go non-sequential today because I am always having secondary turbo issues. I did it the simple way and followed the directions. I didn't do anything with the pre-control actuator because it's hooked up to my AVC-R. Well, I still have a boost leak above 4500 RPM's. What should I look at? Which vaccuum lines should I check? I now have no real low end or high end power.

 

List exactly what you did, then we'll tell you what you might have missed. And by the way, you should just set the precontrol door open and unplug it's actuator from your boost controller.

 

I did exactly what you wrote to do a few weeks ago. You can hear the boost leaking out above 4500 RPM's. It's probably one of the solenoids that control the second turbo. Which ones switch from vaccuum to boost?

 

Which solenoids can I get rid of. I was thinking Turbo Control, Charge Control, and Charge Relief. Are these right? I plan on doing it tomorrow.

 

Here are some questions

-How much boost are you making?
-It sounds like you have a big boost leak, not just a disconected vacumm line or solenoid. Are you sure the boost doesnt leak below 4500?
-Did you cap-off all the lines that you disconnected, in other words.. did you shove a bolt or something else in the vacumm lines?
-Have you checked all the intercooler pipes, especially the y-pipe, for leaks?

If you indeed did every thing you were suppost to, then the solenoids would'nt be in control of the turbos anymore. If your problem was solenoid related, your boost leak would be small. A loose vacumm hose or disconected solenoid would probably not be able to leak out a considerable amount of pressure to keep you from boosting above 10psi. A real boost leak, like an opening of some sort from where the turbo ouputs are all the way to the engine would be more probable. This would include, the y-pipe, the cross-over tube, the intercooler and all the couplings, the intake elbow, and the upper and lower intake manifold.

Tell me in your own words how you made the modifications for the non-sequential.

 

It builds to about 8 psi at 4500 RPM's and then after that it it starts dropping off to about 4.5 psi at redline. That was my same problem before. Sometimes, when the engine was just warmed up, the turbo would sputter above 4500 and after shifting it would catch and I'd get full boost to redline after. These are the directions that I followed.

The conversion is easy. This is what i did:

-Take the turbo contol actuator off. It only has two 10mm nuts on it and can be easily removed from underneath. (its the big fat round thing that has two vacumm lines going to it, one in the middle & one on the side, it has a small arm coming out of it. its also the closest one to the ground) Use the bracket from it to wire the turbo control arm all the way towards where the actuator used to be. I can post a pic if you need one.

-on the precontrol actuator, simply remove the two vacumm lines attached to it an cap it off (the hose too). This will keep the actuator from moving, keeping the gate closed.

(The precontrol actuator is the one located above the turbo control actuator mentioned above. It has the longest arm coming out of it. The wastegate actuator is located above it, so its in the middle of the three. The wastegate and the precontrol look similar and the turbo control looks comletely different.)

-disconect the two small vacumm lines going to the charge control actuator (i think thats the name) which is located on the Y-pipe. Its a small actuator with a very small arm coming out of it. Its right below the secondary turbo's last intake pipe coupling right before it does a 90 degree turn down to the turbo. Cap off the vacumm lines. This will keep the passage way open.


-finally remove the vacumm line going to the secondary turbo's blow off valve (its called something else i think) which is right next to the charge control i just mentioned. Then Tee in a new vacumm line with the vacumm going to the other blow off valve. This will keep it from venting secondary boost before 4500rpms like it is suppost to.

 

Do you still have the stock rubber coupler that joins the y pipe with the first intercooler piping, if so I'd recommend replacing that with a silicone one, that is the one most likely to develop a small hole. Replace all the couplers if you haven't done so, you can pick up a 1 foot length from a rubber supply store in town and cut it up, it'll look just like TOP SECRET's but without the greddy writing.

Also, how is the vac line going out of the wastegate actuator hooked up, is the avc-r controlling it? If so, and the boost controller is keeping the solenoid closed, you won't build very much boost. If you just have the vent line from the wg actuator capped off that will also keep boost low. I'm not using an electonic bc, I have a needle valve on the vent side of the wg actuator opened just a crack (don't leave the wg actuator vent uncapped or you'll build unlimited boost!) and am using a dawes on the inflow vac line to the wg actuator and get very good results. (I'm non seq too, I still have all my solenoids in place only for the electical connection, the only one that has a vac line hooked up is the purge control, the one all by itself on the right)

FD Racer, if there are no vac lines hooked to the charge control actuator (the butterfly valve in the y-pipe) will that keep it open or closed, I don't know because I took mine out and cut an aluminum blocking plate for the hole that was left.

I think most likely you have a leak in one of the couplers or the main pipes, like FD Racer said

 

I have a couple of questions on how this non-sequential works. To go non-sequential should the:
1. Turbo control valve be... open
2. Charge control valve be... open
3. Pre-control valve be... closed
4. Charge relief valve be... closed

If this is true, why can't you just disconect the electrical conectors and either leave them disconected for closed valves and apply voltage to leave the other ones open? Please let me know if there is something wrong with my logic and if I'm forgetting something else. Thanks

 

If you remove all vacumm lines to the charge control it will stay in the open position. I still have mine running this way, i plan to also get a block-off plate made.

 

Well, if you disconnect the electical conections, you'll get an error code if you still have the stock ECU. Also, the charge relief valve needs to be hooked up to a regular manifold pressure source and normally it does not. The turbo control valve would be difficult to force in the open position via electronic control, so would the charge contol. I think its just plain easier to unhook the damm things. Plus you get the added benefit of being able to remove all those vacumm lines and solenoids.

As far as your list of open / closed...

1. Turbo control valve be... open
2. Charge control valve be... open
3. Pre-control valve be... Open or closed (I think open is better, but either will do)
4. Charge relief valve be... hooked up to manifold pressure (T-in with blow off valve)

 

Neevosh,

How loud is your boost leak? Also, how is your boost controler hooked up? Did you cap-off the bleeder lines on the wastegate actuator that go to the stock solenoids? Has you boost controler ever worked properly?

I'd be willing to take a look at it for you, but i'm about 4 hours away. If you PM me, i can call you and maybe help out that way.

 

The boost controller works fine. I did cap off those lines. On colder nights in the winter it would work fine. I thought that I had a short in one of the solenoids and it would act up when hot. I have an Efini Y-pipe and all silicone couplers. Could it be a clogged cat causing this? I need to put on a midpipe but don't have any money right now. Thanks a lot for the replies. I really appreciate it.

 

it could be a clogged cat, but if you hear boost being vented out...you definitely have more than a clogged cat problem.

 

I fixed it. I pulled the intake manifold off and went through everything. I did forget to disconnect one of the lines to the charge control actuator. I also replaced the manifold gasket. And replaced and plugged all the vaccuum lines that go to the turbo control, charge control, and charge relief solenoids. Thanks for all the help.

Oh, and I get full boost around 4500 RPM's, maybe a little lower. And my car is noticely louder.

 

Thanks for your reply. Maybe I should have explained myself more clearly, but what I meant was what if you trigger each solenoid into a permanent on or off position? It would be an easy way to go non-sequential temporarily. What do you think?

 

I understand what your saying. But one of the main reasons people go non-sequential is becouse the stock solenoids and vacumm lines are not functioning properly to begin with. Also, i bet its faster and more reliable to switch back and forth between sequential and non sequential by unplugging vacumm lines and wiring gates open rather than triggering solenoids to force them into a different position. Would'nt you have to take the extension manifold off for that? Besides, the solenoids and actuators were never designed to be forced into a different "normal" position. There might me unforseen complications doing it that way. The actuators would need enough reserve vacumm and boost pressure to hold there position.

Doing the full-out non sequential conversion (where you remove the turbos and weld **** open) would be one thing to argue, but we've been talking about doing the poormans way. It only took me an hour to do my non sequential modification.

No ofence, but i dont think your way is a good idea.

 

FD Racer,

What's the downside on doing the mod the poorman's way vs the removing of turbo and welding?

Do you have any problem with boost creep?

 

I wasn't trying to argue I was just curious if it was possible to do it that way. Thanks for your info anyway.

 

Here are some pros and cons for ya:

Pros:
-Very easy to do.
-Very easy to go back to sequential.
-You dont have to remove the turbos.

Cons:
-Putting coat hanger wire on your turbos is kinda "Half ***."
-You are unable to free-up horsepower with increased exhaust and air flow. (not much)

I personally cant see the need to pull the turbos for these reasons alone. If you need to pull the turbos for another reason, great... do it the full way. The precontrol door can be positioned in the same position by wire or by welding. So all we're really talking about is removing the turbo control gate instead of holding it in the open position. Does anyone know how much of an obstuction it really creates, how much horsepower could removing it really free up?

The only other thing would be the charge control gate on the y-pipe. I guess the poormans way would be to leave it in place in the open position. In this case it would be better to go in and remove it, replacing it with a block-off plate. This would be easy and worth time as you would be increasing airflow.

As far as boost creep, I dont get any at all. I wonder why, as it seems to be such a problem with setups similar to my own. Must be the upgraded twins.

 

If you're not getting boost creep, I would think the turbos aren't working as efficiently as a set of turbos that are getting boost creep (and/or, the exhaust system is more restrictive on the car without boost creep ...and/or the wastegate is larger)

Boost creep happens when the wategate is wide open but the boost is still climbing (ie, "creeping" upwards) ...this must mean the turbos are working damn good to be able to provide increasing boost even tho the waste gate is dumping as much exhaust engergy as it possibly can.

I look at boost creep as a sign that the turbos are healthy and the exhaust system is very free-flowing (especially if you have a ported wastegate).

Of course, you still have to deal with the boost creep (usually by porting the wastegate and/or adding back in a little exhaust restriction... :)

(note: I am biased because I had boost creep even with a ported wastegate until I replace my mid-pipe with my hi-flow cat ;)