well, I know a thing or two about the sequential control system, but I have a dismal situation when tuning my boost pattern, I am using the stock ecu/solenoids...WITH the homedepot bleeder valves the pills usually are so that I could dial down the boost and smooth the transition. I have dp, catabck, and intake now with no ecu yet, so I'm making sure boost is in check.

To get baseline numbers, I did tests with no pills/valves in the lines, and I got the normal 7-5-7 pattern but what was nice was that there was no spikes...not even a blip...a solid 7-5-7 (pulled strong too).

Then I installed the valves and went to work on setting them for a goal of 10-8-10 pattern with minimal spiking on primary and on transition.

But I never get it close becasue of 'the nasty relationship' between the pre-control and wastgate behavior.

For example, I could get it set for 10 primary, but with a huge transition spike, then dip to 7-8 until redline.
Ok, lets get the 7-8 up to 10 now, so open the wastegate right? But I wasn't about to do that with my transition spike getting close to 13-14...Ok, so first dial down the secondary spool up by closing the pre-control a bit...right, sure, except the primary is already hiutting 10, so closeing it to reduce trans-spike will also raise primary ...and it did, I spiked to 13 after a test and wasn't going to try that anymore (luckily never hit fuel cut any time during testing and got off the gas once I saw a out of control spike) .... so, there lies the problem...my primary is high, transition already spiking a bit, and total post transition boost low? ...but the relationship keeps me from being able to tune one without adversly affecting the other...into possible catastrophy :-(

I have 2 though on it:

1) The mods make my boost uncontrolable by the stock ecu/solenoid/valves setup, it can't react fast enough to safely manage the boost properly becasue of the valve style of control.

2) My secondary turbo is dookie and if it was healthy I would be getting 10 after transition wiht this setup, and in fact the setup is working but seems as if it is not because the secondary turbo is not 'pulling' its weight. The only problem with this theory is that I have been able to get 10lbs to hold post-transition when doing previous tests with a valve only setup.

I will try next:

1) Eliminating the ecu/solenoids from the boost control and try just valves (or the ball/spring type)

2) Peer at my secondary turbine and see if it spins freely and note the shaft play. There is a seepage of oil from the secondary turbo housing since I got the car, but its nothing serious from what I can tell.

 

i vote for an electronic boost controller
that way you can force it to work the way you want.

edit:
after a little thought, here's what I would do.

close the prespool valve so that you have no pre-spool going on. yes this will make it laggy, but take care of that after you set the boost.

try to set the boost and see if you can get a 10-8...8....9-10 pattern.

then go back and set the pre-spool to get the desired transition.

that way you don't have to worry about the transition spike blowing your motor.

just my 2 cents

 

>> close the prespool valve so that you have no pre-spool going on. yes this will make it laggy, but take care of that after you set the boost.

heheh,...I already attempted.... but nope, cant even try it completely, even with the wastegate calve open all the way (lowest post-trans boost), if I close the pc all the way I will spike HUGE on the primary since its not diverting any to the pre-spool

see my dilema now :-(

I think the issue is that restriction in the hoses allows some control of the boost (whether pill or valve) but it ALSO slows the reaction time of the wategate (or pre-control gate), in other words, there would be no spiking if the gate solenoid could bleed the air needed wile still getting all the pressure (no pill or valve) so as to be very reactive to the pressure and thus eliminate spikes....does that makes sence?

I think i read that somewhre on one of the turbo tech docsuments...

 

ok, i kinda forgot how the stock wastegate solenoid works. i forgot that you still have it hooked up to the factory solenoids. but if you unhook the solenoids, and just use a valve, that will make your wastegate crack open before you've reached desired boost, therefore making it slower to reach the desired boost level.
you would benefit from a ball and spring type of valve i think.
for the prespool, i just run a regular needle valve from the compressor housing to the actuator and have the other nipple on the actuator capped off.

 

>>i just run a regular needle valve from the compressor housing to the actuator and have the other nipple on the actuator capped off.

Interesting, hmmm... I just ordered a ball/spring valve and may try your pre-control setup...thanks for the idea..

 

by the way, I will be able to make my motor mounts after tuesday, I'll report back after I get it together...

 

i don't know if my presspool set up is a "good" one. I mean it works, and it's very adjustable but I could potentially build boost faster if i hook it back up similar to stock. I'm gonna play around with some different ideas here in the next week or two. i'll let you know if i find anything that works better.


did you end up going with the black urethane?
i must say that now that I have some more miles on the mounts, they still feel really good, and don't vibrate too much. let me know how yours work out.

 

yep, i got black...its good to hear the vibration is 'wearing' down a bit...

another type of bleed setup is this:
the hose from the turbine to the actuator has nothing (no pill or valve), then the other nipple on the actuator has the line with the bleeder, venting to air.

the problem with this (I know, ive tried) is that small 1/4 inch bleeders dont bleed enough to get boost above the actuator spring level, so even all the way open you never get to 10 lbs of boost LOL!!! i tried 3/8 the bleeders and opened the wastegate one all the way with similar results (got higher, but not to 10)...so you need a BIG bleeder there or need to pill/bleed the turbin to actuator line, but then we get into the 'spiking/reaction time' issue again when you dont use the full pressure signal as and a bleeder/valve that han handle the full signal....ok, now im just babaling lol

 

Back in the day I was running some just like what is shown on Rob's website. I could dial them in perfect. I was however running 12psi of boost but I had them so good that it didnt dip or spike. This was with full exhaust and intake. I still use them now but in non seq form. When I was running them seq I used all the stock solenoids and everything. The only thing I did was pull the pills out, which is something I think you should do since there is no reason to have them and they might be causeing probs. I would close down the wg valve till you get the right boost after transition. If you spike at trans more than about 1pri of boost then adjust them precontrol line. Just remember to make changes in small amounts cause I would always fine that there is a sweet spot but anywhere before or after the sweet spot didnt work very well. Going in small turns of about 1/8 turn seemed to work the best for me

 

>>I was however running 12psi of boost but I had them so good that it didnt dip or spike.

yeah, at 12lbs it would probably be ok, but i have a stock ecu, so I cant run 12lbs yet

>>The only thing I did was pull the pills out, which is something I think you should do since there is no reason to have them and they might be causeing probs.

I removed the pills a LONG time ago but thanks for the advice :-)

>>I would close down the wg valve till you get the right boost after transition. If you spike at trans more than about 1pri of boost then adjust them precontrol line.

once i get a valve only setup (no ecu/solenoids) I will use this tweaking order