noob question about wastegate
 

this might be a noob question or it might not be lol... this is my first turbo car... and I am a avid reader of this forum.

94 touring
pfc + Commander
full open exhaust
all emissions removed and blocked off
99 spec simplified sequential
streetport 15k miles ago
lightweight pully
850pri
850sec


so when I have my booost controller turned off (hks evc ez) im running off the WG Spring pressure

during that time I get a perfect transition 8-6-8 or whatever it is the spring pressure is set at

when I turn my boost controllerback on ....


my transition is a 12-8-14 or 12-8- 15 or 10-8-14 (depending on what i have my primary boost set to of course)


so my question is

why do i get perfect transition with the wastegate , but when i use my boost controller it shoots up 2, 3 or 4 more psi and stays there

Isnt perfect boost pattern 10-8-10?

yes 10 8 10 is perfect

the question is more

why am i getting more even values from my wastegate instead of from my boost controller ???


i would rather have 12-10-12 or 14-12-14 instead of my numbers being all over the place

why is my wastegate getting the perfect transition and not my boost controller ?



does that make more sense?

Well I find it odd that your secondary turbo is always pushing more psi than the 1st...

Getting the transition to smooth out is technically not easy. It requires perfectly functioning solenoids and actuators and usually some boost control tuning.

David

How is your boost controller hooked up? Is your solenoid tee'd into both your precontrol and wastegate line? If so that is why your transition is all over the place. From the factory, your wastegate and precontrol lines have restrictor pills in them. These pills have two DIFFERENT bore sizes. Therefore I believe to tune your transition to a more perfect set up I believe two ball and spring MBC's are a superior set up if properly dialed in over the single EBC. Otherwise another set up option that could be nice would be a hybrid ball/spring MBC on your precontrol line and an EBC on your wastegate line. Damian has a write up on this in the FAQ and I believe DaveW and dgeesaman can both chime in on this method of controlling sequential boost. It appears the popular option for MBC's is the Halman pro RX kit for the lightweight spring as well as the ceramic ball. My controllers that I plan on using for this set up when I return from deployment is two Grimmspeed MBC's. They feature a 0-60 psi long spring, laser etched markings to help dial in and reference, as well as POSITIVE LOCKING for each adjustment setting (250 clicks to be exact!)

Hope this helps!
Matt

8-6-8? rather odd

are the pills removed or the lines changed?

with the pills removed you'll get 7psi from the turbos, with the restrictor pills you'll see the 10-8-10 boost pattern (someone correct me if im wrong)

With his mods his exhaust will flow more and increase boost past what is intended from the stock control. That's why people bore out their restrictor pills to help keep boost transition in check with flow mods. Though that is the old school way of doing it, most people get the single EBC and deal with the less than perfect transition. A single EBC is nice for the features and control and what not, but it's also best for NON sequential or SINGLE turbo set ups. Two turbos, two DIFFERENT pill sizes, two controllers. That's the way Mazda intended.

Matt

He might have pills for a single turbo in there which is why hes getting a lower boost pattern, if he had no pills he wouldnt even be pushing 8 psi.

I have 99 spec turbo instead of t'ing my wastegate and precontrol I removed both nipples and used a brass hose fitting (so i have no restrictors in the line or in the nipple fitting)

Thank you for the correction When i have my hks evc ez powered off I get a 7-5-7 boost pattern



I have all pills removed. When i power on my boost controller thats when im having the funky transitions that i posted about in first post

when i power it off...my transition is not doing anything abnormal (except the low boost from running off the spring pressure)

So you have no form of factory restrictor pill set up is what I understand. This leads me to believe that your precontrol and wastegate are both controlled by your hks EBC. There are multiple ways to install a boost controller, you can tee both your wastegate and precontrol lines to both be controlled by your EBC, or you can deal with pill sizes in the precontrol and run only the wastegate using your EBC. With your boost controller off you are, as stated, running off spring pressure. If you would like to raise your boost properly I suggest either fighting with pill sizes in your precontrol line and running your EBC on the wastegate only, or installing a ball/spring MBC on your precontrol line and running the EBC on the wastegate line. That would be the only way to get an "ideal" boost pattern. Again, two turbos, two different pill sizes, two solenoids. If you would like to control your boost sequentially you need two controllers of some sort.

Matt

MrMatt seems to be on the ball on this....


its rather difficult to properly setup electronic boost control on the sequential system especially when the solenoids are aged. I do recall a thread posted some weeks ago about someone getting help on setting up his Blitz or GReddy EBC and had a heck of a time tuning it, but IIRC he did end up getting it close to perfect