If you had a little more grey in your hair, you would have noticed my post was in regard to someone referencing my statement... not the original post.

Kids these days... always trying to promote their "intellect" at the cost of others .

 

Haha.....if you had a little more grey in your hair you would realize that that person was...Me!

I was originally just trying to give you credit for your earlier comments. Not trying to be combatitive, dude, just supportive and throwing out some ideas. I respected your comments and tried to reference them.

The last thing I want to do is "use intellect at the cost of others". I mean really, the test that cdavy did to check static boost came from my suggestions on how to perform that test. Certainly not rocket science I know, but I would hardly call that using intellect at the cost of others.

BTW- I have been building engines, and wrenching on cars since I was fifteen. At 44 I have been through 43 cars (11 turbo cars) and am hardly a novice when it comes to modding and building fast cars/trucks.

Anyway no harm, no foul as I am not out to make adversaries with folks I consider to be fellow enthusiasts. I think at the end of the day, we are all just searching for ways to make our cars faster.

 

Just one more comment to Malibujack. The solenoid is actually fixed in bleed capability, and just cycles open and closed more or less depending on the desired boost requirements of the ECU. A low voltage/no voltage condition might result in an off or baseline solenoid condition(16.5psi). Higher voltage conditions would result in higher duty cycle as the solenoid strives to stay open longer to achieve holding boost at a higher pressure rate. This also allows the ECU to actually request other mid-voltage conditions to provide a slower rate duty cycle to allow for smoother boost ramp at interim pressures.

Each boost solenoid will have its limits of how much it can handle from a duty cycle standpoint. Thats why the smaller single solenoid units that are provided with say the Apexi AVCR, are better for lower boost applications, and dual solenoids set-ups like the Blitz SBC-id (which work in conjuction with one another to vent more pressure at fewer cycles) can more easily control boost at higher pressures. I think the new forthcoming Apexi (AVCRII ?)is supposed to also address that factor.

That clicking is the on/off cycling process.

 

...must be too much grey in my hair not to have noticed that...

...I'm in the "Gov't" business, so I'm not as "thin skined" as I may have appeared...

 

It seems tha tsomeone knows how to mod the eclipse part.

http://cgi.ebay.com/ebaymotors/ws/eB...tem=2414559790

 

Looks like that guy isn't giving-up any of his secrets!

Here's another link to a mod site outlining a stock solenoid modification.Hopefully this link works!

http://www.geocities.com/smoozdog/tweaks/tweaks.html


So lets say we know the factory boost solenoid controls pressure bleed-off/boost psi by cycling on and off at varying rates as the result of increased or decreased voltage supplied by the ECU.The higher the voltage, the higher the frequency of solenoid cycles thus resulting in a higher held boost pressure.

Now lets also say that the we know that the solenoid is either open or closed during that cycle with a fixed size aperature opening.

If you physically modified this aperature to be slighty larger than stock you would still get the ECU driven duty cycles per the factory ECU boost map.....only at an incrementally increased pressure level.

The main problem is that in modifying the aperature size you could end-up with some bad results with overboost etc.... . I think with a little R&D it could be done though. Another option I ran across(I am going to have to search for the link)was an FBC that has been modified to be fully adjustable by drilling/opening-up the stock aperature, then threading-on a precision brass needle valve adjuster. This provides infinite adjustability of the aperature while still allowing the solenoid duty cycles to be managed by the ECU! You can actually start with the needle valve closed-down fairly tight thus avoiding potential overboosting issues.

I actually have one of these precision needle valves from the gauge store.I will have to get the info/links, part numbers etc.... .

I may try and check on the price of a factory EVO solenoid on Monday and try to mod it using my needle valve.

 

Here's the link to the site showing the solenoid being used with a precision needle valve to control bleed flow out of the solenoid.

http://www.performance-mod.com/nuke/...ws&new_topic=7


Heres a link to a nice site that carries aftermarket solenoids and precision needle valves.

http://www.valvestore.com/


A more specific link to the precision needle valve

http://www.valvestore.com/endelbrasnee.html

 

Ok folks one more bit of information. I ran across a link that mentioned a Ralliart modified boost solenoid in an EVO. Unfortunately it took me to a generic site and I couldn't find the specific info.

So I did a search on "Ralliart modified boost solenoid" and heres an interesting an confirming link I found.

http://srd.yahoo.com/S=2766679/K=ral...w.evotrak.com/

Go midway down the page and you will see bullets referencing different mods. Look at (I think) bullet #21! "Remove restrictor in boost solenoid".
If our boost solenoids are constructed in a similar fashion, then all we should have to do is remove the restrictor to see an additional 1-2psi increase across the range. We would thoeretically still see the same boost map of high psi early mid range and taper at high rpm. Something like 21.5-22.0 psi dropping-off to 17.5-18.5 perhaps?

I don't want to raise peoples hopes too high, but in theory this could result in an easy mod worth some decent hp without tacking on an aftermarket boost controller. More importantly the factory ECU-driven boost map w/taper might be retained adding a margin of safety.

You know if I was trying to make a low-key ringer for testing (magazines perhaps?. I would fill the tank with high-test fuel, and remove the solenoid restrictor(if indeed this does exist) to gain a bit of an edge on the comp.

Again I am not saying anyone has done this..... just that the ability to do it might exist. No factory boost gauge = no way to see any differential in boost= "Wow this thing is faster than we expected!".

Conspiracy theory at its best I guess!

Regardless, this is worth removing the air box to get to the solenoid to check if a restrictor does exist....after mothers day festivities of course!

 

I will try this tonight.

Chris

 

Well im runniing a EBC and running 21.5psi to redline.

 

I removed my boost solenoid tonight to get a better look. I wish I had a digital camera as I would have posted some shots for reference.

The solenoid has a part number of K5T48480, and also has a number 3124 stamped on it.The solenoid has a snap on electrical connector on one end, then the metal solenoid body with a plastic fitting on the other end.

The plastic assembly has a main cylindrical body which has two 90 degree barbs/hose fittings. The best way for me to describe this piece of plastic is it looks like a backwards "F" as you look down at it sitting on the fenderwell mount. The fitting closest to the solenoid body has a spring clamp and is the high pressure side facing the actuator/compressor. The fitting on the end is the low pressure bleed and does not have a spring clamp.

I assume(and I don't know for sure without opening it)that the solenoid has a plunger/piston that projects into the body of the plastic fitting. When it is not energized it is closed .....at least I couldn't blow through it.

I would guess that when it is energized the solenoid pulls the rod/piston(or whatever) open and closed to provide minute amounts of air to pass from the high pressure side fitting to the low pressure bleed side.

If there is a restrictor in this solenoid valve, it has to be located in the main body of the plastic fitting I have described. The plastic fitting can be removed form the main solenoid body by taking a set of needle nose pliers and pinching closed a set of splayed-open pins on each corner of the connection of the fitting to the solenoid body.

Call me a wuss, but this is where I stopped, as I am not going to accidently damage my FBC, and then be car-less while I explain to my dealer why I need a new one. Instead, I am going to check on the price of a new boost solenoid and, if its not to expensive, maybe see if I can get one to open-up.

If anyone else runs across, or has any other additional info on the "solenoid restrictor removal mod" let us know. It appears that it could be done to the older cars/solenoids. Our cars may use a totally different design than the older units.

Thats my .02 so far.

 

Well look what I stumbled across! Check item number 4 as it describes the restrictor removal.

http://srd.yahoo.com/S=2766679/K=How.../incrboost.txt

My comments about the restrictor probably being in the main body of the plastic fitting was not correct. It looks like in the restrictor actually resides in the barb hose fitting itself. The procedure is outlined if you check the link out.

Now here's a real fubar on my part. I had the darn solenoid in my hand, and didn't check the inside of the barbs!!!!! Arghhhhh....well I guess you know what I have to do now;-) At least we will know if the new solenoid has a restrictor in it or not!

 

Well... I also looked at this thing.. I was a tad bolder that you... I used a drill bit and **VERY SLIGHTLY**increased the diameter of the holes...

Result: 16PSI max dropping back to about 13PSI... That is being kind, as it appeared that at times the boost was even lower… I will mess around with restrictors in-line to reduce this back down later.. I may also take it apart and see if a small piece of plastic became lodged inside as I VERY carefully drilled it... That could be the problem, so it is a bit early to say definitively the result of my messing with the FBC… It is odd to see it reduce boost with more flow as the mod discussed. On the web sites they described various ways to increase flow to increase boost by a pound or two…

Anyway... I then installed my cheap MBC and adjusted for 1.4 bar. Much better.

 

Well I went back in and took a look a second time, and could find no restrictor in the barb fitting. So it looks like the EVO solenoid is different than the old DSM solenoids in that respect. So I guess that makes an easy solenoid mod out of the question. Still may be possible, but not without some major dissassembly of the solenoid.

I did note that in the solenoid modification instructions it did mention enlarging the diameter of the barbs/fittings through careful drilling. Also mentioned using a larger hose feeding the solenoid to flow slightly better also providing more boost.Interesting (and a bummer)that you got less boost as that doesn't make sense.

I do know that changing an inline restrictor (the one typically in the hose coming off of the turbo compressor housing) to a larger diameter causes less boost response and spike, and that a smaller diameter restrictor increases boost response and tendency to spike. Kind of like letting more air out of a metal balloon vs less if that make sense.

I found this out the hard way when I was running a gray market ProDrive ECU and specially calibrated restrictor in my WRX(which was equipped with a VF23).

Less restriction at the solenoid bleed should not have had that kind of effect though. Unless your drill bit accidently went past the barb length and into the main body possibly? Anyway glad you have the MBC to rely on. I have one as well...just don't have a boost gauge installed yet, so am playing it a bit more cautiously.

If you do take it apart let us know what you find!
The idea of having the FBC control boost at a slighty higher boost pressure is still a great concept. I also have that new in box Deltrol precision needle valve that could possibly be added to the outlet side of the solenoid.

Let me know if you decide to experiment any further, and I will send it to you free gratis if you are intersted.

Email me at jredding@usmo.com

 

Any update on this modification?