Custom Dual Stage boost controller help

[zachakagoat]

I am planning on building a multi-stage boost controller in my GST but have a few questions on some wiring issues. I want to be able to to run low boost in first gear slightly higher boost in 2nd and possibly a bit higher in the rest. I don't want to wire in a manual switch I want it to change on its own depending on the gear you are in. Is there a wire somewhere that I could tap into for each gear like gear indicators use so I could wire it to my switch for first gear switch? I think having the boost lower instead of regulating the throttle will allow me to fine tune the fuel and boost levels in each gear to get the best time because it will be more consistent like an automatic if I can wind out each gear to the fullest.

 

[Quasimondo]

Sounds like a complicated way to re-invent the wheel. They have electronic boost controllers that can do that stuff. The Blitz SBC iD comes to mind.

There's no way the ecu knows what gear the transmission is in, so your other alternative is to have the boost dependent on the vehicle speed, so if you can draw up something that controls boost dependent on the VSS, you might have something.

 

[zachakagoat]

That is a possibility. Well this is a budget and a project so I'm just playin around with some stuff I have laying around the garage. I have all the MBCs, solenoids, and switches in the car just seeing what kind of switch I need to be looking for when I go to my parts store. I have been looking at a few schematics for a custom stutterbox as well. Maybe some kind of switch mounted inside the console that actually gets flipped by the shifter since my low boost will only be in first gear. Does anyone know where I can find an affordable gear indicator if one can be found for the right price it can be modified from that.

 

[zachakagoat]

Ok how about the stock BCS I have seen some people use that. Does the stock solenoid regulate any presure or is it simply a switch used by the ECU. If so I could possibly use something like this instead of an expensive valve. I still can't find the valve very cheap anywhere. Any help out there?

 

[Budget90GST]

It's a little tricky but I once mounted a micro-switch by the shifter console that controlled my low boost for first and second gear. Again, not the easiest thing to rig up. Goodluck.

I now have the LINK and could use one of its features to control boost based on vehicle speed - but then I also now own an AWD.

 

[zachakagoat]

Well Budget90GST can you maybe draw out a schematic and tell me what kind of routing and vacuum source switching you did?

 

[wret]

The cheapest solenoid valve I've found is part# 7876K11 from McMaster-Carr, about $35 for the NC(normally closed) and $56 for the NO. There are tons of valves in the industrial section of ebay but it is rare to find them in 12v. Most are 24v or 110. If you have time, keep watching the actions and you'll eventually find one.

The really cool gadgets you can find on ebay are the programable pressure switches. I have one that's about a 1-inch cube, that controls my water injection and boost through two separate channels.

 

[zachakagoat]

Wret have you ever used any of the grainger valves instead of MBCs for boost control?

 

[wret]

Currently I'm using a Humphrey solenoid valve. I got a bunch of them from ebay a while back. It's a little too small to control boost directly though (spikes). A delrin 1/4" NO valve arrived yesterday from McMaster-Car. I will use this in conjunction with the stock BCS as a two stage boost controller. When not activated, the BCS will function as normal. When activated, the valve will close and then open when the set point on my pressure switch is reached.

 

[zachakagoat]

Ok I am wanting to do two seperate boost controllers and want to know if this is going to work. I have drawn up a picture. Does the stock FPS switch beteen actual boost lines because there is a second nipple capped off or is it simply another nipple much like a T fitting? If so will the second diagram work for a dual stage?

 

[wret]

By "FPS" I assume you mean "BCS." In the stock configuration, the BCS stays open most of the time, bleeding off boost pressure but eventually allowing it to build enough to actuate the waste gate. At certain times the ECU cycles the BCS attempting to modulate boost without completely limiting it to the nominal level. After long term knock detection, the ECU sends a constant 12v to the BCS which closes it completey and prevents bleeding off of the boost pressure. At this point, boost only reaches the nominal level of the wastegate actuator, somewhere around 8 psi.

Can you use the BCS as a solenoid valve to switch between manual boost controllers? I haven't but others have. Your second diagram should work but here are two things to consider: I have heard that a CEL results from removing the stock electrical inputs to the BCS. Also, the BCS is normally open. In diagram two, you would default to low boost until you send 12v to the BCS, closing it and allowing the boost to build to 20psi before getting through to the wastegate.

 

[zachakagoat]

No by FPS I mean the stock Fuel Pressure solenoid that is not used by most people that do the vacuum line elimination. From what I have read the FPS is simply a valve that is controlled by a 12v signal so putting it in line like diagram 2 should work allowing me to put the lowboost MBC on the line with the FPS allowing it only to go to the low pressure when the solenoid is open.Does anyone know if the FPS is a Normal Open or Normal closed solenoid? I believe it is a NO

 

[wret]

You could use either an NO or an NC valve. The NO would be safer though. If it failed, you would default to low boost rather than high.

 

[zachakagoat]

Ok so I just finished hooking it up without the switch. It is running to a T then one line to the MBC and one line to the FPS then both of the lines that come off of that go back into a T and then into the Wastegate. With this setup I am going to run 10psi in 1st and 2nd gear for traction then up to my 20psi in 3rd-5th. I am going to add another MBC after the solenoid and that should allow me to run a higher psi for 1st and 2nd.

 

[Budget90GST]

This was a long time ago and I do not have a diagram anymore. It is similar to your diagram 1 with the solenoid (factory) gets triggred by a switch mounted inside the shifter console. Since 1st and 2nd gear share the same movement (left motion towards the driver) on the shifter plate assemble, all I did was place the microswtich in a position where it is triggered when I'm in 1st or 2nd gear. Just make sure to allow for a little over travel so the switch is triggered after the shifter is placed on either 1st or 2nd gear. When You get out of 1st and 2nd, the microswitch is release and the system goes to high boost. Goodluck.

 

[empie1]

hmmm....sounds like way to much of a pain in the ass for the benefits....imo

 

[zachakagoat]

Budget I get what you are saying. Placing a microswitch that is spring loaded onto the right side of the shift assembly inside the console to allow the switch to only be tripped when your shifter is pushed to the left in 1st or 2nd gear. This is the idea I was thinking about using after I get a regular switch mounted. Fabbing up a microswitch will take me alittle bit so this regular switch should do fine for now. Wish I could have got a push button switch to place in the cig lighter but I was in a hurry and the parts store was low on stuff. I am going to attempt to build a metal casing for the system tommorrow to make a cleaner install and keep everything away from moving parts and the environment. Even thinking about adding nipples to the box so its all plug and play. Maybe a wiring harness quick disconnect for the switches

 

[zachakagoat]

Well when I got up this morning I decided I should go ahead and give my car back its caffeine addiction . This is the prototype box I made, I will be building a sheetmetal box later today that I will mount to the side of the frame rail. Hopefully this will clean up the engine bay some to as there won't be a mess of extra vacuum hoses and stuff runnin around.

 

[zachakagoat]

Ok alittle update, I got everything wired and temporarily installed into the car. It doesnt have a case around it because I am testing it out to find any little bugs or anything. So far I'm only running at stock wastegate pressure for the low gears but plan to add another MBC to it when I build the second one. I just went out and tested it in the rain and its AMAZING! 10psi in 1st and 2nd and still keeping traction then 20 in 3,4,5. Normally I can launch in 1st and roast constantly til 3rd on 20 psi no matter what. Now I can launch and get outta the hole quicker then get pullin hard like a GST should. Now I just have to build some kind of microswitch for 1st and 2nd gear only unless I can discover some circuit on the car that tells me what gear I am in.

Many people think that tuning with a SAFC with a DSMBC will change the fuel maps but I am going to be using it as a constant 10psi in 1 and 2 and a constant 20 in 3,4,5 and when you tune your car with a SAFC you use 3rd gear pulls to get logs anyway so the change in psi shouldnt matter that much in the low gears. If anything I'm simply going to be running rich. Should make a nice backfire when I get the stutterbox haha

 

[Crazy91GSX]

good to see that you got everything working.. this is something usefull for the rest of the fwd crowd.. did you use the first or second diagram configuration?

 

[zachakagoat]

I used the second configuration but I do believe that the first one would be possible because you can blow through the solenoid and it will only come out one nipple and the stock one comes capped from the factory. I didnt test it with a 12v source. I will make sure and test it like that when I build the metal box this weekend. i didnt get a chance to build it today because of a storm but I did get to play with my little toy . I will have to say that this Cheap/free mod is an EXCELLENT mod for any FWD or AWD. I'm hoping that this will save me some gas mileage too if I keep it on low boost instead of smokin ass passing people on the highway . In this version I dont have a second MBC at the moment. Version 2 will be more mass produced and will have 2 mbcs to set.

 

[compression]

i did a write up on this , a very cheap way to switch between stock / set boost

http://dsmtuners.com/forums/showthread.php?t=220530

if you wanted to get more complicated and make it a 3 stage boost controller, you could but i dont see any easy way to make it gear specific + it would be much easier and cheaper to have throttle control instead

 

[zachakagoat]

yea I used yours for help on this one. I don't see how a thorrle control switch would help because I am going to be doing WOT in all gears when making a run. Some people say "just regulate your throttle" but with the boost set lower it allows me to focus on the light and the launch instead of keepin the boost down. It is ALOT more reliable from what I can tell so far which helps me out because I do some bracket racing too.

 

[compression]

yea I used yours for help on this one. I don't see how a thorrle control switch would help because I am going to be doing WOT in all gears when making a run. Some people say "just regulate your throttle" but with the boost set lower it allows me to focus on the light and the launch instead of keepin the boost down. It is ALOT more reliable from what I can tell so far which helps me out because I do some bracket racing too.

by throttle control i ment dont go wot right out of the hole

 

[zachakagoat]

Yea I know what you meant, and I don't go WOT right outta the hole but as soon as I start rollin I open it up. The fact that I can consistantly pull the same times will help me tune out different parts of my run. Now time for more fuel and I can open her wide up in the upper gears.