|
Post by spaz100 on Sept 28, 2009 22:13:12 GMT -5
Is there any sort of simple on/off boost control solenoid product out there that is just a simple on/off switch that also senses the pressure coming out of the turbo?
i've been doing a little reading and from what i read, one of the downsides of using a mbc and wastegate is that the actuator, since it is diaphragm based, starts to open before maximum set boost is reached.
is there a cheap sort of product that blocks off any boost signal to the mbc and wastegate until a couple psi before set boost, then opens to give full signal to the mbc and wastegate to keep psi at desired level.
for example, i want to set my boost to 25psi, when i start boosting, solenoid keeps signal cut off to wastegate and wastegate stays closed due to no signal going to it; thus decreasing lag time until max boost is increased. at 22-23 psi, the solenoid opens, giving pressure to the mbc (which is set at 25psi) and the wastegate has time to open at 25 psi, diverting all other gases away from the turbo and everybody is happy.
ok, if you got what the hell i was talking about, is there anything out there like this? its similar to a electronic boost controller, but just one simple on/off instead of controlled pulses. i figured that somebody out there might have had the know how to make something like this cheaply and released it.
thanks!
|
|
|
Post by wishihadatalon on Sept 28, 2009 22:28:27 GMT -5
it isn't really the solenoid but more so what controls it. If you can control the duty cycle of the solenoid vs pressure, you can essentially map out a boost curve that waits till the last possible second to open the solenoid. Gm solenoids seem to work pretty well for this but you can get really nice stuff from perrin, aem, etc.
|
|
|
Post by spaz100 on Sept 28, 2009 23:00:54 GMT -5
i really wasnt looking for something with a duty cycle due to what controls it. i was looking more for something such as you turn on the solenoid, it cuts signal to the mbc/wastegate, then when certain psi is reached the solenoid is turned off automatically and signal goes to mbc/wastegate.
something with a duty cycle would be more friendly and easier in the long run, but thats pretty much what an ebc is and i want to try to avoid that for cost purposes. duty cycle would be a better idea overall, but i wouldnt know enough to accomplish that and incorporate it with ecmlink.
|
|
|
Post by 99gst_racer on Sept 29, 2009 9:01:20 GMT -5
A solenoid controlled wastegate that opened just before it needed to, would probably promote a nasty boost spike. They make purpose built electronic boost controllers that are capable of accurately doing what you're trying to do. One that comes to mind is the AMS-1000: www.ams1000.com/home/e107_plugins/content/content.php?content.3 But it isn't very affordable.
|
|
|
Post by spaz100 on Sept 29, 2009 10:14:46 GMT -5
would it promote boost creep if it opened a little earlier? like say when 75% of desired boost is achieved? im not exactly sure when i would need it to open up to achieve proper boost control, but cutting down on premature diverted gases going out the wastegate isnt bad.
i would think, and correct me if im wrong, but as long as the wastegate did a good enough job of diverting gases before, shouldnt it be fine with this solenoid added to it? unless of course you were already riding the razors edge of almost getting boost creep i suppose.
a person themselves could control this (although not really advised) with a simple on/off switch as long as they kept a very close eye on the boost gauge and turn the solenoid off at the right time.
|
|
|
Post by wishihadatalon on Sept 29, 2009 10:28:09 GMT -5
so all you really want is some sort of pressure switch. You would still run an mbc but you would run the pressure switch like 2psi below the mbc level? That way you could have a close off line until x-psi then the signal gets fed to the wastegate or the mbc. You would really at the very least need an mbc because having a simple on off switch would give sloppy boost control by its self.
That being said, if you can find a way to have the ecu run an output that you can select a boost level, you could essentially run the switch. I don't know of a standalone adjustable pressure switch but if you could find one, you cold easily run a gm windshield washer solenoid for this. It would just be on or off.
Like Paul said, this could cause an issue with creep if you are running lower boost with a smaller internally gated turbo. At the very least you will probably have some spike issues. Something like this would shine on an external wastegate setup.
|
|
|
Post by spaz100 on Sept 29, 2009 10:42:18 GMT -5
exactly, sorry i dont explain myself well. it would be used with anybody's pre-existing manual boost controller and wastegate.
the simplest way i could think of it, would be the driver turning on the boost solenoid, which would block the signal to the mbc/wastegate. boost would rise, then a boost sensor could send a signal to another solenoid (low voltage im thinking) that would break the electrical connection to the boost solenoid allowing signal to the mbc/wastegate. wastegate opens, and everybody is happy. for adjustment, a resistor could be placed between the sensor and power cutting solenoid.
|
|
|
Post by 99gst_racer on Sept 29, 2009 13:03:44 GMT -5
Sorry - typo. My first post was suuposed to say "boost spike" not creep.
|
|
|
Post by XtremeRS2GNT on Oct 1, 2009 7:18:10 GMT -5
In theory your idea will work using a pressure switch and solenoid(I actually used 2 12volt solenoids with 2 MBC's and a rocker switch for a 3 stage boost controller back in the day). But the pressure switch i think will give inconsistent results and lots of spiking. At the pressure point of the switch, I think it will tend to on/off and oscillate too much causing wild spiking. You dont know until you try though. The solenoids I had used were bought from Grainger's industrial supply.
A good ball/spring type MBC will keep most pressure from the wastegate anyway, until pressure overcomes the internal spring resistance of the MBC. A "bleed" type boost controller is the one that will prematurely open the wastegate. IMO, get a good ball/spring MBC and be done with it. You can make your own 2 stage hi/low controller using one 12volt solenoid, and a MBC. USe the solenoid to bypass the MBC and run wastegate pressure, then flip the switch to divert through the solenoid to the MBC for "hi" boost. The solenoid's I used had 3 ports, two that went straight through with solenoid off, and with it on, diverted to the 3rd port(one inlet from turbo, then 2 outputs- one to wastegate, then one to the MBC to wastegate)
|
|