Boost controller woes - please help!
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Boost controller woes - please help!
Hi,
I just put in a Greddy Profec-B V2 today. I'm having some difficulties setting it up. I want to know if anyone can help me out with configuring the different parameters (Set, gain, start boost, and limiter). I've tried messing with it a bunch, starting with a basic set of of set: 40% gain: 15% start boost: anywhere from 0-1kpa. While the spool happens very quickly, the boost seems to wind up to about 1 bar and then fall off almost immediately, stabilizing somewhere around or under .5.
If I turn it higher, it spikes badly up to almost 1.2, whereupon it again falls very quickly down to around .5. If I turn it down I can get it to spike a little above .6 and then fall down to a steady .5 bar. My Lo setting does this with set: 20, gain, 10, start boost .5kpa, and no limiter set at 0. It seems no matter what I do I can't get it to hold a high boost level where I want it. It always spools up quickly and then falls of just as fast, before holding about .5bar. I think this is about where my stock wastegate spring is.. is that my problem?
By the way, start boost is, according the the manual, the pressure at which the boost controller should start to open the wastegate. Manual says to set it close to the SET boost value.. for quicker spooling.
Any help would be greatly appreciated. Thanks!
-FB123
I just put in a Greddy Profec-B V2 today. I'm having some difficulties setting it up. I want to know if anyone can help me out with configuring the different parameters (Set, gain, start boost, and limiter). I've tried messing with it a bunch, starting with a basic set of of set: 40% gain: 15% start boost: anywhere from 0-1kpa. While the spool happens very quickly, the boost seems to wind up to about 1 bar and then fall off almost immediately, stabilizing somewhere around or under .5.
If I turn it higher, it spikes badly up to almost 1.2, whereupon it again falls very quickly down to around .5. If I turn it down I can get it to spike a little above .6 and then fall down to a steady .5 bar. My Lo setting does this with set: 20, gain, 10, start boost .5kpa, and no limiter set at 0. It seems no matter what I do I can't get it to hold a high boost level where I want it. It always spools up quickly and then falls of just as fast, before holding about .5bar. I think this is about where my stock wastegate spring is.. is that my problem?
By the way, start boost is, according the the manual, the pressure at which the boost controller should start to open the wastegate. Manual says to set it close to the SET boost value.. for quicker spooling.
Any help would be greatly appreciated. Thanks!
-FB123
Last edited by frogbot123; Aug 8, 2003 at 10:02 PM.
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I'm guessing start boost is not "should" as in what you want to set it to. I'd think it means you need to dial in what the physical capacity of your wastegate is... the easiest example is a simple spring activated wastegate. If its a "7lb spring", the wastegate will open at 7psi .. or something like that, you get the idea. You can find this value by running with no boost control. I believe our wastegates are a bit over 7psi.
Also 1kpa is nothing. Its about 0.145psi. Did you mean 1Mpa? What did you set start boost too? I'd set it to 52kPa (0.52MPa)
The settings sound similar to the Blitz, at which I have gain at 18, with set of 45 to get about stock boost (98kPa/14.2psi), 50 to get a limit of just about 110kpa/16.0psi. And when I put the tastey xylene in the tank, 53 and 55 to get close to 17. I have found the computer limits at 123kPa (although this seems to vary from car to car).
jason
Also 1kpa is nothing. Its about 0.145psi. Did you mean 1Mpa? What did you set start boost too? I'd set it to 52kPa (0.52MPa)
The settings sound similar to the Blitz, at which I have gain at 18, with set of 45 to get about stock boost (98kPa/14.2psi), 50 to get a limit of just about 110kpa/16.0psi. And when I put the tastey xylene in the tank, 53 and 55 to get close to 17. I have found the computer limits at 123kPa (although this seems to vary from car to car).
jason
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start boost on a gredddy is to hold the wastegate shut until a set boost, similar to running a higher rate spring.
eg: start boost of 10psi, is like having a 10lb spring. this is to aid in faster spooling. it seems to work pretty good.
the other reason you amy be getting a boost spike is the gain, the higher the gain, the faster the boost wil spike. most people with greddy boost controllers rin a gain of 12-15. i run 15 on mine and it works great.
just my $.02
aaron
eg: start boost of 10psi, is like having a 10lb spring. this is to aid in faster spooling. it seems to work pretty good.
the other reason you amy be getting a boost spike is the gain, the higher the gain, the faster the boost wil spike. most people with greddy boost controllers rin a gain of 12-15. i run 15 on mine and it works great.
just my $.02
aaron
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That's what I was going to say at first, since my brain by passed what he originally said about "start boost". But when I did see that factor I thought that starting at the wrong "start boost" (my definition) would cause this problem too, so it seems to me. Besides, his gain is relatively low (albeit, its not the same one I have).
I went and got the docs for the unit from greddy.com and it says nothing about this feature. How do you know that that is what it is?
jason
I went and got the docs for the unit from greddy.com and it says nothing about this feature. How do you know that that is what it is?
jason
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Hey everyone -
Thanks for the help so far. This is a profec-B v2, so maybe thats why the documents didnt mention start boost. As stated before, it controls when to start opening the wastegate. I still dont understand why the boost controller wont let me hold high boost without just falling off... its very bizarre. Can anyone think of an error in installation that might causes this symptom?
Thanks
-FB123
Thanks for the help so far. This is a profec-B v2, so maybe thats why the documents didnt mention start boost. As stated before, it controls when to start opening the wastegate. I still dont understand why the boost controller wont let me hold high boost without just falling off... its very bizarre. Can anyone think of an error in installation that might causes this symptom?
Thanks
-FB123
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As for error in installation, recheck your boost lines. I pretty much always tighten them down w/ tie-raps... even if the connector is barbed.
Remember, too, that the computer is still in ultimate control and it does taper boost as RPMs get very high. 14psi @ 4000 RPM is not quite as destructive as 14psi @ 6500 RPM.
Try some methodical tests. Turn the gain all the way down. Get on the freeway and make some boost so that you can try to sustain it. FInd out around which RPM it starts to drop. Since you just got a EBC i doubt you have logging capability, but it'd be real helpful
If things seem more normal after this, slowly put the gain up by increments of 3 and try again.
I've foud that the settings for my Blitz is very peaky. Not the boost curve, but the actual settings. There is an optimum and if I move off it, its disappointing (too low) or spiky (too high). It takes a while to find that sweet spot, so be patient.
jason
Remember, too, that the computer is still in ultimate control and it does taper boost as RPMs get very high. 14psi @ 4000 RPM is not quite as destructive as 14psi @ 6500 RPM.
Try some methodical tests. Turn the gain all the way down. Get on the freeway and make some boost so that you can try to sustain it. FInd out around which RPM it starts to drop. Since you just got a EBC i doubt you have logging capability, but it'd be real helpful
If things seem more normal after this, slowly put the gain up by increments of 3 and try again.I've foud that the settings for my Blitz is very peaky. Not the boost curve, but the actual settings. There is an optimum and if I move off it, its disappointing (too low) or spiky (too high). It takes a while to find that sweet spot, so be patient.
jason
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Boost lines are anything that carry the pressure between the compressor and the endgine... like lines to the sensor on your boost controllor, or boost gauge, or the stock bleeder, etc...
Er, well, as for your problem still, read back again over what Aaron and I have been telling you.
jason
Er, well, as for your problem still, read back again over what Aaron and I have been telling you.
jason
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It's odd, but even with my gain set down to zero, I still have this problem. I don't think it's a spike per se, but rather the BC can't sustain high levels of boost. If I keep the set at a normal level (about 40) with a zero gain, it spools nicely and stably to about .6 bars, but just holds there. Then, if I raise my set higher, I still get a quick peaking and the immediately the boosts falls back off, as if the wastegate was being opened by the stock wastegate spring. How much electricity does the boost controller require to operate effectively? Is it possible that because I tapped into the power wires that were only meant to power a stock oil temp gauge, that the BC is not getting enough current and is therefore having trouble controlling the boost?
Thanks,
-FB123
Thanks,
-FB123
Last edited by frogbot123; Aug 10, 2003 at 12:44 PM.
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I'm sure you're getting enough voltage to the unit. Are you sure you have the boost lines placed properly? I installed a profec A a while back and one line needed to co go near the compressor and the other went on the outlet off the manifol near the front of the engine.
Other than that, I dunnow hat to tell you. I'd have to take a look in person. Where'd you buy this unit?
jason
Other than that, I dunnow hat to tell you. I'd have to take a look in person. Where'd you buy this unit?
jason
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