Fluctuating boost...too much wg preload?
Jan 16, 2011, 05:23 PM
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Fluctuating boost...too much wg preload?
I'm having a little issue and I can seem to figure out what it is. FP Red w/18psi wg preloaded (turned the buckle all the way down and then came back up about one full turn), hallman mbc.
I've got the 64mm cover so I'm getting the infamous comp surge. The spoolup looks pretty good but when it gets to peak boost (peak load) it doesn't seem to hold steady and is fluctuating (also reflected in my idc's)...however after peak to redline it holds pretty solid.
Could this be a symptom of too much wg preload? I also considered my bov being the culprit, but the fact that i'm just at 23-24psi and also that I'm using an MR bov with the dejon powerhouse mod I kinda doubt it.
I've attached a couple shots of my logs to show the problem.
Any ideas?
I've got the 64mm cover so I'm getting the infamous comp surge. The spoolup looks pretty good but when it gets to peak boost (peak load) it doesn't seem to hold steady and is fluctuating (also reflected in my idc's)...however after peak to redline it holds pretty solid.
Could this be a symptom of too much wg preload? I also considered my bov being the culprit, but the fact that i'm just at 23-24psi and also that I'm using an MR bov with the dejon powerhouse mod I kinda doubt it.
I've attached a couple shots of my logs to show the problem.
Any ideas?
Jan 16, 2011, 07:26 PM
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Since you have shortened the length of the actuator rod to the max you may indeed have it preloaded beyond the optimal setting.
You need to do the following: Run a hose from the WGA cannister to the compressor housing discharge tube nipple. Loosen the turnbuckle on the end of the WGA rod until it freely slides on and off of the peg on the pivot arm of the Flapper valve.
Now one 360* counterclockwise rotation of the turnbuckle at a time increase boost from the base 11 PSI to a level 3# below your desired peak boost level. The final 3# you can adust with yor boost controller.
You need to do the following: Run a hose from the WGA cannister to the compressor housing discharge tube nipple. Loosen the turnbuckle on the end of the WGA rod until it freely slides on and off of the peg on the pivot arm of the Flapper valve.
Now one 360* counterclockwise rotation of the turnbuckle at a time increase boost from the base 11 PSI to a level 3# below your desired peak boost level. The final 3# you can adust with yor boost controller.
Jan 16, 2011, 10:12 PM
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Sparky thanks for your response.
I'll try this tomorrow and see what results I get, I also strongly feel it's the preload.
Oh for clarification, I have the 18psi actuator so that's what my base would be...do the same instructions apply?
I'll try this tomorrow and see what results I get, I also strongly feel it's the preload.
Oh for clarification, I have the 18psi actuator so that's what my base would be...do the same instructions apply?
Jan 17, 2011, 06:20 AM
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Ok I'll give it a shot today.
Funny thing is when I had just put it on and had the mbc fully open it went to like 16psi and held a little then crept to 23 by redline. So I just turned the mbc down until it hit 23psi, but then it started to fluctuate at peak.
I will report back with some results.
Funny thing is when I had just put it on and had the mbc fully open it went to like 16psi and held a little then crept to 23 by redline. So I just turned the mbc down until it hit 23psi, but then it started to fluctuate at peak.
I will report back with some results.
Jan 17, 2011, 08:32 AM
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Ok I just made a couple passes and it still seems to be hitting like 15-16psi around where it should be hitting peak, and then creeps up to like 20psi (I disconnected the mbc and just looped the comp nipple to the wg nipple, backed off on the preload so the buckle slides over the flapper easily and just went one full 360 turn from that point to keep some pressure on it)
Here are the results:
What do you guys think? Is this how it is suppose to behave or should it be hitting that 20psi much earlier?
(btw there are no pills in the line, don't know if that makes a difference)
Here are the results:
What do you guys think? Is this how it is suppose to behave or should it be hitting that 20psi much earlier?
(btw there are no pills in the line, don't know if that makes a difference)
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Jan 17, 2011, 04:47 PM
#10
It could very well be from surge! It is normal to creep like that. You have the EVO IX 10.5 housing which doesn't seem to flow quite as well as the EVO VIII 10.5 housing. The wastegate holes are larger on the older style.
I really don't think you having the wg cranked down would do this. I cut 3-4 threads off mine and crank it as far as it will go and my car doesn't do this. Mine is almost to the point that it should be welded, it hardly opens.
My bet is surge.
Mikey
I really don't think you having the wg cranked down would do this. I cut 3-4 threads off mine and crank it as far as it will go and my car doesn't do this. Mine is almost to the point that it should be welded, it hardly opens.
My bet is surge.
Mikey
Jan 17, 2011, 07:09 PM
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Jan 17, 2011, 07:36 PM
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I looked throgh your boost data and thought about what Mikey said too. I think that you are gonna have to pull the exhaust housing and port the transition from the turbine inlet area to the WG bypass port(s). You are experiencing classical creep symptoms.
Jan 17, 2011, 07:55 PM
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It could very well be from surge! It is normal to creep like that. You have the EVO IX 10.5 housing which doesn't seem to flow quite as well as the EVO VIII 10.5 housing. The wastegate holes are larger on the older style.
I really don't think you having the wg cranked down would do this. I cut 3-4 threads off mine and crank it as far as it will go and my car doesn't do this. Mine is almost to the point that it should be welded, it hardly opens.
My bet is surge.
Mikey
I really don't think you having the wg cranked down would do this. I cut 3-4 threads off mine and crank it as far as it will go and my car doesn't do this. Mine is almost to the point that it should be welded, it hardly opens.
My bet is surge.
Mikey
Jan 17, 2011, 07:58 PM
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I'm going to try the 2 extreme cases tomorrow and compare the results...very little preload and fully preloaded (w/out the mbc connected)