Seagrams Posted March 10, 2008 Author Report Share Posted March 10, 2008 I still don't understand why you are racking your mind and resources so hard to fix something that really can be properly bandaid-ed? You can just leave a boost controller inline with the BCS and reach 11 or even 12 or 13 pounds of boost, and have a bigger smile on your face than if you had the stock boost level while still being perfectly reliable and safe. This is the performance forum, after all. I don't think I have ever had a stock turbo car reaching 9.6 psi exactly being just controlled by the ECU, I think there are more factors involved in the boost algorithm than most people here acknowledge. It just hurts my brain to see a bright individual trying to solve a problem that I think generally should be overlooked Why you ask???? Because IT'S THERE!!!! no but seriously your point is well taken, it's just that to my opinion this issue (i believe it is an issue) could be indicative of a problem occurring somewhere in the ephemera that is the inner workings of my car. Again maybe it isn't as you say. If something is supposed to work a certain way, and it doesn't I for one would like to find out why before i overlook it and have problems develop down the line as my modifications become more aggressive. It is only a bandaid fix like you said. If you were bit by a raccoon and were bleeding all over the place, and said "my all this blood is an inconvenience, i'll just put a bandaid on it" and then considered the problem solved, you'd probably wind up regretting that decision in the near future. Ok, so that is something of an extreme non sequitor but the point i'm making is that IF there is something causing my car to behave this way (be it the ECU or whatever) i'd like to find out what it is lest it goes ignored, festers and bites me in the arse later on. I'm exhausting most of my options here, so it is possible it'll turn out to be nothing and i'll live with the MBC, but until then i'm going to keep looking. Call it the desire to never settle until satisfied Plus if and when i do find my gremlin unicorn, there is a chance it could be something of importance to others on this board. At the very least, I've learned more about forced induction than i thought possible, and for that alone, this potentially futile quest will not have been in vain ;) Link to comment Share on other sites More sharing options...
HoustonT5-R Posted March 10, 2008 Report Share Posted March 10, 2008 I think we can safely say that this is not a corrective measure being put into effect. So rather, the ECU must believe that what it is doing is achieving the desired boost level. It is either being given improper information or is just stupid.So since if it's not the knock sensors, then the ECU must be right? I don't agree with that. Something is feeding the ECU information that is telling it to limit the boost. We have already established that with the difference between the boost with & without the MBC. We need to rule out input parameters until we find the one responsible. Easy to say, somewhat difficult to achieve. Link to comment Share on other sites More sharing options...
EricF Posted March 10, 2008 Report Share Posted March 10, 2008 So since if it's not the knock sensors, then the ECU must be right? I don't agree with that. Something is feeding the ECU information that is telling it to limit the boost. We have already established that with the difference between the boost with & without the MBC. We need to rule out input parameters until we find the one responsible. Easy to say, somewhat difficult to achieve.Having been in many M4.3 cars which have had boost pulled due to knocking, I'm not suggesting or theorizing that the boost will go up and then back down, I'm explaining that it happens like that. Boost hits at the initial optimal setting, then is knocked down a few pounds until the condition resolves itself then is raised back up. In cars where there is something going on causing them to knock at say 16 pounds, and the ECU is set to achieve 17 or 18 pounds of boost, watching the boost gauge is like watching a ping pong match almost. It's very odd. That is when the knock sensors are working properly. If the engine is receiving knock signals before boost hits, or while it is building, as a result of knock sensor error, it will not build boost past the base wastegate setting (3.5-5 psi IIRC depending on which actuator is on your car and how much pre-load you have). If this were the case, it would also be richening the mixture and pulling timing since pulling boost wasn't getting the job done. The car would be really goofy, the premise of this topic would be very different.I am going to go through the Motronic book and post a little more later. If everything else is functioning properly, the car runs and pulls well and smoothly, then lower boost level is either wastegate calibration or the ECU isn't dishing out the right signal to the BCS. The possible reasons for this lie within the ECU itself or the information it is being given. Link to comment Share on other sites More sharing options...
Cal3thousand Posted March 10, 2008 Report Share Posted March 10, 2008 Having been in many M4.3 cars which have had boost pulled due to knocking, I'm not suggesting or theorizing that the boost will go up and then back down, I'm explaining that it happens like that. Boost hits at the initial optimal setting, then is knocked down a few pounds until the condition resolves itself then is raised back up. In cars where there is something going on causing them to knock at say 16 pounds, and the ECU is set to achieve 17 or 18 pounds of boost, watching the boost gauge is like watching a ping pong match almost. It's very odd. That is when the knock sensors are working properly. If the engine is receiving knock signals before boost hits, or while it is building, as a result of knock sensor error, it will not build boost past the base wastegate setting (3.5-5 psi IIRC depending on which actuator is on your car and how much pre-load you have). If this were the case, it would also be richening the mixture and pulling timing since pulling boost wasn't getting the job done. The car would be really goofy, the premise of this topic would be very different.I am going to go through the Motronic book and post a little more later. If everything else is functioning properly, the car runs and pulls well and smoothly, then lower boost level is either wastegate calibration or the ECU isn't dishing out the right signal to the BCS. The possible reasons for this lie within the ECU itself or the information it is being given.Excuse me if this sounds noobish, but what is the Motronic book... and where can i procure one? Link to comment Share on other sites More sharing options...
JHEIII874T5M Posted March 10, 2008 Report Share Posted March 10, 2008 Totally in agreement with what Eric is saying.Excuse me if this sounds noobish, but what is the Motronic book... and where can i procure one?volvotechinfo.comStore -> Service Parts -> Service Manuals -> Engine Link to comment Share on other sites More sharing options...
EricF Posted March 11, 2008 Report Share Posted March 11, 2008 Sorry guys, fell asleep last night before I was able to find the manual.Here's the thread I posted about M4.3 when I got the book though, back in the day.http://volvospeed.com/vs_forum/index.php?showtopic=20410It has a little more insight into what factors can influence boost level. I am personally wondering now what boost level the cars are automatically limited to in first gear before 3000 RPM and if there is a possible hangup on that level for some reason.One nice tidbit in that thread is Doug calling Poi out for benchracing. One benchracer turned inspirational builder :D Link to comment Share on other sites More sharing options...
HoustonT5-R Posted March 11, 2008 Report Share Posted March 11, 2008 I am personally wondering now what boost level the cars are automatically limited to in first gear before 3000 RPM and if there is a possible hangup on that level for some reason.That doesn't apply to my car because Dad and I clipped that wire coming from the TCU when I bought the car. :ph34r: Link to comment Share on other sites More sharing options...
sconeman Posted March 12, 2008 Report Share Posted March 12, 2008 I wonder if my cars situation will shed light on this topic. It turns out the the ECU has been cutting my boost because of a bad converter. I though it was the CBV diaphram but apparently it's not. The other day at the beginning of a trip to Philly I got a CEL. First time ever with this car. Nothing changed about the way the car behaved or boosted, but the boost remained (as before) slightly below stock as it has been since I installed my IPD ecu and finished Stage 0. Please keep in mind that I had already, several weeks earlier, seperated my DP to check for a clogged cat and pulled my ECU overnight to reboot. No change with either scenario. When I got back from Philly I went over to a friend who has a code reader and pulled code (i forget the number but) "main catalyst below threshhold" was the message. He cleared the code and I drove off happy since I already have a new DP and cat in the works.The next day I noticed significantly more power and the day after that even more. in two days the car was boosting to 14 pounds in second. about 4 days later CEL back on and boost is back down to under stock, maybe 8# in second gear.I'm not saying the your cat is the problem but have you cleared your codes and fixed whatever the code was referring too yet?hope this helps. PS I'm still going to replace the CBV diaphram :lol: Link to comment Share on other sites More sharing options...
lookforjoe Posted March 12, 2008 Report Share Posted March 12, 2008 I wonder if my cars situation will shed light on this topic. It turns out the the ECU has been cutting my boost because of a bad converter. I though it was the CBV diaphram but apparently it's not. The other day at the beginning of a trip to Philly I got a CEL. First time ever with this car. Nothing changed about the way the car behaved or boosted, but the boost remained (as before) slightly below stock as it has been since I installed my IPD ecu and finished Stage 0. Please keep in mind that I had already, several weeks earlier, seperated my DP to check for a clogged cat and pulled my ECU overnight to reboot. No change with either scenario. When I got back from Philly I went over to a friend who has a code reader and pulled code (i forget the number but) "main catalyst below threshhold" was the message. He cleared the code and I drove off happy since I already have a new DP and cat in the works.The next day I noticed significantly more power and the day after that even more. in two days the car was boosting to 14 pounds in second. about 4 days later CEL back on and boost is back down to under stock, maybe 8# in second gear.I'm not saying the your cat is the problem but have you cleared cleared your codes and fixed whatever the code was referring too yet?hope this helps. PS I'm still going to replace the CBV diaphram The bad cat can deteriorate the CBV - that happened with mine - but mine was more severely clogged - it wouldn't go over 3 psi. Link to comment Share on other sites More sharing options...
Seagrams Posted March 13, 2008 Author Report Share Posted March 13, 2008 The bad cat can deteriorate the CBVHow? Just curious to know :) Link to comment Share on other sites More sharing options...
hobbiemantis Posted March 13, 2008 Report Share Posted March 13, 2008 How? Just curious to know Damn going through the same stuff with my 855 96 R. Just replaced the cbv, samcos, full tune up and replce multple vacuum lines with silicon. Great readings on vacuum will only boost to about 6 lbs. Sometimes I get more usually in 1st gear. I tried a ecu from a T5 stock and same result. I dont know if anyone runs 87 octane gas but I am going to try to fill with 91 and see if it changes. Link to comment Share on other sites More sharing options...
lookforjoe Posted March 13, 2008 Report Share Posted March 13, 2008 How? Just curious to know Well, what was suggested to me, by Ken @ IPD, and by a couple of fellas from Volvo NA, was that the excessive backpressure puts a strain on all related components; excessive heat, etc., would cause the diaphragm to deteriorate. On mine, the laminated layers had separated, so that it was leaking in one spot on the vaccum side, and bleeding through on the opposite side of the diaphragm. I determined this by submersing the CBV assembly in a bucket of water, and then sucking down the vacuum port (with my MightyVac) until it was fully retracted; I could see the surface swell on one side, then the air bubbles starting rising on the opposite side. I've seen intercooler hoses on 700's do the same thing. Link to comment Share on other sites More sharing options...
hobbiemantis Posted March 15, 2008 Report Share Posted March 15, 2008 I am over it. Just got an ecu from speedtuning st2. It rocks. Almost 17 lbs on the gauge and the car pulls like crazy. I think the stock ecu was controlling the lower boost. It would spike to 11 but never held there but now oh damn. Love Speedtuning. Link to comment Share on other sites More sharing options...
Seagrams Posted March 16, 2008 Author Report Share Posted March 16, 2008 I am over it. Just got an ecu from speedtuning st2. It rocks. Almost 17 lbs on the gauge and the car pulls like crazy. I think the stock ecu was controlling the lower boost. It would spike to 11 but never held there but now oh damn. Love Speedtuning.so the chip took care of your problem??? Might be time for me to invest then..... where'd you get it? Link to comment Share on other sites More sharing options...
sconeman Posted March 16, 2008 Report Share Posted March 16, 2008 so the chip took care of your problem??? Might be time for me to invest then..... where'd you get it?although even with a chip your ecu could pull back boost on you, like mine (an IPD), if you have the right conditions. (bad cat or whatever)I was wondering the other day. Is this going to turn into the longest performance thread ever? Is there a record? :lol: Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.