HB280ZT Posted March 3, 2009 Share Posted March 3, 2009 Hi All, I had a chance to dyno my car today and was surprised the car did not run as good as I had hoped or as good as it had in the past. Here are the numbers and some of the datalogs and msqs. Run 5 of 8 Max power 281.28 at 4800 rpms Max torque 303.15 at 4200 rpms Here is some background infomation about my setup: 1977 Datsun 280Z Turbo MS 1 V3 with 29y4 Extra code 82 ZX turbo motor with N42 head using turbo cam T3/TO4 - running 14 psi boost Turbine wheel is a stage III. A/R .70 Compressor wheel is a T04B hi-fi A/R .63 and it flows 55lbs/min intercooler tubing 2 1/4 - bar and plate with a fin area measures 3" wide X 8" tall X 20" long- Tial BOV is mounted 12" before the TB. Spark plugs NGK BKR7E gapped to .025 60mm TB For some reason I am not able to post datalogs and msq's in zip format. Any ideas why? HB280ZT Quote Link to comment Share on other sites More sharing options...
HB280ZT Posted March 3, 2009 Author Share Posted March 3, 2009 Hi All, Well I had some issues during the dyno pulls. My car has a miss/flutter/stumble between 3200 and 4000 rpms when doing the 4th gear pulls on the dyno, 3rd gear pulls no issue (very fast respones compared to the 4th gear pulls). In the datalogs (which I hope to post when the system is up and running again) at full throttle I get a dip in MAP, Boost, PW and Duty cycle. Not sure what is causing it but it is very frustrating. I mean, I get a dip in MAP from 179 to 147 in a log period of 1702.901 to 1703.733 with a drop in boost of 11.4 to 6.8 in the same period, plus PW and DC drop also. However my VE and TP numbers stay the same. So what could cause these type of changes and what should I look at in the datalog to help pin point the problem. Thanks for the help will post logs and msq when I can. HB280ZT Quote Link to comment Share on other sites More sharing options...
HB280ZT Posted March 3, 2009 Author Share Posted March 3, 2009 Hi All, Well they got the upload function working again, thanks SuperDan! If you look at datalog 1639D6 and msq 1640D5 you can see the issue I had in the following time periods: -1702.901 MAP 179 Boost 11.4 PW 14.5 Duty Cycle 38.7 -1702.997 MAP 164 Boost 9.2 PW 12.1 Duty Cycle 33.3 -1703.733 MAP 147 Boost 6.8 PW 12.2 Duty Cycle 35.6 If you look at datalog 1646D7 and msq 1645D6 you can see the issue I had in the following time periods: -2108.265 MAP 185 Boost 12.3 PW 14.0 Duty Cycle 39.7 -2108.553 MAP 147 Boost 6.8 PW 12.0 Duty Cycle 33.0 I am really not sure why I get this miss/flutter/stumble between 3200 and 4000 rpms when doing the 4th gear pulls. So if anyone has any ideas please let me know. HB280ZT datalog1639D6.zip datalog1646D7.zip megasquirt1640D5.zip megasquirt1645D6.zip Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted March 3, 2009 Share Posted March 3, 2009 You might be stalling the turbo and pushing the BOV open. Caused by an oversized turbo. Search for surge. Quote Link to comment Share on other sites More sharing options...
HB280ZT Posted March 3, 2009 Author Share Posted March 3, 2009 cygnusx1, The car started this after I replaced the BOV about 2 years ago. I went from a 1st Gen BOV to a Tial 50 mm BOV. So how could a BOV cause this? Or maybe it just masked the real problem. As for the turbo it is not that large compared to some of the large turbos others are using so?? Also I have talked with several Turbo specialist and they tell me it is a tuning issue and not the turbo. I really hate it when I have many more questions then answers but that is the way of it. HB280ZT Quote Link to comment Share on other sites More sharing options...
bradyzq Posted March 4, 2009 Share Posted March 4, 2009 Well, if it started happening when you swapped BOVs, try removing the BOV, blocking it off, and going for a datalog run. Maybe the BOV is leaking badly. Quote Link to comment Share on other sites More sharing options...
bradyzq Posted March 4, 2009 Share Posted March 4, 2009 Do you have a boost controller, or is the wastegate spring a 14 pounder? Quote Link to comment Share on other sites More sharing options...
HB280ZT Posted March 4, 2009 Author Share Posted March 4, 2009 As for the BOV, the 1st gen was hooked up in a recirculation configuration. Then I vented it to the atmosphere and noticed it was leaking badly, so I replaced it. Then I got this new Tial and no more leak, it only vents when I get to -17 inches of vacuum. Also I have blocked off the BOV without any change in the system. I have also done leak tests of the whole system and fixed 2 problems. I even removed the intercooler and ran a straight pipe in its place and it did not miss, flutter or stumble. As for a boost controller I am using a 15 lbs waste gate actuator plumbed to the output of the turbo. I have also tried it plumbed to the intake and no change. Quote Link to comment Share on other sites More sharing options...
bradyzq Posted March 4, 2009 Share Posted March 4, 2009 If I understand correctly, when you removed the intercooler, the problem went away? Even with way higher intake temps? But theoretically with 1 psi or so more boost. Hmm, loose hose clamps maybe? And did you physically remove the BOV? They are guilty of leaking under boost fairly often, though one would think the turbo could overcome such a leak... I haven't downloaded your zip files yet (am at wrong computer), but what is your max boost shown? Is "boost" from the dyno and "MAP" from the MS? Anyways, what I'm getting at is that your wastegate may be sticky. Does this happen when you're first reaching max boost, but smooths out afterwards? If your WG spring is 15lb or about 200kpa, and if 185kpa or about 12.5psi is the max boost you achieve (not counting any boost creep later on), then you may have another issue too. You're losing over 2 psi from the turbo outlet to the intake. Just throwing out ideas here. Hopefully one will help! Quote Link to comment Share on other sites More sharing options...
evildky Posted March 4, 2009 Share Posted March 4, 2009 55 lbs/min seems high for a to4b? a to4e flows 53 lbs/min and if you've ever had then side by side the O4e is noticibley larger, whatever the flow cpacity keep in mind to achieve that flow it's gonna take more than 14psi, honestly for the boost level it sounds pretty decent Quote Link to comment Share on other sites More sharing options...
HB280ZT Posted March 4, 2009 Author Share Posted March 4, 2009 Brady, When you get a chance look at the datalog and msq. They explain things better then I ever could. As for removing the BOV, I have taken it off the car and blocked off the hole with no change in the problem. Also when you see the datalog I have not gotten to full boost when this all happens. All of the numbers provided are from the datalog as the dyno did not tap for vacuum/boost. As for boost creep I fixed that problem a few months ago by getting the waste gate hole matched to the WG puck, now no more creep. Harry aka HB280ZT Quote Link to comment Share on other sites More sharing options...
bradyzq Posted March 4, 2009 Share Posted March 4, 2009 Harry, I'll look at the logs soon. It's too late now, but I suggest that one ALWAYS log MAP and AFR on the dyno. It only takes a couple of minutes longer to set up, and maybe a couple of bucks more, but it should give you confirmation of your numbers at the very least. That, and you have two sets of eyes looking at these valuable numbers during the runs. It's just one extra safeguard. BTW, this is what I do for a living. I tune on a Dynapack dyno. I don't have huge amounts of experience with MS, though I just built one for one of my old Audis, and have tuned a few for customers. I guess that MS experience will shoot up soon though! Quote Link to comment Share on other sites More sharing options...
HB280ZT Posted March 4, 2009 Author Share Posted March 4, 2009 The AFR numbers were close to the same as I had but like I said they did not do any MAP readings. Will have to see if they can next time. Thanks for the help. Harry Quote Link to comment Share on other sites More sharing options...
HB280ZT Posted March 4, 2009 Author Share Posted March 4, 2009 evildky, The 55 lbs/min was the infromation that James Thagard gave me when I got the turbo from him. He also said it was a Hi/Fi wheel which I have never been able to get a map for, so I am guessing that the wheel is really a 60-1 and is not that large compared to other people are running on a Z. Harry Quote Link to comment Share on other sites More sharing options...
bradyzq Posted March 4, 2009 Share Posted March 4, 2009 Harry, I just looked at the first datalog, and the only suspect thing I see so far is that your battery voltage drops below 13V right around the time the problem starts. May be coincidence, but later on in the run, the voltage drops into the LOW 11's!! Something is up here. Is your alternator good? Loose belt perhaps? All EMS's like/need good constant voltage. A lot relies on a good 5V sensor reference, MAP sensor included, or 12V for actuators like fuel injectors. They'll open more slowly when underpowered. I know there is a voltage compensation bin in the MS to take care of this, but it's REALLY not ideal to be running using it. I'm not saying this is the problem, but definitely fix the voltage issue now, because it may be causing other issues. Quote Link to comment Share on other sites More sharing options...
HB280ZT Posted March 4, 2009 Author Share Posted March 4, 2009 Brady, I had to replace the alternator about 3 weeks ago and have noticed the voltage change as the car gets hot. But when it is checked by the auto store (lifetime warranty) it always passes because it never gets hot on the test bench. So I am working on the alternator problem. As for it causing the problem not really sure as it did it with my last unit and I had it on the car for about 5 years. Also it does this at about the same point on all the runs I did on the dyno except with we did a 3rd gear run. The 3rd gear run was just to fast and it did not show much on the datalog or the dyno sheet. Now the 4th gear run loads the engine up pretty good and we get alot of information, and the problem also! Harry Quote Link to comment Share on other sites More sharing options...
bradyzq Posted March 5, 2009 Share Posted March 5, 2009 Harry, Well, maybe it's bad grounds. After all, it's a voltage difference that we're measuring. Do you know if the voltage across the battery agrees with the MS? I suppose I should have suggested checking grounds first, since in the Megamanual, they beat it to death. I looked at the the second datalog, and the same thing is true. Most of your dyno pull is at under 13V. Even while idling after, most of the time the voltage is way too low. Oh, yeah, I assume your O2 and EGT are just not hooked up to the MS since the numbers make no sense. Back to the wastegate. On both datalogs, the boost "bounces" twice, once a lot, and the second time a lot less. And it happens the first time the boost hits 185ish kpa. It's only 7-8kpa or 1psi away from max boost on the datalog. The wastegate may very well be starting to open by then. Are you SURE your wastegate is not sticking (not able to close again fast enough) a bit? Or maybe your boring out of the wastegate has made it less progressive? Quote Link to comment Share on other sites More sharing options...
HB280ZT Posted March 5, 2009 Author Share Posted March 5, 2009 Brady, I have checked all of my gounds and they were good to go, I even added extra ground connections when I setup my new wiring with the MS install. So that being said I will check them again. Here is my wiring setup. As for the wastegate opening early that maybe happening as I am running the WG off of the output of the turbo and the MAP sensor is manifold pressure. So maybe I should try to run both off of the manifold again. I have been using both to fix the same type of problem but only under part throttle. So I may have to change that and do another dyno run to see what happens. So anything else I should try? Have you looked at the msq to see if anything looks screwy? Thanks for the help and to make me think! Harry Quote Link to comment Share on other sites More sharing options...
bradyzq Posted March 5, 2009 Share Posted March 5, 2009 Harry, Haven't looked at the msq because I don't have Megatune on this computer (Mac). Good idea on replumbing the WG signal to the intake. In theory, if the issue is the wastegate fluttering, it should happen about 1 psi or so higher up. All along, I've understood that the miss/stumble WAS the drop in boost. To confirm, does the car do anything other than have uneven power delivery for a second? Is there a real miss, as in a cylinder not firing? Also, do you have AFR logs somewhere, or were you watching a gauge? And what is Column I, labelled "Engine" in the datalogs? Whenever it is not "1" there is some TPS accel enrichment, even though TPS is 100. For the dyno, you can completely turn off TPS accel enrichment. Quote Link to comment Share on other sites More sharing options...
bradyzq Posted March 5, 2009 Share Posted March 5, 2009 Found out what "engine" is. It's just an 8 bit "code". 17, which shows up in your datalogs, means the engine is running (1), and TPS enrichment is active (16). Quote Link to comment Share on other sites More sharing options...
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