[shushikiary]

So I've been lurking on here for a while but havent posted.

I am running an E30 mix with cob E30 map, FBO, but I'm at 5280' altitude, I was was comparing our data logs. I dont have any issues with my LPFP as mine stays above 60 psi the entire time, I did have a few timing corrections but I think that's because my E30 mix was closer to an E28 mix and I've sense upped it to E35 and need to re-do some logs, but I noticed a 1 psi overboost as well as compared to older logs I've seen my high RPM boost is not only 3psi lower than the requested, but my requested is lower than other people using the COBB E30 map than I've seen. For some reason my requested is 27 mean psi and at high RPM I'm 3psi lower were as others seem to only be 2 psi lower.

It appears I have some very minor over boost (about 1 PSI) but I suspect that is small enough to not worry about. The over boost happens in the mid range about 3500 to 4500 RPM, but then something strange happens. Note that my peak boost is only about 17.3 PSI but I believe that is due to the altitude. My FMIC also has trouble keeping up at this altitude (and combined with DCI so my charge air temps start out about 90 (on an 80 degree day) and climb to about 140 by redline 4th gear).

Is the lower boost request and the larger difference between the requested and actual expected at altitude or do I need to adjust the tune's WGDC to keep the boost higher, OR is that pushing the turbo too far beyond its efficiency map at this altitude so I should just leave it? Do I need to modify the tables to reduce the overboost (I suppose I should grab a data log that maps if I'm having throttle closures or not)? Maybe I need to replace the waste gate solenoids?

I guess the most unsettling is why my requested boost is 3 psi lower at high RPM than other E30 map users I've seen.

Here is the data zap:

http://datazap.me/u/shushikiary/ost-...14-15-16-17-18

Thanks! Also note that ambient PSI up here is about 12psi, not 14.4 or so like it is at sea level, so you can just subtract about 12 from the boost mean absolute to get the "boost" psi.


Update: I did some more reading, seems even a 1 psi overboost is too much and can cause throttle closures, so I should get a lot looking at that. Based on other logs I've looked at I should pull some DC from my log in that middle RPM range to prevent the overboost and then increase the DC at high RPM due to dropping too far below boost target. Most people only drop 2 psi below boost target seems above 6k RPM I drop 3 psi, but I dont know if I should do that given the altitude or what. I also still dont know why my requested boost is still 3psi lower than other e30 map logs I've seen.

[Give_Em_The_DD]

Are you running an OTS map OP? Besides elevation issues, a custom tune can/will help you sort a lot of those issues out.

There are a lot of good guys on here, that know about 10000x more than me I'm sure they will chime in soon

[Ingeniator]

Originally Posted by shushikiary

So I've been lurking on here for a while but havent posted.

I am running an E30 mix with cob E30 map, FBO, but I'm at 5280' altitude, I was was comparing our data logs. I dont have any issues with my LPFP as mine stays above 60 psi the entire time, I did have a few timing corrections but I think that's because my E30 mix was closer to an E28 mix and I've sense upped it to E35 and need to re-do some logs, but I noticed a 1 psi overboost as well as compared to older logs I've seen my high RPM boost is not only 3psi lower than the requested, but my requested is lower than other people using the COBB E30 map than I've seen. For some reason my requested is 27 mean psi and at high RPM I'm 3psi lower were as others seem to only be 2 psi lower.

It appears I have some very minor over boost (about 1 PSI) but I suspect that is small enough to not worry about. The over boost happens in the mid range about 3500 to 4500 RPM, but then something strange happens. Note that my peak boost is only about 17.3 PSI but I believe that is due to the altitude. My FMIC also has trouble keeping up at this altitude (and combined with DCI so my charge air temps start out about 90 (on an 80 degree day) and climb to about 140 by redline 4th gear).

Is the lower boost request and the larger difference between the requested and actual expected at altitude or do I need to adjust the tune's WGDC to keep the boost higher, OR is that pushing the turbo too far beyond its efficiency map at this altitude so I should just leave it? Do I need to modify the tables to reduce the overboost (I suppose I should grab a data log that maps if I'm having throttle closures or not)? Maybe I need to replace the waste gate solenoids?

I guess the most unsettling is why my requested boost is 3 psi lower at high RPM than other E30 map users I've seen.

Here is the data zap:

http://datazap.me/u/shushikiary/ost-...14-15-16-17-18

Thanks! Also note that ambient PSI up here is about 12psi, not 14.4 or so like it is at sea level, so you can just subtract about 12 from the boost mean absolute to get the "boost" psi.


Update: I did some more reading, seems even a 1 psi overboost is too much and can cause throttle closures, so I should get a lot looking at that. Based on other logs I've looked at I should pull some DC from my log in that middle RPM range to prevent the overboost and then increase the DC at high RPM due to dropping too far below boost target. Most people only drop 2 psi below boost target seems above 6k RPM I drop 3 psi, but I dont know if I should do that given the altitude or what. I also still dont know why my requested boost is still 3psi lower than other e30 map logs I've seen.

I'm assuming your AT based on the crappy timing post shift. As for the tune. It looks pretty good. I would double check your vac lines/boost solenoids/waste-gate actuators/waste-gates etc. You more than likely are not getting enough vacuum at the waste gate solenoid to get full closure causing the turbo to overwork. Likely why your IAT is up there also.

Also it is generally a good idea to post mods and car type in these type of threads.

EDIT: I'm fairly sure it is the above but wanted to remind you to check the pressure side of the system for leaks. Intercooler BV/DV and throttle-body connection. Also check for cracks if your still OEM charge pipe.

[shushikiary]

I'm actually a 6mt. I don't shift super fast though because I still have the clutch delay valve and if I shift really fast it likes to grind. I have the vrsf 5" fmic and downpipes with bms dci, running Cobb ost e30 map standard throttle. I'm on the stock charge pipe but I don't have any boost leak codes and everything looks fine, memorial day weekend I just replaced the ofh gaskets so that's when I checked that and I replaced all the vacuum lines with silicone then as well. So I'm going to bet that either the solenoids are getting tired or maybe the diverter valves are leaking?

Wouldnt I be able to hear it if there was a vacuum leak or a boost leak even if I'm not throwing a code? I don't have the tools to do a boost leak test and I should get a vacuum gauge and a tee so I can test the vacuum. Most likely sense I was just in there I suspect it's what I mentioned above.

Should I not back out any dc on the wgdc unless I see throttle closures on my next log?

Also no any ideas why my requested boost is 3 psi lower than other logs I've seen?

Oh and thanks!

[Ingeniator]

Originally Posted by shushikiary

is suspect I'm actually a 6mt. I don't shift super fast though because I still have the clutch delay valve and if I shift really fast it likes to grind. I have the vrsf 5" fmic and downsides with bms dci, running Cobb ost e30 map standard throttle. I'm on the stock charge pipe but I don't have any boost leak codes and everything looks fine, memorial day weekend I just replaced the ofh gaskets so that's when I checked that and I replaced all the vacuum lines with silicone then as well. So I'm going to bet that either the solenoids are getting tired or maybe the diverter valves are leaking?

Wouldnt I be able to hear it if there was a vacuum leak or a boost leak even if I'm not throwing a code? I don't have the tools to do a boost leak test and I should get a vacuum gauge and a tee so I can test the vacuum. Most likely sense I was just in there I suspect it's what I mentioned above.

Should I not back out any dc on the wgdc unless I see throttle closures on my next log?

Oh and thanks!

The throttle closures where likely the knock. If you upped the octane re log and check. You can try upping the wgdc at the top end but you should be a little closer to target over the rev band. It might not hurt to increase it up top though. I believe it is just a max limit not a minimum anyway. I still have some things to learn with cobb tuning. Have you adjusted the scalers your fueling looks good and that is the normal issue with the OTS e30 maps

[shushikiary]

Given this was the e30 map I figured the scalers were fine sense I'm running e30 so I haven't touched them. I think I was just a little lean on the ethanol.


Here is a new log running E35 instead of E30, cleaned the timing up beautifully, no throttle closures even with the over boost, so I dont think I'll back out any DC. I still dont get why my requested boost is 3PSI lower than every other E30 log I have ever seen, it must be adjusted for altitude or something.


http://datazap.me/u/shushikiary/e30-...3-4-8-10-11-12

I also looked at my previous data logs and even before I replaced all the vacuum lines with silicone nad I see that my boost drops from the requested at high RPM more than I'd like matching what we are seeing currently. That seems to suggest I didnt add or remove any vacuum leaks with the work I did so that's nice at least. I suspect tired solenoids (the car does have 70k miles on it and all have been here at altitude) Interestingly my boost setpoint factor doesnt move around hardly at all during the run.

Also, on the timing dropping after the shift, I suspect its because when I shift I take my foot off the throttle perhaps? I know some people just mash the pedal the whole time even while shifting... I like to be a little kinder to my clutch than that.

I also noticed that in 4th gear my requested boost to actual boost delta is only 2psi, but for some reason in 3rd gear its 1 psi larger than that... even though the requested boost is exactly the same per RPM... so why the heck cant I make boost under a lighter load?.... I think that lines up with the waste gates not closing as much as they shoot... higher load lets the turbo spinup more to make up for the waste gate not fulling being closed... also explains the large amounts of heat in 4th gear. I'll have to vacuum test....

[shushikiary]

I did a series of vacuum tests after reading several other threads. I dont have any vacuum leaks and I tested both my WGA's, one is right on spec only 5.9mmHg to close, the other took almost 7mmHg to close, but that's only off by 1psi. No cracks on the charge pipe either. I did find one interesting thing though, of the two vacuum lines that go to the boost solenoid tanks one was clogged, which would mean that only 1 of the solenoids was actually pulling on the WGA's, and though they work in tandem I have a feeling that at high WGDC they trade off one out of phase with the other by 180 deg so that you have a constant vacuum on the WGA's. Given that, this might explain the problem of the slightly larger drop off at high RPM and high intake temps (most likely also compounded with poor cooling due to very dry high altitude air). I also did a pressure test on the inlet side of the solenoids, they say its supposed to hold a vacuum and mine rather quickly let all the vacuum out (per this thread: http://www.e90post.com/forums/showthread.php?t=734645 ) so I suspect they also should be replaced. I also keep randomly throwing both intake and exhaust vanos codes so need to replace those too.

The clog will require me to order part number 11666769086 as the part that is clogged is the tiny outlet port (1 of two) on him.

Still doesnt explain the low requested boost however.

[Ingeniator]

Well looks like your on the right track. If this doesn't take care of it post up some more logs. As for target boost not being higher. I think the issue is your not meeting current set point. As a result the DME is not increasing it to meet the load target. I have a feeling it will be working better once you get your boost control system fixed.

[shushikiary]

Hmm I also found this interesting thread... looks like at high RPM high altitude our little snails just plain have trouble, max PSI he could get at redline was 14 psi and that's 100% WGDC... not sure I want to know how much heat he made doing that, wouldnt surprise me if it really is getting outside the efficiency map.

http://www.e90post.com/forums/showthread.php?t=715089

Note that he also has issues hitting target like I do, I also see that I cant hit much above 160 load.... maybe it really is just the nature of the beast at altitude playing in here as well.

I also FINALLY found a thread with some good altitude guys running similar things (and some same maps)... they have the SAME issues as me, 12 psi at redline, reduced requested boost, reduced requested load, almost never going above 160 actual load... looks like it really is just the name of the game..... sad panda, altitude is the devil.

http://www.e90post.com/forums/showthread.php?t=940016

[Ingeniator]

@07tundra was making good boost once he got his boost control figured out. You won't make as much power on the same octane as flatlanders but you can still get 18/19 in mid range tapering up top to 15/16

[shushikiary]

Pulled and tested stock diverter valves, they held back 22psi with only 15psi on the vacuum port (note that's positive pressure as the boost in the intake manifold helps keep the diverter valves closed as boost is building so its a nice feedback loop). So they are working great.

Waiting for the boost solenoids to come in and then I'll install those and re-data log with the clog also fixed.

[07tundra]

Originally Posted by Ingeniator

@07tundra was making good boost once he got his boost control figured out. You won't make as much power on the same octane as flatlanders but you can still get 18/19 in mid range tapering up top to 15/16

I was able to get 18.5 and make good power with RBs. I did get somewhat of custom tune from Terry which was awesome for him to do,

shushikiary have you tried running some e85? On map 7 I was able to it about 16psi

[shushikiary]

Yes I'm currently running E35, so I mix 4 gallons of E85 to 8 gallons 91 (cant really get 93 around here) octane which is 10% ethanol so it comes out to E35 (or 35 % ethanol in mix). The first data log is on about E28 and the second one is on E35.

Straight E85... looking at my LPFP I think it might survive or I could add a second inline pump and then run the cobb race map with adjusted fuel scalars, but honestly I think E35 is good enough and I dont want to worry about what concentrations over E50 do to the fuel system.

On the current cobb E30 map I will typically spike into the low 17's for pressure in the mid range, but I consistently hit at least 16.5 on the stock turbo's. I believe from everything I've been looking at that the DME really does reduce the requested load based on altitude to help keep the turbo's in their efficiency island... I cant prove it, but the other threads I've ready seem to support that hypothesis. I could go poke around in the WGDC tables and force the little guys to make more peak boost and also hold more boost at high RPM but I suspect the heat I would cause due to moving out of the efficiency island would make the turbos die much sooner, then again I guess I could use that as an excuse to get RB's .

I'll replace the boost solenoids and re-log on same map, if the boost doenst change I'll most likely just leave it and chalk it up the altitude, and then do some data logs when I'm at sea level sometime to verify, then someday RB's. Altitude is just a SOB.

I have also been doing some data gathering on the BMS DCI I run. I put a temperature sensor that dangles between both the air cones to get an idea of what the temp they are sucking in looks like under my daily driving. The last week it has been in the 80's each day and I find in the garage it starts up about 80 deg F under the hood and after 30 miles of highway driving its a consistent 130 to 140 deg F. This causes the intake temp to start out in the mid 80's and rise to a about 100 or so once I hit 130 under the hood (air temp). I know there has been lots of talk about scoops so I ordered a pair and I'll put them in and do the same data loging with in them in to see if it really does reduce not only my air temps right at the intake, but also my measured intake temp, I'm hoping that it will help with the stupid hot temps in 4th gear pulls... also thinking about heat wrapping my DP's.


Also! Just heard back from Cobb, they also suspect that the lower requested boost and lower requested load is due to the DME compensating for altitude, so makes me even more confident, though they definitely said to replace the solenoids sense they dont hold pressure on the inlet side, parts are already ordered. They also said that the high intake temperatures are expected under longer pulls like that and that they were nothing to worry about and that on the stock FMIC they see intake temps rise to 180 deg on their dyno many times.... I'll still be upgrading to the VRSF stepped FMIC when it comes out and try out the hood scoops to see if I can lower those numbers.

[shushikiary]

I have also been doing some more digging on the WGDC base map, downloaded access tuner and took a gander...

So my boost setpoint factor (which I'm learning is really the same thing as the pressure ratio on the turbo efficiency maps) is off the chart. Chart goes to 2.4, I'm at 2.54... makes sense due to altitude. Chart also only goes up to a requested WGDC (in gs) of 333 but I'm way above that almost to 500 by redline. So I'm not just "off the chart" I'm off the chart by more than 1/3 of the charts total size.

I dont know if the DME takes this table and just extrapolates beyond it if it does not have an intersecting entry, I mean I can derive that it extrapolates rather linearly between each entry that does exist, but if you're off the table I'm not sure maybe it just uses the last value.

Given that, I'm not sure exactly how I would modify this table to get more boost at high RPM at this altitude, further, given that I know that boost setpoint factor is the pressure ratio it supports my fears that trying to pull more boost at high RPM would push the turbos uncomfortably off their efficiency island and generate a TON of heat among other issues (significantly shortened turbo life).

I've asked cobb about this, we'll see if they are kind enough to answer the question ( given that its effectively self tuning I dont expect them to be so kind as to answer the question).

[shushikiary]

Parts came in, installed all of it and did another log.

Same results really, though the over shoot on the boost is more controlled with the new solenoids. Something interesting is that the ambient temp really didnt seem to have a large effect on the charge air temp.... still got into the 140's at redline in 4th gear. I will say that during highway driving those scoops really do lower the temp around the DCI, it kept it around 100-120 rather than the 130-150 I've been seeing, but in city driving the temp still stays as high as it used to be. The charge air temp drops a good 10 deg F because of those scoops if I drive for a few minutes at speed to reduce the temp around the DCI. The data log below was done after I sat at idle for about 5 minutes and the engine bay temp got back up to about 140.

Sense the setpoint factor and MAF requested WGDC are off the chart in access tuner I'm not sure I want to play around with those to try to increase high end boost, and I havent heard back from Cobb, so I'll just leave it as is... altitude is the devil I tell you.

http://www.datazap.me/u/shushikiary/...12-13-14-15-16