Cold weather boost spike issue

So I read that cold weather can cause boost spike. It's been around 40-50 here and lately I have seen my boost spike at about 20 psi. My target is 18 and I removed about 7% wgdc over time but, it hasn't done a bit of good to resolve the issue. I'm also running a 1mm pill. Do I have to adjust more than just WGDC? Should I use a lager pill? I'd rather not have to load a summer and winter map.

are you knocking? i was under the impression that if you're not knocking, the higher boost that you see during the winter is just fine.

A little. Ive been tuning that out, but fuel cut is annoying. I guess I could just raise the limit, but a 2 psi spike seems pretty excessive and I'd rather deal with the real issue.

Try a 1.1 - 1.2mm pill for a VF40. Then adjust your WGDC accordingly.

did you try adjusting the air temperature correction map for the WGDC?

No I'm using a mickeyd's stage 2 base map setting for that which is the same as his stage 1 so I assumed it was OK. Good callI'll play with that table and see what happens.

Can we see a log of the spike?

 

If it is happening at very low rpm (like 3200 rpm or so) then it is likely the WGDC table.

 

Many people put very high values in the low rpm ranges (like 90s) in the mislead hopes that it will help spool, then they taper it down when the turbo starts to spool. The thing is, the rpm where it starts to spool changes depending on temp.

 

If the WGDC table is very smooth from low to mid-rpm, then look at the IAT WGDC comp table.

 

If you do a log, then log:

 

-rpm

-wgdc

-td pro

-td int

-IAT

-MRP

No I'm using a mickeyd's stage 2 base map setting for that which is the same as his stage 1 so I assumed it was OK. Good callI'll play with that table and see what happens.

 

You need to adjust the WGDC IAT compensation table.

 

IIRC, that map uses the stock compensation table. It was never set up for low temperatures.

Can we see a log of the spike?

 

If it is happening at very low rpm (like 3200 rpm or so) then it is likely the WGDC table.

 

Many people put very high values in the low rpm ranges (like 90s) in the mislead hopes that it will help spool, then they taper it down when the turbo starts to spool. The thing is, the rpm where it starts to spool changes depending on temp.

 

If the WGDC table is very smooth from low to mid-rpm, then look at the IAT WGDC comp table.

 

If you do a log, then log:

 

-rpm

-wgdc

-td pro

-td int

-IAT

-MRP

 

Yes, boost threshold does change with temperature.

 

However, the max WGDC may be in the 90's but the WGDC initial is very low. This combined with the boost target can control overboost. As temperatures drop, the ecu will hit boost target lower.

 

You can control it with WGDC IAT compensation table. The only drawback is that there will be a little dip at about 2400-2500 rpm when the WGDC drops suddenly as it hits the boost target.

Yes, boost threshold does change with temperature.

 

However, the max WGDC may be in the 90's but the WGDC initial is very low. This combined with the boost target can control overboost. As temperatures drop, the ecu will hit boost target lower.

 

You can control it with WGDC IAT compensation table. The only drawback is that there will be a little dip at about 2400-2500 rpm when the WGDC drops suddenly as it hits the boost target.

 

 

I understand that. I have seen many ROMs that also have initial WGDC at 90% in low rpms.

Sorry to threadjack OP.... Hey LBGT... if I get a tune, would I be best to wait until temps are a bit better? You know we have been -20degrees C and lower since beginning of DEC.

 

I mean if I do a log right now, with IAT at like -20c and tune based on those logs, then +30c hits in the summer, am I gonna run like shit?

 

Likewise if I tune in the summer will it majorly affect my running in the winter?

 

Thx

I am having the same issue...my tune was during early fall. Now that it is middle of winter, I am over boosting by 1.5 psi. My e-tuner sent me a winter map. I dont understand why the temperature compensation table can not be adjusted. Maybe it is my Grimmspeed EBCS? Anyways, looks like I will be switching out maps during the winter.... if anyone can explain in simple laymans terms, please post....

Can we see a log of the spike?

 

If it is happening at very low rpm (like 3200 rpm or so) then it is likely the WGDC table.

 

Many people put very high values in the low rpm ranges (like 90s) in the mislead hopes that it will help spool, then they taper it down when the turbo starts to spool. The thing is, the rpm where it starts to spool changes depending on temp.

 

If the WGDC table is very smooth from low to mid-rpm, then look at the IAT WGDC comp table.

 

If you do a log, then log:

 

-rpm

-wgdc

-td pro

-td int

-IAT

-MRP

 

You need to adjust the WGDC IAT compensation table.

 

IIRC, that map uses the stock compensation table. It was never set up for low temperatures.

 

It happens any time I go WOT in the 2800-4000 RPM range. I'm going to put my WGDC back to where they were and try the compensation table. I'll try to post some logs tomrrow.

You can tune in any weather. But (especially in our case in Winnipeg) the car should be logged in the other extreme of temp and possibly some things need to be tweaked.

 

My car can run on its tune in any weather.

OK I set my WGDC back to what it was and adjusted the WGD Compensation. My first two 3rd gear runs seem to be OK. On the way home I did a couple up hill logs in 2nd and 3rd and both times fuel was cut. I looked at the logs, but I didn't see any overboost. Nothing that looked bad anyway. My target is 18 psi from 2800-4000 rpm I can post my ROM if needed. Also is there anything I can do to make my boost more consistent? It always seems to oscillate about 1.5 psi.

 

My mods:

VF46

1mm pill

Perrin TMIC

AVO catted DP

Perrin Crank Pulley

logs.zip

I would change the TD integral cumulative max back to 15% (stock).

 

I would also lower the slope of the TD integral curve.

Ok I'll adjust the TD Integral curve, but TD integral cumulative max was already 15%. Should I do somethig else with that feild? Here is the rom I used for those last logs.

 

http://www.box.net/shared/hiqba1lux3

That is really weird. Your TD integral cumulative increased all the way to 20% in your logs. I don't think I have ever seen it exceed the value in the rom.

I wasn't able to get any 2k-6k logs, but hopefully there is some useful data. I decreased the slope of the TD integral - & + and reduced TD proportional to 15 in the 5 psi column. It appears that boost control disable is kicking in, but the log never showed any FLKC or IAM drop at all. Is it possible that the incident was just missed in between pulling other data? I thought if IAM dropped it took at least a couple of seconds or more to go back to 1. The other log looks like a boost leak, but I did a pressure test several times since this has been happening and never found anything. Could I have a bad BCS? The time of the incidents are part of the file names. Also boost control disable delay is set to 1.

Logs 2.zip

I made a mistake in reading your logs the first time. I confused TD proportional and TD integral cumulative.

 

Change your tD proportional back to 20 in the 5 psi column. Then flatten the slope of the TD proportional curve in the region outside the 5 psi column.

 

The current slope of TD integral looks okay.

 

You are simply overboosting. That's causing the fuel cut.

 

You have about 5% too much WGDC at peak boost. This is really not cold temperature related since your IAT is about 63 degrees. I think you need to reduce WGDC initial at 2800-3000 rpm by about 5%.

Two more 3rd gear runs. I lowered WGDC by 4% at 2800 and tapered up from there. I also changed the IAT compensation back to what it was before and bumped boost in the 2800-4000 range to 18.1 from 18.

romraiderlog_20100108_123404.csv

romraiderlog_20100108_123430.csv

That looks pretty good except for the slight oscillation between 3600 and 4200 rpm.

 

Use TD integral cumulative as a guide. It should be relatively stable after boost is achieved. Notice the TD integral dips by about 1 to 2 percent between 3600 and 4200 rpm. This means the WGDC initial is too high by about 1 to 2 percent in this region.

Awesome, thank you so much for your help.

Use TD integral cumulative as a guide. It should be relatively stable after boost is achieved.

 

All the way to red line? Also how do you determine if any changes need to be made to TD cumulative and or integral?

Near redline, you can let it go. However, if you see TD integral cumulative go up and down like it does between 3600-4200 rpm, you should fix that.