I'm working on autotuning and read on the UTI forums that it's easier to tune the mid-range (30-60%) load columns by lowering the boost. I did that and I'm definitely hitting the middle load columns (10psi vs. 17+psi). I just wanted to confirm with some other people that the AFR results are the same, regardless of the boost. It makes sense that the AFRs would be the same, but I want to make sure that once I get the middle load columns tuned under lower boost that the AFRs won't change when I raise the boost.

Thanks!

Geoff

Anyone?

Bueller? Bueller? :p

Confirmed!

Yes. If you log (using UTI) starting with a clean tables file and running very low (I start with wastegate) boost, you will see that you will fill in only certain load columns as you raise boost. I start with a low value across th board in my boost table and run it hard for a bunch of runs. This will give you LOTS of cell hits in the lower and middle load columns. In contrast, if you run a high boost value, you will pass very quickly through the middle columns and fill in the highest load columns quickly with lots of cell hits. I start by running a low boost value, run it until I see 20+ cell hits in that particular load column, raise the boost values 15-20 (depending on your setup), run again until I see the next higher load column fill with 20+ cell hits in each cell, repeating until the cells are all filled in properly. When tuning, I try to use gears 3-4 for longer pulls through the rpm ranges. When finished, you should be able to configure a pretty decent fueling map through UTI, or UTI-Me.

bcblues> THANK YOU! That's great info.

I reset back to the TurboXS Stage 2 map, reset my boost values (310 until peak boost), reduced my boost values by 90% and drove to work.

I'm still hitting the 80% column (@ 14 PSI) with the BCS essentially wide open (80% column at that RPM is 24 in boost map). I presume that's still wastegate boost at that sort of load (factory turbo, standard wastegate)? If I put 0 in my boost map that basically forces the wastegate wide open (once it overcomes the spring), but only so much exhaust can go thru the quarter-sized wastegate, right?

14 psi is not normal stock turbo wastegate boost. What is your gain?

When I am running wastegate (11 psi on my td0618g), I see 11 psi boost and fill the 50 column. I would have to check and see what I have my boost cut value set to, since that governs the spread of your load columns. I think it is 23 psi.

My gain is set to 48.

I think my boost cut is set to 18, but I can't be sure.

You should set your boost cut at or above what you plan to run ultimately as your max boost. Do this before you begin your tuning, as it governs the spread of your load columns. The boost values that correspond to each column will be different, which will effect your maps tremendously. 50 is the normal gain value. Lower values may cause boost spiking, higher values may cause slow spool. If you have a stock boost control solenoid, you should be fine with 48. I have a GMBCS and I run 50. Some with GMBCS have to run higher gains to prevent spiking (like 55-60).

18psi is as high as I'm going to go for the foreseeable future (stock TMIC/turbo). If I change my boost cut do I need to retune all my maps or just the boost map?

I remember seeing the chart in the UTEC manual/Mick's guide for the load columns vs. PSI (based on a cut of 18, I think). I'm still not hitting (nor ever hit) the 100% column. I've got my boost set to 310 on the first page and the first two rows of the second page then tapering down to 240. Does that mean I need to lower my cut? Raise my PSI? When I had tuned the boost (a year ago, maybe) I followed the stage 2 recommendations in the UTEC manual. What the heck do I need to do to hit the 100% column?

I've got the Perrin EBCS. Up until recently it was set to 50, but I dropped it a couple notches.

To aid in mid-range load tuning, can I crank the boost gain way up to slow the boost from coming on?

One concern that I have... what is the max IDC that one should see before they start considering larger injectors? In my recent tuning I've been seeing 95% IDC in some spots and didn't know if it's time to consider larger injectors/bigger fuel pump.

Thanks for all your help!

I have never run an EBCS on a subie, so I cannot help you with that aspect. I would suspect that your trouble hitting the 100% column may stem from that. I would try to disconnect it and see what you log. You can always add it later if necessary, but with the stock turbo, I don't know why you would need it. With the EBCS, your gain may not be linear any more.

As far as IDC, 95% is high. I would look at larger injectors if you plan to up the boost from there at all. However, you want to look at your AFR as well, as you may need to run leaner, which will lower your IDCs.

Having to go under the hood and crank on an ABC was definitely not my idea of a good time (;)) so I decided to go with a more capable BCS.

What % IDC is getting to the point of needing to consider larger injectors? 85%? 90%?

I am not sure, but I think if you are consistently seeing 90+ you should consider it.

I switched to a GMBCS and it works great. No ABC to deal with. Cheaper than an EBCS.

Alright, I'm still not hitting the 100% column so I'm going to try to retune boost. I remember seeing a target boost chart from TXS but for the life of me I can't find it anymore (and I've been searching for about 45 minutes). I should be able to safely hit 17.5psi on my Stage 2 STi, right? And that should be around 4000-4500 rpm, right? What should it taper down to?

Also, I read it's best to tune boost in 5th, but if I can't I should tune in 4th and drop it back a little, right?

Another chart would be preferred. ;)

Thanks!

The stock turbo is flow limited and will naturally taper to 14-15 psi by redline.

But 17.5psi is acceptable around 4-4.5k rpm? Anyone have an old copy of the UTEC manual that has that chart in it?

Some of the older TXS maps saw 17-18 psi, but all the more recent ones see 16 - 16.5, at least in my car.

I have never run an EBCS on a subie, so I cannot help you with that aspect. I would suspect that your trouble hitting the 100% column may stem from that. I would try to disconnect it and see what you log. You can always add it later if necessary, but with the stock turbo, I don't know why you would need it. With the EBCS, your gain may not be linear any more.

Well, I've had a hard time not boosting with the EBCS and the boost map set to all ones (0-30% are ECU, 40-100% are ones), so I dug out my stock BCS and ABC. I disconnected my Perrin EBCS, reinstalled my BCS/ABC, cranked my ABC all the way in (zero turns out) and I am still boosted the exact same with the stock hardware as I am with the EBCS.

WTF? :confused:

Here's my pull log (sorry for the length, 25 lps...)

[TSMP][RPM][PSIG][MAF][TPS][LOD][KN][SNB][SIG][IDC%][IGN][FMVL][BMV][MMV][WBO2][TAFR]
000.00 3172 +6.2 3.4 35 40 0 12.4 15.4 35.5 16.8 +1.7 1 3.4 12.06 12.5
000.08 3190 +6.4 3.4 35 40 0 12.4 15.3 35.0 16.8 +1.6 1 3.4 12.02 12.5
000.09 3212 +6.4 3.4 36 40 0 12.4 15.5 35.6 16.8 +1.6 1 3.4 11.98 12.5
000.19 3241 +6.4 3.4 37 40 0 12.4 15.2 36.1 16.7 +1.4 1 3.4 11.98 12.5
000.24 3263 +6.4 3.4 38 40 0 12.4 15.0 36.8 16.7 +1.4 1 3.5 11.98 12.5
000.28 3272 +6.6 3.4 39 40 0 12.4 14.9 37.1 16.7 +1.4 1 3.5 11.98 12.5
000.36 3269 +6.8 3.4 40 40 0 12.4 14.7 38.3 16.7 +1.4 1 3.5 11.98 12.5
000.42 3280 +6.8 3.4 43 40 0 12.4 14.6 38.5 16.6 +1.4 1 3.5 11.96 12.5
000.49 3291 +7.0 3.4 43 40 0 12.4 14.4 39.5 16.6 +1.4 1 3.5 11.96 12.5
000.53 3294 +7.2 3.4 43 40 0 12.4 14.3 39.4 16.6 +1.4 1 3.5 11.98 12.5
000.60 3311 +7.2 3.5 44 40 0 12.4 14.1 40.4 16.6 +1.4 1 3.5 11.93 12.5
000.66 3319 +7.2 3.5 44 40 0 12.4 14.4 38.9 16.6 +1.4 1 3.5 11.96 12.5
000.69 3326 +7.4 3.5 44 40 0 12.4 14.2 38.8 16.6 +1.4 1 3.4 11.96 12.5
000.77 3351 +7.2 3.5 45 40 0 12.4 14.4 39.5 16.6 +1.4 1 3.5 11.98 12.5
000.82 3369 +7.2 3.5 45 40 0 12.4 14.3 40.3 16.7 +1.4 1 3.5 11.98 12.5
000.87 3372 +7.4 3.5 45 40 0 12.4 14.3 39.8 16.7 +1.4 1 3.6 11.98 12.5
000.91 3384 +7.4 3.5 45 40 0 12.4 14.2 38.8 16.8 +1.4 1 3.6 12.00 12.5
000.99 3390 +7.4 3.5 46 40 0 12.4 14.2 41.6 16.7 +1.4 1 3.6 12.02 12.5
001.04 3393 +7.6 3.5 47 40 0 12.4 14.2 41.5 16.8 +1.4 1 3.6 12.02 12.5
001.13 3412 +7.4 3.5 47 40 0 12.7 13.9 40.6 16.8 +1.4 1 3.6 12.02 12.5
001.16 3405 +7.6 3.5 47 40 0 12.4 13.9 41.7 16.8 +1.4 1 3.6 12.02 12.5
001.23 3426 +7.6 3.5 48 40 0 12.4 14.0 40.9 16.8 +1.4 1 3.6 11.98 12.5
001.25 3447 +7.6 3.6 48 40 0 12.4 14.2 41.3 16.8 +1.4 1 3.6 12.00 12.5
001.32 3458 +7.6 3.5 48 40 0 12.7 14.2 41.4 16.9 +1.4 1 3.6 12.02 12.5
001.38 3462 +7.6 3.6 48 40 0 12.4 14.0 41.7 16.9 +1.4 1 3.6 12.00 12.5
001.42 3473 +7.6 3.6 48 40 0 12.4 14.0 42.5 17.0 +1.4 1 3.6 12.00 12.5
001.49 3480 +7.8 3.6 48 40 0 12.4 14.2 43.6 17.0 +0.9 1 3.6 12.09 12.5
001.59 3494 +7.8 3.6 48 40 0 12.4 14.1 43.1 17.1 +1.3 1 3.7 12.14 12.5
001.64 3517 +7.6 3.6 48 40 0 12.2 14.3 44.3 17.1 +1.3 1 3.6 12.11 12.5
001.71 3541 +7.8 3.6 49 40 0 12.0 14.2 44.3 17.1 +1.3 1 3.6 12.02 12.5
001.76 3555 +7.8 3.6 49 50 0 rich 14.2 46.0 17.0 +1.2 1 3.6 11.89 12.2
001.82 3570 +7.6 3.6 50 40 0 rich 14.0 45.9 17.0 +1.3 1 3.7 11.80 12.5
001.91 3586 +8.0 3.6 51 50 0 rich 14.1 45.3 17.0 +1.1 1 3.7 11.43 12.2
001.97 3590 +7.8 3.6 53 50 0 rich 14.1 44.8 17.0 +1.1 1 3.7 11.28 12.2
002.03 3604 +8.0 3.6 54 50 0 rich 14.0 46.5 17.0 +1.1 1 3.6 11.14 12.2
002.11 3623 +8.2 3.7 56 50 0 rich 13.8 44.8 17.0 +1.0 1 3.7 11.01 12.2
002.17 3630 +8.4 3.7 58 50 0 rich 13.6 47.1 17.0 +1.0 1 3.7 10.96 12.2
002.21 3624 +8.4 3.7 59 50 0 rich 13.4 46.7 17.0 +1.0 1 3.7 10.96 12.2
002.28 3642 +8.6 3.7 60 50 0 rich 13.5 46.4 17.0 +1.0 1 3.7 11.02 12.2
002.34 3669 +8.6 3.7 61 50 0 rich 13.8 48.4 17.0 +0.9 1 3.7 11.05 12.2
002.40 3690 +8.8 3.7 62 50 0 rich 13.6 47.2 17.0 +0.9 1 3.7 11.05 12.2
002.45 3688 +8.8 3.7 63 50 0 rich 13.7 48.2 17.0 +0.9 1 3.7 11.06 12.2
002.50 3689 +8.8 3.7 64 50 0 rich 13.7 50.0 17.0 +0.9 1 3.7 11.08 12.2
002.55 3708 +8.8 3.7 64 50 0 rich 13.1 48.3 17.0 +0.9 1 3.8 11.08 12.2
002.60 3725 +8.8 3.7 64 50 0 rich 13.2 48.9 17.0 +0.9 1 3.8 11.05 12.2
002.66 3730 +9.0 3.8 64 50 0 rich 13.2 48.2 17.0 +0.8 1 3.8 11.02 12.2
002.70 3738 +9.0 3.8 64 50 0 rich 13.1 48.9 17.0 +0.8 1 3.8 11.01 12.2
002.77 3760 +9.0 3.7 64 50 0 rich 13.3 50.1 17.0 +0.5 1 3.7 10.95 12.2
002.82 3759 +9.0 3.7 64 50 0 rich 13.3 51.0 17.0 +0.8 1 3.8 10.90 12.2
002.88 3769 +9.2 3.8 64 50 0 rich 13.5 50.0 17.1 +0.5 1 3.8 10.89 12.2
002.96 3793 +9.0 3.8 64 50 0 rich 13.5 52.9 17.2 +0.7 1 3.8 10.83 12.2
003.03 3801 +9.0 3.8 64 50 0 rich 13.6 52.2 17.3 +0.7 1 3.8 10.83 12.2
003.11 3819 +9.0 3.8 64 50 0 rich 13.5 51.0 17.4 +0.7 1 3.8 10.73 12.2
003.20 3835 +9.2 3.8 64 50 0 rich 13.6 53.1 17.5 +0.7 1 3.8 10.67 12.2
003.26 3844 +9.2 3.8 64 50 0 rich 13.6 52.9 17.3 +0.7 1 3.8 10.64 12.2
003.30 3861 +9.0 3.8 64 50 0 rich 13.7 53.6 17.5 +0.7 1 3.8 10.58 12.2
003.38 3875 +9.2 3.8 64 50 0 rich 13.4 54.0 17.7 +0.6 1 3.8 10.55 12.2
003.45 3888 +9.2 3.8 64 50 0 rich 13.6 53.6 17.5 +0.6 1 3.8 10.52 12.2
003.49 3910 +9.2 3.8 64 50 0 rich 13.6 53.1 17.5 +0.6 1 3.8 10.52 12.2
003.56 3925 +9.4 3.8 64 50 0 rich 13.6 54.2 17.8 +0.6 1 3.8 10.52 12.2
003.62 3924 +9.4 3.8 64 50 0 rich 13.7 52.4 17.8 +0.6 1 3.8 10.52 12.2
003.66 3930 +9.4 3.8 64 50 0 rich 13.8 54.7 17.8 +0.6 1 3.8 10.52 12.2
003.73 3942 +9.2 3.8 64 50 0 rich 13.9 53.2 17.9 +0.6 1 3.8 10.53 12.2
003.77 3952 +9.4 3.8 64 50 0 rich 14.4 52.2 17.9 +0.5 1 3.8 10.52 12.2
003.82 3976 +9.4 3.8 64 50 0 rich 14.6 53.0 18.0 +0.5 1 3.8 10.55 12.2
003.91 3993 +9.4 3.8 64 50 0 rich 14.7 54.9 18.4 +0.7 1 3.8 10.62 12.2
003.98 4008 +9.2 3.8 64 50 0 rich 14.5 52.7 18.2 +0.5 1 3.8 10.65 12.2
004.05 3998 +9.2 3.9 64 50 0 rich 14.8 55.0 18.4 +0.7 1 3.8 10.64 12.2
004.13 3982 +9.4 3.8 64 50 0 rich 14.4 56.4 18.3 +0.4 1 3.8 10.67 12.2
004.20 4006 +9.4 3.8 64 50 0 rich 14.6 55.8 18.3 +0.4 1 3.8 10.67 12.2
004.27 4034 +9.4 3.9 66 50 0 rich 14.9 56.4 18.3 +0.4 1 3.9 10.64 12.2
004.33 4056 +9.6 3.9 69 50 0 rich 14.9 56.8 18.3 +0.4 1 3.9 10.56 12.2
004.40 4071 +9.4 3.8 72 50 0 rich 14.8 56.5 18.2 +0.7 1 3.8 10.53 12.2
004.47 4089 +9.6 3.9 74 50 0 rich 14.8 56.7 18.2 +0.4 1 3.9 10.53 12.2
004.56 4106 +9.6 3.9 82 50 0 rich 14.9 59.5 18.3 +2.0 1 3.9 10.49 12.2
004.61 4112 +9.6 3.9 83 50 0 rich 14.5 59.8 18.3 +0.4 1 3.9 10.52 12.2
004.69 4118 +9.6 3.8 86 50 0 rich 14.7 56.8 18.4 +2.0 1 4.0 10.46 12.2
004.77 4146 +9.6 3.9 88 60 0 rich 14.3 57.4 18.4 +1.9 1 3.9 10.42 11.8
004.84 4144 +9.6 3.9 88 50 0 rich 14.1 61.4 18.4 +0.5 1 3.9 10.39 12.2
004.86 4131 +10.0 3.9 89 50 0 rich 14.3 59.0 18.4 +1.8 1 4.0 10.39 12.2
004.94 4159 +9.8 3.9 88 60 0 rich 13.7 63.9 18.2 +1.8 1 4.0 10.36 11.8
004.98 4177 +9.8 3.9 87 60 0 rich 13.8 61.4 18.3 +1.8 1 4.0 10.33 11.8
005.04 4185 +9.8 3.9 88 60 0 rich 13.7 62.5 18.2 +1.8 1 4.0 10.30 11.8
005.13 4206 +10.2 3.9 88 60 0 rich 13.7 63.4 18.3 +1.8 1 4.0 10.26 11.8
005.18 4213 +9.8 3.9 88 60 0 rich 13.7 63.4 18.3 +1.8 1 3.9 10.24 11.8
005.23 4206 +10.0 3.9 88 60 0 rich 13.7 66.0 18.2 +1.7 1 4.0 10.23 11.8
005.32 4217 +10.0 3.9 89 60 0 rich 13.7 65.0 18.4 +1.7 1 4.0 10.14 11.8
005.38 4247 +10.0 4.0 87 60 0 rich 13.7 64.7 18.3 +1.7 1 4.0 10.14 11.8
005.43 4279 +10.0 4.0 87 60 0 rich 13.7 63.0 18.4 +1.6 1 4.0 10.14 11.8
005.51 4301 +10.2 3.9 87 60 0 rich 13.6 68.7 18.3 +1.7 1 4.0 10.12 11.8
005.59 4324 +10.2 4.0 83 60 0 rich 13.7 66.3 18.2 +1.6 1 4.0 10.09 11.8
005.65 4339 +10.4 4.0 82 60 0 rich 13.6 66.6 18.4 +1.6 1 4.1 10.08 11.8
005.73 4342 +10.4 4.0 81 60 0 rich 13.7 67.6 18.2 +1.6 1 4.0 10.05 11.8
005.79 4322 +10.2 4.0 81 60 0 rich 15.2 68.9 18.2 +1.6 1 4.1 10.04 11.8
005.84 4344 +10.4 4.0 81 60 0 rich 15.0 69.2 18.3 +1.6 1 4.1 10.01 11.8
005.91 4363 +10.4 4.0 81 60 0 rich 12.9 66.4 18.2 +1.6 1 4.0 9.95 11.8
005.98 4388 +10.8 4.0 82 60 0 rich 13.2 69.3 18.3 +1.6 1 4.0 9.93 11.7
006.05 4411 +10.8 4.0 81 60 0 rich 13.1 69.2 18.1 +1.6 1 4.1 9.93 11.7
006.10 4411 +10.8 4.1 81 60 0 rich 13.0 69.3 18.3 +1.6 1 4.1 9.92 11.7
006.17 4417 +10.4 4.0 81 60 0 rich 13.1 69.2 18.2 +1.6 1 4.1 9.87 11.7
006.23 4420 +10.8 4.0 81 60 0 rich 13.2 69.9 18.3 +1.6 1 4.1 9.90 11.7
006.26 4415 +10.8 4.0 81 60 0 rich 13.1 68.8 18.4 +1.6 1 4.1 9.92 11.7
006.34 4445 +10.6 4.0 81 60 0 rich 13.1 71.5 18.3 +1.6 1 4.1 9.92 11.7
006.40 4452 +10.8 4.0 81 60 0 rich 13.1 71.2 18.3 +1.6 1 4.1 9.95 11.7
006.48 4468 +11.0 4.0 81 60 0 rich 13.3 72.1 18.4 +1.6 1 4.1 9.95 11.7
006.53 4472 +10.8 4.0 81 60 0 rich 13.3 71.6 18.2 +1.6 1 4.2 9.93 11.7
006.59 4493 +11.0 4.1 81 60 0 rich 13.4 71.4 18.4 +1.6 1 4.1 9.98 11.7
006.69 4503 +10.8 4.0 80 60 0 rich 13.5 73.7 18.4 +1.6 1 4.1 9.98 11.7
006.77 4514 +11.3 4.1 80 60 0 rich 13.5 71.3 18.3 +1.6 1 4.1 9.95 11.7
006.82 4532 +11.3 4.1 80 60 0 rich 13.5 71.3 18.5 +1.7 1 4.1 9.95 11.7
006.87 4546 +11.3 4.1 80 60 0 rich 13.4 73.4 18.5 +1.6 1 4.1 9.96 11.7
006.94 4570 +11.3 4.1 81 60 0 13.3 13.7 76.1 18.5 +1.5 1 4.1 9.96 11.7
006.99 4581 +11.3 4.1 80 60 0 13.3 13.5 73.6 18.4 +1.6 1 4.2 9.93 11.7
007.05 4576 +11.3 4.1 80 60 0 rich 13.7 74.8 18.6 +1.7 1 4.1 9.95 11.7
007.14 4583 +11.7 4.2 80 60 0 rich 13.6 74.5 18.6 +1.7 1 4.2 9.92 11.7
007.19 4593 +11.5 4.2 80 70 0 rich 13.7 77.4 18.6 +1.7 1 4.2 9.90 11.3
007.29 4598 +11.7 4.1 80 70 0 rich 13.5 79.1 18.6 +1.9 1 4.2 9.86 11.3
007.37 4606 +12.1 4.1 80 70 0 rich 13.5 79.1 18.6 +2.0 1 4.2 9.84 11.3
007.43 4640 +12.1 4.1 80 70 0 rich 13.9 81.3 18.9 +2.0 1 4.2 9.76 11.2
007.47 4656 +12.3 4.1 80 70 0 rich 13.8 80.2 18.7 +2.0 1 4.3 9.68 11.2
007.57 4663 +12.3 4.2 80 70 0 rich 13.4 82.6 19.0 +1.9 1 4.3 9.62 11.2
007.62 4705 +12.5 4.2 80 70 0 rich 13.5 86.8 19.0 +1.9 1 4.3 9.56 11.2
007.67 4697 +13.1 4.2 73 70 0 rich 13.6 84.4 18.9 +1.9 1 4.3 9.54 11.2
007.76 4689 +13.1 4.2 57 70 0 rich 13.6 85.6 19.1 +1.9 1 4.3 9.48 11.2
007.81 4698 +13.1 4.2 46 70 0 rich 13.6 85.8 19.1 +1.9 1 4.3 9.48 11.2


So what the heck do I need to do to run lower boost? Isn't wastegate something like 7 psi? Should I be able to stay at 7 psi all the way to redline?

Oh, yeah, I still haven't tuned fuel quite yet. ;) Can you say "oink oink"?

Any ideas with what boost I should be hitting with my boost map on one and my ABC turned all the way in? Identical results with my Perrin EBCS.

Bumpity. Hit 15psi coming home tonight doing a 4th gear pull. ABC all the way in and boost map set to all ones.

Under the recommendation of a reliable source, I hooked a plain hose between the boost side and the wastegate and had the exact same results, so both BCSs are working properly and it's simply boost creep. I hadn't even thought about that. For some strange reason I thought boost creep was different. Unless I port the wastegate I'm stuck with it. I'm okay with that, as long as I know what's going on.

Now, anyone happen to find that Stage #/PSI chart showing how much boost I should be running (Stage 2... TBE/CAI)?

One thing I noticed in your log is that your throttle never shows you actually flooring the accelerator. I assume that you were.

Boost creep is when the turbo wastegate cannot keep up (physically flow enough) to prevent the boost from rising above your target. So what you see is a spike in boost psi and then the natural taper as the turbo (the stock one anyway) becomes flow limited. So, if you are targeting 17 psi, in a roll on (flooring the accellerator in 4th gear from say 2500 rpm) you would see the stock turbo settle into 17 psi quite quickly (before 3000 rpm), then you would see it climb (boost spike) as the wastegate is unable to flow enough to prevent boost from rising. This normally happens at about 5000 rpm. Then, if you don't lift (if the boost spike is not too high), you will see the boost naturally taper off again as the turbo's flow capacity is exceeded. Is that the pattern you are seeing?

Please check all of your hoses, especially the ones from your BCS. The local dealer (who is usually pretty good at wrenching), was not used to seeing a GMBCS and switched two of the hoses when they installed my new motor. It caused SEVERE boost issues (hitting boost cut - 24 psi - at 3000 rpm).

By running a hose from your wastegate to your turbo compressor nipple, you will force your turbo to attempt to run whatever psi the wastegate spring dictates (stock about 8 psi). Then you will see if you have boost spike issues (if you still see the spiking above wastegate spring pressure), or if it is a BCS/hose issue (if the turbo runs solid, steady wastegate spring pressure).

My TPS is calibrated in UTEC, so according to the log I must not have had it to the floor.

I was seeing the the boost taper slightly towards the end of my runs, just like it does normally. I hooked my EBCS back up yesterday after work so the hoses are all good.

I know you can get the wastegate ported (or a larger one installed) but aside from the load tuning that I'm doing right now I don't know why that would be necessary. The boost produced that the wastegate isn't passing is still less than my target boost, so I don't know the benefit to modifying the wastegate (unless I want to run 8psi up to redline). Any opinions on that?

Yeah, that is what I thought form your description. It does NOT sound like boost creep to me at all. Sounds like your BCS or your map values to me. Does your EBCS totally replace your stock BCS?

The Perrin EBCS completely replaced the stock BCS. I installed it in interrupt mode, so it is the only equipment between the boost port and wastegate port. There are three ports on the EBCS and you only use two of the three. Which two ports are used is based on which mode you want (fast/interrupt or slow/bleed). I have it setup as fast/interrupt so I have the boost side going to one port, wastegate side going to another port and the third port isn't used. I have capped the port on the intake that the stock BCS hooked into (right after the MAF).

I just checked the thread of the GMBCS install and it looks like it's the same way (boost side to one, wastegate side to the other, no restrictors in the mix).

When I have the EBCS installed (with the boost map set to all 1s) I have the exact same boost being generated as if I connect an unrestricted hose directly between the boost side port and the wastegate port.

I have the same boost being generated if I put the stock BCS (w/ABC 0 turns out) in place, too.