I've been working on getting my UTEC tuned up with my VF24 stage 4 setup.

Here's a partial sample of a log i took today


2083 -0.2 2.4 24 10 00 W/B +34.9 10.4 +30.4 -2.6 ECU. 2.2 13.81
2128 +0.2 2.5 31 10 00 W/B +34.9 11.3 +30.0 -2.7 ECU. 2.3 13.81
2127 +0.6 2.6 40 10 00 W/B +34.7 11.8 +29.8 -2.7 320.00 2.3 13.50
2175 +1.2 2.6 54 20 00 W/B +34.7 12.1 +28.8 -2.7 320.00 2.3 13.23
2200 +1.9 2.6 61 20 00 W/B +34.3 12.2 +28.2 -2.7 320.00 2.3 13.23
2262 +2.5 2.7 75 20 00 W/B +33.8 12.4 +28.0 -2.8 362.50 2.4 13.28
2258 +2.9 2.7 91 20 00 W/B +34.1 12.6 +27.8 -2.8 390.00 2.4 13.39
2335 +3.3 2.7 102 20 00 W/B +33.4 12.8 +27.7 -2.8 390.00 2.4 13.59
2380 +3.5 2.7 102 30 00 W/B +32.7 13.1 +23.6 -1.1 390.00 2.5 13.65
2427 +3.9 2.8 102 30 00 W/B +30.3 15.0 +23.3 -1.1 390.00 2.5 13.56
2465 +4.3 2.8 102 30 00 W/B +29.7 15.7 +23.1 -1.1 390.00 2.5 13.23
2542 +4.5 2.8 102 30 00 W/B +31.3 15.7 +22.9 -1.1 390.00 2.6 12.92
2554 +4.9 2.8 102 30 00 W/B +30.9 16.4 +22.7 -1.1 390.00 2.6 12.92
2630 +5.1 2.8 102 30 00 W/B +29.8 17.5 +22.4 -1.1 390.00 2.6 12.96
2668 +5.3 3.0 102 40 00 W/B +29.3 18.2 +18.3 +0.0 390.00 2.7 13.03
2730 +5.7 3.0 102 40 00 W/B +27.1 19.7 +18.1 +0.1 390.00 2.8 12.93
2784 +5.9 3.0 102 40 00 W/B +24.0 21.9 +18.0 +0.2 390.00 2.8 12.52
2829 +6.3 3.1 102 40 00 W/B +23.0 23.3 +18.0 +0.2 390.00 2.9 12.17
2891 +6.7 3.1 102 40 00 W/B +21.5 24.7 +18.0 +0.2 390.00 2.9 12.11
2944 +7.2 3.2 102 50 00 W/B +19.0 26.8 +16.0 +0.8 390.00 3.0 12.14
3008 +8.0 3.3 102 50 00 W/B +22.1 29.5 +16.0 +0.9 390.00 3.0 11.98
3080 +8.6 3.4 102 50 00 W/B +18.6 31.7 +16.0 +0.9 390.00 3.2 11.62
3150 +9.8 3.4 102 60 00 W/B +18.9 35.6 +16.0 +1.2 390.00 3.2 11.42
3252 +10.6 3.5 102 60 00 W/B +15.0 39.1 +16.0 +0.0 390.00 3.3 11.20
3320 +11.9 3.5 102 70 00 W/B +14.2 42.6 +15.0 +0.9 390.00 3.4 10.90
3429 +13.1 3.5 102 80 00 W/B +13.9 42.9 +14.0 +0.5 390.00 3.3 10.67
3508 +14.3 3.6 102 80 00 W/B +16.6 47.3 +14.0 -0.2 390.00 3.4 10.65
3568 +15.5 3.7 101 90 00 W/B +16.4 48.4 +14.0 -0.2 390.00 3.4 10.81
3658 +16.1 3.6 102 90 00 W/B +16.5 49.2 +14.0 -0.3 390.00 3.5 10.80
3779 +16.3 3.8 101 90 00 W/B +16.9 50.7 +14.4 -0.4 390.00 3.4 10.74
3805 +16.6 3.8 102 90 00 W/B +17.4 50.7 +15.0 -0.1 390.00 3.5 10.76
3972 +16.3 3.9 102 90 00 W/B +17.9 51.4 +15.6 +0.0 390.00 3.6 10.73
4040 +16.1 3.9 101 80 00 W/B +16.9 54.7 +16.1 +0.3 390.00 3.5 10.78
4070 +16.1 3.9 102 80 00 W/B +17.6 55.4 +16.4 +0.2 390.00 3.5 10.71
4214 +15.5 3.8 101 80 00 W/B +17.2 54.5 +17.0 -0.1 390.00 3.6 10.67
4262 +15.5 3.8 101 80 00 W/B +16.5 55.7 +17.0 +0.4 390.00 3.6 10.78
4374 +15.7 3.9 102 90 00 W/B +16.8 58.1 +17.0 +0.1 390.00 3.6 10.76
4480 +15.5 3.9 101 80 00 W/B +16.5 58.1 +17.0 -0.1 390.00 3.6 10.65
4585 +15.7 3.9 102 80 00 W/B +17.4 58.9 +17.6 -0.4 390.00 3.6 10.65
4681 +15.5 4.0 102 80 00 W/B +18.1 61.6 +18.2 -0.5 390.00 3.6 10.64
4768 +15.3 4.0 101 80 00 W/B +18.8 64.5 +18.4 -2.1 390.00 3.6 10.62
4775 +15.7 4.0 102 90 00 W/B +18.8 62.0 +19.2 -1.3 390.00 3.6 10.65
4873 +15.7 4.1 102 90 00 W/B +20.9 65.9 +20.0 -1.7 390.00 3.6 10.62
4997 +16.3 4.0 101 90 00 W/B +22.4 66.2 +20.8 -2.3 390.00 3.6 10.62
5112 +16.3 4.1 102 90 00 W/B +21.9 67.5 +21.2 -2.3 390.00 3.7 10.67
5224 +16.6 4.1 101 90 00 W/B +22.5 69.5 +21.7 -2.3 390.00 3.7 10.73
5224 +16.6 4.1 102 90 00 W/B +22.3 72.6 +21.9 -2.3 390.00 3.7 10.71
5341 +16.5 4.2 102 90 00 W/B +22.5 73.2 +22.0 -2.3 390.00 3.7 10.62
5420 +16.6 4.2 98 90 00 W/B +22.9 75.9 +22.0 -2.3 390.00 3.8 10.58
5341 +15.5 3.8 20 00 00 W/B +39.3 16.3 ECU. -1.0 330.00 2.5 10.49
5112 +9.6 2.6 1 00 00 W/B +10.9 15.6 ECU. -1.0 ECU. 2.3 11.17


Thats a 3rd gear pull on a 85 degree day here in Atlanta. I'm trying to get the boost to hold a bit closer to 17 psi and spool up sooner. I've been slowly rasing the boost numbers and while it does raise the boost, it does not change the spool up. I have the CLB gain set at 47 because any lower and I get a pretty decent spike if I punch it instead of rolling into the throttle.

Any suggestions?

The best way to lower the boost threshold is to lean out the mixture. In this case you are already running pretty lean, so you are not going to gain much/anything there. If you really want to "build boost" sooner then you could take out more timing, but that would make less power, so I do not recommend that.

In short you may have the lowest boost threshold tuning can achieve on your setup. You can look to hardware on your car to try to improve it a little more, but the sucess of that will be dependent on what you currently have, and how much you are willing to spend.

Well I've got all the stage 4 bits except for the vf24 instead of the 34. I'm currently running the stock airbox minus the silencer, I've got a turboXS shorty intake sitting in the closet. I was running it but when the weather got hot here I took it off because my logs were showing very high intake temps in slow traffic (Atlanta traffic SUCKS).

I've tried a few other things like the perrin turbo inlet pipe and I'm only running 1 high flow cat.

Any suggestions for things to look at next?

You can run stoich until about 6.5 psi so you have got at least a full point more you can lean it out.

Have you tried really increasing you boost number below full spool. I generally ran 500 until 2 rpm blocks before I knew I would hit full spool. Then I tapered it down so I wouldn't spike.


Boost Map
[0] [0] [0] [0] [0] [0] [0] [0] [0] [0] [0]
[0] [0] [0] [0] [0] [0] [0] [0] [0] [0] [0]
[0] [0] [0] [0] [0] [0] [0] [500] [500] [500] [500]
[0] [0] [0] [0] [0] [0] [0] [500] [500] [500] [500]
[0] [0] [0] [0] [0] [0] [0] [500] [500] [500] [500]
[0] [0] [0] [0] [0] [0] [0] [500] [500] [500] [500]
[0] [0] [0] [0] [0] [0] [0] [500] [500] [500] [500]
[0] [0] [0] [0] [0] [0] [0] [500] [500] [500] [500]
[0] [0] [0] [0] [0] [0] [0] [500] [500] [500] [500]
[0] [0] [0] [0] [0] [0] [0] [500] [500] [500] [500]
[0] [0] [0] [0] [0] [0] [0] [500] [500] [500] [500]
[0] [0] [0] [0] [0] [0] [0] [395] [420] [445] [445]
[0] [0] [0] [0] [0] [0] [0] [385] [410] [435] [435]
[0] [0] [0] [0] [0] [0] [0] [385] [410] [435] [435]
[0] [0] [0] [0] [0] [0] [0] [385] [385] [410] [435]
[0] [0] [0] [0] [0] [0] [0] [370] [370] [395] [420]
[0] [0] [0] [0] [0] [0] [0] [370] [370] [395] [420]
[0] [0] [0] [0] [0] [0] [0] [370] [370] [395] [420]


p.s. The code tag with the new software is really cool.

You can run stoich until about 6.5 psi so you have got at least a full point more you can lean it out.

ime, you can do that a bit further, and push it some... ;) up to full wastegate pressure (7 or 8 psi) safely. that's like the middle of your 40% load column if you use the default utec map scale.

remember when in partial throttle/closed loop ecu fueling it's locked at ~14.7:1, and there is no such thing as boost control under wastegate pressure, so it MUST be fine for the car.

ken

ime, you can do that a bit further, and push it some... ;) up to full wastegate pressure (7 or 8 psi) safely. that's like the middle of your 40% load column if you use the default utec map scale.

remember when in partial throttle/closed loop ecu fueling it's locked at ~14.7:1, and there is no such thing as boost control under wastegate pressure, so it MUST be fine for the car.

ken

Yea you can, but I usually play safe and I'd let the 6.5-8 psi range be the rampdown for the AFR so you know you aren't running it lean when you hit around 8, because after that the boost just skyrockets quickly. On a WOT hit say with you already around 7 PSI and quickly jumping approaching the 100 load column could try and hit stioch, then one eighth of a second later try and hit your other AFR level, say 10.8:1 and it could get messy.

IMHO 14.7 is a little lean to run all the way up to 6 PSI. In stock form the STi V4 ran about 13.7:1 it up to about 45 PSI. The key thing to watch here is EGTs. If you're cruising along in 5th gear and only making 5 PSI then you certainly don't want to hold it there if it's going to burn a valve. Personally when I tune a car I keep it around 13.0:1-13.5:1 while building boost.

-Michael

d00f you have a minor typo ,4.5 not 45

The other question is how much more are you going to make by leaning it out more. You will increase the torque a little down low, but you are not going to pull the whole torque curve over 300 RPM.

If you have two high flow cats in there try removing them and seeing if it lowers your spool any. What up pipe do you have?

I've got a M2 up pipe, TurboXS down pipe, random tech cat, and a scoobiesport muffler.

Veck -

1. Try adding a helper spring to your wastegate actuator - on vf turbos that's usually good for a couple of hundred rpm AND it will let you hold MUCH steadier boost up top. Home Depot sells two basic sizes, a 9lb size and a 19lb size. Put 1's in your boost map (giving you wastegate pressure), close the ABC completely (very important!), and try first the smaller spring, and if that doesn't get wastegate boost over 14psi, try the larger spring. You should shoot for wastegate boost at ~14psi when you floor it. Then, dial the boost up slowly with the UTEC. Probably start at 150 everywhere and tune it out.

2. Try an MBC - the UTEC is only OK at boost control, and you can boost much faster with another solution. The spring trick will work about as well as an MBC or EBC though, and it costs a dollar.

-Sean

IMHO 14.7 is a little lean to run all the way up to 6 PSI. In stock form the STi V4 ran about 13.7:1 it up to about 45 PSI. The key thing to watch here is EGTs. If you're cruising along in 5th gear and only making 5 PSI then you certainly don't want to hold it there if it's going to burn a valve. Personally when I tune a car I keep it around 13.0:1-13.5:1 while building boost.

-Michael

i see what folks are saying: better safe than sorry. cdvma's point about dynamic conditions being hard to predict is a good one too.

however, i must say that the highest egts i ever see are in closed loop ECU fueling, 5th gear, holding ~100 mph for a few minutes at a time. manifold pressure is <5psi. in these operating conditions i see the egts at #2/#4 junction asymptotically approach 1600* F. at this point, more throttle generally either crosses the open loop TPS threshold, or causes rpms to rise above the open loop RPM threshold, both of which causing about a 200* drop in egts.

i don't have any cats and i have done as much as i can to improve intake and exhaust efficiency. i do not have an ECU reflash. i observed the same trends before i fitted a utec, and after. the bottom line is that i have to say that i would be completely shocked if a stock car (with all cats + oem muffler) didn't have egts even higher than what i have observed, probably by ~100*. that's HOT.

since we don't have stories of stock rexs burning valves, even when driven at 100 mph for some time, i have to surmise that it is not a problem. has anyone EVER burned a valve on a rex? :confused:

jm2c
ken