Need help safely upping boost

[JayRolla]

Yea its under the IM almost in the middle of the block closer to the drivers side I think. It has a big metal butt for the sensor and there should be nothing else like that.

 

[kenamond]

Yea its under the IM almost in the middle of the block closer to the drivers side I think. It has a big metal butt for the sensor and there should be nothing else like that.

Any clue what the goo is? Should I wear gloves or wash my hands immediately if it's gooey?

 

[JayRolla]

Have no idea at all about that. From what I know is its ok to eat. JUST JOKING!!!!!!

 

[kenamond]

Okay.

First off, I warmed my motor up completely, shut her down, and did a boost leak test on a warmed up motor. When I did a test on a cold motor, I was getting blowby and valve stem seal leaks that bled off ~1psi/second. Warm, I was losing 1psi every 5 seconds. BIG difference.

Then I installed my Joe P IL MBC.

Then I drove around town brake boosting. First shot: 16psi. Doh! Eventually, I got it so low that I think the WGA was limiting boost at 9psi, so I did a 3rd gear pull, but only to 6200rpm before I got to a turn (started a bit late). That's the first log below.

Then I brake boosted a few more times and got it set to 11-12psi, probably closer to 12psi. Boost spikes were maybe 15psi.

Then I logged a 3rd gear pull from 2100 to 7044rpm. That's the 2nd log below. It started raining, so I didn't try upping the boost to 14psi and getting one last log. I'll do that on the way back from softball tomorrow.

Logs are below. I still see some timing getting pulled sporadically, but it seemed worse at 9psi than 12psi (I think I like that trend ). Timing is really smooth in the second log from about 4200-7000rpm except for one spot at 5600rpm.

First log: 9psi boost, ~75*F outside. Didn't log TPS, but it was tromped. I thinned the data out in the smooth timing regions to keep it shorter. It was an uphill pull, so it took a bit of time and logged much data. Had to let off for a turn at 6200rpm.

Time RPM Timing O2v
00:06.26 2052.0 22.0 0.88
00:06.82 2104.0 22.0 0.92
00:07.40 2180.0 22.0 0.92
00:07.96 2264.0 22.0 0.94
00:08.53 2324.0 21.0 0.94
00:09.10 2392.0 22.0 0.94
00:09.67 2464.0 23.0 0.92
00:10.25 2536.0 22.0 0.92
00:10.81 2600.0 23.0 0.92
00:11.39 2700.0 22.0 0.92
00:11.94 2788.0 22.0 0.92
00:12.51 2868.0 21.0 0.94
00:13.07 2964.0 20.0 0.94
00:13.65 3064.0 19.0 0.94
00:14.47 3244.0 16.0 0.94
00:15.31 3404.0 15.0 0.94
00:15.60 3456.0 14.0 0.94
00:15.88 3512.0 15.0 0.94
00:16.42 3632.0 14.0 0.94
00:16.97 3748.0 13.0 0.94
00:17.28 3816.0 14.0 0.94
00:17.55 3852.0 13.0 0.94
00:17.84 3920.0 14.0 0.94
00:18.12 3976.0 14.0 0.94
00:18.42 4044.0 15.0 0.94
00:18.70 4104.0 14.0 0.94
00:18.97 4160.0 14.0 0.94
00:19.28 4224.0 13.0 0.94
00:19.55 4276.0 15.0 0.94
00:19.84 4324.0 16.0 0.94
00:20.42 4428.0 16.0 0.94
00:20.97 4532.0 16.0 0.94
00:21.55 4636.0 16.0 0.94
00:22.12 4732.0 16.0 0.94
00:22.69 4828.0 16.0 0.94
00:23.27 4928.0 17.0 0.94
00:23.82 5024.0 17.0 0.94
00:24.39 5112.0 17.0 0.94
00:24.96 5188.0 17.0 0.94
00:25.54 5288.0 18.0 0.94
00:26.10 5368.0 18.0 0.92
00:26.93 5500.0 20.0 0.92
00:27.51 5596.0 21.0 0.92
00:28.06 5672.0 20.0 0.92
00:29.17 5824.0 21.0 0.92
00:29.75 5896.0 22.0 0.92
00:30.32 5972.0 22.0 0.92
00:30.88 6036.0 23.0 0.92
00:31.46 6112.0 23.0 0.92
00:32.02 6172.0 23.0 0.90
00:32.86 6252.0 24.0 0.90
00:33.43 6312.0 26.0 0.90

Second log: 12psi boost, ~75*F outside temp. Hit 12psi at ~3400rpm (staring at boost gauge and then glancing at the tach when it hit 12psi). Need that 3" exhaust! Same uphill stretch of road. Started earlier, so I got to redline. Data thinned in smooth regions of timing.

Time RPM Timing O2v
00:00.29 2108.0 21.0 0.92
00:01.41 2264.0 22.0 0.92
00:02.55 2456.0 23.0 0.90
00:03.70 2616.0 23.0 0.90
00:04.28 2728.0 22.0 0.92
00:04.84 2832.0 22.0 0.92
00:05.67 3008.0 19.0 0.92
00:06.23 3144.0 16.0 0.94
00:07.07 3340.0 11.0 0.94
00:07.36 3420.0 13.0 0.94
00:07.63 3504.0 11.0 0.94
00:08.21 3676.0 11.0 0.94
00:08.50 3776.0 10.0 0.94
00:08.77 3844.0 11.0 0.94
00:10.48 4332.0 11.0 0.94
00:10.77 4428.0 12.0 0.94
00:11.34 4592.0 13.0 0.94
00:11.61 4676.0 13.0 0.94
00:12.18 4812.0 14.0 0.92
00:12.47 4896.0 15.0 0.92
00:13.03 5052.0 16.0 0.92
00:13.60 5188.0 16.0 0.92
00:13.88 5252.0 15.0 0.92
00:14.17 5308.0 16.0 0.92
00:14.73 5444.0 17.0 0.92
00:15.31 5564.0 17.0 0.92
00:15.60 5620.0 20.0 0.92
00:15.88 5688.0 20.0 0.92
00:16.15 5748.0 19.0 0.92
00:16.71 5852.0 21.0 0.90
00:17.29 5952.0 21.0 0.90
00:17.56 6016.0 20.0 0.90
00:17.85 6056.0 21.0 0.90
00:18.42 6152.0 22.0 0.90
00:19.55 6312.0 22.0 0.90
00:20.70 6472.0 23.0 0.90
00:21.28 6540.0 24.0 0.90
00:22.40 6688.0 24.0 0.90
00:23.54 6796.0 24.0 0.88
00:24.09 6868.0 23.0 0.88
00:24.37 6892.0 24.0 0.88
00:24.94 6940.0 23.0 0.88
00:25.52 6992.0 23.0 0.88
00:25.79 7020.0 23.0 0.88
00:26.07 7044.0 24.0 0.88

I'll look at coolant temps tomorrow as well as log a 3rd gear pull at 14psi.

 

[JayRolla]

Actually the second pull in my eyes looks worse. See how it pulls the timing further all the way to 11 and the other with 9psi hits 13. Meaning you are getting more knock with the higher boost run. Still something is wrong you should not be getting any knock at 9psi.

 

[daren_p]

Actually the second pull in my eyes looks worse. See how it pulls the timing further all the way to 11 and the other with 9psi hits 13. Meaning you are getting more knock with the higher boost run. Still something is wrong you should not be getting any knock at 9psi.

Pulling 11 where? Are you talking in the mid 3000 range? If so this is completely normal. Timing is retarded on spool up & then should climb to the redline, a dip or a "flat" spot willl indicate knock. The reason why the timing is pulled more when running more boost on initial spool is the MAS is seeing more airflow at the higher boost level so it retards the timing further, timing being pulled in this area has nothing to do with knock. The more you increase the boost the lower the timing will dip on initial onset of boost. Just for reference mine dips to ~7 deg at 20 psi & I have zero knock.

 

[JayRolla]

Cool, im still learning this crap too. Thats a good point

 

[kenamond]

So I'm wondering if this is PK. I'll set the MBC to 14psi tonight and log another pull. Any reason I should log other sensor values like airflow or intake temp?

daren_p: What do you think about my idea of using octane booster to try to identify PK? If I boost the octane to 100 and still see the same sort of timing behavior, wouldn't that indicate PK? I admit I haven't yet searched on PK, so you can tell me to bugger off and do my homework, and I'll not be offended.

 

[daren_p]

Octane booster is pretty much useless, the way they label it is missleading. I'll just throw out some numbers (as I don't know the specificsc) but when they say it adds 10 octane points, that doesn't mean if you run 91 octane & add the booster it will make it 101 octane. There are a certain number of octane points in 1 octane. It will only add something like 1 octane all together.

Your last log looks alright, turn it up to 14 psi & see what happens. Its good to log intake temps just to see what they are but your logger is probably limited in that the more items you add, the slower the sample rate. You can do some logs with all the "extras" added just to see what going on, but only log the basics when trying to tune to get the most amount of data (samples).

 

[matt97gst]

It looks to me that you're running out of fuel above 5800 rpms. Although going off the O2 voltage isn't very accurate the rule of thumb is to keep them at about .92-.94

Go ahead and log airflow on your next log to give a better idea of the power you're making/ fuel you're using.

I bet once you get your wish list - exhaust, fuel, and dsmlink - you wont have any trouble turning up the boost.

 

[JayRolla]

Yea but why would he get so much knock at low boost. I run 11psi and almost 10* advanced base timing with no knock and a smooth timing curve that hits 26 before redline. I dont understand why he gets such a jumpy timing curve at such a low boost. Doesnt something have to be wrong. Did you try to check your knock sensor???

 

[kenamond]

It looks to me that you're running out of fuel above 5800 rpms. Although going off the O2 voltage isn't very accurate the rule of thumb is to keep them at about .92-.94

Go ahead and log airflow on your next log to give a better idea of the power you're making/ fuel you're using.

I bet once you get your wish list - exhaust, fuel, and dsmlink - you wont have any trouble turning up the boost.

I wouldn't expect the B28 to be any more efficient than the T25 at 11psi (may even be less efficient), so you'd have more fuel "headroom" in that case than you would with the stock T25.

The problem with logging airflow now is that I don't know what I was drawing with the T25, so I don't know if it's higher at 11psi than the T25 or lower. And since this only gives you volume flowrate and not mass flowrate, I can't tie it to timing or fuel maps. It may be helpful to have the data so that others can compare it to their volume flowrates and see if it looks high, low, normal, etc., but this would require someone to be running at 7200ft elevation as well (atmospheric pressure up here is only 11.8psi as opposed to 14.7 at sea level). It would be good to see how the airflow increases at fixed boost versus RPM, as that would give me an idea of how well the turbo is flowing at high rpm.

I hope I'm not running lean, but I thought that the O2v would drop below 0.5 for a lean condition (please correct me if I'm wrong - I don't know too much about the narrowband O2 on our DSMs). I would expect serious knock if I was lean, and I don't see signs of it at high RPM.

 

[kenamond]

Yea but why would he get so much knock at low boost. I run 11psi and almost 10* advanced base timing with no knock and a smooth timing curve that hits 26 before redline. I dont understand why he gets such a jumpy timing curve at such a low boost. Doesnt something have to be wrong. Did you try to check your knock sensor???

My motor was too hot for me to grope for goo last night. I kept it hot for my boost leak test and installed the MBC on it still hot and took off to log those pulls I posted, and my wife was done with me working on my car when I got home. Maybe tonight after the car has cooled down a bit, I'll feel her up (the car...and then maybe...).

 

[kenamond]

Octane booster is pretty much useless, the way they label it is missleading. I'll just throw out some numbers (as I don't know the specificsc) but when they say it adds 10 octane points, that doesn't mean if you run 91 octane & add the booster it will make it 101 octane. There are a certain number of octane points in 1 octane. It will only add something like 1 octane all together.

Is there a limit to how much I can add to my fuel? If so, how much higher would that push my octane? I'd expect 94-95 octane to show a difference in my timing compared to 91 if it was true knock.

Your last log looks alright, turn it up to 14 psi & see what happens. Its good to log intake temps just to see what they are but your logger is probably limited in that the more items you add, the slower the sample rate. You can do some logs with all the "extras" added just to see what going on, but only log the basics when trying to tune to get the most amount of data (samples).

I've been thinning my data because there was so much of it (uphill pulls and 10-11S/s), so I may be able to get sufficient sample rates even while logging 2 more parameters (and maybe not logging O2v). The hill I pulled up last night is probably steeper than what I'll be on coming home tonight, so I'll probably just judge it there on the spot and pick what I'll log. Then again, I'll be at 14psi and zipping through the RPM range more quickly, too...

 

[JayRolla]

Maybe tonight after the car has cooled down a bit, I'll feel her up (the car...and then maybe...).

good one man.........

Im lazy and did not read it all but here's a test on octane boosters and says they actually work!!!!
http://www.europeancarweb.com/tech/0...ted/index.html

 

[Budget90GST]

Is this on a 2G? I ask cause I thought that 2G's timing max out at 16 degrees. Or am I missing something?

 

[JayRolla]

Ive been told 24-28 is ideal by redline. So think your missing something. Look at his logs he hits over 16

 

[kenamond]

Is this on a 2G? I ask cause I thought that 2G's timing max out at 16 degrees. Or am I missing something?

Yes, this is a 2g. I've seen many logs from other folks that go to low-mid 20s at redline. Most start in the 20s before boost hits. All drop down below 12-13 at stock boost. I've seen some dip as low as 4* when boost hits. Mine dropped to 13 at 9psi and 11 at 12psi. I'll see how it drops tonight. Softball game cancelled due to rain, but I'll still head out and do the 14psi pull. MBC is already set to 14.

One thing I noticed last night was that my intake air temps were mid 90s even coasting down the hill (maybe 1.25 miles downhill). I have the K&N FIPK, and I'm thinking about cutting out above the SMIC (widen the UICP hole) and building a cold air intake box around the filter. The outside temp was 73*, so that's a lot of temp to go down.

 

[kenamond]

Okay. Did two pulls on that same hill. Looks like my MBC is more like 15psi than 14psi.

Intake temps were 95*F. Second pull was interrupted by headlights, so went back down and got a good second one. Logged coolant temp on this 3rd run (2nd log), and they were 190*F the whole way through.

First log looks scary. Looks like I'm leaning out at 6500rpm. Weird, because the 3rd pull (2nd log) didn't do that. I was watching the boost gauge in the 2nd pull and it dropped to about 12psi by 7k rpm. Any idea what that is (stock exhaust)? Didn't watch the boost gauge all the way through the 1st pull, so I don't know if it did it, too. If it didn't, maybe I overran the injectors the first pull but getting less boost on the top end in the second pull left fuel to spare... I haven't rewired my stock pump, so would I be hitting the limits at 15psi?

First log. Logged airflow, too:

Time RPM Timing Airflow O2v
00:04.92 2004.0 21.0 3.71 0.90
00:05.32 2032.0 22.0 3.80 0.90
00:05.69 2056.0 22.0 3.88 0.90
00:06.07 2088.0 22.0 3.93 0.90
00:06.46 2140.0 22.0 4.02 0.90
00:06.84 2156.0 22.0 4.06 0.90
00:07.21 2220.0 22.0 4.15 0.90
00:07.59 2244.0 23.0 4.30 0.90
00:07.98 2304.0 23.0 4.45 0.90
00:08.35 2332.0 23.0 4.46 0.90
00:08.73 2368.0 23.0 4.65 0.90
00:09.10 2440.0 23.0 4.70 0.90
00:09.51 2484.0 24.0 4.88 0.90
00:09.88 2524.0 23.0 5.10 0.90
00:10.27 2588.0 24.0 5.39 0.90
00:10.64 2664.0 23.0 5.68 0.90
00:11.02 2724.0 22.0 6.04 0.90
00:11.40 2800.0 21.0 6.39 0.90
00:11.77 2864.0 21.0 6.75 0.92
00:12.15 2948.0 21.0 7.14 0.92
00:12.52 3024.0 19.0 7.73 0.92
00:13.17 3192.0 17.0 8.84 0.92
00:13.55 3268.0 15.0 9.54 0.92
00:13.92 3388.0 13.0 10.53 0.92
00:14.31 3504.0 11.0 11.46 0.92
00:14.68 3588.0 10.0 12.43 0.92
00:15.06 3724.0 9.0 13.39 0.92
00:15.46 3840.0 10.0 13.94 0.92
00:15.82 3960.0 10.0 14.57 0.92
00:16.21 4084.0 10.0 15.18 0.92
00:16.60 4216.0 13.0 16.13 0.92
00:16.97 4332.0 11.0 16.88 0.92
00:17.36 4496.0 10.0 17.58 0.92
00:17.73 4564.0 10.0 18.21 0.92
00:18.12 4692.0 12.0 18.26 0.92
00:18.50 4800.0 12.0 18.47 0.92
00:18.87 4908.0 12.0 18.78 0.90
00:19.27 5016.0 13.0 18.86 0.90
00:19.64 5124.0 14.0 19.09 0.90
00:20.03 5228.0 14.0 19.36 0.90
00:20.42 5324.0 16.0 19.69 0.90
00:20.79 5436.0 16.0 19.87 0.90
00:21.17 5524.0 17.0 20.17 0.90
00:21.54 5628.0 17.0 20.35 0.90
00:21.92 5712.0 18.0 20.41 0.90
00:22.30 5800.0 18.0 20.62 0.90
00:22.68 5880.0 19.0 20.66 0.88
00:23.05 5944.0 19.0 20.69 0.88
00:23.45 6028.0 19.0 20.60 0.88
00:24.07 6144.0 20.0 20.61 0.88
00:24.45 6200.0 20.0 20.61 0.88
00:24.84 6264.0 20.0 20.74 0.88
00:25.47 6356.0 20.0 20.82 0.86
00:25.86 6420.0 21.0 20.81 0.86
00:26.25 6464.0 22.0 20.94 0.84
00:26.62 6516.0 22.0 20.88 0.84
00:27.00 6564.0 22.0 21.13 0.82
00:27.37 6632.0 21.0 21.19 0.78
00:27.76 6676.0 22.0 21.22 0.74
00:28.13 6712.0 22.0 21.35 0.68
00:28.52 6760.0 21.0 21.44 0.62
00:28.89 6808.0 21.0 21.52 0.58
00:29.28 6832.0 22.0 21.37 0.54
00:29.65 6880.0 22.0 21.31 0.52
00:30.04 6916.0 21.0 21.37 0.50
00:30.43 6956.0 21.0 21.31 0.48
00:30.80 6992.0 22.0 21.31 0.46
00:31.18 7020.0 22.0 21.48 0.44
00:31.55 7044.0 20.0 21.44 0.42
00:31.94 7084.0 20.0 21.48 0.42
00:32.33 7124.0 21.0 21.55 0.40

Second log:

Time RPM Timing O2v
00:00.37 2064.0 29.0 0.18
00:00.76 2064.0 23.0 0.88
00:01.39 2104.0 23.0 0.88
00:02.03 2120.0 22.0 0.88
00:02.42 2176.0 22.0 0.88
00:02.79 2204.0 22.0 0.88
00:03.17 2244.0 22.0 0.88
00:03.53 2272.0 22.0 0.88
00:03.92 2308.0 23.0 0.88
00:04.28 2360.0 22.0 0.88
00:04.94 2392.0 23.0 0.88
00:05.32 2472.0 23.0 0.88
00:05.69 2532.0 23.0 0.88
00:06.07 2584.0 23.0 0.88
00:06.44 2640.0 22.0 0.88
00:06.84 2704.0 22.0 0.90
00:07.21 2776.0 22.0 0.90
00:07.59 2844.0 20.0 0.90
00:07.96 2928.0 19.0 0.90
00:08.32 3008.0 17.0 0.92
00:08.71 3088.0 16.0 0.92
00:09.07 3188.0 15.0 0.92
00:09.44 3272.0 11.0 0.92
00:09.82 3356.0 11.0 0.92
00:10.21 3484.0 10.0 0.92
00:10.57 3588.0 9.0 0.92
00:10.96 3692.0 10.0 0.92
00:11.34 3820.0 10.0 0.92
00:11.71 3944.0 10.0 0.92
00:12.07 4052.0 11.0 0.92
00:12.44 4168.0 11.0 0.92
00:12.84 4280.0 10.0 0.92
00:13.21 4432.0 10.0 0.92
00:13.59 4560.0 11.0 0.92
00:13.96 4668.0 11.0 0.90
00:14.34 4752.0 12.0 0.90
00:14.71 4884.0 13.0 0.90
00:15.07 4992.0 14.0 0.90
00:15.46 5096.0 14.0 0.90
00:15.84 5200.0 15.0 0.90
00:16.20 5316.0 15.0 0.90
00:16.59 5436.0 16.0 0.90
00:16.96 5492.0 17.0 0.90
00:17.34 5604.0 18.0 0.90
00:17.71 5696.0 19.0 0.88
00:18.10 5800.0 19.0 0.88
00:18.46 5880.0 17.0 0.88
00:18.86 5952.0 19.0 0.88
00:19.22 6028.0 20.0 0.88
00:19.60 6104.0 19.0 0.88
00:19.97 6180.0 20.0 0.88
00:20.36 6232.0 19.0 0.88
00:20.75 6284.0 20.0 0.88
00:21.12 6356.0 20.0 0.88
00:21.48 6408.0 21.0 0.88
00:21.87 6484.0 21.0 0.86
00:22.25 6516.0 21.0 0.86
00:22.62 6572.0 21.0 0.86
00:23.00 6620.0 21.0 0.86
00:23.37 6676.0 21.0 0.86
00:23.76 6724.0 21.0 0.86
00:24.12 6760.0 20.0 0.86
00:24.51 6808.0 20.0 0.84
00:24.88 6844.0 20.0 0.84
00:25.26 6892.0 20.0 0.84
00:25.63 6940.0 22.0 0.84
00:26.03 6968.0 22.0 0.82

 

[hottboost]

You still have dips all over it. Your o2's are still very low. Even way out of tune mine never dropped below 0.93. Yes you ARE hitting the limit of the stock fuel Pump. Try the rewire. You want it to pull timing as boost hits, then climp with NO dips all the way to redline.

Here is a log befor I did the safc and 550's @ 17psi. Did have the 190Lph though.

Timing O2 Rpms

13 0.91 2516
10 0.93 2648
09 0.93 2796
07 0.93 2932
06 0.95 3104
04 0.95 3288
04 0.95 3492
05 0.95 3700
06 0.95 3904
07 0.95 4096
08 0.95 4256
08 0.95 4484
08 0.95 4660
09 0.95 4828
10 0.95 4984
11 0.95 5144
11 0.95 5316
12 0.95 5468
13 0.95 5620
13 0.95 5756
14 0.95 5916
16 0.95 6044
16 0.95 6180
17 0.95 6284
17 0.95 6400
17 0.95 6516
17 0.95 6596
17 0.95 6688
18 0.95 6784
18 0.95 6856

I didnt like that it dipped to 4* as boost hit, but It climbed a nice line to redline. That is what you want to shoot for. Now that I can control it with the safc, I tried to never let it dip below 6* at full boost.

 

[JayRolla]

Well thats what I was saying earlier. I have a 1g and when I notice that the timing pulls that low that I get a large count of knock right when boost hits. So if the timing pulls that low when boost hits you will never get a high timing pull. Right? My brothers car was tuned at a dyno and he hits, I think 11-14 at the lowest and by redline has about 26*, which the guy at the dyno said was real good. So how would you get the timing not to drop so low, because when it does you will not beable to get as high as advance as you would want by redline.

 

[daren_p]

Looks like you could be leaning out abit on the 15 psi pull in the top end. NB O2's while not very accurate look abit on the lean side (personally mine read ~.90 for 11 to 1, which seems to be low compared to other, but like I said can't really compare from one O2 sensor to another). I would pull the boost down to maybe 12-13 psi for now & get some logs. Get that FP rewired if you haven't sone it yet, you'd be surprised how much of an effecct pump voltage has on flow. Once that is down crank it back up to 14-15 and try again. Its best to take a couple logs and you want to try and be on flat ground.

 

[hottboost]

I think it is natural to see it pull down to 8*-10*! Now I am still a little new to this but on a stock motor you should be shooting for now more than 22*-24* max by redline. If I am wrong then someone correct me. The only way to completely know what is going on is to have dsmlink on a 2G. Then you can read your knock, and be able to adjust your timing. You can mask knock by adding fuel but realy all your doing is covering the problem. Now that Ive got a decent tune Im dipping to 6*-8* as boost hits then pulling to 22* at redline. Ill add to this just give me a few min.

 

[kenamond]

Looks like you could be leaning out abit on the 15 psi pull in the top end. NB O2's while not very accurate look abit on the lean side (personally mine read ~.90 for 11 to 1, which seems to be low compared to other, but like I said can't really compare from one O2 sensor to another). I would pull the boost down to maybe 12-13 psi for now & get some logs. Get that FP rewired if you haven't sone it yet, you'd be surprised how much of an effecct pump voltage has on flow. Once that is down crank it back up to 14-15 and try again. Its best to take a couple logs and you want to try and be on flat ground.

Okay. Thanks. I'll turn the boost back down to 11psi until I have time for the rewire. As for flat ground, I live in the mountains, so that is a scarce commodity. I can do it, but the one good flat-ish spot is a bit farther of a drive, and then I need to pull up 1000ft elevation at a substantial grade to get back home which might not be good if my motor is running lean or knocking badly.

My O2v have never been higher than 0.92v, so I'm guessing that the volts vary from sensor to sensor. I think .88v or .86v was the lowest I had ever logged on the stock (modded) BCS, so that first log startled me - 0.4v

I still need to do a compression test and wire the boost gauge light (very hard to make out boost at night on a mountain road during a pull in elk country without that). Maybe I can pick up the hardware for the rewire and work on those three projects this weekend.

Any thoughts on the boost dropping to 12psi on the last pull?

 

[hottboost]

Remember that the key to strong performance on pump gas in the absence of being able to cool the air charge properly is to lower timing to some extent and stave off detonation. Boost always makes more power than timing on pump gas. In the real world, consider this scenario:

22 psi at 16 degrees of timing with no knock will make more power than 19 psi with 18 degrees of timing and some knock. If your block is stock, I'd recommend you stick with a stock timing map. For a 2G this would peak at around 16 degrees and for a 1G, well, it would be much higher since the compression is lower and it can tolerate more timing. Higher compression built motors will require (and even want) less timing than that.