Need help safely upping boost

[hottboost]

1 degree of timing retard is 10 counts of knock.

For reference, the 2G ECU holds timing at 7 counts and retards 1 degree of timing for every 3 degrees over that (i.e. 10,13,16, etc)

Just an FYI

Also I cant take full credit for this info because it was provided to me by Andymoraitis in some previous post of mine. Hope this will help you understand a little better!

 

[kenamond]

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. As an example, I run my 8.8:1 stroker at 12 degrees of maximum advance. With a pump gas friendly turbo, this will allow for fairly high boost on pump gas without knocking all over the place.

I apologize, but I didn't follow that. My timing has always ended up way beyond 16* at high rpm and has always dropped below 16* when boost hits - even at 9psi. And I have no control over the timing map, as I have completely stock ECU and fuel system. I'm not sure how high I can boost with a rewired pump and not lean out, but this knock at low boost is really bothering me.

I can still do a cold air intake and cut out the fender splash guard behind the SMIC to help lower charge temps, and that should help with knock, but I'm quite honestly afraid to push the boost up at all at this point based on the knock I'm seeing. I'm almost ready for a new tank of gas, so maybe I got a bad tank last time, and I'll see a change. I think that before I start upping the boost that I really need to figure out why I get knock on 11psi while others normally don't. Something's wrong, but I'm stumped.

 

[kenamond]

1 degree of timing retard is 10 counts of knock.

For reference, the 2G ECU holds timing at 7 counts and retards 1 degree of timing for every 3 degrees over that (i.e. 10,13,16, etc)

Just an FYI

Also I cant take full credit for this info because it was provided to me by Andymoraitis in some previous post of mine. Hope this will help you understand a little better!

That's good to know, but I don't know what the timing should be, so I don't know if its being pulled unless there's a dip. For example, in my last log, was I knocking from 5800rpm all the way to redline? The timing stopped advancing there for the most part, but was that because the stock exhaust was choking my turbine thus decreasing airflow or was it due to knock?

 

[matt97gst]

Like I said earlier it looks that you're running out of fuel. It's hard to safely turn up the boost when you don't have enough support mods especially something to tune with. All you reallly have left is fuel pump, injectors, a tuning device, and hopefully a more efficient intercooler - oh I think you need an exhaust system too. Save up and get them ASAP. An example of a good log - on a bigt28 with all support mods, tuning with safcII back in the day:

RPM TIMING 02
4428.0 8.0 0.94
4744.0 10.0 0.94
5024.0 10.0 0.96
5392.0 12.0 0.96
5636.0 13.0 0.94
5924.0 15.0 0.94
6160.0 15.0 0.94
6388.0 17.0 0.94
6632.0 17.0 0.94
6820.0 20.0 0.94

As for why you're having problems running low boost, I'm not sure. It could be the lack of support mods, or maybe you're just running 100% and very efficient - I say this b/c I saw your other thread how you fixed all boost leaks and it seems you're on top of everything.

 

[hottboost]

Also I cant take full credit for this info because it was provided to me by Andymoraitis in some previous post of mine.
That was a cut and paste from that post . Yeah I do agree with that. When I have some time Ill search around and see if I can find some info to help ya. This is where the dsmlink comes into play. You could see your IDC's and be able to verify that they are working properly. If I think of anything else Ill post

 

[hottboost]

Cold air intake" location can help decrease intake charge temps, which help to lower knock. But if there is still a problem with the fuel system not delivering enough fuel to meet the demands of the engine, that can cause lean conditions which will possibly create knock. Another condition that can create knock is hot spots inside the cylinder, on the head, piston, or the spark plug (usually carbon deposits). If the hot spot pre-ignites the air/fuel mixture, it may cause detonation and knock.

In my experience, phantom knock presents itself at partial throttle, at low rpms, and with lots of timing suddenly pulled due to knock. If there's no knock at WOT from 3-7k rpms, but if there's 43 counts of knock at 17% throttle and 2500 rpms at cruising speed, that's more than likely caused by phantom knock. That was what happened to me.

If you think your engine has a lot of carbon build-up you can try to run half a bottle of SeaFoam through it to clean it out. Do a search for how to use this chemical, since doing it wrong can mess up your engine.

 

[kenamond]

Thanks again.

I'll probably repeat a boost leak test. The drop in boost on my last pull made me wonder if something started leaking.

Also, I really need to do everything I can think of that will eliminate knock at stock boost levels, because I'm convince that it should not be happening and I need to fix whatever's wrong. The fact that I have stock exhaust and non-rewired fuel pump shouldn't have any bearing on why I'm getting knock in the 4k range at 9psi boost. The things I can think of are bad knock sensor and carbon deposits, so I'll see if my sensor is oozing, and I'll do the seafoam treatment. I'm also going to do a compression test, because I have no idea what it is (never had a compression test) and I should be aware of low compression if it exists.

Thanks for the schooling, and PLEASE keep it coming if you have anything of value to add.

 

[JayRolla]

If you had a boost leak wouldnt the turbo work harder and still push the set boost unless it was a huge leak?

 

[hottboost]

Im tapped out at the moment! let me know how it turns out and good luck.

 

[kenamond]

If you had a boost leak wouldnt the turbo work harder and still push the set boost unless it was a huge leak?

Probably. I'm grasping at straws at this point. It pulled quite nicely on the way to work (still set at 15psi), but I wasn't logging. I have about 5 seconds during my commute where I can actually open it up in 1st and 2nd.

This weekend I'll be Sherlock Holmes in "The Mystery of the 9psi knocking 2g DSM"

Im tapped out at the moment! let me know how it turns out and good luck.

Thanks a bunch!

 

[JayRolla]

Yea I think its crazy that you are knocking a 9psi. Time to talk the wife into DSMLINK and tell her you will beable to read detonation and may save yourself a rebuild that is twice as much.

 

[kenamond]

Okay guys, I got some help from a couple other guys in another thread and redirected them here. This is the proper forum than Newbie. Maybe peek at that thread to see what all we were talking about.

Continuing...

I put about 10oz of NOS Racing Formula into about 10-11 gallons of gas this afternoon and did two pulls tonight. Still seeing timing dips. It said on the bottle that it would treat 18 gallons, so I figured ~2/3 of a bottle was about right. Said it would raise the octane 60 points which would give me 97 octane. It's an opaque bottle to keep light out, so I couldn't see exactly how much I added, but could tell fairly well based on weight and sloshing it around. My 4yr old daughter got a kick out of me zig-zagging around town trying to mix it up. Should I put more of it in there?

Didn't have any time this weekend to work on the car, so I didn't check for knock sensor goo yet. I'll try to do that tomorrow evening along with a compression test. I'm completely baffled about this still unless I needed to add more NOS to my tank.

I searched around, and at ~8000 feet elevation, I need to adjust my compression numbers by 0.81 (I should get 0.81*178psi for perfect and 0.81*133psi for service limit). Does that sound right to you guys?

The first pull at 10psi dropped to 8psi by 6k rpm. The second pull at 14-15psi dropped to 10-11psi by redline. Is that due to pressure losses in the intake tract? Should I consider running my MBC off of the IM or somewhere closer to the TB?

Anyway, first pull was about 10psi, but it dropped to 8 by the mid 6k range. See timing dips at 4100, 4400, 5200, and 6400rpm.

Time RPM Timing O2v
00:04.86 2808.0 22.0 0.9
00:05.15 2852.0 21.0 0.9
00:05.44 2924.0 21.0 0.9
00:05.72 2964.0 20.0 0.9
00:06.01 3032.0 19.0 0.92
00:06.28 3084.0 19.0 0.92
00:06.57 3152.0 17.0 0.92
00:06.86 3232.0 16.0 0.92
00:07.13 3284.0 16.0 0.92
00:07.42 3344.0 15.0 0.92
00:07.71 3404.0 16.0 0.92
00:08.00 3472.0 15.0 0.92
00:08.27 3536.0 14.0 0.92
00:08.56 3624.0 14.0 0.92
00:08.85 3672.0 13.0 0.92
00:09.39 3812.0 14.0 0.92
00:09.94 3960.0 14.0 0.92
00:10.22 4028.0 15.0 0.92
00:10.51 4096.0 15.0 0.92
00:10.79 4164.0 14.0 0.92
00:11.07 4228.0 14.0 0.92
00:11.36 4304.0 15.0 0.92
00:11.64 4372.0 15.0 0.92
00:11.93 4436.0 14.0 0.92
00:12.22 4488.0 14.0 0.92
00:12.51 4548.0 15.0 0.92
00:12.79 4604.0 15.0 0.92
00:13.06 4660.0 15.0 0.92
00:13.35 4728.0 15.0 0.92
00:13.64 4776.0 15.0 0.92
00:13.93 4828.0 15.0 0.92
00:14.22 4884.0 15.0 0.92
00:14.50 4928.0 16.0 0.92
00:14.77 4984.0 17.0 0.92
00:15.06 5032.0 17.0 0.92
00:15.35 5072.0 17.0 0.92
00:15.63 5124.0 17.0 0.92
00:15.93 5168.0 17.0 0.92
00:16.20 5216.0 16.0 0.92
00:16.50 5264.0 17.0 0.92
00:16.78 5308.0 18.0 0.92
00:17.05 5352.0 18.0 0.92
00:17.35 5392.0 19.0 0.92
00:17.62 5436.0 19.0 0.92
00:17.93 5492.0 19.0 0.92
00:18.20 5524.0 19.0 0.92
00:18.48 5572.0 20.0 0.92
00:18.77 5612.0 20.0 0.92
00:19.05 5660.0 21.0 0.92
00:19.34 5696.0 21.0 0.92
00:19.62 5736.0 22.0 0.92
00:19.92 5780.0 22.0 0.92
00:20.20 5824.0 22.0 0.92
00:20.48 5860.0 22.0 0.92
00:20.77 5888.0 22.0 0.92
00:21.05 5932.0 22.0 0.9
00:21.35 5980.0 22.0 0.9
00:21.62 6016.0 22.0 0.9
00:21.92 6056.0 22.0 0.9
00:22.20 6084.0 24.0 0.9
00:22.48 6112.0 24.0 0.9
00:22.77 6152.0 24.0 0.9
00:23.05 6172.0 24.0 0.9
00:23.35 6212.0 24.0 0.9
00:23.62 6240.0 24.0 0.9
00:23.92 6272.0 24.0 0.9
00:24.20 6304.0 26.0 0.9
00:24.48 6336.0 26.0 0.9
00:24.77 6368.0 26.0 0.9
00:25.05 6388.0 26.0 0.9
00:25.34 6420.0 26.0 0.9
00:25.62 6452.0 25.0 0.9
00:25.92 6472.0 26.0 0.9
00:26.20 6496.0 26.0 0.9
00:26.48 6528.0 26.0 0.9
00:27.04 6572.0 27.0 0.9
00:27.31 6608.0 26.0 0.9
00:27.60 6632.0 26.0 0.88
00:27.87 6640.0 26.0 0.9

Second pull at 14psi. Dropped to 10 by redline. Didn't lean out on me, which was nice. I see timing pulled at 3900, 5000, 5300, 5700, and 6100rpm.

Time RPM Timing O2v
00:09.97 2880.0 22.0 0.90
00:10.26 2932.0 22.0 0.90
00:10.55 2996.0 21.0 0.90
00:10.82 3048.0 21.0 0.92
00:11.10 3112.0 19.0 0.92
00:11.39 3176.0 17.0 0.92
00:11.68 3252.0 16.0 0.92
00:11.97 3312.0 16.0 0.92
00:12.26 3392.0 15.0 0.92
00:12.55 3456.0 13.0 0.92
00:12.82 3536.0 11.0 0.92
00:13.10 3620.0 11.0 0.92
00:13.39 3716.0 10.0 0.92
00:13.67 3780.0 10.0 0.92
00:13.94 3840.0 12.0 0.92
00:14.23 3948.0 10.0 0.92
00:14.52 4032.0 11.0 0.92
00:14.81 4120.0 11.0 0.92
00:15.09 4208.0 11.0 0.92
00:15.38 4284.0 11.0 0.92
00:15.65 4376.0 11.0 0.92
00:15.93 4456.0 11.0 0.92
00:16.22 4552.0 11.0 0.92
00:16.52 4648.0 11.0 0.92
00:16.79 4720.0 11.0 0.92
00:17.07 4812.0 11.0 0.92
00:17.37 4872.0 13.0 0.92
00:17.64 4928.0 14.0 0.92
00:17.93 5004.0 13.0 0.92
00:18.21 5092.0 15.0 0.92
00:18.51 5152.0 15.0 0.92
00:18.79 5224.0 15.0 0.92
00:19.06 5288.0 15.0 0.92
00:19.36 5360.0 14.0 0.92
00:19.63 5416.0 15.0 0.92
00:19.93 5476.0 16.0 0.90
00:20.20 5524.0 16.0 0.90
00:20.50 5604.0 18.0 0.90
00:20.78 5660.0 18.0 0.90
00:21.05 5728.0 17.0 0.90
00:21.36 5780.0 17.0 0.90
00:21.62 5832.0 19.0 0.90
00:21.90 5896.0 19.0 0.90
00:22.20 5932.0 19.0 0.90
00:22.48 5988.0 20.0 0.90
00:22.77 6036.0 20.0 0.90
00:23.04 6084.0 21.0 0.90
00:23.35 6144.0 20.0 0.88
00:23.62 6180.0 21.0 0.88
00:23.90 6232.0 21.0 0.88
00:24.20 6264.0 21.0 0.88
00:24.48 6304.0 21.0 0.88
00:24.77 6336.0 21.0 0.88
00:25.05 6388.0 22.0 0.88
00:25.36 6408.0 23.0 0.88
00:25.63 6464.0 23.0 0.88
00:25.92 6508.0 23.0 0.88
00:26.20 6528.0 23.0 0.88
00:26.48 6564.0 23.0 0.88
00:26.77 6596.0 23.0 0.88
00:27.04 6632.0 23.0 0.88
00:27.35 6664.0 23.0 0.88
00:27.62 6700.0 23.0 0.88
00:27.90 6748.0 23.0 0.86
00:28.19 6784.0 23.0 0.86
00:28.47 6796.0 23.0 0.86
00:28.76 6832.0 23.0 0.86
00:29.04 6856.0 23.0 0.86
00:29.34 6892.0 23.0 0.86
00:29.62 6916.0 23.0 0.86
00:29.89 6940.0 24.0 0.84
00:30.19 6968.0 24.0 0.84
00:30.46 7004.0 24.0 0.84
00:30.75 6748.0 24.0 0.84

 

[andymoraitis]

What I find strange is how much timing you're running. Generally at above 2.1g/rev on the 2G stock ECU map, timing isn't supposed to peak that high. You could add the rest of the octane booster as it does take some time to disperse through the fuel, but that's still way too much timing. I have to admit that I'm a bit stumped. I've never tried to run 26 degrees of advance on race gas. The most I have my chips capped for is 23 and I run 12 daily. I'm going to PM our local ECU guru (steve) and see if he can offer some help here.

Andy

 

[kenamond]

What I find strange is how much timing you're running. Generally at above 2.1g/rev on the 2G stock ECU map, timing isn't supposed to peak that high. You could add the rest of the octane booster as it does take some time to disperse through the fuel, but that's still way too much timing. I have to admit that I'm a bit stumped. I've never tried to run 26 degrees of advance on race gas. The most I have my chips capped for is 23 and I run 12 daily. I'm going to PM our local ECU guru (steve) and see if he can offer some help here.

Andy

Here's a thought...I did that pull at around 7600ft elevation. Atmospheric pressure up here is 0.8 bar. That means I have a lower mass flowrate of air at 14psi boost than someone at sea level, right? That means the ECU would give me more advance, right? So maybe 26* is normal at this elevation?

Also, my boost was dropping like a pegged duck, so that would also lower my mass flowrate at high revs, too.

I bought FP rewire stuff today and was going to do a compression test tonight, but then this happened, so I've been drinking beer instead.

 

[JayRolla]

My timing stops at around 22*. My brothers car hits 26* and was fully tuned with minimal knock. So im not sure. I thought the most timing advance you could get without knock would create more power, am I wrong here?

 

[hottboost]

I posted this on the 2nd page of this thread!
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.

 

[kenamond]

I posted this on the 2nd page of this thread!
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.

I'm running stock timing. Andy seemed perplexed that I was seeing 26* on that 9psi pull. We are trying to figure out why I see knock with the stock timing, fuel, and boost (actually, lower-than-stock boost). I was suggesting that high altitude would decrease mass flowrate which would put me at a more advanced section of the stock timing map and that maybe that's why I'm seeing 26*.

So I don't disagree at all with what you're saying about boost making more power than timing - but I'm not fiddling with timing, I'm just trying to figure out what's going on with my car so I don't damage something. You wouldn't think I'd knock at 9psi boost.

EDIT: Okay, I see that you were responding to JayRolla.

 

[hottboost]

Yeah sorry! I should have put a quote in.

 

[kenamond]

Yeah sorry! I should have put a quote in.

No problemo. You wouldn't happen to have the stock timing map for a 2g ECU would you?

 

[hottboost]

Let me do some research but Im pretty sure it max's out at 16*. Let me do a little research and ill post back. Alright from what I can see your base timing is 5*! The stock map is a max advance of 16* with an a/f of 9.5:1! Now that a/f is pig rich. Most people I have talked to and researching you should want an a/f of 11.0-11.5:1! with as little timing advance as possible but a nice smooth line.SOMEONE CHIME IN HERE IF I AM WRONG PLEASE!! When you are at 9.5:1 a/f you will stay on the stock timing map, as your a/f change you will begin to work away from the stock map.AGAIN IF SOMEONE WITH MORE EXPIERENCE CAN CHIME IN CAUSE IM NOT 100% SURE ON THIS Now knock or Ph. knock will also affect this. If I find some more info Ill pass it on to ya. Your gonna have to get it on a wideband to see where your a/f ratios are at. That should help make it alot less complicated to figure out.

Carl

 

[JayRolla]

Ok if thats true about the timing than what should a 1g timing hit. My brother hits 26 but the tuner played with his timing advance. I am at 7*btdc because I run such low boost. Am I hitting 22* because of the base timing?

 

[hottboost]

On a 1G it would be much higher since the compression is much lower it will handle more timing ! Again I am still learning this as I go also. I am hitting 20*-22* max at 6500 rpms at wot. From what I am understanding with a stock bottom end you want to stay as close as possible to the stock timing map. After I get some dyno pulls( If I ever find time) Ill post back with my a/f ratios. I have found alot of good information in previous post by http://www.dsmtuners.com/forums/member.php?u=26146.

 

[JayRolla]

I am running 2g pistons so maybe I get knock sooner because of the higher timing map and the pistons. I saw lots of knock at only 13psi with my set up so I only run 11psi.

 

[kenamond]

Let me do some research but Im pretty sure it max's out at 16*. Let me do a little research and ill post back. Alright from what I can see your base timing is 5*! The stock map is a max advance of 16* with an a/f of 9.5:1! Now that a/f is pig rich. Most people I have talked to and researching you should want an a/f of 11.0-11.5:1! with as little timing advance as possible but a nice smooth line.SOMEONE CHIME IN HERE IF I AM WRONG PLEASE!! When you are at 9.5:1 a/f you will stay on the stock timing map, as your a/f change you will begin to work away from the stock map.AGAIN IF SOMEONE WITH MORE EXPIERENCE CAN CHIME IN CAUSE IM NOT 100% SURE ON THIS Now knock or Ph. knock will also affect this. If I find some more info Ill pass it on to ya. Your gonna have to get it on a wideband to see where your a/f ratios are at. That should help make it alot less complicated to figure out.

Carl

So am I to assume that my pocketlogger timing advance is base + advance? And if 21* is the max advance, is this at sea level? If you draw less mass flowrate per rev, it should advance more, right? I'm drawing roughly 80% as much air at a given boost than someone at sea level. Also, that pull was at 9psi, not the stock 11psi, so that would be less flow, too. So maybe 21* is the max at sea level on 11psi boost, but at 7500ft and 8-9psi boost, I should advance past 21*.

Maybe the 2g timing map is just not very good at high elevation and doesn't pull enough timing in that region of the map, so I get knock. I dunno.

 

[JayRolla]

Did you check to see if your sensor has the goo coming out. I had pk and so did my brother because of this. I would really look at this because ive heard they go bad around 80000 miles. I would really look when your car is cool. Or feel her up because like we said earlier you cant see it