Just completed my first logging session with the Predator

I can't seem to find a comprehensive write up on how much ST or LT knock is acceptable. Does someone have some time to take a quick look at my log file (running 91 CAI tune) and tell me if the amount of knock I'm seeing at WOT is okay. If there is too much can you suggest what I do from there, add fuel or pull timing?

Any help or guidance would be appreciated.

http://www.telusplanet.net/public/cpeirens/Logs/SuperBee_2009-05-14.log

If this log isn't comprehensive enough, let me know and I'll do it all over again with more/different PIDs.

 

I'd say it's too much knock and too constant. It's not danger! danger! levels but it's too much. What you're looking for is up to maybe 2* right around shift points and when you first put your foot down (or none, but then you'd be on the too conservative side). Maybe just maybe a spike somewhere (still 2* to 3* max). The knock retard you do see should spike and then taper off to zero right away. No knock retard most of the time.

Looks like your knock retard is kicking in right around 3800 rpm. Try adding 10% fuel in the middle range and 7% in the top band. If knock retard goes to zero all the time then try backing off a bit. Sort of hunt around until you see just one or two knock retard events as described above.

Could be the gas you're using (often is). Try some different brands (diablo has a recommended list). If you don't have a PCV catch can you should get one. Our engines tend to suck a bit of oil through the PCV valve into the manifold where it eventually gets burned. This will tend to cause knock like you're using bad gas.

If you end up adding around 22% gas and the knock retard is still there then you would pull a degree of timing and start over with the gas adjustment. But if you have to do that then it's even more likely it's the oil or bad gas.

 

Thanks for the comments.

One thing, Diablo's recommended list doesn't have any credence up here in Canada. Even Shell isn't the same Shell. But I can try different brands. Esso/Mohawk/Husky and see what I get.

I'll go and update the tune starting where you suggest. Just pointing out that the knock I'm seeing is too much, is enough for me to focus my efforts. I've tuned my fuel injected Harley's so once I know what is good and what isn't I'm usually good to go. Of course, with just the Predator, it's quite limited in what you can change. I'm used to being able to adjust more minutely, but I guess there's not much point until I do some engine upgrades.

Thanks. I'm off to go tweak. :magic:

 

The Diablo canned tunes are pretty good. A CMR isn't going to buy you too much more performance wise until you go past minor mods. It can still be worth it if you want things just so. You're right about the Predator being limited as to what you can access and to what granularity.

The sample rate in the log looks to be pretty slow. Don't log so may pids. Try to keep it down to about 8 at a time. The way that work is that the polling for pids is done serially, one at a time. The spec says the scanner is only allowed 1 outstanding poll at a time so it has to wait for the reply or a timeout before polling for the next pid. Some responses take longer than others (PCM has to calculate some, poll other modules for info for some, etc. so the more you're logging the longer it take to get back to any particular one. I'd keep
IAT
ECT (maybe, probably not since you know where that's going to be at anyway)
RPM
Pedal Position %
Actual Spark Cyl 1
KNK ST
KNK LT

Get yourself a 180* or 185* t-stat (and set your fans accordingly). That will make a noticeable difference. Motorad 4128 is a good 185* t-stat that fits (a little snug... and save your gasket because it doesn't come with one).

A PCV oil catch can really is a must have if you're going to run any kind of tune. The stock tune is mild enough that burning a bit of oil from the manifold doesn't really effect things much, but anything a bit more aggressive and you may not be able to get the knock retard resolved.

There's a few Canucks around here... Hemisfear comes to mind (he wears mukluks, be prepared if you meet him). Somebody can make recommendations on gas.

 

Gotcha on the PIDs, I'll reduce them for tomorrow's logging.

Tstat is on the way. I'm actually gonna run the Motorad 4127 (170º). Waiting on a shipment of 5 from Autozone. Can't order from Canada, so a buddy in MA did it for me.

Hmmm, you know I'm just not convinced about those catch cans yet. Not enough empirical evidence in my view. Although, I suppose for the minor cost it wouldn't kill me. Sigh, something else to add to the list. Anyone have one they wanna get rid of?

I'll do my best to be prepared. LOL Thanks.

 

Get a good catch can. BT has a good one, and they have the bling too (I have a McKinney). We have a pretty good amount of empirical evidence. Invariably, when people pull their manifold without a catch can there's oil laying in it. Everyone using a catch can catches oil. Those that measure it find it to be right about 10 ml of oil every 500 miles. There's no doubt theres oil going through there. Is it that it contributes to knock that you're not sure about?

 

Quick is our resident, thinks he knows it all, guru. lol

Dave (Quick) has given you great advice.

 

dahahahaha. A long list of things I've never done and didn't happen to me immediately popped into my mind... :whistle:

A 170 t-stat is even better but you're getting close living up North there. If the engine doesn't get up somewhere over 167 in some amount of time over some number of key cycles it will throw codes. Then there's debate about getting other fluids up to some minimum operating temp. Shouldn't be a problem in the summer. You just set the fans where you want.

 

teeee heeee


Here is a How-To for fan control settings. http://www.srtconnection.com/forums/showthread.php?t=7403

 

That and if there's really any benefit to having it at all. I would imagine the techs at Dodge would have thought this through. LOL Yeah, I know they don't know everything and it's probably within whatever limits they've established. I would be more than eager to sift through a thread or two discussing catch cans and their true benefits, just point me in the right direction.

No worries. As I understand it the 4127 opens at approximately 175º. A buddy of mine has been running his all winter, not one code. Agreed, fan settings are the key.

 

No, no, the SRT8 engineers do know everything. But they designed with a 100K duty cycle, and the stock tune. With the stock tune the engine will go 100K, knock is not a problem and they still meet emissions to boot. It's when you add timing and adjust a/f with a little better air flow, etc. to squeeze that extra 40 hp out of it that it becomes an issue. There were miles of threads but it was over a year ago (maybe two)... You might have to dig a bit.

 

Digging I can do. LOL

So, anyone got a used catch can then wanna sell? Working on a budget here.

 

There will be a bit here. You can search on srt8oc.com and lxforums.com. It got hashed out a couple years ago and since then it's been mostly who has the nicest looking one or the easiest mounting solution.

Good luck on that. There are only about 3 decent ones. No one decides later that they don't need/want one, and they don't break or wear. I guess a couple of people might have got another one when they changed their engine bay color scheme. :grin:

 

I guess $110 + shipping from BT isn't too bad, although after exchange it's like $1000 Cdn. LOL

 

So, I'd like to revisit this. Quick, if you're the "Quick" over on Diablo's forum, I promise not to get into the no ABS on the track discussion.

So, a quick recap. I've been under-performing at the drag strip compared to similarly equipped (CAI, exhaust, tstat, Predator tune) SRT8's in this area. Car seems to bog down at the start and doesn't wind up as much either.

Through data logging and some investigation, I see a huge drop in timing as you drop the hammer. I've seen instances dropping from 18º down to 4º or less (-1º). Part of this is due to the fact that the 09's (and maybe some late 08's, yet unconfirmed) now have a three-stage ESP system. You are no longer able to completely disable ESP using the dash button (hold until chime) or turn it off with the Predator (dyno mode). The system is now so integrated/intertwined that if you want ESP completely disabled, then ABS/BAS are also disabled.

So, given the following log file, do I still need to add more fuel (91 oct tune with 91 fuel with the ABS/BAS/ESP off). I see no LT knk, and the majority of the ST knk is around shift points. I was also told that sometimes ST knk is recorded (falsely) riding over bumps. Comments on this?

http://www.telusplanet.net/public/cpeirens/testing_91_CP_noESP.log

I still need to get a catch can. Mileage on the car is just over 6000.

 

The same. You should bring it up. I think you (or me) will be surprised at the response. We got a whole lot of people with a whole lot of drag racing experience here.

The issue was: Is it all that big of a thing to turn off your ABS on the drag strip. Not the ESC or torque management (that's good for the track), just the ABS.

Log looks great with respect to knock retard -- perfect. You're getting a lot of timing but the commanded afr is in the 9 to 11 range?? Just how much have you added with the Predator? With your basically stock car that's probably going to be in the same ball park as actual afr. You really need to get a wideband afr gauge. The stock 6.1s are going to do best around 12 afr. That may involve less timing but that's where they seem to make the best power.

You may also just be drowning the knock from whatever gas you're running or the lack of a catch can by running it pig rich. No knock but maybe not so good. Your cats wouldn't last as long either. Again, can't be sure without the wideband. If you don't want to invest in a wideband then you could take it for a pull on the dyno. That would tell you where you're at on afr along with some indication of the power you're making. Then you'd have something to compare.

 

Actually, I should clarify this. I wasn't condoning turning off just ABS. What I was saying, with these 09's, that the only way to turn ESP completely off is to turn the whole system (ABS/BAS/ESP) off, and that in my opinion the gains of removing ESP outweighed the need for ABS. I hope that's clear.

If I had extra cash, I would already have the catch can and the wideband (cat-less). Guys up here don't do just a pull on the dyno, so that's not an option. You pay for an hour or more of shop time ($115+) plus the hassle (time == $) of securing and un-securing the car.

I suspect you're right about it being overly-rich. After I did the logging, I confirmed with Johan that the adjustments (fan settings, raised rev and shift points, WOT Fuel, etc) I had made to the original stock 91 tune were "hidden" within the tweaked (turning off ABS/BAS/ESP) custom tune file he sent back. I didn't know that so I added more fuel (5/8/8) to the already set up 6/10/10. Typically up here (3400 ft, 4000 DA) that's what gets added to a base tune file to remove the KR. I had logged before that to get those numbers into the tune. I should go out with his tune file (with no fuel added) and log it to see if the AFR is more aligned to what you're suggesting.

 

Well, before the locals complained (back road, way out in the boonies), I got a couple of runs in with a 91 CAI tune that has 1.5%, 3%, 3% added to the WOT Fuel tables.

http://www.telusplanet.net/public/cpeirens/Friday_2009-07-17_91oct_1.5-3-3.log

No LT knk, but too much ST knk for my liking. Best of the runs produced a 14.24 at 103 mph on the EVIC, with ESP partially off.

As far as I can tell this is about the best gas I can find around here. I'll keep trying once this tank is burnt off, but there are few choices without wasting an 1/8 of a tank just to go fill up.

My next attempt would have been 3%, 6%, 6%. Thoughts? Comments? Suggestions?

I'm off to the track at 7:30 EDT. Elevation is 3400 ft. Temp will be at/near 75º F, Humidity around 47% and Pressure about 102.28 kPa. Hopefully they'll let me data log during my runs so I can continue to tweak the tune.

 

Can't imagine they wouldn't let you data log? Just don't have it lying loose up on the dash when you stage

The knr is not bad... just a bit too constant. If you're going to adjust fuel I'd move in larger increments initially and then smaller increments if you overshoot. Like go to 4,8,8 or maybe 5,10,10 next shot?

Your IATs are really high at the start of a run. It's be nicer if you could test when it's cooler. Or maybe just cruise at about 35 until it comes down to something reasonable, and then do a stop'n'go before it goes way up again? Your IAT was almost 140 at the start of the first run and 130 at the start of the second.

 

LOL. Nope, not on the dash, on the passenger seat. Within arms reach to press the spacebar to start a recording.

Do you know of any reason why I wouldn't run the same % in each area? I'm not sure why I chose 1.5/3/3 in the first place. What about 8% or 10% across the board? Just asking. Hopefully I can get a few runs in tonight and produce a decent sub 14.0 sec ET.