Timing numbers ok or not? (91 vs 93 that I tested)

[05MAGNUMRT]

I use 91 octane fuel but I have an oil catch can and a breather filter for the crankcase on my 5.7L Hemi, so removing oil from the intake air leads me to believe I run a higher octane number, so I went from 91 CAI to 93 CAI settings, and the 93 CAI is more aggressive, which I like.

I tested LT, ST and total knock and I found those results when running WOT:
91CAI:
LT: 0
ST: goes up to 3.5
Total knock: 125

93 CAI:
LT: 0
ST: goes up to 8
Total knock: 125

Are those number ok? is running 93 CAI safe?

Other question is, I have the 9r05 version, it shows the 9r06 has better fuel economy for the 2006, does it affect the 2005 models too, should I upgrade to 9r17?

[mikel]

Well, obviously the 93 tune does not not like the 91 octane fuel judging by the KR present.

[05MAGNUMRT]

What's the difference between LT and ST?

Why does it still get ST 3.5 with 91 octane, shouldn't it be at 0 to have no knock?

If I don't go WOT it stay at 0, why is that? and is it safe to stay at 93 since I only occasionally go WOT?

Should I update or stay at 9r05?

[Quick]

What's the difference between LT and ST?

LT is just a slower reacting "memory". If you have ST over some value for some period of time it will store that value in LT and use that for a "base" and adding ST on top of that. Earlier cars didn't have LT. Only ST. You should adjust something if you see any LT.

Why does it still get ST 3.5 with 91 octane, shouldn't it be at 0 to have no knock?

Probably the gas and maybe oil in the manifold from the PCV. Do you have a catch can? If not, you should. Then you might have to try different brands of gas and/or even different stations for the same brand. The tunes seem to assume you have good/best gas of whatever octane (91 or 93). Not all brands supply that (mostly due to their additive package) and then there are area differences like they force all kinds of crap in the gas out here during the summer.

If you get it to zero and no knock at any time then you're probably leaving a bit on the table (but it's fine). I think ideally you would want to see maybe 1* (or 2*) right at shift points or when first putting your foot down.

If I don't go WOT it stay at 0, why is that? and is it safe to stay at 93 since I only occasionally go WOT?

If you don't go WOT then you're in a cruising mode where the PCM maintains 14:1 AFR, and mainly because the motor isn't under full load. and you CAN get it to knock. Try going about 25 or 30 in automatic. You'll be down under 1500 rpm or so. Then roll into the throttle about 3/4 but not enough to make it downshift. It will knock... The canned tunes only adjust fuel and timing for WOT mode.

Stay with the 93 tune? I wouldn't. Not with 8* knock retard. Knock retard is the PCM reacting to knock. You still get that initial knock event that the PCM detects before it reacts to it. The 93 tune is to take advantage of 93 octane gas. You're going to have too much timing for 91 octane gas.

[johan]

He did say he has a catch can.
I would try a different brand of gasoline and tune the 91oct tune again.
Cat back does not require any custom tuning.

[05MAGNUMRT]

Thanks for the info, I updated to 9r12 and I noticed the knock can be adjusted at different RPM ranges, so should I lower it by 3 at the high rpm range to make ST go lower with the 91 tune?

I went from 93 CAI to 91 CAI and it's not as aggressive, so that sucks to be running 91, and if 93 CAI setting makes the car run more efficiently, isn't that an indication that the engine runs better?

[Quick]

You do know that the predator will not prevent you from damaging your engine right?

[05MAGNUMRT]

Well,some weird stuff happened.

I updated from 9r05 to 9r12 and I get totally different readings.
Now I get ST 0.0 for both 91 CAI and 93 CAI but total knock is 15 at idle and to 1/2 to 3/4 throttle, but it goes down to 5 when I floor it, go figure??????????????
Either the new update dramatically reduced knock or the readings from DS are not reliable.

I noticed that the 93 CAI is more aggressive than the 91 CAI in the form of throttle response, when I step on it, it is more awake and downshifts more quickly and more aggressively.

Gas I use is still the same, nothing changed, any thoughts on what the new update did, it looks like it lowered knock by a whole lot, which I like.

[05MAGNUMRT]

Well, obviously the 93 tune does not not like the 91 octane fuel judging by the KR present.

I would expect more of an expert answer from you, especially since the DS comes with nothing to explain what all that stuff means.

[Quick]

There really isn't much more to say about it. I'm not defending MikeL (who may be king of the short answer ) but from your posts in this thread you've given the impression that you really don't have much idea of basic tuning concepts for gas engines. Diablo has addressed that market by selling the handheld bundled with some generic tunes for basically stock engines. Since they are generic they have made them pretty safe. The tunes are mostly tied to a grade of gas. The 91 octane tune assumes you're using good 91 octane gas. The 93 octane tune can take advantage of good 93 octane gas if you have it available and choose to use it. The 93 octane tune is not for use with 91 octane gas. The differences between the 91 octane tune and the 93 octane tune are only changes for the difference in the gas (primarily more timing).

The handheld also gives limited capabilities to adjust/tune a number of parameters but it's basically a delivery mechanism to program your car with an existing tune that may or may not have changes the handheld is not capable of making. Then there's all the peripheral stuff like fans, tire sizes, gears, shift firmness, stick behavior, rev limiters, etc.

Note that the handheld assumes you know what you're doing. The handheld is a tool allowing you to tune your car (or get one on there). Think of it like a wrench. Craftsman is going to tell you what the wrench is for and what it will do but they're not so much going to teach you how and why you should torque a bolt and what the effect of the threads being dirty or oiled will be. You can strip your bolt with their wrench and you can ruin your engine with the Predator.

Having said that, and given Diablo's market for this product it might be nice if they had an online wiki/tutorial type of thing explaining tuning basics in the context of the predator.

My suggestion would be to go to one or more of the car forums and run these same questions/observations. Lxforums.com might be a good choice. You'll have hundreds to thousands of people with info and advice to help with what's going on. You'll get some of that from people here as well but there isn't near the volume of people here.

[fordomatic69]

^^^ I could not have said it any better myself. Good Show Quick

[05MAGNUMRT]

how about an answer to this: Now I get ST 0.0 for both 91 CAI and 93 CAI but total knock is 15 at idle and 1/2 to 3/4 throttle, but it goes down to 5 when I floor it, go figure??????????????

Why did the 9r12 update cause my total knock to go from 125 to 15?

[johan]

The total knock pid is the total amount of spark allowed to be pulled due to knock, it is not actually your spark knock, ST and LT are the parameters you need to look at for spark knock.
We revised the tunes between those rev quite a bit.

[Quick]

The total knock pid is the total amount of spark allowed to be pulled due to knock,

ooooh. now that's cool! I always knew the amount was limited but I had thought it was a constant number at something like 9* (at least for the 6.1s).

[johan]

Stock 5.7L
RPM deg pulled ST and LT combined
6000 5
5200 7
4800 9
4000 10
3600 10
3000 12
2000 12
1200 15
600 15

Stock 6.1L
6500 10
6000 12
5000 12
4200 14
3600 15
3000 17
2000 18
1200 20
600 20