Help interpreting DataMaster file - Source of knock?
I ran my car the other day and as usual it's knocking like crazy. I think I may have figured some of it out though. If it's a base of 6 * and the spark advance is 33 *, this means total is 39 * right? And I looked at the .bin of my chip and it thinks the base is 4 *. So, since the base is actually 6, does this mean it's actually throwing 2 * more meaning a total of 41 * timing? And, when I look at the L Term Counts under WOT, it's reading 141 (meaning way lean) and the O2's are between 850-915 or so).
So, when I go WOT, is it reading way lean and too much spark? It's pulling a programmed 7 degrees max timing under knock retard. I've been trying to figure it out for a while now. I have been meaning to retard it to 0 * base to see what happens, but haven't gotten around to it yet cuz I don't have the tools.
Any thoughts? I'll see if I can attach my .bin and .uni from the chip and datamaster log.
__________________ 1989 super rammed 383 stroker No dyno runs or track times on the new motor yet 150 hp TNT nitrous ready and hoping not to twist any more half shafts!!
I*. So, since the base is actually 6, does this mean it's actually throwing 2 * more meaning a total of 41 * timing? And, when I look at the L Term Counts under WOT, it's reading 141 (meaning way lean) and the O2's are between 850-915 or so).
So, when I go WOT, is it reading way lean and too much spark?
Both correct. Too much timing and lean are a dangerous combo. AND the chip is programmed to only pull 7* max out of the timing? Timebomb
Looked at your .bin...don't like it, they played with things that are meant to save your engine like knock retard. And changed the base timing to 3.94*...what the hell for?
Man I literally have no idea what the tuner did to my chip and/or why. Initally after my 383 was done I got an Ed Wright chip. Well, my mechanic took it out saying it was pig rich, like way too rich. So, he ended up putting my stock chip back in and it seemed to run much better.
I took it to a dyno the once and the dyno operator knew a chip tuner he called in. Well, they got my car on the dyno and he brought it up to 2500 rpm and then went wot. Well, he backed out of it by 3500 rpm saying it was detonating like crazy. The chip guy started tinkering around with the chip. He added a lot of fuel to it to see if it was pinging from octane or whatever. Not the case, so at this moment I don't really know what is on it, let alone what has been changed. Well, I do have the .bin file (as you saw) but I don't really know how to interpret the results as of yet. I do have a Pocket Programmer and this week have ordered some stuff off Moates.net. I ordered 2 flash chips and an adapter which fits my memcal and the new chips.
Well the mechanic said he figured it out on paper to be like 9.5 : 1 but some guys here on the forum said with our heads (58cc) is different than most pistons recommendations (63cc) that it's actually closer to 10:1.
I had him do a compression test and I think he said everything checked out. Maybe I'll have him do another one just to double check everything. How would I check the cam timing without pulling the engine apart?
Well the mechanic said he figured it out on paper to be like 9.5 : 1 but some guys here on the forum said with our heads (58cc) is different than most pistons recommendations (63cc) that it's actually closer to 10:1.
I had him do a compression test and I think he said everything checked out.
Yes, 9.5 sounds very low to me. I think a stock LT-1 is 10.5 or a little better. Unless he used a deep dished piston and thick head gasket then 9.5 can't be right.
I'm not sure what he did for a compression test but it sounds like he just checked to see if the compression was balanced between cylinders. You need to use a "whistler" to measure the actual compression ratio of an assembled engine. Most engine shops would have one. You need to know the bore and stroke exactly to get an accurate result from a whistler.
The reason I ask is my Uncle had a similar problem. He had a 383 built for a Camaro, had bad detonation problems which ended up beating the rod bearings out of the engine in less than a year. When he finally had the CR checked it was very high, something like 12:1+. The engine builder made a mistake in his math when the engine was assembled.
Well, when I went to Agostino Racing to attempt to have a dyno run. The operator took it off the dyno saying it was detonating like crazy. He said it sounded like it had over 12:1 CR, kinda like a can of rocks. SO, the chip guy that was there played with the fuel and got it like a pig rich 10:1 afr and it still did it. I also one time got some 114 race gas which I mixed up with some 91 making a total of 96 octane and it still did it.
Yep, that's exactly what my Uncle went though. I'd bet your compression is real high and your engine builder made a mistake in his calculation.
One thing some people miss when calculating CR on a stroker is the fact that the cylinder volume is larger than a 350. Therefore you need a larger combustion chamber to keep the CR to a reasonable level. Sometimes people run the numbers as if it's a 350 and end up with a CR higher than they think.
Example, assume a 70cc combustion chamber (including all area when piston is at TDC):
What exactly do I need to figure out the CR on paper?
cc of heads, dished or non dished pistons? thickness of gaskets?
You need to have the engine disassembled. cc the heads, cc the pistons including deck height, crushed gasket thickness and diameter. Any little bit of volume must be measured.
It's easier for you just to find a whistler. Pull a plug, insert the whistler, and turn the engine slowly....bingo it'll measure your CR fairly accurately.
Seems like you should be able to pull enough timing to make it quite detonating.. What was the AFR like?
Do you have any oil consumption issues especially threw the PCV?
Have you thought about trying to make the car run even cooler?
Have you thought about a heat range or 2 colder plug?
You shouldn't nessisarly have to tear it apart. The trouble with high compression motors in street cars is they are extremely picky. If they get to warm, to hair to lean, etc they will ping. They have no play in them.
Yeah I think my next plan of action is to actually run 0 * base timing to see if this helps any. The AFR I believe was like 12.5 : 1 cuz the guy said he wanted it fat for nitrous. But then he started playing around with it and at one point got it to 10 : 1 to see if it'd help any. So, at the moment I have no idea what it'd be.
I don't have any oil consumption that I'm aware of.
I run NGK TR6 which is a heat range colder for the nitrous.
I'll ask my mechanic about this "whistler" tester.
Have you thought about using a stock binary? I don't like to re-use anything that someone else has made because you can't tell exactly what has been done.
That's exactly what I am thinking of doing once I get the rest of my programming stuff. I still need the adapter which has the memcal and the flash chip as well as the flash chips to come in.
First order of business is to put the stock (apyp.bin ?) on and see how it runs. Then start asking questions about how to tune for the 30 # injectors. I thought I kept my stock ones but am having trouble locating them, so I'm not gonna go out and buy new ones since I'm on a budget.
The timing is set at a base of 6 *. At least I think it is. I'm tool limited. It's either 6 or 4 , but I'm leaning towards the 6.
I have just visited your site and will be very interested soon. So, since I can datalog and program my own chip, you send the tune to me and I just program it, is that how the option works?
Yes, 9.5 sounds very low to me. I think a stock LT-1 is 10.5 or a little better. Unless he used a deep dished piston and thick head gasket then 9.5 can't be right.
I'm not sure what he did for a compression test but it sounds like he just checked to see if the compression was balanced between cylinders. You need to use a "whistler" to measure the actual compression ratio of an assembled engine. Most engine shops would have one. You need to know the bore and stroke exactly to get an accurate result from a whistler.
The reason I ask is my Uncle had a similar problem. He had a 383 built for a Camaro, had bad detonation problems which ended up beating the rod bearings out of the engine in less than a year. When he finally had the CR checked it was very high, something like 12:1+. The engine builder made a mistake in his math when the engine was assembled.
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Help interpreting DataMaster file - Source of knock?
