Sorry I have been gone so long. Lots happening, plus I had to hang out at the DevilsOwn forum to get the scoop on how this thing works.

Water injection is installed, but with smallest nozzle as per their suggestions. It is possible to change the nozzle size, and the rate at which the presure builds with this set up. So I could go with a bigger nozzle, but set it so it actually sprayed less water. Preignition is still there. It is clear that what is needed now is to just fool around with tuning parameters. I have no doubt I can get this working well, but there are manty permutations and combinations that could be trii I am not sure where to start. I thought I might start with at least one step colder plug; maybe even two steps. Here is the rundown.


1. Timing map has 20 degrees advanced at 1 bar pretty much across the RPM range. The timing goes down to 14 by 9 lbs boost, which is the max right now.

2. As stated, the boost is 9 lbs max. Waste gate is adjustable.

3. Am running 3 gph nozzle.

4. Turn on is 2, max is 6. This means it reaches max prssure by 6 lbs.

5. Have straight windshield washer fluid from advance auto in bottle.

6. Am running NGK- ZFR6f-11, plugs, which is one step colder than stock.

7. Have 195 thermostat,but it never got that hot with the cool weather of the evening here in Maryland.

Lights on controller indicate the injection is working fine.

If I stay out of the throttle enough to keep the boost down to 6 lbs: no preignition. If I go clear to nine: preignition is there. No bucking or jerking at all, which indicates I have not sprayed too much water yet. It wants to pull strong, but just sends the boost gauge into motion. The preignition is audible as well.

So: colder plugs? Less boost? bigger nozzle? Reconfigure the timing map? It seems as if I should be able to run 14 degrees at 9 lbs, but maybe 20 degrees at 1 lb gets the engine worked into a preignition hysteria cycle that can't be easily broken. I must say, I didn't think to look at the AF ratio, which I have a gauge for. The gurus on the DevilsOwn forum say you can reduce your AF ratio by two full points with water/meth injection. That would be to move up from 10.5:1 to 12.5:1. Too many things to think about the first time out. Next time I will look.Any brilliant thoughts here? Thanks in advance for thinking about it.

BTW, shaker223 has posted on the Devilsown forum that his fastest time is 13.23. That's pretty quick for a stock slant with nothing but a turbo and water injection. I have seen stock 340 Darts that were slower at the track.

Sam

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when you say the plugs are 1 step colder ,what plug are you refereing to, most call for a rv17yc in champion stock, with 5lbs of boost i was using rv9cy and found them to be on the border line, so i am considering rv59yc or 57 both are the coldest in champions.

I think the NGK application for stock plugs for a slant is ZFR5F-11. So the ZFR6F-11 would be one step colder than that. What would be your next jump up if you wereusing the NGK plugs? I think they go all the way to 9. I'll wait until I hear something back from you.

What is the down side to putting a colder plug in? It seems as if it might get fouled if you don;t go into boost routinely. This car is a daily driver in good weather. Drivability is probably more important than HP. I want it all of course.

What do you think about the timing map? What is your timing curve like as you cross the line from NA to boost? And, I can up the water injection easily.

Sam

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Hi Sam,

I have a few dumb questions:

1. Do you know what the air temp is coming out of your Intercooler?

2. Do you know what your EGT is?

3. Have you tried more fuel in your curve?

4. Do you have a wide band O2 sensor? Can you beg/borrow/steal one?

Answers to these questions will help understand what is happening.

Greg

I thought I was the guy who asked dumb questions around here.
The temp IAT last night was not hot. It never got over 100*. Still detonation under full boost. I do have a wide band O2 sensor. It is on a Inovate gauge, which I t hik can be daisy chained to the Accel ECU. I have to check into that.

I don;t think the problem is too little fuel.

I think the variable that are the best to play with now are
1, Spark plugs
2.timing
3.Injection GPH and rate of increase.
4. Boost. I can simply cut the boost back, and then sneak back up with boost rate as I figure the changes that will allow me to do that.

The questions are, which changes to make first.

Sam

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i have no exsperience with fuel injection, but i have seen the effects of to hot a plugs and too much timing under boost, i run a 4-71 blower thats carburated. i don`t know the cross reference from ngk`s to champion`s, but if an 11 in ngk`s is 1 colder step that is not very much colder.when i ask for a stock plug here it is a 17 in champion, with my high comp engine 10.5/1 if i tried to run a 17 it would missfire right at idle,with that engine a rv9yc was perfect,that is 8#`s colder.now with the blown engine i finding the rv9yc might be to hot and i am going to try a few steps colder. with the timing from what i have learned from this site and from trying what was suggested your engine with 14degs at 9lbs boost should work.

With the NGK plugs the temp is the number right after the first 3 letters. So ZFR5 is standard, (kind of like the Delco 45) and the ZFR6 is one step colder,(kind of like the delco 46). I don;t know what the -11 stands for. I think I have room to go at least two or three steps colder here though, based on your experience. I think I will go buy 8's maybe tomorrow. They say run the gap a little closer with water injection.

Sam

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just found a cross reference chart for ngk`s to champion`s, zfr6f-11=rc9mc4 and zfr5f-11=rc12mc4, i am used to rv9yc so i going to have to find if the #9 stands for the same heat range, if it does then i should be close for you but the zfr5f-11 is to hot if the #12 is the same heat range as rv12yc.

So you think I should try a number 9? I suspect that number means the same thing. AC delco's numbers go up as plugs get cooler in about the same way, so maybe champions do too. I currently have 6's in there.

The 14 for full boost sounds good to me too, and is confirmed by others as well. But what about right at 0 vacuum and no boost. Is 20 too high. How fast can you dump timing out when you are climbing through the KPA chart without causing a stumble, or miss caused by too sudden a change in timing?

Sam

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a cold plug will only hurt you on warmup once your engine temp is normal it should be alright, as for the plug range your #6 seems to be equal to my #9 if i am looking at this chart right so if you can get 2or 3 steps colder i would,in champion`s once you pass #9 they go higher#`s mean colder(#9,#57,#59) and so on

with the timing can you try a locked timing just to get a base and then increase it untill it stumgles or has a miss,just try keeping it at 14degs all the way to full boost

I have a full map of timing values I can shape. This means that for every RPM range and every vacuum boost range in a grid that is 16x16 I can chose a value, and when the engine is operating in that RPM and vacuum/boost range, the timing will be the value inserted into the cell.

I have been working to get the timing in the NA part of the map right, with the process being to raise it until you get a miss there, and then back it off a few degrees. This has worked pretty well, but there is still work to do. There are still some cells that I have not operated in yet. I am begining to get a feel for when the timing is too advanced by a hesitant kind of hunting, surging quality. At first it had to be bad before i knew it needed to be changed, but I am getting fair at feeling incipient missing due to timing that is too advanced.

I can back the timing down a little right at 100 KPA, (no vacuum and no boost), from the present 20* to 14* and see if that keep it out of detonation. I still wonder if jumping from 20 to 14 in adjacent cells is going to cause a miss of some kind. I guess it won;t hurt to try. Maybe I will just play around with this idea for awhile.

However, the plug thing is certainly a route to go also.

I just went out and pulled a plug and looked at it, and it was squeeky clean. No nothing on it. I think that is the result of the water injection. It was not melted, so it was clearly not exteme in the too hot range, but it was certainly not fouled either, which means I can go colder with it.

Sam

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i never used water injection so i don`t know how it will affect plug color but you should try to check plug color after a fuel throttle shut down so you can get a full load reading on your plugs, make sure you have a good soot base on the plugs to keep on rich side

The purpose of water injection is to keep the plugs and combustion chamer cool in the same way that a rich mixture does, wthout having to make it rich with fuel. The rich mixture has more fuel than is needed in order to control the heat in the combustion chamber. So, what I am told is, you can use a leaner mixture by 2 points when you add water. For instance, if you needed 10.5:1 without water, you can go to 12.5:1 with water. MOst racers use alchohol instead because it adds to the combustion process and produces more power.

Sam

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so tuning by plug color should still work, just the amount of water injected will be combined with fuel for a finial mix ratio,another tuning variable that has to be put in the mix,sparkplug base color or amount of soot deposit on the base is still going to give you a good idea what the ratio is doing to your engine.