niphilli

Hey Matt-
Just tried to call but could not get through.

I was doing some research on the predator and came across some info. Diablo tuning Guru was saying that lots of times KR comes from being overly rich. I am not sure how this works because I know that leaning out causes detonation/pinging which causes KR. But apparently do does being too rich. Your car is extremely rich off of idle, burned the **** out of my eyes. I think you mentioned that the guy from Grundy also had an overly rich idle. Could be that you are dumping too much fule down low and at idle and when you first roll into it the too much fuel burns off and causes KR- All of this is just thinking outloud.

Also forgot to ask on the phone. Are you hearing/feeling any detonation or pinging?

Anyone know exactly why being overly rich causes detonation??

VTtransam

Nick, I think you could be right on this one. I pulled one of my plugs last night and the electrode seemed to be gone! There was black residue around the outter ring of the plug (carbon?). The inner part of the ring was covered with a redish residue. Also there seemed to be oil on the threads . I'm also going to try and run a slightly heavier oil to hopefully clear up some of my blowby.

My dad says that not all my fuel is burning and that I may need a hotter plug. I do have the TR6's currently but will be installing the TR55's gapped at .048" when they arrive. I guess the old man still has it in him.

Does all this sound about right? Does my plug indicate that I'm way too rich? Any suggestions?

Thanks,
Matt

niphilli

Yep, a rich plug will be black and the electrode can be burned off. Lean will be white. a perfect plug will be a non-damaged electrode with some white on it. Switch to a non-synthetic 5 or 10w 30. Use the 10W 30 if you plan to spin the motor to your redline. The guy at diablo said that a rich condition will definately cause KR.

Can someone clear up why being rich will cause KR?

NoGo

iTrader: (2)

It takes one hell of a rich condition to cause KR, but it is caused by the fuel not atomizing properly with the air.

A properly mixed air to fuel ratio entering the cylinder will burn smoothly and cleanly.

When you start injecting gobs of fuel into a given amount of air you reach the saturation point of the air. Saturation is the amount of fuel that a given volumn of air can hold in suspension before fuel begins to drop out of suspension. When the fuel drops out of suspension it forms droplets in the air. These droplets combust like little bomblets in the combustion chamber.

VTtransam

Very interesting Kevin...

Is there a way to if this is happening?

At about what amount of fuel does the air reach its saturation point in a 5.3 head combustion chamber?

Thanks
Matt

niphilli

Kevin,
What would the plugs look like if you were getting this condition?

VTtransam

Well I got the plugs in. I talked to Brent from TEA and he recommended the TR55's gapped at .045. So I did that and drove the car around a little with Atap monitoring the KR. I didn't see nearly as much as I have been seeing in the past week, but I still saw a little KR.

Well I got brave and decided to take the car to test and tune at my local tack. I Atapped each of my runs... I got KR through first and second gear, timing was as low as 21 at WOT in second. This run only yeilded 112 mph. The weather was hot and humid (about 86* 90% humidity aprox.), tack elevation is 1250ft. My short time was 2.34 and I granny shifted my way to a 13.6 et.

Nick I'll show you my logs when I get down to school. There is definately a partern. Right after I shift and got to WOT, I see KR. I think its dumping so much fuel into the mixture as soon as I go to WOT. My O2 readings vary between 1016 and 930. I've heard you can't really go by those though.

I may just tear it down over Thanksgiving break and reassemble everything. I don't know what else to do. Mike says the injector tuning is right on.

I'm gettin pretty frustrated

Matt

niphilli

Hey Matt,
Those track numbers actually sound pretty decent. From the sound of things the DA was probably around + 3000-3500. That would correct to 116 mph (+3000) and 117mph (+3500) at sea level with good weather. Granny shifting I bet that you were not even near the cams peak. Sounds like your car has 118-119 MPH in it when you get all of the tuning sorted out and spin it a little higher.

IMHO your problem is not mechanical, could have something to do with "blow-by" but dont tear anything apart yet. It still "sounds" like fuel delivery to me because it is pretty consistent in when it happens and seems to only happen at part throttle. An o2 reading of 1016 is VERY high, though o2s are not good tuning devices they still give you a ballpark figure and 1016 MV is out of it. Was this in-between shifts or right after a shift? Part throttle or full? If I remember correctly part-throttle o2 reading should be more lean than WOT, but you could get a spike at a shift (expecially a powershift). How is your gas-mileage? Could you possibly have an 02 sensor going bad? Did you delete your rear o2s?

VTtransam

Nick, I was seeing that 1016 at WOT. I was thinking it could be the O2's as well. I didn't delete my rear o2's, but I'm not sure if Mike did with LS1edit, I didn't even think about asking him to. I'll show you my data tomorrow and you can take a look and tell me what you think. I logged 2 runs, the other run I hit 5th instead of 3rd, but I guess thats better than hitting 1st!

I'll give you a call tonight when I get down to school.

Matt

niphilli

Cool, have a safe trip.

https://ls1tech.com/threads/showflat...=2&fpart=1