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Discussion Starter · #1 ·
I had 2003 ford mod motor w/Kenne Bell on alcohol built. I am running 28-29 #s of boost. Car dynoed 780 at the wheel. Motor is in my newly built 2008 tube chasis full fiberglass shelby. I have not gotten a full pass down the track yet due to the identical reoccurances every time and have now lifted the head gaskets twice. I am running the fast xfi fuel inj. and msd digital 7al ignition.
The datalogs shows about 2/3 track every time the boost spiking to the gauges max of 31#s and my rpm completely falling off @ the exact same time instantaneously. It is like the motor is just loosing all hp. The plugs are NGK TR6 and are snow white and have noticed the porceline is being peppered and some electrodes even being burned off. This was happening most recently in the retunes that were put on the computer. I finally talked to tech @ Kinsler Fuel Inj. who did my fuel system and what he is saying is my plugs heat range is way to hot, he is essentially saying which I'm finding is that I pretty much starting detonation. I have put in the 3 step colder plugs, but have not had a chance to put it down the track yet. Hoping to this Saturday. Numbers so far down the track as far as I've gotten have been great. Car w/ me in it weighs 2600#, 60' time 1.17, 1/8 mile if I remember was low 6's, fastest in the 1/4 the car shutting down was 8.78- that time had a mph of 131 in the 1/8 and 131 in the 1/4.. So the car is pulling hard, but I am stumbling with this boost/hp/fuel/ign./plug issue. If anyone would have any insight in this, anything would help to possibly look at before putting it down the track with this issue.

thanks in advance,

Armageddon Racing
 

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DANGER WILL ROBINSON!!!!

If you were trying to run NGK 6's that is your problem. It's causing preignition and/or detonation. I ran into the same deal when I first switched to alcohol - it pulled pretty well to 1/2 track on the gas plugs I was using but then nosed over hard. Once I switched to a NGK 9 it fixed the problem.
 

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AR 94 or the Ar 472 473 474 will fit the head. the AR103 is about the same as a
tr6. Also note to you. Be easy on the timming the 4v mod motors do not really need it.
 

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The colder plugs are definitely a big step in the right direction. As far as timing, most mod motor combos seem to be happiest around 16-18 degrees of total timing. That is assuming you aren't running outrageously high compression.. If it still detonates after the plug change and with modest timing, then add fuel. You may be surprised how much fuel you can put in it..

-Chris
 

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Discussion Starter · #6 ·
Timing is 16 and compression is slightly higher than stock. I believe it is like 9.5. The A/F guideline Cal @ Heartline Performance has it set @ with alcohol is 4.0. Thruout the pull it is always below 4.0 . it is like 3.75 I believe. I forget who posted first sounds like the exact situation that I am encountering. What combo are you or were you running when you encountered this symtom? If anyone knows how I can post my datalogs thru my fast system I would love to post then to see what you guys think or see. Thanks for your input everyone.

Armageddon Racing
 

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Discussion Starter · #7 ·
Just tried the 3 degree colder plug and did the same thing. Now wondering about the blow off valve shutting and forcing the boost into the motor and lifting the head. Then somebody just mentioned about the msd possibly failing on high rpm. I know someone had mentioned about even adding more fuel, but a/f doesn't to appear to have spiked in the datalog. Any ideas.
 

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A safe A/F to start with on a roots blown motor is going to be 3:1. Your 3.75-4:1 is a bit lean to be starting with.

What MSD box are you using?
 

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I'm running M3 in my Lightning with a 5.4 and a turbo. I'm deep down in the 3:1 range on it to get it to run clean. Ironically I'm using TR6s as well, and the first time out had some "lean running" feeling at about 4:1. I have some 8s I was going to put in it but I havent had the truck out since February, trying to get it looking pretty again after the mishap last fall.
 

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Discussion Starter · #10 ·
Running a msd programmable 7digital plus. I thinking we are getting false readings about the a/f being rich. Because in the last testing this weekend the car ran faster every run we added fuel, but it was only the last run and ironically the fastest run of the day that the car lost all hp @ the end of the run. But it still was not a great pull even before it shut down. I talked to K.B. and they believe it is electrical, i.e. either msd or FAST. He's maintaining when the boost spikes, the rpms are dropping instantly at the same time. He is saying I am under load/boost and motor is shutting down electrically which is essentially a closed system/block and there is no where for the boost to go and that is why I am lifting head gaskets. Talked to msd and they said no way, but k.b. says yes. Saw another forum guy was talking about him lifting gaskets due to his msd shutting down, put another one on and didn't have anymore problems. What k.b. was saying I thought was making sense. Blower still spinning making boost, but motor shutting down and pressure has no where to go. Interesting msd mentioned my ignition is the only ignition has a boost safety shut down that I was not familiar with. I first thought this was great, no more lifted gaskets, but if truely my problem is that the msd is shutting down seems to be a failure of the msd, thats no different than having it shut down at a predetermined boost level. Now looking at previous runs it is happening @ higher rpm's and or higher boost levels. Wondering if there is a setting shutting me down in the msd or boost level that is set too low. I thought I maxed all of the setting so they never interfered w/ my runs. However it could be failing internally also. I am going to email the setting I have in it right now to msd so they can tell me if they see anything incorrect. I don't know, this is just very frustrating, it might not even be that. Maybe it needs more fuel. I apparently was lucky this last test session, just did a leak down and nothing hurt at all thankfully.
 

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I dont buy that bullshit at all.

Stop watching that damn A/F meter and read the plugs.

Let the plugs tell you what the motor wants for fuel/timing.

Run the correct heat range plugs (NGK 5671A-8, 9, or 10) for alky before you detonate the pistons out of it.
 

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Not sure about your setup, but what I see is that you might be talking to way too many people -- first Kinsler who set up your fuel system, then Cal who did a XFI tune and then Kenne Bell.

I'd say get back to the basics, listen to the guy who put the original tune in (Cal Hartline), make sure you've got enough fuel, starting reading the plugs like WJB just said and then learn the system.

Good Luck, you'll get if figured out.
 

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Discussion Starter · #13 ·
I here what you guys are saying and I am trying to just rule out by talking to people the different possibilities just in case it is not the tune. Incidentally, talked with msd today and explained to someone else @ msd and his first question after I told him what was happening was what kind of trans brake button am I using. He asked if it was adjustable. I thought this was an odd question, but I am in fact using an adjustable one. He said he personally has seen numerous adjustable buttons being the problem. He explained that they are so sensitive sometimes to vibration particularly @ hi rpm that it is sending signal due to vibration to the msd and shutting it down for a short second and allowing the rpm to go back up if you give it gas. I do know there is a safety feature that does not allow the trans brake button acitvate after release for a certain period of time for safety you don't hit it when you are at speed. He is saying the msd does in fact shut down when you hit the trans button @ speed for safety. He had replaced the adjustable with the simple non adjustable w/ a car having this same shutdown issue and immediately it was fixed on the next pass. He recommeded just for shit and disconnect the wire from the msd going to the trans button and try a pass foot braking it, this I have never tried. This will be interesting. He recommended also getting msd's engine ignition tester to check for loose connection or faulty equipment. Hell, I don't know, just trying to eliminate the different possibilities.
 

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I had 2003 ford mod motor w/Kenne Bell on alcohol built. I am running 28-29 #s of boost. Car dynoed 780 at the wheel. Motor is in my newly built 2008 tube chasis full fiberglass shelby. I have not gotten a full pass down the track yet due to the identical reoccurances every time and have now lifted the head gaskets twice. I am running the fast xfi fuel inj. and msd digital 7al ignition.
The datalogs shows about 2/3 track every time the boost spiking to the gauges max of 31#s and my rpm completely falling off @ the exact same time instantaneously. It is like the motor is just loosing all hp. The plugs are NGK TR6 and are snow white and have noticed the porceline is being peppered and some electrodes even being burned off. This was happening most recently in the retunes that were put on the computer. I finally talked to tech @ Kinsler Fuel Inj. who did my fuel system and what he is saying is my plugs heat range is way to hot, he is essentially saying which I'm finding is that I pretty much starting detonation. I have put in the 3 step colder plugs, but have not had a chance to put it down the track yet. Hoping to this Saturday. Numbers so far down the track as far as I've gotten have been great. Car w/ me in it weighs 2600#, 60' time 1.17, 1/8 mile if I remember was low 6's, fastest in the 1/4 the car shutting down was 8.78- that time had a mph of 131 in the 1/8 and 131 in the 1/4.. So the car is pulling hard, but I am stumbling with this boost/hp/fuel/ign./plug issue. If anyone would have any insight in this, anything would help to possibly look at before putting it down the track with this issue.

thanks in advance,

Armageddon Racing


you have answered your own problems....

if you are pushing out head gaskets , tipping plugs, and show pepper on the poicilin ( spelling), you have too much cylinder pressure, and or too much heat too soon in the firing stroke.(dentination)

bit more fuel , to cool the intake charge, cooler plug to draw heat out of the chamber, to have a controled burn in the cylinder.

steps taken to lessen the dentination will fix the problems
can you post any pictures of the plugs?
is the cad burnt off the plugs before 1/2 track ??
where is the timing mark on the earth strap ??

cheers
ash
 
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