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New Best Time


tawss04

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I got a new best time a NHRA Unleashed - 12.47 @ 107mph with a 1.6 60' time. I swapped to the TB torque converter and upped the NOS to a 175hp shot. Made 6 passes this weekend and on the last qualifying pass the truck was running good, left light (.176 on a pro tree, best reaction time all weekend and first time running a pro tree) The truck luanched hard and spun off the line. Had a 1.91 60' time (the worst so far) ended up running a 12.866 @ 108mph When I came to the trun off the truck stalled and when I restarted it I hard a tapping noise. We pulled the valve covers and checked all the rockers, pushrods and springs, they all are ok. It does not sound like a rod knock but it is time to tear into it.

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Well congrats on the new PB!. Sucks that she got hurt in the process. Just out of curiosity, what plugs were you running and how much timing did you pull?

The plugs are NGK TR5's they look good, not lean or anything abnormal. To be honest not sure what the timing is at, PCM4less tuned it for the nitrous. the engine has 113k on it and 60 or better passes with the tune. Its sitting in my shop right know and my other tech agrees its sound like a scared up cam lobe, I;'m not ruling out a piston until its torn down. I have the MSD LS6 controller I will be installing when I swap the engine.

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Honestly, you should be running at least 2 steps colder on the plugs and a non projected plug at that. NGK TR55s will become little blow torches at N2O levels you are spraying. You need to run BR7EF plugs or even B8EFS plugs gapped at 030-.035 (I prefer a tighter gap). As for timing, I would run 16*, do a run and pull the plugs to see where timing mark is at. Increase as needed. There is no "correct" timing value, plugs will tell the story.

 

I hope you are up and running soon!

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Honestly, you should be running at least 2 steps colder on the plugs and a non projected plug at that. NGK TR55s will become little blow torches at N2O levels you are spraying. You need to run BR7EF plugs or even B8EFS plugs gapped at 030-.035 (I prefer a tighter gap). As for timing, I would run 16*, do a run and pull the plugs to see where timing mark is at. Increase as needed. There is no "correct" timing value, plugs will tell the story.

 

I hope you are up and running soon!

I will do some checking on the plugs. When I researched for plugs these are what were recommended, as for projected :dunno: I do know not to run platinum or iridium. I'm always up for suggestions. I have been an auto tech for close to 20yrs, I'm not one to say I "know " everything. You can't know everything in this field. I learn something new everyday. Thanks for they advice :thumbs: I do check the plugs.

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I will do some checking on the plugs. When I researched for plugs these are what were recommended, as for projected :dunno: I do know not to run platinum or iridium. I'm always up for suggestions. I have been an auto tech for close to 20yrs, I'm not one to say I "know " everything. You can't know everything in this field. I learn something new everyday. Thanks for they advice :thumbs: I do check the plugs.

 

 

Here you go, this is a tr6 vs. the br7, Projected vs. NON Projected. The six is one heat range colder than the stock/tr55 andt he br7 is two heat ranges colder...

 

plugs%20TR6%20vs%20TR7%20resize.JPG

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I will do some checking on the plugs. When I researched for plugs these are what were recommended, as for projected :dunno: I do know not to run platinum or iridium. I'm always up for suggestions. I have been an auto tech for close to 20yrs, I'm not one to say I "know " everything. You can't know everything in this field. I learn something new everyday. Thanks for they advice :thumbs: I do check the plugs.

 

 

No iridium or platinum for nitrous. Plugs will make a big difference in a nitrous application when it comes to a meltdown or detonation. The ability for the plug to remove heat from the combustion chamber just may save your motor. I also wouldn't hesitate to sprinkle some race fuel in there at over a 150 shot. Back in the day, it was common to hear of a plug suggestion of a TR6 for nitrous however more recently a non projected plug has become a much better choice. For the old school SBC motors, a projected tip was often needed due to the poor ignition systems used and the inefficient head design. With the new LSx heads and the more than adequate ignition coils, a non-projected plug is required. Pulling the electrode out of the "hot" part of the combustion process aids in keeping the ground strap from becoming a glowing ember and eventually failing. I am very surprised that the tips of all of your plugs didn't melt (burn) off and look like the picture below:

 

dyno%20plugs.jpg

 

I would suggest reading through some of the info on LS1Tech as there are dozens of very good technical posts regarding plug choice for nitrous. Here is a good link from where the pictures in this thread originated from:

 

LS1 Tech thread (Projected vs. Non-projected plugs)

 

For the lazy (myself included) here is what a projected vs a non projected plug looks like when seated in the head:

 

Projected:

 

sparkplugs3.jpg

 

Non-Projected:

 

sparkplugs4.jpg

 

 

 

I hope you are up and running ASAP as your new motor sounds like a great platform for some power adder! :thumbs:

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