narcszm

I've got a 346 LS1 with 5.3L heads milled 0.020" yielding about 11.7:1 static compression. I'm getting some pinging in 6th gear at low rpm and I know it's because of pre-ignition causing detonation. I could pull some timing but HP Tuners hasn't showed up yet. I've learned that changing to a colder-temp spark plug is probably a good idea and I'm having trouble deciding which ones to put in. I bought both NGK TR6 and NGK BP7EFS and am comparing them to the stock plugs right now.

As expected, the TR6 has a slightly shorter insulator tip and it's even shorter on the BP7. I'm running N/A right now and am not planning on juicing it. I might be supercharging the motor with low boost (4psi) soon, but want to know which plug to run until I get there.

Here are the plugs;
TR6 on the left, Stock AC Delco in the middle, and BP7EFS on the right.

strokedls1

iTrader: (1)

I have run the tr6 for years. I used to have a 346 with about 11.8-1 compression, and I still had some pinging with 91 octane. It may work better if you have higher octane fuel available. Lowering the coolant temp helps alot to decrease the detonation. 160 thermo with lower turn on temps for the fans. You will be able to tune it out with hp when you get, but what I suggested will allow you to run more timing.

Bill Bowling

iTrader: (6)

TR6's should be fine.

Bill

narcszm

OK I just put in the TR6 and I'm fixin' to go out on a test drive. Will post results.

Visceral

iTrader: (1)

fixin'ta.

fixin'to sounds like some kind of hybrid Texan/metrosexual confusion.

CAT3

iTrader: (9)

Hell running stock still bad enough reason to cause det. Make sure you tell us how it worked for you and the gap you used.
NA TR6 mine was .040"
175shot TR6 was .030-.032"
also used R5724-8 (V groove) for 175+ at same gap and on street worked fine.

goober35

iTrader: (1)

If the TR6 have problems try a even cooler plug like a TR7 or even a TR8. When it gets hot here i go from a TR55 to a TR6. I am fixen'ta put my motor back in the car after X-Mas and will be running a TR55 because i have 9.1:1 CR and i have 93oct.

narcszm

There was a slight improvement with the TR6 but there's still some ping. I tried straight pump fuel (without xylene which I've always added since I did the heads) and it was noticeably worse so there's still quite a bit of pre-ignition going on. I knew I should have gone straight to the BP7s. I'm gonna pull the TR6 plugs to make sure they're not fouling (unlikely) and if they're clean I'm going to move on the the BP7EFS.

I'm not sure what to gap these at but I hear most peops are running 0.030-0.040" on these colder plugs. I left the TR6 plugs gapped as they were from NGK. I can't imagine I'm having any spark or burn issues related to plug gap.

narcszm

TR6 are NGK spark plugs. TR7 and TR8 are british sports cars.

00Trans Am

need help will the alum. heads from my trans fit the ls1 iron 6 liter block

narcszm

why are you posting in here? did you mean to start a new thread? yes they will fit but your compression will be up on the LQ motor as a result.

goober35

iTrader: (1)

That is a TVR not a TR7/8. You have to custom order them from NGK. Do some research before you open your mouth again and say they do not make TR7/8 plugs.

goober35

iTrader: (1)

Are u asking if the ls1 heads will bolt up to a 6.0 LQ9/4 iron block. If this is what u are asking than yes they are a straigh swap.

narcszm

OK, I didn't want to further embarass you but you asked for it. NGK has no spark plug named TR7. Nor do they have one named TR8. Do yourself a little favor and search this site and you'll find that you're highly mistaken. The BP7EFS, which I reference in my first post, is the NGK spark plug that is one step cooler in temperature range than the TR6. There is no such thing as a TR7. I'll say it again if you want me to. Learn here.

Further, there's a British car company called Triumph. You might know that they made, and still make, motorcycles, as well. They made a series of sport cars with the TRx name designation. Two of which are the TR7 and TR8. Have a look. http://www.tr7-tr8.com/ Find out that I was not referencing TVR.

jrp

iTrader: (16)

whats your DCR?

narcszm

I'd love help calculating it. I've got a pretty wide LSA and single pattern cam. How do I calc the dynamic compression ratio?

CAT3

iTrader: (9)

Damn Goob got OWNED!

I know the frustration of TR7 ect BS. Everyone refers to them, but according to NGK, the makers there is no such animal.

I am sure once you get your HPT, you will see a big improvement with a little timing taking away, not sure if the R5724-8 (gee must be TR8s huh?) will take out the ping, but they are a damn good plug, going from the BP7... to the R57... I seen better flame front when reading the plugs, looked cleaner burning to me, nice mid ground strap timing mark and even coloring.

Good luck.

Charlie

jrp

iTrader: (16)

you'd need to know your seat to seat or advertised duratation (.004/.006). just google "dynamic compression ratio" and you should come up with several different calculators to mess around with.

my static CR is 12.02 and DCR is 8.5. im going to attempt running 91 and well see what kind of power i can make with a tune. if its not much i'll run a 50/50 mix. i've done all i can to ward off detonation; polished chambers, tight quench (.035), 160 stat, tr6's gapped @ .038 and a late intake closing point on my cam to help bleed off some cyl pressure. like i said, we'll see how it goes.

narcszm

I just went through all the measuremeants pretty carefully. I don't have my cam card here but I'd say these estimates are fairly close.

My static compression ratio is approximately 11.88:1 Having the intake valve close 67° ABDC yields a DCR of 9.27:1. This is about what I was expecting. What does that tell me, though?

If I put 5psi to the motor, that would yield a DCR of 12.42:1 - can anyone tell me if that's high for a supercharged LS1?

Thanks, all.

jrp

iTrader: (16)

thats way high . what are your total cam specs? on top of the basics i had my cam spec'd with the SCR in mind and asked that my DCR be kept in line to avoid excess cyl pressure.

spec'd out at 238/236 112+ with an intake valve closing 51* @.050 and 84* @.004. total overlap @.050 is 15* and @.004 its 78*

http://members.uia.net/pkelley2/DynamicCR.html