quickWS6

Is there any reason not to change to colder plugs with the same gap on a N/A LS1? Thanks!

horist

idle quality will go down a little, but not enough to cause probs,

possible loss of power due to the colder heat range spark plug not creating a flame front as quickly (not sure on that but seems to make sense?)

Colonel

In my three F-bods I've never noticed an idle quality reduction...BUT, I've always lowered the gap to .037-.038.

I don't think there will be a measurable power reduction. In theory, yes. So bump the timing advance up a degree. You can do this with the cooler plugs and I bet you'll get back you 1/2 of a HP and then some. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

Oh yeah, you will likely have to change cooler plugs more often.

Colonel

You got it on all accounts.

quickWS6

Thanks for the info horist and Colonel!

spanktu

iTrader: (19)

Idle quality does go down, mine are gapped at .35
right now.
Mine developed a slight stumble, but I raised my idle to 850 and it is hardly noticeable

I wouldn't switch unless I was runnin gas

Colonel

spanktu, I'd be interested to see what would happen if you swapped em out with a new set gapped at .038-.040 and lowered the idle back down. Not saying it would cure it for you, just curious.

quickWS6

Alright, so what are some of the advantages of colder plugs?

I was thinking less chance of detonation the biggest one.

Most people just run TR6s right? Only one range colder than stock.

<small>[ March 13, 2003, 12:17 PM: Message edited by: quickWS6 ]</small>

bigoneZ28

<img border="0" alt="[worship]" title="" src="graemlins/gr_hail.gif" /> Colonel, I installed TR6 plugs (0.39 gap)just over 2 months/1600 miles ago. I've sprayed the car 4 times since then. How of often should these plugs be changed since my car is driven 3/4 days a week? Changing plugs is a PITA for me <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> Many thanks.

Zeta

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by quickWS6:
<strong> Is there any reason not to change to colder plugs with the same gap on a N/A LS1? Thanks! </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yes. If they fowl with oil and carbon deposits, then you do not want a colder plug.

Colonel

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by bigoneZ28:
<strong> <img border="0" alt="[worship]" title="" src="graemlins/gr_hail.gif" /> Colonel, I installed TR6 plugs (0.39 gap)just over 2 months/1600 miles ago. I've sprayed the car 4 times since then. How of often should these plugs be changed since my car is driven 3/4 days a week? Changing plugs is a PITA for me <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> Many thanks. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif"><img border="0" alt="[worship]" title="" src="graemlins/gr_hail.gif" /> bigoneZ28...Whenever the idle quality degrades or whenever the electrodes appear worn (the center one may have rounded edges. The side electrode may look eaten towards the end.) With TR-6s I think 20,000 miles is good (the above notwithstanding.) 30,000 with TR-55s.

It's easy to pull a couple of the easy to reach plugs to take a look every so often.

Ole Blue

I have ran Tr6's and Tr55's. As a matter of fact when I had the TR55's in my car it idled 100 rpms higher oppose to the TR6's. When I start the car in the morning, with e Tr6's the car is cold natured and when I had the TR55's in there it seemed to ilde smoother and not cold natured. Final result, with the TR6's I lost a .1 and 1-2mph. I am changing back to my TR55's.I can't speak for the people who run nitrous, I don't have nitrous so I am going back with the TR55's. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Colonel

That's kinda strange since the idle speed is controlled by the IAC. The idle speed is programmed into the PCM. If the PCM sees a lower idle speed than what is programmed, it will command the IAC to let more air into the engine, thereby returning the idle to the programmed value. Any deviation of idle speed caused by a modification should only be temporary so long as the IAC is working properly.

I bet if you track tested TR-55s and TR-6s on the same day under like conditions you would see pretty much the same trap speeds.

The extra heat dissipated (this is where your theoretical loss of energy comes from) by a cooler plug is VERY minute.

Ole Blue

However, I did try both plugs with the same weather and the Tr6's were a .1 slower and I loss 2 mph.This was at HOuston Raceway Park on Sunday and Wednesday. Spark Plugs play a major part in power. I once had bosch +4 in my car and raced a LT1 with bolt-ons and lost bad out of the hole from a roll. The next day I changed my plugs to NGK TR55's and killed him from a start , roll and top end. How do you explain that? I figure those plugs caused me to lose Hosepower. Alot of people might not believe it but guys who have been racing along time no that this is true. You can lose alot if you don't have the right plugs. I think TR6's work well with Nitrous cars, but N/A I would have to have Tr55's.

Colonel

"I once had bosch +4 in my car and raced a LT1 with bolt-ons and lost bad out of the hole from a roll. The next day I changed my plugs to NGK TR55's and killed him from a start , roll and top end. How do you explain that?"

No offense, but I can think of alot more scientific ways to judge power than that.

2 MPH in the 1/4...that would be about 20 RWHP, no? Go to a dyno, check both sets of NEW plugs making three pulls each with the engine fully warmed in both cases. Average the results. You'll likely see the averages be within 3-4 RWHP of another (that's within dyno variance.)

Unless you are changing out badly worn plugs, I don't see gaining 20 RWHP just from going one heat range hotter on the plugs.