Plug choice based on ambient temps?

[FORMONTOYA]

I'm curious if anyone has noticed the need to change heat ranges based on ambient temperatures?

My issue:

I've been using the 6's since the car hit the ground Dec. 05 without any issues. Now in Houston the ambient temps have gone to regularly being in the high 90's+ and the car cruises great, however, if I do a blast through the gears and then come to a stop I notice a minor backfire in the 1-2 and 2-3 shift cruising for the first stop or 2 and then everything is fine.

I'm wondering if I should bump to the 7's in the summer heat and use 6's in the winter when it's a lot cooler. Has anyone else had a similar issue? Or just try it and see what happens?

Any advice?

I'm running 16psi for now but plan on 20psi in the winter and if I can manage a water injection kit, 20psi on a regular basis.

My previous toys have been N/A.

 

[andymoraitis]

Jim,

I haven't experienced anything like this with a change in ambient temps and I'm running stock heat range Autolite 63's at 22 psi on an 8.8:1 motor. I would pull the plugs and read them to be sure, but I don't think the heat range has anything to do with your misfire issues. Then again, I've had minor misfires ever since the cams went in, but they don't change even if I run an 8 series plug. All I get is more fouling at low RPM. I'd suspect plug gap more than anything else if it is in fact plug related.

I think you have gremlins elsewhere.

Andy

 

[FORMONTOYA]

Thanks...it's nothing major, as a matter of fact DSMLink shows nothing out of the ordinary. If I do a blast, come to a stop and do another blast I don't have any issues during the second "blast". It's just when I finish my blast(s) and then the first maybe second easy cruise off the line I get the "pop" between shifts. It's more annoying and I "feel" like an idiot with a car making unusual noises.

The issue actually started a month or so ago when the temps started to get into the 90's.

I do know I need to isolate my filter as my intake temps get ridiculously high. At a light they can get to 120+. Pulling into the garage after work I've seen 140+ intake temps. The bad thing is that it hasn't even been hot yet (for Houston).

According to this:
http://www.spark-plugs.co.uk/pages/technical/diagnosis.htm
my plugs are normal.

However, I didn't think about the gap as it only happens as described.

 

[Defiant]

I'd look for the exhaust leak.

When I took auto shop, right after how they showed us how to true a wooden-spoked wheel and dress the iron-slat tire, it was stressed that plug heat range is not related to engine operating temperature, but to the operating temperature of the plug and its tip. Now, big as all shit, NGK has on their site:

"It's important to remember spark plugs do not create heat, they only remove heat. The spark plug works as a heat exchanger by pulling unwanted thermal energy away from the combustion chamber, and transferring the heat to the engine's cooling system. The heat range is defined as a plug's ability to dissipate heat."
http://www.ngksparkplugs.com/techinfo/spark_plugs/techtips.asp?nav=31000&country=

Which is just wrong, from what I'd been taught. I hope it's only a matter of being poorly-worded.

Now, I'd love to chat longer, but the acetone generator needs its carbide replenished.