Frickin' Fomoco plugs

[Darth Vader]

I just changed out the oem FoMoCo spark plugs, at 27,000 KILOMETERS, because I found 3 cracked insulators and the bases all rusted to hell. I had to shoot canned air down the holes for about a minute each to stop the red cloud pouring up. Im-pressive for something I'm not supposed to even look at for 100 billion miles or something, as per the owner's manual. Good thing I don't believe anything any company tells me about service intervals.

Car was running fine but, I couldn't just put those rusty POS back in. Got stock spark plugs, at MASSIVE expense, from Mazda, just to avoid any hassles, should Hell freeze over and a Mazda tech even lay eyes on this thing.

Did a comp test while I was at it, all four between 210 and 220 and the motor wasn't really warm anymore and the electronic throttle was closed. Don't have the spec in front of me but, that seems likely fine to me. Anybody know what the spec is?

 

[Rudeboy3]

Those compression numbers look good and are on the high end of range iIrc. Where abouts in Van are you?

 

[ECSpeedSound]

Denso iridium ftw

 

[Nliiitend1]

Hmmm...

Can't say there was anything wrong with mine when I took them out at ~20K and replaced them with ITV22s... (dunno)

Good that you got some fresh ones in.

 

[Sport6]

210psi seems a little high according to the standard which is 185psi and minimum of 129psi. Might be because of the throttle being closed?

 

[MSMS3]

Hey Darth, with your downpipe you need one step colder plugs anyway. Good time to upgrade.

Iridium, either NGK or Denso, whichever you can get cheapest. Both are great. Will have to regap NGK's, but no prob.

 

[Darth Vader]

I don't think I need colder plugs in Canada. Colder plugs will foul in the winters we get here.

Throttle closed can do all kinds of things but typically it causes low readings. It may be time to retire my ancient compression tester I've had for 20+ years.

 

[NTIMD8R]

This may sound stupid to you but... What does using one step colder spark plugs do for your engine? What does it actually mean by "one step colder"? I'm getting ready to change the plugs in my 3 and was curious whether or not "one step colder" spark plugs would be beneficial or not? Thanks for your help (knowledge)!

 

[Darth Vader]

Colder plugs run cooler (reject heat faster). In a boosted application this can help stave off pre-ignition, as the plug's electrode or the ground strap are among the principal causes of that.

If you are not experiencing pre-ignition, you don't need colder plugs. Colder plugs can wet fuel foul, because there is insufficient plug temp to burn off fuel deposits on them when the engine is warming up. This can lead to no starts or rough running.

 

[NTIMD8R]

Thanks Lord Vader! I appreciate you, sharing your knowledge of the Force, err....spark plugs!

 

[Darth Vader]

Yeah, seriously, why would anyone go to the "light" side of the Force? Nancy boys. (drive2)

 

[MSMS3]

Colder plugs run cooler (reject heat faster). In a boosted application this can help stave off pre-ignition, as the plug's electrode or the ground strap are among the principal causes of that.

If you are not experiencing pre-ignition, you don't need colder plugs. Colder plugs can wet fuel foul, because there is insufficient plug temp to burn off fuel deposits on them when the engine is warming up. This can lead to no starts or rough running.

+1. Excellent explanation, Darth. Yep, maintaining plug temp in the proper range is the goal. Hot enough to keep the tip and electrode clean, but without contributing to pre-ignition.

I envy your cooler weather sometimes. Canada ain't south Mississippi, where we are still hitting the low 90's in late September and probably will into early October, and almost never see snow that accumulates. AC compressors don't last as long here, that's for sure.

But I don't get much fuel cut, and don't need winter tires, lol. Being at sea level also has its advantages in performance, provided we get through another hurricane season without being hit.

I forgot you were up there. Weather is probably quite beautiful there now.

 

[Darth Vader]

It's 30 degrees C (~90F) today...which is pretty hot for the first day of Fall, around here. (thumb)

I'm hitting the track this Friday to try my new mods out. Supposed to be around 75 F that night, which is pretty perfect, if the humidity stays low.

 

[MSMS3]

It's 30 degrees C (~90F) today...which is pretty hot for the first day of Fall, around here. (thumb)

I'm hitting the track this Friday to try my new mods out. Supposed to be around 75 F that night, which is pretty perfect, if the humidity stays low.

I'm betting you will see a big gain in trap speed. And with a decent launch and good track conditions, should see mid 13's don't you think?

 

[Darth Vader]

Here's hoping...with granny shifts and running out the back door in 4th, the best it did was 14.2 at 99, with just the CAI. I'm thinking a quick flat-shift to 5th might yield better times.

 

[MSMS3]

May the Force (turbo boosted downpipe assisted force) be with you Darth.