I was just wondering if it is worth replacing the stock plugs in our car for better plugs. I did this in my old Z28 and it really improved ignition and slight power responce.

Anyone done this to the CLS? If so what are the best plugs to use? And how hard are they to replace. The Camaro was a complete plain to get them all out.

 

bump

 

gains are minimal... when I removed the stock plugs at 30kmiles they were in excellent shape... see what I have in sig.

 

personally I wouldn't mess with the plugs until their trash cause the power gain you won't even notice. maybe 1 or 2 HP. and you'll have 15-20 bucks in plugs so dollar to power gain ratio is pretty good though . it's like 10 bucks per HP
Where a CAI is like 250 bucks you pick up 15 HP
so it's like 16 bucks per HP.
the Comptech supercharger(they haven't put a CL on they dyno but lets say our car at 220 at the wheel)(you loose about 20-30% going through transmission) anyhow they said it's about 300 HP at the wheels
so you gain 80 HP at the wheels
so for 4000 you pick up 80 ponies at the wheel. it comes out to 50 bucks per HP.

 

So from what you are saying though it would be a good HP investment money wise. I mean what is $20 right. Even if it is just 1-2 HP every little bit helps right!!!

And isn't there an ignition box available for bolt on ?? There must be. There were like 3 or 4 made for the Z28. That would provide even extra spark and consistnacy to the plugs for better burst in the cylander and fuel economy. Anyone know of any of these for our car?

And to Nashua - how hard was the plug install? Time? Knuckle pain?

 

I have not personally done it, but it has to be a pain because of how close the rear ones are to the firewall and you may have to remove the actuator to get them

 

There are no ignition boxes for our car. Our car uses coil on plug meaning each spark plug has it's own ignition coil on it. The cars computer controls it.

 

Oh ok that answers my question on that! This is my first foreigh car and I haven't done much work to it. Just the cold air intake. Which is pretty standard.

 

personally I wouldn't run anything but NGK. I've tried about them all(AC-Delco,Champion,Denso(which is a close 2nd to NGK),)
I know this sounds stupid but when I put NGKs in usually the car runs smoother and has a tad(i didn't say like 40 or 50 hp maybe just a shade) more pickup. but that's from going from old shot plugs to fresh new plugs.:P
plugs is like motor oil it's basically what brand you prefer

 

I really didn't notice anything what I dropped in the Denso plugs. The front 3 were easy to install (duh) and the back 3, well, my back still hurts.

 

But the question still remains what are the best? I believe we all can agree that NGKs are the best around. But what kind? Also are the Irduraniums an element all it own, like copper and platinum.

Juker008

 

I like the Iridium spark plugs. It's only because dyno results say that they're better than Platinum plugs. I don't like Platinum plugs because they aren't performance-oriented but more consumer-oriented. If I couldn't afford Iridium spark plugs, I'd just get copper plugs. I get a better spark but have to change them every 30K miles instead of 100K miles.

So it's up to you. Iridium or copper plugs every 30K miles or platinum plugs every 80-100K miles. But for the CL-S, I'm not sure how much difference plugs make since the bottleneck may be in the coils and compensation built in the ECU. But theoretically iridium and copper plugs ignite better than platinum plugs.