So, what temperature plugs are going with, 16, 20 or 22?

 

i think i'm gonna go with 16. I don't track my car and only on occation I go up the mountains. 16 sounds better for just regular driving style.

 

finally got time to search around for the best prices online. found a place for the Denso Iridium IK16 plugs for $10.95 each and free shipping over $100 purchase. http://www.ltbmotorsports.com/denso....FSaiSAod61DfZQ

also found a site for Magnecor 8.5mm wires part #65211 for $129 shipped. www.ultrarev.com

gonna check with another place before I make decision to order at these two places.

 

Frank, thanks for doing the legwork. Too late for me, though - I just got mine in the mail from another source (impatient)

 

I could see staying with 20 and maybe going colder to 22 but I'd question going hotter with a 16. People say they feel something at higher RPM ranges but if you are running your car at higher RPM ranges, you really should be going colder if you have a modified motor because the engine is running hotter. If you have a stock motor then you are probably safer but I'd still hesitate to got hotter than what they recommend for the motor.

 

I see what you are saying, but according to what people has researched on the IK16 is colder than the stock plugs.

I think the only person that has the closest mods to my car is yours, topgun's, and Vadim's. and few others of course. I think Vadim has been running on the IK16 even for track use, but he does have the header as well that decrease some exhaust temp and those heat spacer thing for the manifold.

If people are correct that the IK16 is colder than stock, than it shouldn't be a problem. It just won't perform as well under extensive heat condition on the track. that's my non-factual based guess anyway. lol

I'm gonna study a little more on the plug difference for sure. gonna work on the interior trim project first.

 

I was under the impression that the IK16 was hotter than the stock plug and therefore the concern. The Denso site recommends the IK20 for the stock motor. I bought 16s myself but I haven't installed them yet because of this thread. The Denso site recommends the 16s for the a C43 so I was just going to get 4 more and use them on that and get 20s or 22s for the SLK.

 

I read someone said they're colder than stock and hotter than the IK20 Denso suggested.

let me know how your IK20 will work on the SLK.

One of the question I didn't see people ask and I didn't find any feedback is that if the stock plugs are already Iridium assuming Bosch or NGK made it and the Denso IK16 is not colder or hotter. Would simply changing the ignition wire do the trick?

 

I guess I keep coming back to this, from Denso's site...

"Q. Why are there different heat ranges? Which one should I use?
A. Part of your spark plug’s responsibilities, in addition to firing a spark, is to remove heat from the combustion chamber. This is accomplished by channeling the heat through the insulator material and metal housing. From there, the heat is transferred to the cylinder head where the engine cooling system can go to work. A spark plug’s heat range is its ability to dissipate heat. The “colder” the plug, the more heat it can channel out of the combustion chamber. In a performance application, colder heat ranges may be necessary to handle the extreme temperatures brought on by higher compression ratios, forced induction, and high RPM’s. While “Colder” plugs may seem to be the way to go, please remember that the spark plug must achieve its “self-cleaning” temperature where it can burn off fuel and carbon deposits. Otherwise, the plug could “foul out” where it is prone to misfiring and poor acceleration. A plug that is too “hot” can overheat, also causing power loss, detonation, pre-ignition, and possible engine damage. A good, general rule of thumb is to start with the factory recommended heat range. For every 75 to 100 hp you add to your engine, you may go to the next colder step. DENSO heat ranges move up as they get colder; 16 would be our hottest Iridium Power plug, 34 would be our coldest (ranges; 16,20,22,24,27,31,34)"

So I can see people going with the IK20, as recommended for our motors, even for a modified motor as not too many people have 75 to 100 hp more than stock but I can't understand why people would go hotter. You would think that Denso knows the proper temperature range and therefore recommends an appropriate plug. Also, it not like the IK20 is all that cold, it is the second hottest plug they make. I really wonder if the improvement people mention all comes down to the wires.

 

Steve,

I changed just the plugs to IK-22 and left the stock wires on. It made a big difference with just the plugs in the upper RPM band. Everyone that I know that has put in the Denso Iridium plugs has immediately noticed this strong pull in the 5k to 6k rpm range that was not there before. (even IK-16 installers notice this)

And the IK-22 will lower your water temp by 5 degrees or so.

 

Zep, what other mods do you have?

I think in the end I may end up with the IK20 that Denso suggested.

 

I think I am leaning that way now as well. I'll put 20s in the SLK and 16s in the C43. I'm hoping to get headers before too long which should get me up to the 450 range but the headers should help with temperatures so 22s should not be necessary unless you track the car a fair bit.

 

Just changing plugs, to new plugs, after 6k to 10k miles will yield an improvement at high RPM. I see no need to use IK22s, unless there are detenation issues from huge amounts of boost. Colder plugs are more prone to fouling, when not running under boost.

The C series 4s and 6s seem to use IK16 for N/A & IK20 for blown applications, probably to prevent detenation under max boost and high temps. Normally with colder plugs, one can use more aggressive timming.

 

ODPS
ECU
Y-splitter
K&N Filters

 

I'm doing the Evosport Stage II, and I'll stick with their recommended IK16 (got 'em already). They've done the R&D - why play with fire?

 

From reading previous thread's, I never saw a clear recommendation from Evosport for IK16s. That's why I have been following this thread so closely. No one will come and say that 16 is better than 20 or 22 or vice versa. Everthing seems to be just here say. There are no dyno results I have seen. If you have seen such a recommendation, please post a link.

Lacking that, I expect that the spark plug manufacturer would provide the most knowledgable recommendation.

 

I take that back, at least part of it. I see that Evosport includes the plugs with their stage II. That is certainly an edorsement but I would still like them to reply on this thread providing a reason for Ik16 vs IK20 when Denso recommends IK20 and they are adding about 75 hp or so and Denso would likely recommend IK22 under those conditions.

 

I had my mind made up until I read this thread. I'm now stuck...16 or 20?

Part of me wants to go with the 16 because others have reported no issues and the other part of me says go with the 20 and be safe. I do have the RennTech Pulley / ECU upgrade, and the SL55 Intake Splitter so maybe the 20 is better for me. I drive the car hard and have a 70 mile a day commute to and from work. I do plan on getting headers at some point.....

 

The real question is, what do the IK16 plugs look like after 10k to 20k miles
of use?

Do they have melted electrodes and cracked insulators? Has anyone ever removed and looked at the IK16 plugs on a C32, with stage 2 setup after more than 10k miles heavy throttle?

If the IK16 have seen no problems, after lots of abuse, then they are probably ok.

Does the C32 have knock sensors and does the C32 stage 2, pull timming with IK16? If not, then just use the IK16s.

 

After reading this entire thread and several other forums, its seems the best plug would be the 20 or 22 and NOT the hottest running 16. This is especially true for anyone running in southern states (I'm on the beach in MS...HOT!). 20 Seems to be a good, safe, all around temp plug.
Every time I think I have my mind made up someone else has another post to counter the other. As mentioned above, someone needs to actually pull a plug or 2 (front and back) and see what they actually look like after a few hard miles. Seems this will be the only definitive answer...

 

OK, I went with the IK-20 & Magnecor wires.

Got the wires from UltraRev (Part # 65211).
They were $130 shipped UPS 3 Day.

Got the plugs from LTB motorsports.
They were $80.68 shipped UPS 3 Day.

Hope this helps...

 

$81 for a set of plugs shipped? Did you just get 6 or...? Great price either way.

 

Yeah, I only need 6. I assume it won't be an issue using IK-20's from a friend? They were never used.

 

Jerry you need 12 we have 2 plugs per cylinder

 

Yeah, I know. I got 6 from a guy in Atlanta.