7/8 Months ago, I upgraded the plugs to the Denso's that everyone has been raving about, now after changing 2 sets of plugs plus the coilpacks for the cylinder that showed up the missfire (on my 3rd set of plugs now) I still occasionally get the missfire returning. I will say my car runs super good but when on it at the track and WOT occasionally I get the missfire (only occasionally). Plugs are gapped to 0.27.

Now again I have spoke with 3 different people on this subject now, Manthey Racing, Fearnsport that run Cup Cars and JZ Machtech, these 3 are pretty much respected over here and asked the question what they run and the answer was the Beru stock plugs. Now this might be the case as most are GT3 and Cup Cars which are not outputting some of the numbers we are in our Turbo's plus they will replace after every meet/race/trackday etc, but I am starting to think these Denso's are just not up to the job and I might have to return to the a more solid Plug.

I'm really wondering if anyone else has had similar issues and what their thoughts are on these Denso's, It might also be a case that these plugs are great for Street and Strip, but on track mmmmmmm!

 

Stick with copper plugs on a boosted engine. Copper provides the best heat transfer. Reduceing gap will insure adequate spark at higher engine speeds. Platinum plugs provide absolutely NO increase in performance over copper.

 

This is very very true.

In many of our high horse power cars, we use ngk bkr7e's gapped to .025 or so.

These plugs do require more regular change intervals, however function better then any other plug we have tried.....and at 3 dollars a plug, I swap mine just about every oil change .

 

I use to use Densos Iridium, they are not to the task of high hp application,eg.High boost, I now use standard copper NGK plugs gapped at .022", they don't miss a beat.

 

Yip! just want to get constructive feedback from others regarding these Denso's, IMHO I just feel these are not best performing plugs especially for tracked cars. Thanks

 

How do you check if your plugs are up to the task? Just switched to Denso IK22 ...

 

NGK bkr7e .028 gapping for above 700hp. Never skipped a beat and any other plug gave me coil issues.

Suman

 

It is interesting that both EVOMS and Proto use the Denso plugs for their high HP cars. Mine have been fine up until my recent issue, but I may have a coil pack problem as 4 have cracks in them.

I too have had the odd missfire at high rpm when I am giving her. Other than that they seem to be fine... the debate continues

 

+100000 on the copper plugs. Keep it simple. If I could figure out the correct Autolite part number I'd run them all day.

 

I, Scott, Bobby who has 3 800+hp P cars, etc all run Denso plugs..
I have no complaints...
Its only when we run leaded gas that they go bad.. .but thats with any plug...
markski

Are you detonating... do you have picks of the plugs? maybe something else is causing your problem...
How much boost and what kind of fuel are you running....

 

A visual of a spark plug will not necessarily identify a problem. A plug that does not cool down fast enough after the combustion can cause detonation. It is a fact that copper is only exceeded by gold and silver in it's conductivity. Platinum is far down the conductivity list.

It is always advised to run the best conductive sparkplug (which is determined by material and heat rating) whenever they provide spark to a boosted engine. This is not to say that platinum plugs will cause problems, but the only thing you gain with platinum is that they last a little longer. What you lose is money and protection.

Everything being equal, an engine running copper plugs can be more safely tuned to a greater extreme that can one running platinum plugs.

 

I've been recommended the Bosch plugs

 

But it is a good indicator of whats going on....
I have a feeling he is running 1.4 bars on pump gas and messing up the plugs...

My point is that I can and DO run 1.5 to 1.6x bars of boost and put down close to 900 rwhp and I do not have such issues... a few others guys are in a similar situation.

I also think that each tuner has different preferences... mine has had good results with the Denso PK20PR-P8 plugs.... so he recommends them.
I can tell you that I had very poor results with Beru's...

 

We have has issues with Beru's in other markets....

NGK, Bosch or Denso.

 

Mark, that also crossed my mind, but I always run Optimax here in UK which is now 100 octane and when at track I have a mix roughly 6 to 1 of 109 octane just incase detonation is occurring, also running 1.2/1.3bar. The last set looked ok when removed, I will check this set also.