E85 Spark Plugs and Gaps
 

http://www.carcraft.com/howto/ccrp_0...wer/index.html


http://www.carcraft.com/howto/ccrp_0.../photo_14.html




I was wondering which plugs everyone is running and what plug gaps. I have run the stock NGK ILFR7H and the Denso IKH22 so far in my car. I have found that at higher boost levels the gap needs to be lowered from stock around 24-26 down.

I gapped at 22 and this worked for a while but maybe due to gap erosion I had to re-gap last weekend to 20 based on a tip by someone who runs high boost and big power. I have read that smaller gap makes less power although getting the car to fire is better than the "stutter" or misfire that occurs when the mixture does not fire. I am currently way down to 20 gap with no apparant misfire.

I just picked up some IKH24 Denso plugs (1 range colder) and want to see if they are more knock resistant than the stock plugs allowing maybe more timing and or more boost (not to mention more peace of mind after reading article ). I will be installing these soon after getting some new (hopefully lower resistance) plug wires.

The other thing that is interesting to me is it looks like NGK makes a Iridium plug with similar specs. to our oem ngk and the only difference is the electrode on the factory plug has what appears to be a iridium tab attached to electrode probably for better wear characteristics than the NGK LFR7AIX. The LFR7AIX might be a better stock heat range plug (if it's reach and size same as stock) due to not having this extra piece on it. I have read that Iridium has higher electrical resistance than other metals (copper) but better wear characteristics and this is why it is chosen. Anyway as always have a hard time putting thoughts to paper so check out the link.

So.... What gaps and plugs are you running

I have always ran ngk's 24-26

On E85? If so what PSI

.020 up to 32psi no misfires

Running BP8ES gapped at .022-23 at 29psi

I originally tried 22 and got misfires so I am now at 20 wonder if this a Evo 9 thing vs. 8 New plugs in tomorrow one heat range cooler. It will be interesting to see if cooler plugs are more knock resistant although my tune is so conservative right now under load peak 323 and 0 knock with 2-3 degrees at peak only around 10-11 up top. I figure better safe than sorry although boost is peaking at 29 and change stock 9 turbo. I wanted to wait to change plugs till I got these wires in I ordered but we will see. I measured some gen. 1 NGK ignition wires and they were 2k ohm less resistance which means quality aftermarket wires could allow more voltage and current to spark due to less drop across cable.


PS thanks for the replies

10-11* up top on E85? That's a waste of E85. ;)

.022 here at 28psi on Evo IX plugs.

:o
Yeah I know I had been blowing out spark and hesitating so I backed everything off.


Is it safe to guess you are running 10 tapering up to 19 degrees 5 -7k+ rpm range :)

.019 good for around 35 pounds no issues.

evo 8 here on e85.... ngk bpr9s .019 28 psi

On my personal 8 I run around 2-3* at peak boost and ramp up to around 19-21 or so.

On the 9's I've ran around 1-2* at peak boost and ramp up to around 17 or so on the stock turbo.

The timing up top I have set using MBT and backing off a little.

On a related question...

Has anyone been able to find a wire-type plug gap measuring tool that goes down to 0.019"? Even the expensive one from Summit only gaps down to 0.025". I have to use a feeler gauge on my plugs, which I don't think is as accurate or as easy to use as a wire gauge.

I'm looking for one like this...that gaps down to, say, 0.015".

http://www.gokartsupply.com/img/32-1707.jpg

:mitsu:

I use something that looks like this

http://www.vtwinmama.com/images/Feeler_Gauge.jpg

i forget the smallest measurement blade it has, but it does go a lot smaller than my needs. I got mine at Pep Boys

^^^^^^^
Right...that's a feeler gauge. Great for adjusting valves, or checking machinery clearances, but not so great for setting spark plug gap. IMHO...

:mitsu: