A BPR8ES is too cold for E85. Combustion temperatures with E85 are significantly less than with gasoline, which causes an -8 series plug to run too cold and foul quickly. Switch to the factory heat range and your issue will disappear.

 

**** i just bought 8s from stm thinking colder would be better.

 

Figured I would update my own thread. It's not confirmed just yet but my OEM FPR was bad which may fix my problem. I'll find out tomorrow hopefully. I want to try running warmer plugs now too. That will be my next step if the FPR doesn't fix this.

 

You'll want the hotter plugs regardless. Switching from gasoline to E85 drops EGT by ~150C at steady cruise with no other changes (as per my own observations), which drops the operating temp of a cooler plug into fouling territory.

 

If I bought COP's from spoolin'up is there a chance my denso coils are weak after just a year of use? My current gap is .024 on iradiums with 10k plus on them with minor bolt ons, stock fuel system, 91 pump.

 

Turns out there was a minor crack in my FPR hose and was leaking air. My tuner suggests .26 which is what the car is tuned with. Sounds a little big to me and from what I've read. That's what I'm sticking with. BR8ES for now until I need new plugs then I'll try out the BR7ES.

My throttle body plate bent during a test pull though which I've never heard happen before. Scary when that happens because you apparently loose your brakes too. Not sure how that plate bent, there's no strike damage. Anyone ever encounter this?

 

The 0.026 should be ok ... when you switch to BPR7ES. When you do, any stumbling and misfires (both part and WOT) will instantly disappear.

 

8's are one step colder than stock plugs which are 7's, but people saying that your fouling plugs because they are too cold are not accurate. Although e85 probably wouldn't need a colder plug since it does burn bit cooler. 8's should work just fine with e85. I would run iridiums though. I'm sure it's another issue causing you to have blow outs and misfires. I used to run 8's on my stock turbo car at 400hp with no problems and I've run them on my 800+ hp setup with no issues, but much hotter ignition setup now so I run a tad bigger gap.

 

It is accurate and factual. There is no guesswork here. Whether the plug is copper/nickel or iridium makes no difference. Ask me how I know this.

Plugs come in different heat ranges for good reason. Read post #19, view the chart below, and it should become clear why this is the case.

 

ch53avitech the chart shows you just need to drive faster.

 

Sorry I worded that wrong, I'm not saying that if they are too cold that it couldn't cause issues I'm just saying from personal experience that I've never had any issues running bpr8eix plugs with ethanol.... Not tryin to say u guys don't know what your talking about, just sharing my experience.

 

Nevertheless, the factory heat range plugs are better suited to ethanol due to the large drop in combustion temperatures. There is nothing to be gained by using a colder plug with ethanol, only disadvantages. If one notices anything, it's that the engine runs better, makes more power, and the plugs last longer.

 

I would personally not use a 7 heat range if you were making over 500-600 hp, but ya a stock turbo car does not benefit from them.

 

I personally do, every time, and recommend nothing else. The only reason to go to a colder plug in any case is to prevent an excessively hot plug from creating a preignition issue. Switching from gasoline to E85 alone is akin to dropping the plug operating temp 1-2 heat ranges.

 

If Im no running e85 should I have to run a gap smaller than .025? I just got new BPR7ES's and I am still getting a miisfire at 12afrs while going into boost, cruise is smooth, no problems and 15afrs