Upgrading from NGK BPR9ES from BPR6ES.

[Chim55117]

I was doing some reading online and found that with higher boost applications, horsepower, and modification, the stock BPR6ES spark plugs are more prone to detonation.

Sometimes while driving the VR-4, I get backfires around 4-5K RPM. And to some extent this would make sense in relation to my problem (of backfires). I have access to free NGK BPR9ES, and was wondering since I should spring for them and install them.

Is there any any "downside" from me running plugs that are 3 steps colder? There are also the options of BPR7ES, or BPR8ES. I just want to make sure that if I run the BPR9ES it isn't overkill for my application.

The VR-4 has a 20G with full supporting mods and the like and 324 WHP at 18 LB of boost. Relatively low street/daily boost is what it is at now. During the summer I will likely crank the boost and retune with my DSMLink.

Thanks in advance,

- Stephen

[Shane@DBPerformance]

It will be more prone to fouling out the plugs, starting can be harder, more likely to misfire, possible loss of power, part throttle drivability could be worse, gas milage could go down a tiny bit. Or you might not notice anything. 9s are a very cold plugs though, the main problem would be them being prone to fouling out. Most people run 7s on DSMs, you normally wouldn't run 9s unless your running 40+psi and make over 700whp.

[Constant_Project21]

I remember a friend of mine switching to 9's and seeing nothing good (pretty much identical set up as yours). I also went to an 8 for a bit, but my fuel was loading up, and I was shooting 3ft. flames out my exhaust. If ya have access to all of them, why not try going colder and see what works best?

[Swifty1638]

With that setup, I'd run some 7's. Start there.

[Kracka]

7's for sure.

[Constant_Project21]

I shouldve added that I ended up sticking with 7's.

[Halon]

I'd say hell no to 9's. With those mods, i'd stick with 6's or 7's.

[blackrosenova400]

Try running non projected spark plugs, they help prevent pre-detonation as the ground electrode is shorter and is less likely to get hot and pre-ignite the fuel.

Id go with BR7ES's at .026 gap

[jrohner]

I second the BR7ES @ .026.

[blackrosenova400]

Or get a Dynatek Arc-2 CDI

I just got mine today, I will post a followup how well it runs.

[awd-drifter]

i've got the 7s right now.

[Halon]

Originally Posted by blackrosenova400

Or get a Dynatek Arc-2 CDI

I just got mine today, I will post a followup how well it runs.

Have they fixed their issues? The newer ones were sucking. I think I got a newer one because it didn't do squat. Mine ran the same with it plugged in or not.

[s1ngletracker]

I'd run the hottest plug you can run without your car blowing the spark out or cutting out under boost, for the aforementioned reasons.

[CarPsyco84]

I would check the gap of your current plugs first... it should be somewhere in the .026"-.030" range. I worked on a gst one time that someone had put the NA plugs in there gapped at .046" It ran fine till it started making boost, then it would buck and miss bad.

[Chim55117]

I ended up going to NAPA and picking up a pair of NGK BPR7ES'. Thanks guys.

[blackrosenova400]

No kidding? I installed mine, seemed to idle exactly the same as before. Air fuels being pig rich in the cold when first staring up. I havent driven it yet as I dont drive my car in the winter. This kinda sucks now that you say that, not im worried.

Originally Posted by Halon

Have they fixed their issues? The newer ones were sucking. I think I got a newer one because it didn't do squat. Mine ran the same with it plugged in or not.

[At-Least-It's-An-Evo]

ya, 9s are crappy unless you're a big baller big power car. I've had to get them before because 8's were out of stock and I had to keep doing pulls to clean 'em up every 20 miles or so... then finally just found some 8s to put in. This was on c16 also, so 7's are probably whats right for you.

[Halon]

Originally Posted by blackrosenova400

No kidding? I installed mine, seemed to idle exactly the same as before. Air fuels being pig rich in the cold when first staring up. I havent driven it yet as I dont drive my car in the winter. This kinda sucks now that you say that, not im worried.

Yeah, they seemed to be the best Ignition Amp that was still at an affordable price there for awhile, and then I got word that something must have changed because the newer ones were not performing well at all. I had to run such a small gap for the stock ignition to work (if I recall I had to go down to somewhere around .018 or .020). So I was hoping the Dynatek would allow me to get back to the stock gap, but nope. It was missfiring like crazy on DB's dyno. The next day I dropped the gap back down to like .020 and it was fine, and that was with the Dynatek. Bunch of crap.

[blackrosenova400]

Well your post there scared me a little so I went and did my own test. I pulled the injector harness off of number 4 cylinder and then pulled the spark plug. I then attached the plug back onto the wire and grounded the plug, and stuck the plug in front of my windshield so I can watch.

Fired the car and the spark almost looked like a flame. So it looked pretty powerful. Well as it was running the spark plug slipped down the windshield and into the engine bay a bit, my ground clip fell off my plug and it started arcing against my hood! It must have been a good 1/2 to 3/4 of an inch and it looked just like those globe things you touch the outside of and the the arc moves towards your hand. It then kinda fell down below the intake, I tried to grab it carfully, well it gave me a couple of good shocks, lol. Im gonna have to say mines working

[mdost03]

Originally Posted by blackrosenova400

Try running non projected spark plugs, they help prevent pre-detonation as the ground electrode is shorter and is less likely to get hot and pre-ignite the fuel.

Id go with BR7ES's at .026 gap

This.

When I had my DSM, I ran that plug and it worked great to help with a little knock I was receiving.