SolaraGuy.com

Dawgz wrote:yea, im pretty sure they are also guessing that you are at stock boost psi.

Then just run a colder stock plug if you're comcerned (7 instead of 6). I run 5.5 with totally stock plugs..no problems.

I am running E3 Diamond Fire plugs in my car. Asked Greg about them when he installed my s/c and he didn't even know they existed. Heard about them on Horsepower TV, read some articles and figured "WTF, I'll try them". So far haven't had one problem with them. Greg and I agreed that I would be the test mule for them

I installed them on my girlfriends Cheve Aveo and noticed a difference immediately. If you can notice a difference on a Aveo, that has to say something, lol. I will keep everyone posted on their progress.

*For the record, I am not saying these plugs are better than others and I am not saying they will add power. Simply saying I am trying them out.

I'm digging back up this thread in light of some info I've recently come across. I don't think the concern with running colder plugs should be performance, but rather engine longevity.

NGK.com wrote:When making spark plug heat range changes, it is better to err on the side of too cold a plug. The worst thing that can happen from too cold a plug is a fouled spark plug, too hot a spark plug can cause severe engine damage.

While the life on the BKR7EIX-11 may be shortened considerably due to it's single-cathode design, it may be worth the hassle IMO. For those only pushing 4psi, the stock plugs are probably still sufficient. Anything above that might want to consider a colder plug.

NGK.com wrote:An unaltered engine will run within the optimum operating range straight from the manufacturer, but if you make modifications such as a turbo, supercharger, increase compression, timing changes, use of alternate racing fuels, or sustained use of nitrous oxide, these can alter the plug tip temperature and may necessitate a colder plug. A rule of thumb is, one heat range colder per modification or one heat range colder for every 75–100hp you increase. In identical spark plug types, the difference from one full heat range to the next is the ability to remove 70°C to 100°C from the combustion chamber.

I am using stock temp NGK iridiums

Has anyone used the Supra NGK 4554 spark plugs? Is this even a feasible option for 6 psi?

For our coilpack ignition system, it is best to use Iridium plugs... The coppers do work, but you'd realize that the spark is much weaker than it should be, versus a distributor ignition system. Our coilpack systems take the advantage of a long consistent spark duration and only works well with really fined tip sparkplug; a copper spark plug works well for distributor systems which is one strong output spark with less duration.

I run all Denso plugs, ranging from IK24's for up to 350 WHP levels, and now I am running IK34's which are really cold plugs for 550+. And still, I managed to have plugs that do not foul up at all and still retain close to my stock gas mileage (about 19-20 MPG city).

HOW IS THAT POSSIBLE?!?

Tony, you still get 19-20mpg in the city? That's ridiculous, I can only get about 22-24 HIGHWAY and average more like 18-19 city. And I only have 153whp. I guess it has a lot to do with volumetric efficiency? Holy crap, that makes me really hate my gas mileage. Also gives me another reason to be jealous of your Camry.

It does have a lot to do with how efficient the engine is, but also how the car is driven and how the transmission is as well...

It's hard to pin point exactly what increase power, increase gas mileage or make it worse; but over the years of my build, I somehow managed to get better gas mileage as I progressed into my build. The worse gas mileage days I had was with the E-manage blue + 720cc/min injectors back in '03. The car was averaging like 10 MPG of mixed driving.

The moment I went with an AEM standalone a few years ago, the car still guzzled gas like crazy... After many days or even weeks of street tuning, I managed to get the car to achieve about 16 MPG, which is not too shabby and close to what I had stock. There were some unsmooth and leaner regions in the fuel map, but cruising there helped mileage big time. Since I have full gear control, I was also able to cruise at whichever gear I want and that helped me stay at those good lean spots in cruising. I was also able to control lock-up on the converter and basically, it locks up whenever I don't plan to accelerate hard. Compared to a stock auto ECU, you have to blip the gas to "kick it out" of lock-up, and then accelerate which is a lot of unnecessary gas being wasted.

When I decided to go with the custom sidewinder manifolds and a huge T51R turbo from beginning of 2009, the car drove really well and was pretty peppy too. My high stall converter was a huge problem though because it soaks up a lot of power at low revs and slips a lot, but locking up the T/C frequently helped again. I was still averaging about 16-17 mpg mixed regular driving. If I drove only city though, I get like 12-13 mpg.

Recently, I've swapped over to my old 3000RPM stall converter which was much tighter and doesn't slip much at all. Accompanied with the full lock-up control and twincharged, the car has lots of torque and I don't even have to downshift. So I stick it in 4th gear and lock-up under most occasions. I've then also switched to the new Injector Dynamics 1000cc injectors which boasts amazing spray pattern and idles just like stock injectors. At $125 a piece, it was no joke, and my car runs amazing on ID 1000cc/min injectors. I automatically got insane gas mileage (scored over 100km per tank of gas average). I now get an average of 17-18 MPG city and pushing it quite often, and could get 20 MPG if I was working late for the week (leaving late means much less traffic). I haven't done much highway driving, but soon to find out when the weather warms up and I'd be driving on the highway for track days or out of town meets

Wow, that's a lot of great information. Factory stall is about 2600 right, so you're barely above that. That's cool. You guys must have some great tuning skills too. Awesome, awesome, awesome.

well my car is nowhere near the level of tony's - i only have an safc to help control a set of sc300 injectors (330cc if i remember right) and am only running 7.5psi on the s/c. and yet i average 22mpg mixed, and around 24-25mpg highway (cruise engaged) - and my car is stick. i DO NOT have an EGR system at the moment, and i honestly believe that once i get it hooked back up, i will get even better mpg.

i agree with tony that adding the s/c actually helped MPGs because it adds so much usable low-rpm torque that you don't have to downshift for anything, so you waste less gas.

back on topic, i have the NGK iridium IXs, one step colder. had I read this thread before installing them, i would have spent a little more time looking for the dual-ground and double platinum plugs before changing them this last time. live n learn i guess...