should I just through out my bosch platinum 4+'s and get NGK copper's BKR5E-11? and gap them to what with 10psi S/C'ed? or should I go one step colder? BKR6E-11's? and also gap those to what?

 

For 10 psi I recommend the BKR7's (two step colder) gapped to .028-.032".

 

2 step colder gapped to .032"? coppers? i thought coppers were in essence colder anyway and on top of it gapping them to .032" would take care of any possibility of detonating...

what are most of you on the 3.125" pulley running as far as spark plugs go?

 

I was running 1 step colder (on Iridium) plugs (normal gap) with my 3.12" pulley and it seemed fine... I have 2 steps colder now but will go back to 1, especially when my AWAC is almost done.

You may want to gap them a little smaller but I think 0.038 would be plenty (depending on the type of plug... copper, platinum or iridium)

Gapping down ensures that they "light off" not to prevent detonation... that is what the colder heat range is for...

 

I thaught for 10psi 1 step colder is safe running at a regap of .034 ?? all the old post state that

 

That is probably good enough, but it's borderline at 10 psi. I myself found that 1 step colder plugs were not sufficient to suppress detonation, but I'm running 11.5 psi. Anyway, when giving advice, it's better to err on the side of caution. The sparkplugs.com site recommends one step for every 75-100 hp increase over stock.

 

ill be at about 10.5-11.5psi when im all done...you would recommend 2 step colder plugs. werent you running 1 step for a long time ??

-matt

 

Yes, I had no problems with 1 step colder plugs when I had the 3.25" pulley on. Then when I reduced to 3" and had the redline extended the problems began.

 

so definetly run the two step colder ?? is there a side affect if they're one step too cold, or just more protection ??

 

You can start out with 1 step colder and see if you have any detonation. If you do, install 2 step colder plugs and see if that helps.

The colder a plug is, the more easily it accumulates carbon deposits, since a plug has to be at a certain minimum temperature to keep the soot off. This means that the plugs will have to be changed more often. I change plugs about every 10k miles anyway, since it is so easy to do on a Maxima and the plugs are so cheap.

 

Well how will I know if detonation is present after the blower is installed ??

-matt

 

J&S Safeguard? Increase in egt readings?

 

in everything I have read...now that the forums are back up I had more time to do research...every 75-100 hp increase, you should go with 1 step colder..so for those of you running 10psi (3.125) pulley, should be just fine with 1 step colder coppers if they are gapped to 0.034 or so....then you should be fine as long as your running premium grade as well combined with the above.....


what I am not clear now is this whole FMU thing....typically, don't S/C'ed max's with the 3.125 pulley put out around 300hp @wheels on a dyno (5spd) so therefore our stock maf's can handle up to 350 crank hp which is about 300@wheels...would this mean that the stock maf would be okay and you wouldn't need a FMU or fuel management system???!!??? or a Z32 maf?

 

MAF is a totally different component to the setup then what the FMU does..MAF is air and FMU is fuel management...you will need to change the disk in the Vortech Unit or On the Cartech, play with the setting on top, depending on what pulley you are running...

-matt

 

350 hp at the crank is 160 more than stock, so I think 1 step colder plugs are borderline. Like I said, I had to go to 2 step colder, but others have not had to. Sorry we can't be more definitive, you'll have to find out what works best for you.

Disregarding the A32 vs Z32 maf issue for the moment. Even though the A32 maf can meter air flow up to an amount needed to satisfy 350 hp, there are two issues that need to be addressed.

1) The oem injectors can not flow enough fuel to satisfy 350 hp. I forget what maximum hp they are good for, but if I recall correctly it is only in the mid 200's. The best way to overcome that is to install larger injectors, but then you also have to have your ecu programmed for the larger injectors. This is basically what JWT does, along with raising the fuel cutoff and changing ignition timing in places. Or you can go with e-manage, etc. The far less expensive method is to overcome the limited fuel flow capacity of the injectors by raising the fuel pressure based on how much boost the engine is seeing. More fuel pressure means more flow, at a rate proportional to the square root of the pressure increase. This is what the fmu does.

2) The oem ecu is programmed to deliver fuel at wide open throttle to produce an afr for a naturally aspirated VQ somewhere in the 13's. Boosted engines, especially high compression engines, need to have an afr in the mid 11's or thereabouts, certainly lower than what is provided for by the oem ecu. So even if the oem injectors were big enough to handle 350 hp, the ecu isn't programmed to deliver sufficient fuel to suppress detonation. Again, the best way to handle this is ecu reprogramming or to use a piggyback or AFC, but the inexpensive way is to use the fmu.

 

I have never had an Autolite plug fail even at over 17lbs boost with other engines .

They are pretty tough although no state of the art marketing comes with them .