With the addition of the HKS DLI II Ignition Amplifier, I want to have my spark plugs changed out and re-gapped.

I'm running the APS ST, using NGK Iridium 1-step colder plugs (LFR6AIX-11).

Anyone FI and with the DLI II have any input???

I've been told you can run a wider gap...and have seen some say they are running 0.040-0.045"

Thank you.

 

I'm curious also. at my power level, my ignition setup seems stout. anybody make a case for the DLI on our cars?

 

+1 on the benefits of a DLI for FI VQ'S

 

prefer an answer to the first question regarding gapping before we discuss benefits of the DLI II unit

the DLI II unit has been discussed before in previous threads.

many in the FI crowd believes it helps smooth out engine response in higher RPMs, while others don't see it as much else than a piece of mind install.

some say better gas mileage...some argue it's only beneficial at really high HP levels.

the Supra guys swear by this unit. but again, their ignition system is different than ours.

there's no hard numbers (ie dyno graphs) that show an improvement.

alberto says he trapped a couple miles higher in the 1/4 mile.

SO IN CONCLUSION...any benefit derived from the HKS Twin Power will be subjective.

But I'm happy with the price I paid for the unit (thanks Ebay) and hoping to have it installed soon.

 

PM Sent Vinh,

I have a DLI II with the same plugs on my car and did not gap them. You are not suppose to gap iridium plugs because they are very sensitive and can be damaged easily. With the addition of the DLI II I felt there was even less of a need to do so. Remember we made 855rwhp on a stock ignition system with not DLI and we did not have any signs of issues with spark blow-out.

Hope this helps,

-George
GT Motorsports

 

I just bought some NGK laser platnium, are those just as good as iridium plugs? And should I not gap them?

 

No need to gap them down. The old gap down strategy, was more applicable in the olden days of distributors, and spark plug wires, where a lot of spark engery was wasted in transit. The 350Z coil over plug system is pretty robust. George is right.....lots of high powered cars run stock gaps and Iridiums. The one step colder plugs come pre-gapped to about .040-.044 and the two step colders come pre-gapped at about .030
Just leave them alone, IMHO.

 

+100

nice

 

When running FI...is it better to run Iridium plugs or Copper? I was told by a few people that Copper is more suited with FI setup. Can someone explains the cons/pros please? Thanks.

 

thanks george and sharif

i've been told the pros of running copper is that copper absorbs heat much better than iridium, BUT those who do run copper change them out every 3000-5000 miles because they don't last as long.

 

I was told the opposite. Iridium is easier to burn and it burns faster than copper

 

Iridium requires less energy to fire, and they undisputably last longer than a cooper plug, or a platinum plug.

Now, with richer FI mixtures, all plugs take a beating, and require more frequent changes. But cooper will not last longer than Iridium. And cooper will have a greatly likelyhood of misfires.

 

Thank you for the explaination. What can happened when plugs mal function or don't work? Can it cause an engine to blow up? Thanks.

 

http://www.ngksparkplugs.com/techinf...000&country=US

some info on spark plugs.

"Most frequently caused by hot spots in the combustion chamber.
Hot spots will allow the air/fuel mixture to pre-ignite. As the piston is being forced upward by mechanical action of the connecting rod, the pre-ignited explosion will try to force the piston downward. If the piston can't go up (because of the force of the premature explosion) and it can't go down (because of the upward mo-tion of the connecting rod), the piston will rattle from side to side. The resulting shock wave causes an audible pinging sound. This is detonation."

so i've been told copper plugs do a better job of removing heat, so less chance of pre-ignition when running these plugs. But if your car was tuned with iridium plugs, than I'd assume the chance of this happening is less likely. plus in FI cars, we run one-step colder plugs to help abosrb some of the extra heat produced in the combustion chamber.

benefits of an iridium plug sharif listed.

 

Usually, when a sparkplug fails, the engine will start misfiring badly. It's not terrible for the engine, but you definatly want to refresh the plugs. If some detonation or extreme heat causes the spark plug causes pieces of the plug to fall off, then yes, it can do some serious engine damage.

For a street car, I suggest changing the plugs once a year, just to be safe, although you could run them much longer than that. Spark plugs are cheap, so its good preventative maintenance, IMHO.
We have both one step and two step colder Iridiums in stock...if anyone needs them: http://www.forgedperformance.com/store/home.php?cat=275

 

I keep getting misfires every so often also.. Not sure if its my plugs or just my setup....

 

So are the NGK laser platnium any good?

 

It is not recommended to us a platinum spark plug on a Forced Induction application (Turbo, SC, Nitrous) due to its heat properties. Iridium is the way to go.

-George
GT Motorsports

 

FWIW, Vortech manual says use them if the OEM plugs were platinum. I have them now with 12k miles and at 10k they looked fine..Car runs fine.

 

I am not saying that platinums will not work, I am saying that it is recommenced to use 1 step colder Iridiums (vs using stock heat range platinum plugs) I am sure the Vortech manual says to use what is OEM since there kit out of the box is a low boost, low output kit.

Hope this helps,

-George
GT Motorsports