What kind of spark plugs are you guys riding? Iridium plugs are suppose to be better than platinum but are they twice as good? They are twice as expensive. What are your thoughts? Thanks a ton!

race plugs.
only available directly from the racing department in NY


but seriously before that
copper plugs

I've used the iridium plugs for the last 6 months and haven't had to change them once. Used to change plugs every other event. Like them.

Race plugs from Porsche?

Copper plugs?

Don't keep these a secret.

Not porsche.

racing department of bosche
probably help... but hard to feel the differnece
the tips are shapped differently, the insulator has large gaps around it
supposed to give more room for ignition I guess?

impossible to find as the local builder has to order them and wait months to get them. I have to keep spares. But at 50 racing hours they show zero wear and look brand new.

What are you doing that requires you to change plugs every other event? What's the motor?

My motor? It's a 2.4 (4) running 13 to 1 with fuel injection at 60psi. The plugs I used to use (NGK DP8EA) with the Len Hoffman heads just didn't seem to last long. I'd get a stumble at low RPM's, which was a sure sign to change them. After I put in the Iridium plugs I haven't had any issues. In fact I think it was Len Hoffman who suggested the Iridium.

So is platinum garbage? I thought that back in the day that platinum was the way to go!

I've never heard of fuel pressure having any effect on plug life. 13:1 is high, but not so much that it should kill plugs. To give a frame of reference, our 3.6 RSR and 3.8 RSR motors go 40 hours on a set of plugs without problem. Trans Am V-8 motors are doing more than that without trouble. Weird you're having trouble.

You asked about my engine, so gave the fuel pressure as a data point as it's higher than most run.

Anyway think it could have been my fuel map (Link ECU) that was not properly set at start up, which Vic Sias just fixed. The fuel at start up option wasn't selected, so was having a tough time getting the car started the first time. Now it starts right up, but up at Cascade a couple of guys, behind me in line, came up to said they were getting gassed out by the fumes at idle, so maybe a bit rich at idle now.

Anyway when it used to start to stumble going off idle I'd just changed the plugs and the stumble would go away. I should try the old plugs again now to see if the issue was fixed. They sure are a bunch cheaper.

Are the RSR motors you have in 914's? If so what a hill climb car you've got! If I had a 3.6 in mine I could go after King of the Hill.

The RSR motors aren't mine. They are set up for short track/long track work and live in a early 911. They are pretty cool motors - somewhere around 450 HP. The 3.6 smoked the tires on a chassis dyno!

It sounds like your injection maps might be a little off. What system do you run? You normally need a *little* bit of start enrichment even when warm.

It's an early Link system and yes you're right, the map wasn't correct for start up, but now corrected. Otherwise the system has been great.

Love to see your 911 on a hill climb. Sounds like the perfect setup, with lots of torque out of the corners...like to try a motor like that in my car.