Spark plug & gap - yours?
 

Just a data point discussion - what is your spark plug type and gap for your 930?

Mine: Bosch W2CS RO388

I use the cheapo NGK's that Wayne sells and the .6mm gap BA says with stock ign, B&B w/ k27-7006. Runs great.. I heard the MSD guys use .85mm

Currently Using NGK iridium BKR6EIX .030" gap

bp8es at 0.032" with msd ignition. ...however i do change them after every race.

Bringing this one back from the dead as I'm in need of some advice.

I'm a 3.4L with 7.3:1 CR and Electromotive XDi twin plug ignition. I run on 93 octane pump gas and my car is not tracked, but is daily driven.

I'm currently running the NGK BP8ES (can't remember the gap). I like them 'cause they're cheap...considering I need 12 of them! I'm wondering, however, if this is the right plug - temperature wise - for my twin plug engine. I've noticed that it can be hard to start in the morning and I'm not sure if this is typical of inductive ignition or if it's the plugs. This of course considering that my CIS is all working properly. What do you guys think? Try a hotter or colder plug?

I'm thinking about the following:
NGK B8EGV
NGK BKR6EIX

I know that as NGK numbers decrease the plug gets hotter, so I'm wondering if the NGK BKR6EIX would be too much of a jump into hotter temps? I wonder if I should look at a 7?

8 is what NGK calls for stock so I wouldn't go hotter. I run BPR8ES on top and DPR8EA-9 on the bottom with stock gap. I'd like to run Iridiums like I do in the kart but I have a hard time justifying the price for 1 plug so I can't see buying 12 of them.

I'd also stay with the projector plugs so I'd get BP8EGV's.

I've only ever run W3DPO's on my car... damn expensive, I know :mad:

Installed 8 months ago, I am very pleased with my Beru Silverstone S9 plugs at standard gap. Pelican research made me decide on the change, though they were a bit hard to find.

What kind of power levels do the BP8ES plugs support? My setup is a turbocharged EFI Carrera motor, with 930 P&C's. I'm told the only effective plugs for this setup is the W3DPO plugs :confused:

I've been running 12 of the NGK BKR7EIX plugs since April with no problems. Just a range cooler than stock (but I'm running a big intercooler).

I think there are lot's of effective choices. Hence my indecision. I ran the W3DPOs for a while in mine, but when I went to twin plug, it was just cost prohibitive. These BP8ES are hella cheap and I think do a fair job. What 125shifter mentions about running hotter plugs on top and colder on bottom is a pretty cool idea! Reminds me of "tube rolling"...for the vacuum tube audio guys!

What happens if I run a hotter plug? I was just about to order the NGK BKR7EIX. Which is hotter. I dunno, I don't hurt anything...

I think with NGKs as the numbers decrease the plugs get hotter...and with Bosch as the numbers increase the plugs get hotter...I THINK. So I think the NGKs that you are running are actually hotter than stock.

EDIT: or maybe I'm just talking out of my @ss and I've got this hot/cold thing all wrong!

If you run a hotter plug, you run the risk of running your engine hotter. Not a good idea for a blown air cooled engine, especially one that's been modifed and produces significantly more HP than stock, via more boost = more compression. You need a colder plug for modified engines.

BTW, I'm told by a reputable tuner that the BOSCH W3CS work really good too. They are equivalent to the NGK B9EV's.

Actually both my upper and lower plugs are an 8 heat range.

If you run a hotter plug you have less chance of fouling the plugs but you need to check them after a hard run to make sure they don't look too lean. If you're running on the track, I wouldn't risk it.

There's been lots of discussion over the years about the ideal plug for 930s. From what I know, the W3DPO (platinum) is too cold for even a track 930 with EFI. I'm running a W4CS (silver), which has often received acclaim. From my engine dyno tuning sessions, there was a vast improvement from the W3DPO to the W4CS, based on runability and from looking at the plugs. Of course this was for my engine (not yours!) and I don't know how "engine specific" this choice is. BTW, if anyone wants a set of 12 W3DPO plugs (with about 2 hours on them) I'll sell them for a fraction of what I paid for them!

Okay, I've made an "executive decision": Bosch W4CS it is. I'll order them from our host as I have a few other items that I need! Thanks for all the input, gents! Oh, and FWIW, I too have heard that the typical W3DPO is on the cold side even for these engines.

For what its worth, I am running the Bosch W4CS plug at Geoffrey from the rennlists recommendation. My turbo has mild mods and does not see track time. After the change from the W3DPO plugs, I have seen much less plug fouling and the engine appears to run and accelerate smoother.

JP

For me, NGK B8EGV or B9EGV (for track-work) are preffered.

BP8ES aren't really Turbo plugs. Cheap, yeah...but I wouldn't use them.

WydRyd:
Engine doesn't "run hotter" when plugs are hotter. Only thing that runs hotter is plug electrode. It has to be hot enough to burn off deposits, but not too hot or it will melt.

To hot: it melts (engine missfires or knocks, it doesn't go hotter). Too cold and plugs go foul.

OK, so for a purely daily street driven car that sees occassional full boost burts, what kind of plugs do you recommend? This is for a car with Motronics EFI, so it already burns fairly cleanly. W4CS or W3CS plugs?