Which Spark Plugs?

[K Simmonds]

I've gone for NGK BKR8EIX after reading the about the various disasters and near disasters with the OE Bosch plugs, BKR7EIX is probably a better choice but I went for the 8's as I had a set of four new ones in stock. Not done enough miles yet to give an opinion but the car seemed fine on it's first couple of test blasts.

I tried the Denso Iridum's a few years ago and they did foul up very easily.

[A1quattro]

I am so glad ive read this post ,we run bosch dpor in the rally car , have done for years we had just recently run out of a set of 20 i got a couple of years ago , we fitted a new set on the last event and noticed the new plugs looked slightly different , also we had to close the gap which we didnt have to do before ,As i am haveing a new engine built over the winter [alloy block] this warning is perfect timeing

[bilko0795]

Anyone tried NGK PFR7B Platinums I was just about to order the Oem ones from Tps it was fate that this thread came up.


Just went on NGK website and they recommend the PFR7B with upgrade plug N/A

[GazzaG60]

jus use stock plugs. they work the best overall..by far.

i felt slight misfres so tried a few types from bkr7e to denso ik24. each hd pro's and cons. stock plug was best on mot occasions.

all i can say is dont try to gap th stockplug check it for cracks.

i tried fair few in the time i was just tuning vems.

real issue on boost is coil charge. not plug. mor coil chage is way to go.

[Error404]

Good info here guys. I am erring towards either the NGK BKR7EIX or Bosch FR5DTC seeing as I don't do more than 3k miles a year

[EspenW]

So Bosch F3CS will work fine on stock AAN with tune? What gap? Waiting for VEMS to come in with some other stuff to start messing with 93 octane and E85 mapping.

It is a racing plug, so might foul on petrol and regular driving.
Gap: they are 0.6mm stock, but on E85, I had some bucking at that gap. Took them down to 0.5mm, but from German forums, I see that 0.45mm is prefererred, and I agree with that, as occasional missing started fairly soon.
So: will gap the new ones to 0.45mm and crank the boost.

About plugs coming apart: it can and does happen on NGKs as well. I did some research on this a few weeks ago. NGK even has an info page on why ground electrodes can break off.

Never attempt to adjust the gap on F5DPOR (or use them for that matter, unless they were produced before 2009 or so, possibly earlier)

As a general rule, do not regap plugs. The heat cycling of a turbo engine will weaken the ground electrode and make the material more brittle.
Plugs are very cheap when bought from the right vendors, like for example www.carsparkplugs.com in the UK.

[quattrostyle]

Never attempt to adjust the gap on F5DPOR (or use them for that matter, unless they were produced before 2009 or so, possibly earlier)

I might have the old stock ones then, is there a way to check it?

[fundahl]

Damn I'm worried then. I am running stock plugs that I pulled and cleaned with sand blaster tool. The gap was .030" and I could not close them.

Best all around plug for 93/e85 and less than 30psi? I need to buy asap.

[V6quattro]

Damn I'm worried then. I am running stock plugs that I pulled and cleaned with sand blaster tool. The gap was .030" and I could not close them.

Best all around plug for 93/e85 and less than 30psi? I need to buy asap.

I'm running BKR8E-11 gaped at 0.6mm.

[fundahl]

I'm running BKR8E-11 gaped at 0.6mm.

What boost and motor? BKR7E-11 Are a step colder and would resist pre -ignition better no?

[V6quattro]

What boost and motor? BKR7E-11 Are a step colder and would resist pre -ignition better no?

5 cylinder on 32PSI and E85.

BKR8E-11 is colder than a BKR7E

[fundahl]

5 cylinder on 32PSI and E85.

BKR8E-11 is colder than a BKR7E

And that sounds perfect. .6mm gap and no misfires? Thank you. I ran those plugs in my Z at .022".

[GazzaG60]

gotta say I got my worst results from bkr7e and was surprised. maybe I should have gapped them down a bit more

[fundahl]

gotta say I got my worst results from bkr7e and was surprised. maybe I should have gapped them down a bit more

What do you mean by worst results? What did you have them gapped to? I think they are 1.1mm out of the box which is too wide for boost.

[GazzaG60]

0.7 iirc.

way too wide out of box. probly me to be honest not trying harder at the time to gap them better.

they were ok on cruise. didn't clog too much but on boost over 1.4bar were a bot iffy. ik's were poor on cruise. clogged in no time. on boost were great. stock plugs worked well all the time. when i went 1.6bar or so i started to get stutters at about 4500-5000. increasing the charge on vems sorted this out. up to 2 bar no problems and no coil issues. that on original stock coils.

turbo size for me means no boost below 4500 or so.

when i get the engine in the car ill see what happens again. hopefull before end of year.