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Spark plug options..

 
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 1561
Location: MI

PostPosted: Sun Jul 01, 2018 3:27 am    Post subject: Spark plug options.. Reply with quote

Spark plugs..
I'm debating options.. The main contenders so far are..

NGK BR8ES standard "snowmobile" plugs.. I think 9's might be too cold..

NGK R5671A-8 4554 V-Power RACING plugs..
The Honda and LS guys seem to like these for high boost..

NGK BR8EG are like the ES but are supposedly designed to operate at a wider range of engine temps, for 2-smoke air cooled engines..

I'm definitely going to start with non-projected tip plugs, like NGK BPR plugs are.. These cars are supposed to take BPR#ES projected tip plugs for clarification but are more det prone..

I think I will eventually try some NGK BUE plugs
See what they do.. They are the ULTIMATE for detonation resistance, and nothing to break off and destroy your engine..


Surface Gap plugs!!

Surface gap plugs are the coldest you can get, they don't even have a heat range.. Mostly used in marine applications I think for ultimate reliability..

Formula 1 cars run surface gap plugs

I will probably start with the R5671A-8 or BR8ES.. Should try 9's and see if they foul out.. I have a lot of machines around here that run these spec plugs so spares from testing will not be wasted..

What do you think?

Anything 14mm gasketed with 3/4" reach should fit/work I think..

For visuals..
Projected.. bPr


Non-Projected BR

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Last edited by Fasteddie313 on Tue Jul 03, 2018 12:33 am; edited 1 time in total
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 1602
Location: Somerset, UK

PostPosted: Sun Jul 01, 2018 6:56 pm    Post subject: Reply with quote

Think I posted a question a couple of years ago surrounding plugs and received little to no feedback. So I went on this journey almost alone.

I swapped out from engine builder recommended NGK BR8EIX to 10’s when I upped the boost and leaned off the mid range fuelling circa 2yrs ago. From memory they are closer to non projected tip image. I noticed the egt’s a touch cooler and less prone to triggering the knock sensor over 1bar. I pulled them back out last April during the spring service after a year or so being allowed to do their job uniterupted. The tip colour was spot on with no fouling or carbon build up.

Mittelmotor said they used surface gap plugs on their race GTS running high boost and 395bhp. Reduced hot spots and far more det friendly. I couldn’t find any on a very brief search around, I didn’t try hard enough, so would be interested to hear of any feedback.
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1980 931 - forged pistons, Piper cam, CGT turbo, 951 ducted FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife LSD
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Cédric  



Joined: 27 Aug 2004
Posts: 1766
Location: Sweden

PostPosted: Sun Jul 01, 2018 9:02 pm    Post subject: Reply with quote

If the car is mostly street driven it will be other demands than for a track day car.

I use ngk b8 egv, many people use it for racing, and tuned turbo cars. I use them successfully in bikes aswell. They are supposed to be very sturdy, and give a really good spark. Which you really notice in the startability of the single cylinder bikes. They seem tolerant to low speed street driving aswell.

I heard that the surface gap plugs fouls very easily, amd need a really hefty ignition system, especially on a turbo car. Nothing for my car, but might be possible to get some benefits if you build a good ign.system and use the car for track only.
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 1602
Location: Somerset, UK

PostPosted: Sun Jul 01, 2018 10:57 pm    Post subject: Reply with quote

Just tried googling my BR. EIX and the B.EGV to understand the differences Apart from temperature. Hard to find good info. Must try harder. Assume it will be internal materials......??
Did find an eBay add listing the B8EGV as a racing plug for a 924
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1980 931 - forged pistons, Piper cam, CGT turbo, 951 ducted FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife LSD
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 1561
Location: MI

PostPosted: Mon Jul 02, 2018 3:36 am    Post subject: Reply with quote

https://jtune.co.nz/products/ngk-b8egv-gold-palladium-spark-plug
NGK's Gold Palladium Plugs Feature a Fine Wire Gold Palladium Center Electrode for Improved Ignitability, Increased Durability and Enhanced Anti-Fouling Capabilities.
Trivalent Metal Plating Provides Superior Anti-Corrosion and Anti-Seizing Properties
Corrugated Ribs Prevent Flashover
Pure Alumina Silicate Ceramic Insulator, Provides Superior Strength and Better Heat Transfer
Copper Core Aids in Heat Removal
Triple Seals Prevent Leakage
http://www.ngk-racingsparkplugs.com/shop/racing/b8egv/

Forgot about those for a moment.. They are Gold Palladium Plugs but I think they might be discontinued?
They sure want a lot of money for them on ebay but I found that a local parts store shows them "in stock" for $6 each, it says..

I think I ruled them out because they aren't resister plugs..
Well, I don't have a (functioning) radio on the 931, nor do I plan to add one, but do have an MS box, so I'm not sure about non-resistor plugs..
You don't experience any problems with non-resistor plugs Cedric?
I guess I could try them and see what happens..

I had no idea that Mittelmotor used surface gap plugs!! I thought that was a crazy idea of mine..
They look like they would be pretty easy to clean up if they foul out..

Do you have any idea which surface gap plugs Mittelmotor used?
A problem with them is you cannot change the gap, and you need a small gap to not "blow out' the spark with high boost.. Because dense air is harder to throw an arc through if I understand correctly.. Maybe Mittelmotor uses different ones with a closer gap, don't know..

Have you ever tried 9's?
Surick told me that he is running plugs with a heat range equivalent to a Bosh 3, which is a NGK 9.. But also says he idles at 14.7 to keep them from fouling, good idle, but I'm having trouble getting a smooth idle that lean..

Here is a heat range chart for Xref..


I don't know exactly what plugs he is running but Bosch 3 = NGK 9 and he is running what? 20-22psi ish iirc..

It seems a lot of tuners swear by standard br8es plugs but their is a tuning channel on youtube I have been watching to try to learn how to tune, and he swears by 4554 plugs which are the R5671A-8 4554 V-Power RACING plugs.. And I'm seeing him tuning 1000HP 2.0ish Hondas so that's pretty serious boost in the high 30's.. https://www.youtube.com/watch?v=k4b1peZwaP0
It's a bit Honda ricey but pretty entertaining and he actually shows what he is doing on his laptop tuning at times, hard to find..

Carrera RSR wrote:

I swapped out from engine builder recommended NGK BR8EIX to 10’s when I upped the boost and leaned off the mid range fuelling circa 2yrs ago.


10s!?
You have been running 10s for 2 years and haven't fouled them out in your street driven car? Wow..
What is your IAT and EGT on boost?
Maybe I should try 9s or 10s since you have such good luck that cold..
They say run the coldest plug you can keep from fouling out..
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Last edited by Fasteddie313 on Mon Jul 02, 2018 4:46 am; edited 1 time in total
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Cédric  



Joined: 27 Aug 2004
Posts: 1766
Location: Sweden

PostPosted: Mon Jul 02, 2018 4:32 am    Post subject: Reply with quote

Have no issues running without resistors. However those eix plugs seems similar and maybe more easy to get hold on. With our engines(not that tuned) its probably not super sensitive, if you buy a quality plug and at a good heat range.
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 1602
Location: Somerset, UK

PostPosted: Mon Jul 02, 2018 6:28 am    Post subject: Reply with quote

I jumped from 8's to 10 thinking, if i had bought the 9's and they didn't foul, I'd wish I had gone for 10's. If the 10 fouled, then I knew I could back pedal to the 9. The 10 worked, so I'll stay there for now

In a nutshell, my specs are
IAT's usually 6-8deg higher than ambient air.
EGT's usually 850deg pushing into 900's on a long boost
Idle and cruise bob on 14.7's
WOT at 10.1
Mid range AFR on WOT/full boost at high 11's to low 12's until the boost switch opens up the WUR's fuelling at 4800rpm
Usually 1.1-1.2bar boost which feels like the sweet spot of power and boost noise/theatre of fun. Probably overspinning it though!
Forged pistons to take a little battering from boost, temps and the occasional det occurrence
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1980 931 - forged pistons, Piper cam, CGT turbo, 951 ducted FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife LSD
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morghen  



Joined: 21 Jan 2005
Posts: 7908
Location: Romania

PostPosted: Mon Jul 02, 2018 7:59 am    Post subject: Reply with quote

Used Bosch #2 plugs. Worked just fine. Those are the coldest that Bosch makes.
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Shurick  



Joined: 15 May 2005
Posts: 489
Location: Russia, Moscow.

PostPosted: Mon Jul 02, 2018 9:20 am    Post subject: Reply with quote

I use NGK BPR8ES plugs and everything is working just fine. Just avoid rich mixtures at low load and idle to avoid fouling em.
Keep in mind that if you run EFI with some kind of VR crank sensor, than non-resistive plugs can interfere with it and jam or spoil it's readings
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'79 931 -- intercooled K26-3060-6.10 turbo @ 1.2 bar, EFI+EDIS, 951S brakes, stripped interior, 951 look.
'86 924S -- R.I.P.
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