Blowing spark out past 24psi?
 

My current setup:

Gtx4294r 1.0 t4 exhaust housing
4" exhaust
Large streetport motor
E85 fuel (4xID2000, 2xBosch 044 pumps, parallel -6 lines)
AEM EMS v1
Direct fire IGN-1A coils with MSD 10mm wires (Ludwig harness)
R6725-11 plugs x4 (tried new set of 10.5's as well)

My tune is spot on at 22 psi and the car runs great down low and up top. If I start to turn the boost up past 22 (25+ usually), sometimes it will run perfect (11.5afr), but most of the time it bogs and goes super rich (9.7afr). It feels like it's missing or blowing the spark out. I've tried different plugs and wires. I'm running 4.5ms of dwell on the coils with 5.2ms dwell above 4500 rpm.

I wanted to see if anyone else has had this issue or had any suggestions for it. Should I try different plugs or do you think it's something else?

Thanks,
Copeland

I'm running a similar set up with a slightly smaller turbo (BW S366). I am using R7420-11 which are the iridium versions of what you run I believe and I have the direct fire IGN-1A coils set to 4.5ms dwell at all rpms using a AEM Series 1. When the temperature is not to hot out I run a red line peak of 26psi at all times with a mid range spike of 27psi without issue so far.

I'm leaning towards a plug issue, I'll order some new ones and see how it does. I may also move the engine grounds for the coils to see if that helps.

What do you have your plugs gapped at? Too large of a gap causes issues at high RPM/boost

Stock gap on the R6725's, I wasn't sure if I should gap them or not. I think they're set at 0.028 stock.

https://www.rx7club.com/attachment.p...1&d=1407419200

I would definitely re gap them down to 0.018. I personally use the rx-8 plugs and just re gap them so boost doesn't blow spark. But rx8 are very similar...

I'll try gapping them down and see if it helps any. Anything free is worth trying.

I think this ^^^may be the problem. I am running over 25psi on a GT4094R at .018 plug gaps.

Awesome, I'll give it a shot and let everyone know the results.

The plugs are a little difficult to regap but after dropping them to 0.018", the spark issue is almost all gone.

Thanks for the suggestions and help. I'll do some further testing and see how it responds during the heat.

Subscribed.

i had erratic spark up top at 27 psi w a GT4094r w the IGN-1A coils at 4.5 dwell. we dropped the gap to .023 it has worked well.

i just got off the dyno w another one of my engines also w a GT4094r E85 27 psi etc and seem to have found a really nice plug. ( thanks to my customer as to the plug pick)

NGK BR10 EG. it is a racing plug w a resisitor which is somewhat unusual. the copper nickel ground strap works well w inductive and it has a smallish center electrode. special socket needed.

i am sure this isn't news to many but it was to me and i am impressed and will be running it going forward. a nice light brown color so it seems to be happy in the 575 power range to 9000. around five bucks.

stay in touch as you have a killer turbo.

Howard

been running the BR10 EG for last 24 months in my daily ( on LPG fuel ) at a 0.60 mm/ .0236 gap on ls1 coils with 4.5 ms dwell

( LPG being notoriously hard to spark )

and it will run out to 20 psi at times if i allow it

however swapping in a set of old b9 egv's ( not noise suppressed ) will lift the idle speed and quality and response seems a bit better down low
( but the b9 egv wont support 20 psi cleanly or for long )

i would suggest the non suppressed version B10 EG is possibly the best option for down low and up top.. provided you have the trigger setup and filters to cope with RFI signal colouration of the CAS pickups

What's the stock # on these? They seem to have more then one set. These do sound perfect for my FD. How do they perform with E85 I still can't believe the cost on these. I'm used to paying 100 bucks on a set of plugs :(

NGK BR10 EG stock number is 3830

thanks bumpstart

you will need to lathe your plug socket tool to thinwall with the EG and EGV

here's the link to NGK specs

http://www.ngksparkplugs.com/docs/RacingSpecs2013.pdf


i believe two BR10EG plugs are listed

product code 3993 is "SOLID", i believe that means the plug end does not screw off

product code 3830 is "LOOSE" and has a threaded tip.

Sparkplugs.com indicates as such.

HC

thinks the term "solid" and "loose" may refer to the presence of the indexing washer gasket

loose ( 3830 ) is the traditional version most of us would expect

Solid and loose refer to the top of the plug, when the plug wire connects. The solid plugs have the terminal permanently attached. Loose terminals are screwed on and can be removed. Some bikes and small engines run without the terminal and the plug wire attaches directly to the threaded stud underneath the "loose" terminals.

^^He knows his stuff

Hey I'm very interested in ur opinion on br10eg compared to r7420-11 to use on a LPG vapour injected 20b turbo borg warner s300sx.? (No dual fuel, just LPG)

I was told to run the coldest plugs possible.
Are the br10eg 's gonna work well and last well with this set up? Or do I really need to spend 40-50 per plug for the others?

It will be a daily driver set to 16psi 500hp ish plus some drift racing with more boost and 600-700hp.

Advice appreciated.

Plug Boot Design
 

The Plug Boot Design needs to be pictured, MUST touch steel.

Would it be possible to send a picture ?

You could state your BMEP then I could test in my CO-2 Chamber.

Your could ALSO state you coil Duty Cycle.

Lance