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View Full Version : sr20det 300whp what plugs and gap do you run?


spools420a
04-18-2021, 10:04 AM
Just like the title says what spark plug /heat range and gap should be used when making 300whp?I searched and just found one person recommending BKR8 and no mention of gap.

Mikester
04-18-2021, 06:23 PM
8 is too cold.

NGK BKR6E or BKR7E copper
.028-.030”

Results may vary depending on your air/fuel delivery, but that will get you in the ball park. I run a built 400hp setup and use BKR7E coppers.

Mike

spools420a
04-19-2021, 11:02 AM
Thank you!My air/fuel will probably be a tad rich as its a enthalpy ecu tune,I read they tend to tune safe so slightly rich and ret timing some.So In your opinion would you choose NGK BKR6E or BKR7E copper for 2871 turbo tuned by enthalpy?

jedi03
04-20-2021, 09:06 AM
i would do the BKR7E

TheRealSy90
04-28-2021, 11:20 AM
you could ask Martin what plugs he recommends for his tune. I have always used BKR6E copper. Increase gap until spark blowout and then close a bit.

Kingtal0n
08-10-2021, 11:13 AM
With old OEM coilpacks from 1995:
300rwhp I would use .037" copper or .034" iridium
400rwhp I would use .034" copper or .031" iridium
500rwhp I would use .029" copper or .028" iridium

If you get some new coils open them up another .002 to .004"
Do not recommend going below .025"

larger gap = superior for fuel economy and efficiency, as long as it doesn't blow out
We use slightly larger gaps for copper than iridium because the coppers do not last as long and both will gradually open their gaps over time, so the iridium end-of-service life gap is going to be similar to the copper end-of-service gap due to it's being installed 3x to 4x longer

The way I choose copper/iridium:
First, use copper because it is cheap. Tune the engine very well. Then put in fresh coppers and make SURE its tuned well and everything is solid for many miles (5000miles+) Then once everything is settled, check the coppers with serious mileage on them. They should look fairly new, white with a little bit of tan. A nice dark ring and no signs of oil or damage. THEN you install the iridiums and call it day. I also dyno the vehicle right after putting in the iridiums.

spooled240
08-10-2021, 11:39 AM
I used coppers and they suck imo. They are good for about a few thousand miles before starting to break up and needing to be replaced. Now I run the iridium 7's (2 steps colder) pregapped at like .28 or something (was for a Polaris or something IIRC) for my distributor KA turbo and it's perfect. No break up under 16 psi of boost and I consistently get a combined city/hwy 25mpg. If you have coilpacks then you can use the standard model that comes pregapped at .35-.36.

Kingtal0n
08-10-2021, 11:49 AM
The NGK copper is a standard OEM replacement and good for 45,000 miles in the stock engine.

If you are not getting that kind of mileage out of them, then there is some issue with the setup or tuning.

The NGK plugs we pulled from 1992-2002 sr20det engines with 88,000km to 144,000km , they all used these plugs for 10 to 20 years with great success before coming to America.

I have also used NGK copper plugs for tuning a hundred sr20 engines and have no issues for 10~ years.

The correct gasoline a/f ratio to use which will preserve these plugs is:
Idle: 14.7 to 15.2
cruise: 14.8 to 15.5
part throttle -2psi of boost: 13.3 to 13.5:1
0psi of boost threshold: 13.0 to 12.8:1
0 to 7psi of boost: 12.4 to 12.7:1
7 to 15psi of boost: 11.8 to 12.2:1
15 to 22psi of boost: 11.5 to 11.8:1
22+ psi of boost: not recommended for 93 octane gasoline unless you are a professional tuner

The engine needs a fully intact OEM pcv system. The crankcase pressure should be monitored at least initially to verify the pcv is working.
The engine needs a high quality paper air filter, similar to OEM style paper.
If the engine has a MAF it needs a recirculated bypass. This is the number one offender of spark plugs and cylinder walls, people not using a recirculated bypass for their blow-off valve causes gasoline to wash down the cylinder walls and fouls plugs ruining their life span and the engine's life span.


If you lack these tuning a/f ratios or crankcase PCV system, or a sufficient air filter, or recirculated bypass, the plugs will seem to not last very long.

Recap:
-tuning: poor tuning fouls the plugs. If plugs are fouled once they should be replaced.
-After engine tuning, replace the plugs.
-lack of recirculated bypass from blow-off ruins plugs and cylinder walls.
-lack of high quality air filtration ruins plugs and trashes the engine (internally it will erode, degrade, and oil passages will clog and the enngine block will become unsalvagable and unreusable)
-lack of pcv system causes myriad issues related to oil quality and oil aspiration, hydrocarbon-oil contamination, which leads to plug fouling

*The most important thing for any piston-engine is cleanliness. These features and goals are all aimed towards cleanliness. If the air is not clean, the oil will not be clean. If the oil is not clean, the engine will quickly become ruined, trash. Air filters, pcv, proper tuning, all help keep the engine clean internally which will maximize service life and intervals.

spooled240
08-10-2021, 12:15 PM
I thought platinum was OE? Thats at least what my 97 s14 calls for.

Kingtal0n
08-10-2021, 12:17 PM
I am talking JDM sr20det engines and RB25 and 2jzgte etc...

Turbo engines

If you seek to replicate the turbo engine variant you should be using the turbo variant plugs, not OE for a naturally aspirated truck engine.


From google
platinum plugs stay too hot (that's why they run cleaner) and cause premature ignition in turbo and supercharged engines. the platinum burns off in turbo cars, they simply come apart under high cylinder pressures. Running them could cost you your engine.

spools420a
09-07-2021, 10:43 AM
The NGK copper is a standard OEM replacement and good for 45,000 miles in the stock engine.

If you are not getting that kind of mileage out of them, then there is some issue with the setup or tuning.

The NGK plugs we pulled from 1992-2002 sr20det engines with 88,000km to 144,000km , they all used these plugs for 10 to 20 years with great success before coming to America.

I have also used NGK copper plugs for tuning a hundred sr20 engines and have no issues for 10~ years.

The correct gasoline a/f ratio to use which will preserve these plugs is:
Idle: 14.7 to 15.2
cruise: 14.8 to 15.5
part throttle -2psi of boost: 13.3 to 13.5:1
0psi of boost threshold: 13.0 to 12.8:1
0 to 7psi of boost: 12.4 to 12.7:1
7 to 15psi of boost: 11.8 to 12.2:1
15 to 22psi of boost: 11.5 to 11.8:1
22+ psi of boost: not recommended for 93 octane gasoline unless you are a professional tuner

The engine needs a fully intact OEM pcv system. The crankcase pressure should be monitored at least initially to verify the pcv is working.
The engine needs a high quality paper air filter, similar to OEM style paper.
If the engine has a MAF it needs a recirculated bypass. This is the number one offender of spark plugs and cylinder walls, people not using a recirculated bypass for their blow-off valve causes gasoline to wash down the cylinder walls and fouls plugs ruining their life span and the engine's life span.


If you lack these tuning a/f ratios or crankcase PCV system, or a sufficient air filter, or recirculated bypass, the plugs will seem to not last very long.

Recap:
-tuning: poor tuning fouls the plugs. If plugs are fouled once they should be replaced.
-After engine tuning, replace the plugs.
-lack of recirculated bypass from blow-off ruins plugs and cylinder walls.
-lack of high quality air filtration ruins plugs and trashes the engine (internally it will erode, degrade, and oil passages will clog and the enngine block will become unsalvagable and unreusable)
-lack of pcv system causes myriad issues related to oil quality and oil aspiration, hydrocarbon-oil contamination, which leads to plug fouling

*The most important thing for any piston-engine is cleanliness. These features and goals are all aimed towards cleanliness. If the air is not clean, the oil will not be clean. If the oil is not clean, the engine will quickly become ruined, trash. Air filters, pcv, proper tuning, all help keep the engine clean internally which will maximize service life and intervals.

this is great!will a rich mix make you need to run plugs gap tighter?im running pig rich under boost mid 10 afr and had to run a 0.25" gap or it would sputter under boost.this is a fresh setup and only ran like this for a mile or so right after install as we have to start somewhere.im using the afpr to lean it out some will this allow me to widen the gap you think.the 0.25" makes idle kinda ruff and would like to run closer to 0.28"-0.30" if i can.

my fuel pressure is set at stock but martin recomends i turn down pressure 3 psi do you think i can safely lean out the afr from mid 10s to high 11s with turning down fuel pressure alone?
its a basic setup of redtop with 2871r/550cc/walbro 255lph/enthalpy ecu/z32 maf and using tomei type s afpr and plan on running 15 psi.

another question.im running 12-13 psi and will turn up boost to 15-16psi after afr looks better.normally increasing boost will help lean the afr but because were using a 1:1 ratio afpr will increasing the boost keep the afr around the same you think?

Kingtal0n
09-09-2021, 02:24 PM
this is great!will a rich mix make you need to run plugs gap tighter?im running pig rich under boost mid 10 afr and had to run a 0.25" gap or it would sputter under boost.this is a fresh setup and only ran like this for a mile or so right after install as we have to start somewhere.im using the afpr to lean it out some will this allow me to widen the gap you think.the 0.25" makes idle kinda ruff and would like to run closer to 0.28"-0.30" if i can.

my fuel pressure is set at stock but martin recomends i turn down pressure 3 psi do you think i can safely lean out the afr from mid 10s to high 11s with turning down fuel pressure alone?
its a basic setup of redtop with 2871r/550cc/walbro 255lph/enthalpy ecu/z32 maf and using tomei type s afpr and plan on running 15 psi.

another question.im running 12-13 psi and will turn up boost to 15-16psi after afr looks better.normally increasing boost will help lean the afr but because were using a 1:1 ratio afpr will increasing the boost keep the afr around the same you think?

You don't want to be in 10's a/f ratio at all
You can lean out using AFPR some but try to keep fuel pressure base more than 35psi minimum

I recommend a SAFC to dial in the a/f ratio better, when using rom tune
or get a Power FC and tune it properly

=Follow the a/f ratios I posted
=use the gaps I posted

spools420a
10-02-2021, 12:26 PM
i cant run .028" as it breaks up???.im at 024" and it runs great under boost,my afr at full boost is 11.1-11.3 so a tad rich,i plan on lowering the fp a tad and try to get 11.5ish afr could my afr be the reason i need to run such a close gap?

the coil packs are delivering good spark as i put a spark tester on it and i can get the spark to jump pretty far making a nice crisp snap but under boost i cant run over 025"maybe its normal in my altitude or climate? (phoenix az)

spools420a
10-13-2021, 11:25 AM
bump last post,had to go down to .023" on NGK BKR7E to prevent blowout at high rpm.this all started when i swapped generic 2871r/550cc/z32 maf/walbro pump.before this i was running stock t25 and stock gap no issues so its not a engine compressiom problem.

im at 15 psi 2871r on 91 octane,im seeing afr around 11.0 - 11.3.

im running 39 psi fuel pressure so i can lean the mix down do you guys think this would allow me to open the gap some more?

also tested spark from coils and each coil has no issue jumping a nice big gap making a crisp "snap" sound nice looking spark but i only did this at idle,ill try revving it up to see if somthing changes.

what else could it be causing me to need such a tight gap?