cant gap plugs bigger then 0.23" but why?

[spools420a]

Car was gapped at 0.30" when i was runnng stock t25 on redtop,after installing generic 2871r/550cc/walbro pump/enthalpy ecu/z32 maf and the plugs are NGK BKR7E.the car would buck under boost.to fix this i had to tighten the gap,the most i can run is 0.23" but why?

since this happened right aftter the 2871 swap and was running fine on stock gap this says its not a issue with compression or engine but somthing with the turbo upgrade.

afr are at 11-0 - 11.3 at full boost 15 psi on 91 octane

i put a spark tester and tested the spark from each coil and it has no troubl jumping a large gap making a nice crisp snap and nice looking spark,that tested perfect.

I feel that such a tight gap will make me lose some of the power,is this normal to have to gap this tight?would leaning the mix a tad help you think to maybe 11.5ish? we only have 91 octane here so im trying to stay in the safe zone.if its normal to have this tight a gap then thats great but shouldnt i be able to run closer to 0.28"?

note: i posted this on another thread and appologize for having two topics on this but i cant delete the thread as i intended.

[tuzzio]

Sounds like you have an SR.
I don't have much knowledge with the SR, but I know the stock coils suck. May be time for an upgrade if you're experiencing spark blow out.

Also, I assume you got a tune after your upgrades?

[spools420a]

Yes its enthalpy tune.
Do you think the small gap will rob me of any power?If not I wont worry about it.

Is there a rule of thumb for how far the spark should jump on the sr when testing spark I couldnt find it in the FSM?

if its not robbing me of power I can live with it even though its a little ruff at idle on cold starts.

[silviaks2nr]

That gap is fine. Hell go to .020

[Kingtal0n]

You don't want a small gap because it will reduce efficiency & economy, and will cause tuning related (spark timing) offset depending how dense the cylinder charge is (low density + small gap = more timing required) which creates a dangerous or inefficient curve depending how the tuning is done


It sounds like a grounding issue or a age-related issue. The coil packs are 20+ years old then its probably age.
otherwise I would unwrap the wiring and re-wire the grounds/harness and increase ground wire size and attach to multiple sites around the engine not just the one on the back of the head.

Also make sure you are using the correct plug

[tunermt]

Stronger coils will go a long ways! I ran Honda k series coils for year but recently changed to R35 ignition coils. Plugs gapped back out to .029” and running strong at 21psi. Looking forward to testing with more boost
With the r35 coils you can also remove/bypass the ignitor.
I used the extended length coils and plugs/pins to make my own harness.

[spools420a]

update:
for anyone with this issue,i went and swapped coils with audi r8/harness/and icm delete and no able to run 0.40" without blowout.no joke the car feels soo so much smoother especially at idle,the revs are much cleaner and smooth,it made a huge improvement all around,it feels like a before and after when getting a tuneup on a car that needed it.
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[spools420a]

Originally Posted by silviaks2nr

That gap is fine. Hell go to .020

it really wasnt fine at 020" the idle was choppy,the revs were terrible and power a little off.using r8 coils was a dramatic improvement and id go as far to say a must in my case.

anyone with this problem i cant recommend this upgrade enough

btw thanks for all the imput,thread can close if needed.

[jr_ss]

Originally Posted by spools420a

it really wasnt fine at 020" the idle was choppy,the revs were terrible and power a little off.using r8 coils was a dramatic improvement and id go as far to say a must in my case.

anyone with this problem i cant recommend this upgrade enough

btw thanks for all the imput,thread can close if needed.

You were blowing the spark out at that gap. The factory coils/ignition system is weak and you cannot increase dwell much on the factory coils before they start to melt.

Upgraded ignition components were your only option. I had CBR coils with a factory ignitor at .025 and no issues. I have since upgraded to VQ coils.

[tunermt]

My personal favorite coil atm is the R35 coils.
Super hot spark compared to any other COP option, cheap, easy to find, replacement boot/stalks, simple 3 wire coil with built in ignitor.
I?ve ran the ngk r35 coils, VE r35 coils, hitachi r35 coils and oem Nissan r35 coils all of which work like a charm and can be triggered directly off ecu no need for ignitor.

[jedi03]

do you guys have a diagram to follow for anyone else to swap to the same?

[tunermt]

Originally Posted by jedi03

do you guys have a diagram to follow for anyone else to swap to the same?

sure super easy to swap over to the R35 coils.

- s13/14 you'll need to bypass the ignitor (s15 doesn't use the ignitor so nothing to do there)

- R35 coils are 3 wire just like the OEM sr20det coils (12v, cylinderhead/chassis ground, signal from ECU). **i'll grab the pin out/picture and tomorrow and update this post for you.

[jedi03]

i appreciate it! i also saw another forum post asking for similar lol

[inopsey]

Originally Posted by tunermt

sure super easy to swap over to the R35 coils.

- s13/14 you'll need to bypass the ignitor (s15 doesn't use the ignitor so nothing to do there)

- R35 coils are 3 wire just like the OEM sr20det coils (12v, cylinderhead/chassis ground, signal from ECU). **i'll grab the pin out/picture and tomorrow and update this post for you.

what about the connection between the sr coilpack harness and R35 coils? is it plug and play

[tunermt]

Originally Posted by inopsey

what about the connection between the sr coilpack harness and R35 coils? is it plug and play

No you need the R35 coil plugs and pins to make a new coil harness or mod you stock one. (i recommend making a new one) Alternatively you can just buy one if you don't want to make a harness, they are only 125-150 usd depending on the brand you get.

[jr_ss]

Originally Posted by inopsey

what about the connection between the sr coilpack harness and R35 coils? is it plug and play

The SR harness plugs directly into the VQ37 coils. I am not sure about the VR38 coils.

[tunermt]

Originally Posted by jr_ss

The SR harness plugs directly into the VQ37 coils. I am not sure about the VR38 coils.

vr38/r35 coils did not match my s14 coil harness. (close but the the pins do not fully engage on the coil so i would not recommend using the oem harness. Get the plugs/pins with your coils to ensure strong connection between the harness and coils.)

[inopsey]

Originally Posted by jr_ss

The SR harness plugs directly into the VQ37 coils. I am not sure about the VR38 coils.

how is the fitment of the VQ37 coils on the valve cover? do you have any pics of how they would mount ?

[jr_ss]

Originally Posted by inopsey

how is the fitment of the VQ37 coils on the valve cover? do you have any pics of how they would mount ?

I?ll try to get some for you later today. Keep in mind this is on a P11 VC and a VET setup, so there are no mounting tabs. I can provide a picture of an S15 VC with these mounted, with and without the PRP bracket. I will say, without securing the coils, the bracket and boots keep these anchored very well.

[silviaks2nr]

Get iridium plugs it will make all the difference.

[jr_ss]

So here are some photos of the VQ37 coils in a P11 head/VC and an S15 VC w/PRP bracket.

What I can say is that the P11 birds are extremely tight and requires some force to get the coil on to the plug with the rubber isolator at the bottom of the coil.

[tunermt]

Old setup using Honda K series Coils, since changed to R35 coils but i don't seem to have a picture saved on my computer with the VR38 coils installed.

[spools420a]

i also tried vw jetta 2.5l coils since they plug right into my r8 harness and i swear they are identical,i can run same gap as r8 no blowout so if anyone wants a cheap option you can use vw jetta 2.5 100% confirmed.

im honestlly blown away on how much smoother the car runs all around with r8/jetta coils compared to oem.the oem sr are just junk,my engines never felt this smooth

[spools420a]

Originally Posted by jr_ss

So here are some photos of the VQ37 coils in a P11 head/VC and an S15 VC w/PRP bracket.

What I can say is that the P11 birds are extremely tight and requires some force to get the coil on to the plug with the rubber isolator at the bottom of the coil.

thanks for taking the time to throw this together

[tunermt]

R35 coils ftw �� love the PRP coil brackets they are gorgeous pieces.

8 months later these bkr7eix-11 are still factory 1.1mm gap and running strong (no spark blow out) at 21psi with the VE r35 coil packs.