SR20 boost/misfiring problems after 14psi

[dorkidori_s13]

im wondering if ne one else has had this issue...

currently we have 2 cars at the shop who are encountering this issue (mine and the owner/foreman of the shop)...we both are currently running PowerFC DJetros with a 2.8bar MAP sensor with upgraded injectors (mine are 630cc and his are 770cc)...both of our cars have been tuned on a mustang dyno up to 12 PSI...however when we go up one more boost level to 14psi tuning with a datalogger and wideband 02...BOTH cars begin to misfire and rev bounce at 4000rpm on the dot

currently im running a S14 T28 and his is a redtop T25...we both run stock wastegates and hallman boost controllers...his plugs are one step colder than stock...mine are stock heat range

this is really weird to both of us and we havent been able to pin down exactly what the cause of this problem is...both cars run perfect air/fuel ratios and stay in the stoich range at lower boost levels...power curves are perfect at 12psi

before we put my car on the dyno the last time...we checked for boost leaks with a tool we made...the turbo system is air tight...so PLEASE dont tell me to check for boost leaks

hes running a stock FPR and mine is a Aeromotive FPR...fuel pressure rises properly on mine with boost

we both seem to think it may have something to do with the coilpacks as he has read in a few places that some stock coilpacks just wont handle the spark and some will (kind of random)

both motors have great compression across the board as well

so ne one have any ideas??? i was already saving some money tword Spitfire coilpacks but i wanted some input from people before i ran out and blew 450 bux to solve a problem with the wrong answer

here is a list of mods i currently have on my motor so you can get an idea of what im workin with...

SR20det 2nd Gen Redtop
S14 T28 turbo
MEGAN 02 housing
MEGAN 3 inch downpipe
5Zigen ProRacer Aspec Catback
Greddy TypeS BOV
TREVTEC Hotpipe
TREVTEC Turbo Intake Pipe
HYBRID FMIC kit
CTune Rocker Arm Stoppers
Greddy Intake Manifold
Deatchworks 630cc Injectors
APEX-I PowerFC DJetro
AEROMOTIVE Fuel Pressure Regulator
DENSO Supra TT Fuel Pump
KOYO 55mm Radiator
SAMCO Radiator Hoses
DORKIDORI Water Temp Sensor Adaptor
CTune Air Dam Cover

input please...input =)

[Z U L8R]

close the gap on your spark plugs, you should be running NGK BCPR7ES (part #3330) they're not even 2 bucks a plug. they come gapped at .030 which is fine for stock boost but if you're running 14 psi you need your plugs gapped to .028

[dorkidori_s13]

we checked that as well...we did all mine to .026 and his to .028

[emersonLP]

Could very well be coilpacks. We just discovered my buddy's coilpacks were causing problems at about 12psi on his stock blacktop. We switched out his coilpacks for some known good ones from another blacktop and his car worked great all the way to 14psi after that.

[s13silvia123]

one of your spark plugs could be possibly bad happen to me my car was misfiring.

[Blues13]

Ahh.. having the same problem. Similar setup, S13 blacktop, power fc d-jetro, cp 9:1 pistons, fp big28 turbo. Around 14-20psi of boost.

Just got it tuned, but when I raise the boost, it starts missing quite bad at times after around one bar like yourself. Still not sure what the problem is.

I've changed the plugs already from fresh coppers heat range 7 gapped at 0.026, to iridiums at same gap, but still the same problem.

Thinking its some part of the ignition, but don't want to get splitfires on a guess.

[Blues13]

My other guess is the injectors - I have the Deatchworks as well, 650cc versions.

They don't seem to be performing like 650cc - inj duty at around 88% WOT.

Anyone having problems with them?

[longdy]

i honestly think that you have a boost leak.... did you check all of you cupplings????

gl

[Blues13]

Piping was checked for leaks with a leak detector and compressed air - holds tight.

[cutter]

did you ever solve this?sounds like a grounding issue.

[dorkidori_s13]

well see the thing is i had the car boosting at 14psi back when it was on the stock turbo and ECU and never had misfiring problems

i may try out one of those phase2 coilpack ground plates before i sink 400 bones on some spitfires...but im still guessing it has to do with my coilpacks

[Pstl_pete]

Had the same problem. 12psi car would run great, 15psi it would break up. Tried different plugs, gaps, etc. Nada. Installed an HKS ignition amplifier and voila break up went away and has never come back.

I just think the coils are weak or fragile as they get older.