parish8

iTrader: (6)

i am geting a significant top end miss when i turn up the boost. somewhere between 18psi and 22psi it will kick in depending on the weather. on a good weather day it will kick in sooner. on a hot day later.

while on drag week i only had tr6 plugs so i haven't tried a cooler plug but i did gap a set of tr6's down to .025 and that didn't change the condition at all. i will be trying a cooler plug and they come set at around .025 out of the box. i expect the same problem with the cooler plug. i have also tried a/f ratios from high 11's down into the 10's with no effect.

Kurt from W2W sugested i ramp up the ignition dwell to around 6ms up top but edit and efilive do not seem to have this option, i do not have acess to hptuners.

what else should i try? even smaller gap? how much smaller? any other ideas?

i am near the limit of the turbo right now and plan on hiting it with a little nitrous to push me into the 9's but i would like to fix this miss.

peppersac

How about trying some cooler plugs. The tr6 is only one heat range cooler. http://www.thunderracing.com/catalog...vid=9&pcid=102 They have some 3 and 4 heat ranges colder. Might be an idea.

Pro Stock John

iTrader: (34)

I run BS3, NGK TR8's, and truck coils.

427

iTrader: (3)

Can you get a backpressure reading before the turbo? Is the boost dropping before the engine missfires?


Kurt

parish8

iTrader: (6)

i have loged the back presure in the cross over pipe before. i was seeing about a 3-1 ratio but that was with a t76 and 3" dp. i haven't loged back presure with the pt88 and 4"dp.

my boost holds steady at this level. on the dyno when i cranked it all the way up i would see 26psi and it would settle down to 22psi, i haven't tried to turn it up much past 21psi at the track yet.

is there something worth learning that would make it worth my time to log the exhaust presure?

427

iTrader: (3)

Just me being curious about backpressure. I would like to have a boost reading before your intercooler also. I just like that stuff!!


Kurt

camcojb

I'm using the BR7EF's on mine at up to 22 psi. The Lightning guys often go these plugs once they exceed the TR6's and I've had no problems at all with misfire at a .032" gap and 22 psi. They are a step colder than the TR6's.

I have had issues with too big of an alky nozzle, but didn't really misfire, just flat shut the spark off.

Jody

TchargedLS1TA

iTrader: (9)

Measure your drive pressure and call presicion turbo and see if its a good ratio for their 88mm turbo

parish8

iTrader: (6)

i just ordered 3 sets of plugs to try.

br7ef
ar94
ar93

i tried the br7ef plugs once and they had a prety strong miss at idle. i might just throw in the ar93's and make a glory run(20psi and a 100+shot), let the parts land where they may or get a nice solid 9sec run . they dont have any of these plugs just laying around in town so i am going to load up and try a few diferent set up's. i have seen a a couple of posts where people say the autolight ar93 will not missfire at idle as easy or foul as easy as you would think for a plug that is 3 ranges colder. the reason i am running the 6's still is because of the way the 7's ran like *** just putting around. maybe the ar's are the trick?

camcojb

I do like your attitude Jim! Some of the Lightning guys say the same about the idle on the BR7EF's too, but mine idle fine and always have, at least for the last 13K miles I've had the built motor. Don't think it's because of my tuning! I think you're on the right track, try a couple different setups. You're beyond where most any of us have been as far as power, but boost and cylinder pressure-wise not that far off.

Jody

2001WS6Vert

Does the log show the miss on any particular cylinder? If it stayed on one cylinder after a plug change maybe its something else in the ignition system or maybe it lies elsewhere.

parish8

iTrader: (6)

i have the missfire test shut off. between trying cold plugs and a bigish cam i have enough missfires to set a code and kill my converter lockup.

it is definately more than one or even two cylinders. i think it is probably spark blow out and am just wondering if there are other things i can do to reduce spark blow out other than plugs and gap changes.

GoldRust

iTrader: (2)

Not sure this will help but on wormboy's car we run a ngk 10 with the gap around .021

Pro Stock John

iTrader: (34)

Magnus (Keith@HPTuners.com) said you can change the dwell time of the coils with their software.

94SS

http://www.kennebell.net/accessories...oostaspark.htm

http://www.msdignition.com/2005/2005_2.htm

I have heard of a dirty fuel injector causing a misfire that seemed like a ignition problem.

parish8

iTrader: (6)

yes, but i dont have acess to hptuners, i do have edit and efilive but no hptuners.

smokinHawk

iTrader: (48)

time to upgrade.

parish8

iTrader: (6)

time to throw it all away and put my ignition on megasquirt

hellbents10

iTrader: (10)

Will the megasquirt do the job on the ignition side with cylinder pressures that are that high? As far as I know the only engine managment besids the stock pcm that can do it is the bs3, other aftermarket stand alones are having a hard time with spark beyond were you are at now.

parish8

iTrader: (6)

there are a couple of ways to do it. i think mega can run the stock coils but in a wasted spark set up and i think you can set the dwell with mega too. there are other ways to make it work too but i dont know how well they work at these cylinder presures.