Hey guys its been a while since Ive been on here, had account issues but nwo im back..anywho, I am trying to adjust the dwell to suit the LS1 coils I installed a little bit ago cause ever since then the car hasnt been 100%. I know the dwell is suppose to be at 5.5 ms (optimal) but the problem is the power FC measures by degrees of crank angle ...I have tried looking for some type of conversion chart but havent had such luck..I know there has been some talk on this but Id really like some help on this cause right now this whole thing is extremely aggrivating....


thanks for the help


Mark

wow, really; nobody?!?!?!

I increased my dwell considerably but I'm not sure what values I used exactly. PM me your e-mail and I'll try to shoot you a spreadsheet tonight that calculates it. I am in the middle of moving so I don't have my home computer set up yet.

The car should run smoothly without the modified dwell settings.

if anything the stock ecu will throw a code for ignition circuit because of the different coils but the pfc shouldnt care...

I hear what your saying Carl, but if the coils are looking for a specific value in order to run where they are suppose to then i need to try to correct that first...

The coils are fine running at lower dwell than 5 ms. Five ms is about the maximum amount of dwell you would want to run before there is no real gain. I ran them for about a year on standard PFC settings with no problems.

hey Darius, any luck on that spreadsheet?

I'll see if 240z4u can chime in. I sent him my spreadsheet a while ago and it still had the settings on it.

awesome man thank you!!

Darius sent me a text but I forgot, I will try to remember tonight.

aight man, no worries....would be cool to play around with this during the weekend ..

10k rpm - 101
8k - 82
4k - 43
2k - 24
1k - 14
480 - 9

ok thats odd, thats the same exact settings that mine has as well.....guess yours were never touched??

I thought I had used darius' numbers but apparently not! FWIW my holset hx35 at 28psi doesn't blow out spark.

Paging Darius.

I FOUND IT!!!!!!!!



ok IGN Dwell vs Time


Time = 166.6667 x angle ( / ) <-- that means divided by RPM

so here are my numbers for a 5.0001 ms dwell

RPM------------------Stock--------------modified for 5.0001 ms of dwell

10000 -----------------101----------------------------300
8000--------------------82-----------------------------240
4000--------------------43-----------------------------120
2000--------------------24------------------------------60
1000--------------------14------------------------------30
48------------------------9-------------------------(left alone)

Sweet. Any noticeable changes after increasing it?

i have not adjusted it yet seems how i just now found it this morning...i am going to have a few tuners check my math and test that formula to make sure its accurate....if all goes well then im gonna be dialing that thing up...hehe

ok so I dialed the dwell up on my setup and I have to say its absolutely incredible. throttle response is very crisp and nearly as lazy as it once was before.. overall I am very pleased with doing this and i recommend this to anyone who has done a similar type of swap to thiers....NOTE: i also had to adjust the water temp table as well to brign the AFR's more inline with where they need to be...i still plan on getting it back on the dyno just to tighten up the tune and stuff...

would aftermarket coil need or could use some modifying the dwell? ive always wondered about this but never knew anyone that was experienced enough to talk to them about it.

i only changed the dwell cause the coils i am now using run at a different optimal dwell than my stock coils did...i guess it really depends on what coils you would be wanting to run...

S14-NEO wrote:i only changed the dwell cause the coils i am now using run at a different optimal dwell than my stock coils did...i guess it really depends on what coils you would be wanting to run...

i have to okada coil packs, there suppose to be 4times more spark but idk if they can be tweaked to be better optimized.

if they are stock replacement drop ins then i would prob leave the dwell alone..

oh ok didnt know if they can be tweaked to be good but how would i know if it needs tweaking?

S14-NEO wrote:if they are stock replacement drop ins then i would prob leave the dwell alone..

Could you shed some light on this rocker-replacement-same-symptom-t569376.html

Bump...

Found this thread searching on google. I jumped into my PFC datalogit and found the IGN Dwell vs RPM section. Punched in the settings Neo put up but for some reason, 10000 will only adjust to 255. Can anybody shed light to that?

My PFC only lets the max value be 255 as well, but Im not worried as I wont ever be revving past 8k..

Easy to follow/use equation for calculating Coil dwell in MS/crank angle for anyone else setting up after market coils on the Power FC http://brewedmotors.com/blog/power-fc-c ... -swap.html