Currently I have a basic setup running that retards spark -40 and kicks into power enrich at a specific rpm but doesn't seem to be building much pressure. How important are things like leading into retard gradually (like a 2 step) and how much fuel/when should I be adding? It's at 11:1 now, maybe more like 10:1? It's not shooting flames just rumbling and popping a bit.

 

it wont shoot flames unless u do a spark drop

auto car? what rpm can u stall it upto?

40* atdc is a lil excessive try 15*atdc
-40 isnt going to let it get up on the converter

 

I should say it retards by -40, so it ends up around -10 total. Auto and 2800rpm is the most I can get out of it, you did anti lag with your last motor didn't you? What was your set up like?

 

In my experimentation, with 2 step auto trans, my car showed more signs of boost buildup when adding as much timing as possible and not changing fuel.

I was under stalled so to get up on converter higher, i jacked timing up and kept air fuel somewhat leaner for max torque to get more stall speed. 2 step kicking in helped pulse exhaust i guess and it started to build pressure, just too low in rpm to really work. So i added nitrous to quick shoot the turbos and that worked very good so i now will restall my converter to get right rpm range

Anti lag stuff like said should drop spark alternating across cylinders and that raw fuel dump seems to light off in the manifold and really pulse the turbine.

I only tried pulling 10-15 deg i think when on the 2 step and richened it up alot but it didnt seem to do anything. Others i talked to say to add as much timing as you can to get on converter to create more load. Need really good footbrake or transbrake to get something out of it

 

i only tested antilag setup on my car never actually used it at the track since the car was already cutting 1.7 60"s

rpm retard at 2,800 -10* btdc
spark drop at 3,200 3 out of 8 ignition pulses
10% more fuel

u using the s10 style converter? 2,800 is all ur going to get out of it till u start making more boost


on pilsburys car i have
spark retard at 2,100 10 or 15atdc
spark cut at 2,400 3 out of 8
10% more fuel when active


i think u have seen the video of his car thing will make full boost in a second with his being a stick car, i have it wired upto the clucth switch for launch and flat shift

mine will make 15+ psi in about 3 seconds

 

Yea s10 converter. So spark drop is where it's at... not sure how I'm going to do that with DIS. I guess I could just richen the crap out of it... other suggestions?

 

Is the transition off anti lag into full throttle mode smooth?

 

yes i had to play with it lil bit to get the fueling right, if its to rich it will bog if it dead hooks . so i got it to were it would rotate the slicks 2-3 revolutions and it is perfect

not all setups will require aditional fuel if u can get away without adding a ton of fuel it should be like leaving off a transbrake, its just trail and error till u get it to launch nice and smooth.

on my car to use the antilag i pre stage step on the brakes hold my momentary button down and go half throttle to creep into the stage beam once its lit i just go wot and the system takes care of the rest. by the time i launch the car will make 13 psi , and i just release the button and the brakes.

ive only tested at the track with it as i didnt want to continually use it and bust the rear, on the antilag system the car could cut 1.5x 60's and im sure had i played with it i could have goten it down into the 1.4's and as we all know 1.5/1.6 is pushing it on a 10 bolt

 

richening it is either going to help or cause a massive bog off the line, spark drop is what really makes the whole system shine as it allows raw fuel to be ignited in the headers, being ddis i dont belive u can do a spark cut with the factory stuff.

an msd dis-6 should allow u to get the spark cut u need


how much boost can u get with the current setup
u can try reatarding the timing back to 15* adtc , or even go the other way and try say 35*btdc , going advanced causes alot of heat though in the chambers/and pistons so be careful.

going with a ton of retard causes the heatbuildup to be in the headers/turbine housing while keeping the chambers and pistons cool

 

There's a guy on 60degreeV6.com working on adding a spark-cut limiter to his modified A1 code called nAst1. He says it will be ready with the next release. It currently has a functional 2/3-step fuel-cut limiter but that's not too useful for boost. There's already 2/3 bar MAP support.

 

Saar

 

Just a heads up though, if you consider using nAst1 you need either a 9396 ECM for 2+BAR MAP support or IIRC an extra RAM chip soldered onto a 7730/7727.

It has some other cool features too like higher VE resolution up to 8400 rpm and there is/will be MAF support as well.

 

Just 2 psi. I'm wondering if these turbos are simply too big to launch well even with launch assist.

caffeine- how exactly is he doing spark cut with nAst1??? Is there an external relay or something?

 

I should find out how the Holley Dominator with 2 step and boost builder function works here in a few months

 

Don't know how he is doing it, but all that is required is to set the dwell to 0. If the coil isn't charged there won't be a spark.

RBob.

 

I don't really know any technical details, except that it's supposed to work with DIS and he already has some semi-working code. Apparently the problem he's been having on his test bench is making the spark-cut consistent.

 

IIRC, I looked into that couple years ago and I don't think setting the dwell via ecm was possible for some reason, although I didn't spend much time messing with the code...

 

once u get 2 psi and launch how long till it starts to build more boost?
if ur using the turbos i think u are u should be able to get around 5-6 psi on antilag with ur current converter , more then likley they will want something around 4,200 rpm stall

 

It takes a moment to shove me in the seat. Maybe 1 1/2 secs at most but it feels like an eternity... on the logs pressure rise looks like an exponential curve.

 

If u can get more boost ont he system it will help but more then likley its going to want a looser converter.

if u can get some sort of spark drop it should help u get a few more psi.

on the dis system i could in therory install a relay into the power supply line for the coil packs and use something to switch it on and off at a predetermined speed to get some randomized spark drop.im sure u can figur eout a way to get the ecm to control the relay if not a simple circut built with an lm555 timer chip could work and would alow u to adjust how fast it pulses the relay

the down side to doing something like this is u have no control of the sprak drop and it coul drop spark to the same cyl repeatedly cuasing fuel wash , not an issue if ur on the system for 1-3 seconds but it could become an issue if ur on the system longer and it will also call for more frequent oil changes


edit

an lm556 has 2 timer circuts with one of those u could randomize the on and off time to prevent fuel wash

 

I talked to robersaar on 60* and I think he came up with a good work around for the ICM, it'll take some time for me to reproduce what he's done but basically you just hold the bypass high and stop the EST signal. Hopefully I can get this working without hardware changes...

 

For the Chevy DIS set ups you are correct. I keep forgetting about that. They control dwell within the ICM.

The Buick DIS (which I work with more often) the dwell is ECM controlled. This is along with distributor set ups that are computer controlled, the ECM handles dwell.

RBob.

 

prolly be eaier to just build an interuptable power supply to the coil packs , then again if u kill power to the coils will the injectors still fire?

i know i could build the timer circut to control a relay for a few bucks in parts from radio shack

 

Yes, if it's between the ICM and coils. Kill the ICM and you don't have RPM.

 

BTW, something just occured to me. Should I be setting the spark latency table (LC0FC) to 0 since I don't have a distributor?

 

Over at DH were developing a programmable delco compatible ignition module so we can run currently not compatible trigger systems (such as 36-1 triggers, toyota, nissan etc) and fire up to 8 coils for coil pack support etc. Part of this means we get a programmable spark drop rev limiter. Because its a hardware module it can drop different cylinder spark each time so they all still get some burn time. The results are here:

http://www.delcohacking.net/forums/v...9902rpm#p29902

Its not available yet, but its certainly looking interesting.

And heres a delco running a toyota twin distributor v8 with the toyota trigger.
http://www.delcohacking.net/forums/v...16&t=92#p27207

 

Well it turns out this was suprisingly easy to do! Datalogs cut out while it's active for some reason but that's a problem for another day. Excited this thing's doing what it's supposed to without pulling my hair out.

Video here.

 

RBob, the 60V6 DIS ICM still uses the ECM for dwell time just like the 3800 and others of the era. in steady-state, about 5mS of dwell time is seen. i THINK that can be cut down to 3mS and still have a full energy spark event, but i haven't tested it myself. i sold my last car to my brother for basically nothing so my first test vehicle is gone, i'm waiting for good weather to get another on the road.

but yes, the road i went down was to cut actual dwell time(3FDC) to nothing/nearly nothing in place of cutting BPW down to 0.

 

Interesting, I take it these are the early 2.8l FWD cars. I bench tested a 3.4l Camaro DIS set up and it did do the dwell internally. With the coil removed it went to max dwell, leaving just the 600 usec firing time.

RBob.

 

ok so why was mine and bl's posts deleted????

 

There are no deleted posts in this thread. The posts in question may have been to the other related thread: "hey V6 guys look at this," or with a similar title.

RBob.

 

opps for some reason i thought it was posted here sorry

 

fairly certain that the 2.8/3.1/3.4/3100/3400 DIS ICMs are all the same...

i really need a scope, watching stuff on LEDs is difficult. according to GM(the most reliable source ever), the ECM calculates dwell when the bypass line is held high, but when low, the ICM does and when it's in ICM mode, it uses a REALLY long dwell period(i think i've seen it as the entire time that the reference pulse circuit is held high, so 60* engine rotation of dwell, regardless of RPM, i think). all of the code in the PCM supports this, the dwell times between the 60V6 dizzy and DIS applications also seem to be similar/identical.

i either need to get a 7X wheel made up and test this directly with my spare ICM/coilset or test it in-car, see if running REALLY low dwell times(~1mSec) affect it's ability to run.

 

Anyone know what I should do with the sp latency?

 

I would set it at all RPMs at the same value as stock for that DIS set up.

RBob.

 

So RBob, you think this is similar to what happened w the LT-5 DIS?

 

Yes. The LT5 FSM also supports this.

RBob.

 

RBob,

What was the dwell time for the 3.4L?

 

Never measured the dwell with the coils in place. Something about HV & scopes, they don't always play nice together.

RBob.

 

To really get a proper two step the spark needs to be cut in and out to build boost at the desired RPM limit. Just retarding the timing may not send a large enough volume of exhaust gasses through the turbo to do it. This isn't too hard to do with the later computers that have direct control of the coils, but it may be a little tricker on the earlier ECMs.

The dwell is a good place to start for sure. Dropping it down into the usec range should be enough to cut the coils out and snuff the spark to give the desired two-step limiter.

Its hard to say how the drivers will react to the short PW, though. Not sure how fast they can cut in and out. Its relatively easy to measure on the coil primary and see what voltage is building up there. The voltage will be much less, around 800-1000 V, which is a lot easier to deal with using a standard HV probe. The maximum voltage at the secondary will be roughly a 100 times that.

 

FWIW: i've seen quotes of 85:1 turn ratios on some of the aftermarket DIS coils, i think MSD blasters?

anyways, those also quote up to 45,000 volts, so one might expect around 500 volts on the primary side.

i was actually building a coilpack tester when i found all of this out, now it's going back to the drawing board.