crewdawg16

Does anybody know what I would have to do to run a DIS on a Holley Stealth Ram setup??

bigals87z28

DIS? explain?

crewdawg16

The DIS, I think stands for Digital Ignition System?? Anyway, it is the 8 separate coil packs that come on the LS1s.

bigals87z28

umm why couldnt you be able too? maybe if you use the commander 950 ecu and all. But even then i think the DIS system just hooks up into that.

And its Distrbutorless Ign. System.

crewdawg16

Thanks, but what I mean is, what else would I need? Is there a crank trigger or something to tell it where the timing is?

MrDude_1

most aftermarket DIS systems work off a crank trigger.


some can use a converted distrib though.. that lets you get the power of 4 or 8 seperate coils while still having a way to turn your oil pump...

crewdawg16

sweet! Where can I find one of those??

biggtime

F.A.S.T. Makes a box for EDIST. You will also need to use ls1 coils, a crank trigger, distributer 'plug' that will still drive the oil pump. Why would you want to spend all of this money on this when there is no proven performance gain. I think you could spend your money other places better. There are some guys doing a DIY setup but it is still expensive and they are just into it.

crewdawg16

Just exploring some options, since I'm building a complete new engine, I figured, why not?

Scott_92RS

I'm not saying that I know for a fact that there is a proven performance gain, but why would GM use this type of system on the LS1? For looks? To waste money? It must make SOME type of improvement. A few possible improvements that I can think of: coil longevity ( I would assume since they are doing 1/8 the work), more powerful spark to each plug, better control over timing, no distributor to mess with, shorter plug wires, easier routing of plug wires.

MrDude_1

you hit a few of them.

the better spark lets the motor light off better... improving emmissions.

they could ditch the opti spark.... a distrib doesnt fit on the back of the motor with a 4tgen cowl over it, and there isnt any place up front to put it...



IMO thats why GM chose to go DIS for the LS1.

MrDude_1

also.. its probly cheaper for them.


because of ODBII, all the sensors needed for DIS are installed in the motor anyway.... and the computer was already controlling spark...

they just needed to pop power to diff coils instead of having a rotating switch.....

1bad91Z

iTrader: (1)

MSD makes a billet distrib plug that will still turn your oil pump and block off the dizzy hole in the intake at the same time.

biggtime

Yep thats my bet. Packaging and emissions........

crewdawg16

Well, I guess those would be all the reasons for doing it... Emissions is of a concern to me, anything that will help and improve performance I'm up for.

biggtime

Well then call F.A.S.T. order your sequential DFI and your EDIST box. You will have performance and emissions. I think motec sells a DFI that also controls the EDIST. about $8,000.00. But more realisticly I have a Accel DFIV7 that I run in batch and I can pass any sniffer here in PA. BUT its the visual you will fail. (no egr)

crewdawg16

I don't have to worry about the visual in Illinois, but I can't decide what ignition to get, because I do have to lose my large cap distributor for the HSR, where can I learn more about the Accel system you are running?? I had no idea it would be THAT expensive for the DIS.

bigals87z28

ahhhhh no? the LS1 was set up for the corvette, then put into the fbody. Modifications to the nose of the fbody had to be made because of teh higher sitting engine. They went to coil packs because of the high-technology of the LS1. the Gen III small block is the biggest step up in revolutionary small block design... next is the Gen IV which is gunna kick the Gen III in the nuts.

biggtime

http://www.mrgasket.com/dfigen7.html

Ricktpi

Iam running the HSR/C950 combo with MSD crank trigger, MSD 6A box & a MSD "dummy" distributor with a single coil. I believe you you can use the DIS-4 series box & seperate coils, the C950 will control it as well.

Guest

The high technology? Boy if that isnt vague. DIS has been around for a LONG time, it is nothing new. My 92 Ranger has DIS... and 8 plugs!!! Why? Runs cleaner, hotter spark. I'd bet it gets better mileage too. I wouldnt exactly call a 2.3 liter 4 banger in a bottom level pickup truck 'high tech' either.

bigals87z28

you know, for a mod you arent all that nice. This is 2 times you have bashed me in about 2 hrs. A DIS system is very high tech compared to the distributors of old days... Why are you constantaly fighting me.

biggtime

Don't take it personal he's got a ford with a 4 banger in it.

Guest

Sorry I didnt realize this was a nice contest around here, and its been alot less than 2 hours it was less than 10 minutes... and happened totally by chance I might add.

But anyway if you reread your post, why are you fighting with the other guy? Everything he said is right, and you say

"ahhhhhh no?"

I think you need to stop fighting yourself.

Guest

Yea, its a real barn-burner. Watch out... might knock off a couple of the TBI guys with it!

MrDude_1

dude, its not that we're trying to bash you.


its that you're talking over your head and either sound like a idiot, or worse yet, you mislead people into thinking into vauge stereotypes.



DIS has been around since atLEAST the 80s...


and theres no such thing as high technology... esp in the world of production machines.

Vader

1986. Buick V-6. Distributorless ignition system, using paired coil packs (Wasted Spark). All run by an old-fashioned (OBD) GM ECM, not an OBD-II PCM. One cam position sensor, one crank position sensor, and plenty of spark. Had a digital MAF, too.

The LS1 really doesn't have much ignition "technical" advantage over that 18-year old design, other than shorter wires for higher energy.

"Everything old is new again."

Ed Maher

Grand nationals were using distruborless ignition since the mid 80s. As were a lot of the GM econo cars of the era.

and bigal, i think these guys are right. You're just spouting off in vague terms about blah blah the LS1 is high tech, DIS is high tech, blah blah blah. What's your point? Can you even name benfits to DIS besides that its what most cars use today?


You know what else is high tech. The ignition module in a HEI disrtribnutor from the 80s. For such a small part in such a high stress environment, it does a fine job of lighting the spark for cars making even 3x the power of stock. Adaptive dwell control, etc. While you can't get as much dwell as with DIS, it does good enough for 99 out of 100 situations. Emmisions and economy standards what they are, the higher energy and slightlyu more accurate spark timing of DIS help the manufacturers get cars through the tests/standards that much easier. But in a street car, you'll never see a 'real' difference.

DIS is neat, but it is no way a power adder. Put the money you'd waste on DIS into your heads. THAT is where you make power.


BTW, madmax, not entirely sure, but i think most cars with 2 plugs per and DIS do so because they ONLY have crank sensor and are thus 'waste spark' engines. So you're likely not firing both plugs at the same time. One goes at the right time, the other goes on exhaust.

Ed Maher

damnit vader, i walked away while typing and you beat me the GN reference. Pretty sure my grandma's old 88 corsica with 2.8 has DIS too, am i right?

bigals87z28

never said DIS would ADD power and if it came off like that, sorry. My point is that DIS is a very new technology(relitive to the age of cars and how long people have used dist. ignition set ups) only really being put on more and more cars now. Never said they werent used before LS1's.

and holy crap.. i just realized that I ment to quote the person under Mr. dude... talking about how they had to put DIS on the LS1 because of the fenderwall lip... sorry for the confusion.

mastrdrver

I think one of the big reasons why they went with DIS on the LS1, is bcuz of better timing control. You dont have to worry about the spark being scattered with a DIS setup and therefor you get a stronger spark and get a better burn.

Ed Maher

Or maybe it's because they don't have to worry about the 9 out of 10 car owners who think changing the cap and rotor is optional, and check the timing, WTF is that?

The government knows thats how people think, which is why cars have to meet certain emmisions and efficiency standard OVER AN EXTENDED INTERVAL of time. Why do you think all modern cars come with '100k mile' spark plugs and such too? Along with 100k mile plugs, you also have to worry about 100k miles on a cap / rotor? Not going to happen.

There's really not THAT much timing accuracy to be gained by moving the coils to the valve covers. If you want to look up the speed of spark energy through a plug wire, i'll wait. You DO buy A LOT of extra available dwell time on the coils, but all that extra spark energy doesn't do anything as long as the original burn was clean anyway. A standard ignition, or even a CD box upgrade is mre than capable of providing ample spark despite haveing to tend 8 cylionder in 99 out of 100 situations. But try to cold start an engine with dirty injectors in Nome Alaska and let me know how it works out. EPA DOES test **** like that, and modern cars have to meet RIDICULOUS standards compared to anything any of us will really ever see.


There's always a big picture to be looked at. The general basically NEVER does ANYTHING strictly for performance unless it's a very limited edition car. If they could have saved a few bucks by running a dizzy on the LS1, they would have , IF it would have met EPA / CAFE standards. But given the range of lunacy they need to cover, they do what they have to do.

robertg

iTrader: (2)

ed.. for what it's worth.. i think 86 was the last year for the conventional distributor in some of the gm models.... i had an 86 cavalier that used a distributor.. a friend had an 87 that used 2 coil packs in place of a distributor.

my grandfather has an 89 pontiac 6000 with a 2.8 in it. pretty sure it has coil packs on it...

crewdawg16

Wow, look what I've started.........:lala:

metalhead212121

for the record Ed Maher & robertg are right about when GM started using DIS systems on 2.8/3.1 FWD engines. 86 was the last year GM ran a distributor. In 87 they started running coilpacks w/ignition control modules(1 coil pack for 2 cylinders). To this day on engines like the 3100 & 3400 they use coilpacks w/ignition control modules. They just got smarter about it.. They moved the coils & ICM (Ignition control module) to a spot more "mechanic friendly."

Dan

Guest

You're right, they do not fire at the same time. It fires one on the intake, one on the exhaust (to lower emissions, and it does work). Some do in fact have redundant sensors though. I've only seen a crank sensor on mine, but I havent looked real close either.

Grumpy

DIS Distributorless Ignition System
CNP Coil Near Plug
COP Coil on plug

At 6,000 rpm you have 2.5 ms to charge and fire a single ignition coil on a 8 cylinder engine. Maybe one of the EE will chime in with the math to show how lousy of deal that is.

DIS, get you to 5 msec, alot better but still marginal.

CNP, gets you 10, and all the time in the world to charge, and fire the coil.

Plus ease of individual cylinder timing control. Not a big deal, but, when your doing millions of cars, and dealing with the EPA things add up. On you big HP there are some that do show some nice gains, but that's not always the case. If a particular design leaves one cylinder detonation prone, being able to taylor that one cylinders timing is a bennie.

Ed Maher

Noone said there weren't benefits. And since normal dizzy cars have no problems running some damn impressive numbers in real street cars, you have to weigh the costs vs. gains.

Some fellas were trying to act like a significant increase in performance could be realized with DIS. Fact is, dizzy cars go very fast and get great gas mileage and pass california emmisions all the time. So maybe they'd be better of spending the money on headwork, rather than chasing after some silly 'ideal'

Grumpy

I'd say it varies with engine combination.
While a high turbulence, high compression engine might get by with a point ignition system, a low turbulence low compression engine might need darn near a Plasma generator to get an arc going to cascade the reaction.
Not to mention what, the min and max fuel droplet sizes are, and ratio to vaporized fuel, is.

In retrospect it's always easy to say, I didn't need so and so, and I could have spend money else where, but for some it's worth having the insurance of having enough spark, to do it and not worry about it.

In some respects chasing after ideals are a good idea, for the few dolllars difference, IMO, going for a Walbro 340 pump is better the using a 255. While the 255 might get you by, in a given application, IMO, I'd rather have some reserve fuel capacity rather then be right at the limits. And the list can continue to Ti retainers, 4 bolt mains, studs vs bolts, etc..

Again, YMMV

Ed Maher

Of course, given application, results may vary. This is a TPI board though, so results on some other engine family / etc aren't germane. Plenty of very fast thirdgens using stock dizzys and ECMs out there. In order to avoid senseless arguments (like LS1s are super high tech and they use DIS so it must be better and necessary, which is where this thread started) it's important to narrow the discussion to something manageable. If the goal is to go faster in a SBC, DIS is pretty low on the list of 'needed' toys.

crewdawg16

I am seeing both sides of the story here, and I have to say, that when I originally posted this, I was thinking along the lines the Grumpy is. Why not have it? If it is not INCREDIBLY expensive, and since I already have to buy a whole new ignition system for my new engine, why not? I do see others' points on not having any power gains, but then again it does help emissions which is a concern of mine. I guess the whole thing comes down to cost vs. gains. Does anyone have figures of how much a DIS setup would cost?

Grumpy

A 305 is a different application as compared to 350/355/383/400/406. Oops, almost forgot the 89 TTA 231.

I didn't say there weren't.

I've never seen any back to back testing of Distributor to DIS on a SBC, so I'll refrain from saying one is in fact needed or not.
I would wonder why thou, GM would go to such an expensive system if they didn't see it as being worth while.

But, on my 89TTA type drivetrain, I have run DIS to CNP and the CNP is noticibly better drivibility wise, and the best MPG runs I've gotten have been with CNP. And I also know a few v8 guys that swear by the CNP conversion.

Is newer automaticlly better?, no, but it's worth fully investigating it fully, to be sure that it is or isn't, IMO.

Grumpy

There was a DIS on the ZR-1's, but all the compnent pieces have gone thru the roof pricewise. There is the Northstar setup but it uses some really odd sensors, and sensor timing offsets.

About the only real conversion is for the LS1 coil near plug setup and that uses the F.A.S.T. eDist. The eDist is about 300, and the coils are a little over 30 each. You can rehash a dual sensor GM distributor to get the reguired signals. At my home page is some pics of what my CNP set up looks like.

http://home.woh.rr.com/brucesgn/

HTH