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I would like to upgrade my ignition system and I was thinking at the same time raise the rev limit. If I get a MSD ignition system that I can use with a 6 cylinder (MSD DIS-2 & MSD DIS-4) would I be able to control the rev limit and timing? Would I even be able to use this system along with the ECU? Or would I have to some how disable the ECU's control of the ignition system and control everything off of the MSD? Can I do this?

Justin
 

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Rev limiters

Generally systems liek that work by using the stock ignition control to trigger them - they then spark the plug with a hotter spark. as such they cannot override the stock computer's rev limiter. You might be able to goto standalone ignition control but IMO that would be foolish as chances are it wouold be nowhere near as sophisticated as the OEM setup and would lose knock sensing controls. For that matter, I'm not even sure that the MSD DIS systems will work with the Toyota ignition - if they will then that's terrific news IMO. th eMSD systems that are digital are pretty good but the ones that use discrete components like th eold MSD6 are junk.

Anyone looked into using the MSD stuff rather than the HKS etc.? At what level of power will this even show gains? I've noticed that gapping plugs down is done as boost goes up, I'd think that if a hotter spark could be gotten that this might not be needed?
 
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Re: Rev limiters

BLKMGK said:
I've noticed that gapping plugs down is done as boost goes up, I'd think that if a hotter spark could be gotten that this might not be needed?
I have wondered the same thing.
 

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OK thanks for the reply. Well is there an easy way of raising the rev limiter other then spending $1000 on a g-force cpu upgrade? If there is then all I will do is get that and then install the HKS unit to help keep the power up and stabile accross all the coils.

Justin
 

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Discussion Starter #6
Any more info then that JZ1?? Can you raise the rev limit using these? Are you still using the ECU for timing or are you using a stand alone MSD unit to control them?

Justin
 
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I helped the lead engineer at MSD develop it for use on these cars. Jared at P/House put it on a car but had some problems that I believe were unrelated and took it off. I've had mine for over 3 years. It cannot advance timing since it uses the signals from the ignitor grounding the coil as a trigger. It can retard though. It is relatively straight forward to do except you must connect the powerside of the MSD for the coils at the harness where it comes out the valve cover near the throttle body. If you do not, you will feed 450volts back into the wire harness and the ignitor and other components. I suspect that was Jareds problems since the EWD was incorrect as to location of all splice joints and may have tried to shortcut it. He's sharp so who knows what happened. I don't know anyone else with it on a stock ignition system

It works well. No misfire at .035" plug gap. I got rid of the standard connectors and used Toyota connections exclusively for reliability too.
 
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Oh sorry. Factory rev limit still applies! I have a G-Force with my own timing and rev limit maps
 

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Is there a wiring diagram of set of pics anywhere for the MSD install? Seems to be that's a pretty good piece and that people would be interested in it. Multispark certainly couldn't hurt for lower RPM operation either. Was the wiring very complicated and do you know if MSD is working on a setup for th eSupra in particular?
 
J

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hey JZ1,

i have a msd dis2/dis4 setup also but i disconnected it as i burned out my ignitor. i've been wanting to connect it back up but was afraid of burning out another 300 dollar ignitor.

can you privately email me. thanks.
[email protected]
 
J

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Basically (and this should answer both your questions) the coils have 12v going to them fed from the harness at various splice points. The 12v for the coils is shared from one power source and also supplies the ignitor (brown wire, orange trace). However each coil has its own ground wire to the ignitor to contol charge and discharge the individual coil. For reference, the green wire under the connector cover you attach a tach lead for a dyno to is one of these coil to ignitor wires. The MSD intercepts the ground wire for the coil from the ignitor to trigger the box. If you cut the ground wire from the coil to the ignitor, the wire coming out of the ignitor goes to the input trigger of the MSD, the wire end that is connected to the coil, goes to the MSD box coil output. The MSD sends 450v to the B+ of the coil and controls the ground the coil to fire it. Between the wire from the ignitor to the MSD box, you must use a tach adapter box (3 required) to simulate the coil current load on the ignitor so it can generate an IGF signal for the ECM to allow injection. MSD does have a wiring diagram including wire colors detailing installation. They do not provide the specific location of these wires. Its up to you.

What I suspect happened to your ignitor was you either back fed the 450v to the ignitor because you did not seperate the B+ of the coil wires correctly or you connected the trigger and grounds incorrectly. Intercepting the IGT wires which are the ignitor triggers from the ECM to the ignitor will make the system work but overload the ignitor and burn it up. The ignitor will spark the coils but the voltage levels are way higher than it can handle. It will work for a while then crap out.

Hope that answers your questions. Careful installation is important and you MUST make sure you are putting the B+ for the coils ONLY to the coils. I would recommend cutting the wires near the coil connector and sealing the cut end of the factory harness to be sure. Also make sure you connect B+ and ground wires of the DIS 2 to the same coils. Meaning, don't use the power side of the DIS 4 on one coil and the ground wire from the DIS 2. The box regulates the voltage to the coil to make it more stable. Also make sure you connect the DIS 2 to a paired cylinder 1&5, 2&4, or 3&6.

JZ
 

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We installed a MSD DIS 4 & 2 on a car 3-4 years ago when those units first came out. The MSD techs were very helpful, and sent me free tach adapters. They were very interested to see if it would work as at that time no one had tried on a supra that did no have a standalone in it. The car has been running without a problem since.


Lar
SP
 
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Hmm. from your description, i have it installed correctly except for the DIS boxes on the correct cylinders.

i have DIS 4 wired up to the 1-4 cylinders and DIS 2 wired to 5-6.

i have the wires tapped near the coils and the input to the MSD boxes are tapped AFTER the ignitor. of course going through the tach adapaters. I have the output of the msd goign to the coil.

the power for the msd boxes are tapped to the battery.

i'm goign to go through and check my wiring later today. see if i spliced the coils correctly.

thanks
 
J

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Did you splice into the wires or cut them? If you tapped into them you did it wrong. You have to cut them to get everything out of the circuit or you will send 450v into the car.

Hey Larry, its Dave, Edwin's friend you sent the stock turbo parts to a while back. I remember Steve at MSD saying something about you installing one of these after I got mine running. [email protected] also told me your install worked out for you.
 

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Hey Dave, How's it going? I was wondering who JZ1 was after seeing a highly intelligent post made!! Figures it would be you!


Hope all is well, take care.

Lar
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Intellegent? I don't know about that! But thanks. Drop me a line sometime to BS. I've got to do Edwin's twins and clutch soon. More projects! I'm thinking about some crazy MR2 stuff for a friend too.

If I don't talk to you, happy holidays!
Dave
 

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Hey all.....

-you guys do realize that you don't need two MSD boxes to run a Supra (dis-2 & 4) right!?

My Supra is being run with no problems using one MSD Dis-4 box...see pics of it here:

Jay's Supra

Read it straight from MSD:

MSD Dis-4

Jay
 
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jz1, sorry i have it cut. not tapped.

philly single, yeah the MSD -4 is only for cars with 3 to 4 coils. we have 6 coils. therefore the need for the MSD4+MSD2

you can use 1 msd box because you have a haltech and can operate your ignition in "waste spark" mode.
 
J

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I've run the DIS4 with the haltech and stock coils. Didn't last very long. The coils from a C5 corvette work great with the Haltech.

Javeman, I wasn't sure that you actually cut them or not. Had to ask! If you are you certain you got the right wires at your ignitor, it may have just gone bad on its own. Actually the switching load on the ignitor is less with the DIS. Rememer if one of the wires you cut was the solid green, you got the right ones. Of course if you did it all at the coil packs, you are sure to have the right wires. I'd try running it again!
 

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Any tech articles?

Has anyone writtenup a step by step guide on this? Say somehting that shows how to setup a DIS-4 (2 also?) to work with the stock ECU and then say with other coils from another (cheaper?) app? Obviously some are getting wires crossed and frying things so having a clear writeup with some pics would sure be a help.

At what level of performance is someone going to see a benefit from having done this? Not looking to build a drag car but I've noticed more than once that higher boost often also mentions lowering the plug gap. I'd think that having a wider gap exposed to the fuel would be best so higher voltages seems like the key. DIS systems have more time to charge the coil I thought, I'm surprised that ignition is an issue. Lastly, I wonder how the AEM ECU will interface with all of this. Will be running waste spark and if so does that mean that the DIS-4 will be easier to install?

You guys have obviously been around the block and then some on this so any answers or advice you can give others would be helpful. Thanks!
 
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