LT1 with no steenking Optispark!

[speeder]

 

Megasquirt, EDIS, Cadillac Northstar coilpack. Sweet!

[mark]

got any more info on that?

[Jeff]

got any more info on that?

 

Ditto on that.

[speeder]

This is a project I did for a customer - It's in an '87 RX7 convertible that's getting a big turbo.

 

Custom 36-1 trigger wheel and crank angle sensor mount, Ford EDIS Module, Megasquirt 1/3.0 MSNS, Gutted and rewired Cadillac Northstar coil pack, 65 pound injectors , no MAF or distributor.

 

I would probably do the next one with a Megasquirt 2 to provide IAC control.

 

Looks like there's some interest in this, so I'll do a writeup with pictures in the Megasquirt forum when I get time. I "could" also produce some to sell.

 

Feels like I picked up some power with this setup - It's got crisp response and pulls hard up to redline.

 

The Crank Angle sensor:

[deja]

Very cool, looks like a potential answer to the dreaded opti.

[Danno74Z]

Using the MSII system is a unique way to eliminate the Optispark. I looked into this system a long time ago myself and felt like it was one way on eliminating the opti but it requires a lot of work. The Megasquirt is a true DIY FI system and for the most part you are on your own - not much support. Do your homework if you really want to go this way. To my knowledge you will loose your sequential fuel injection and your MAF. You will have to go bank to bank and use a MAP sensor. When it comes to tuning you will have to generate your own fuel and spark tables. Is it worth all the work just to loose the Optispark? I just don't know. Some people have no problems with them and others hate it. It does tend to self-destruct at very high RPM's but in a normal operating range I think it does OK. Final Note. If you really want to get rid of the Opti at a minimum it's going to run you $1000 to get MSII, crank wheel and sensor, North Star coils and the list goes on and on.

 

Danno74Z

[speeder]

you will loose your sequential fuel injection and your MAF

Losing sequential is not a significant loss. Losing the MAF = more flow.

Some people have no problems with them and others hate it.

Depends on the skill of the builder/installer/tuner.

It does tend to self-destruct at very high RPM's but in a normal operating range I think it does OK.

Huh? Like,"Look out, dood, 7000 rpm! She's ready to blow!"?

 

This is probably an expensive and labor - intensive solution to the troublesome Opti... But very economical when comparing it to "ready made" ECUs. Eliminating a distributor will result in the same cost for CAS fabrication no matter what Fuel management you use.

 

In this case, the guy needs way more fuel and air than the stock system can handle. I suppose that programmable fuel management would mostly be considered by those who have modified their engines to the point of outgrowing the OEM system.

[Danno74Z]

Hi Rick,

 

My reply to your thread was to make others aware of what you loose by dropping the Opti. ignition system. Don't get me wrong, I think the MS DIY FI system is way cool but as you noted it IS expensive (not as most others) and labor intensive. Just like 90% of what we due to our Z's. From what I know (not much) the sequential FI helps with emissions mostly at idle and low rpm's. As soon as the engine move up to say 2000 rpm the injectors are firing so fast it is practically bank to bank anyway. The MAF does restrict some flow but it does compensate for SOME engine mods before you have to reprogram the computer. With a SD system every engine change you make you have to dial in the trim tables again. Most racers use SD but again it will take a lot of effort (dyno time) to get it right. I really want to get rid of my opti system too but I'm weighing all my options.

 

What is CAS?

 

Danno74Z

[Scottie-GNZ]

In this case, the guy needs way more fuel and air than the stock system can handle. I suppose that programmable fuel management would mostly be considered by those who have modified their engines to the point of outgrowing the OEM system.

Here is a tease for why this setup is needed. The Mobil1 bottle is for a point of reference.

[Danno74Z]

Scottie,

 

If that guy is going to be using that turbo on an LT1 engine he will most likely have to throw out the OEM system and make a ton of other engine mods too boot. But that cat is spending a lot of money least on the list is tosing the Opti. I would like to know what internal engine changes he is making - WOW!

 

Danno74Z

[Bartman]

So this system would be somewhat similar to the Delteq system which also uses the Northstar coilpacks.

http://www.delteq.com/opti_direct.htm

 

Although I think the Delteq is designed to work with the stock PCM and still uses the Opti to some extent. They claim that with high voltage removed from the Opti-Spark, the problems of cap & rotor wear, internal arc-over and cross-firing vanish.

 

Speeder, what advantages does your system have over the Delteq system?

[Scottie-GNZ]

The engine is being left stock for starters but everything is being built/configured to support well over 700hp. Until the engine is built, boost will be severely limited, engine tuned accordingly and it will have a progressive alky inj system.

[Danno74Z]

Bart,

 

The Megasquirt DIY FI system totally removes the OEM FI system except for the sensors on the motor. The MS can use these so it saves a lot of money and if you are adventuresome you can even build the MS box - like an old Heath Kit (I'm dating myself). The OEM system can't monitor boost very well (I'm out of my league) so you have to use an aftermarket system. I'm not sure but most turbo's run 15-20 psi boost. I don't see how an LT1 can handle that pressure without pulling the guts and lowering the CR to 8-1. At the normal 10.5-1 the engine will just explode.

 

Danno74z

[mark]

I've got the delteq on my car now so I can address some of those points. It still uses the stock PCM and optispark. As Bart says, it does remove the high voltage from the optispark.

 

I have been less than impressed with the system. THe car ran better before I did the delteq system. I'll be going back to stock stuff when time permits.

 

The bracket for the coils is a joke. For the cost of the system, I should not have to modify it to make the coils stay on the bracket.

 

The wiring is very simple with high quality connectors. The install is easy with good instructions and the system looks very nice once installed.

 

I'd probably give the megasquirt a try if a kit were available.

 

BTW my engine is a 93 lt-1 so no mass air to deal with.

[Danno74Z]

Mark,

 

That is too bad your car ran worse after the delteq install - I was looking at that system. What a lot of people don't understand is if you have a marginal OPTI going on the Delteq MAY improve the Opti system. Yes you get rid of the high voltage but you still have a rotor and cap which is still prone to breakage and a opti wheel.

 

Yes you totally build your MS system! Here is just one link (there are thousands).

 

http://www.teglerizer.com/fi/megasquirt/index.html

 

Danno74z

[mark]

Thanks for the link. BTW all this was with a brand new optispark.

What I meant by kit was UPS delivers it, I put it on the car and the car runs. I don't want to modify, hammer, cut, beat, reduce, enlarge, streach, shrink, paint, epoxy, buy another one do it again and then get it to run. I've been doing the hybrid thing way too long.

Mark,

 

That is too bad your car ran worse after the delteq install - I was looking at that system. What a lot of people don't understand is if you have a marginal OPTI going on the Delteq MAY improve the Opti system. Yes you get rid of the high voltage but you still have a rotor and cap which is still prone to breakage and a opti wheel.

 

Yes you totally build your MS system! Here is just one link (there are thousands).

 

http://www.teglerizer.com/fi/megasquirt/index.html

 

Danno74z

[Danno74Z]

Mark,

 

I want to be clear on this issue. The MS FI SYSTEM is just that not just a pseudo Opti replacement like Delteq. If I'm not mistaken you can run a lawnmower engine with MS. This is like starting with a blank sheet of paper.

 

Mark,

 

The MS system is not for you. With the MS FI you will be doing "I don't want to modify, hammer, cut, beat, reduce, enlarge, streach, shrink, paint, epoxy" forever - maybe not the last 5 or 6 and I can tell you if you beat it you go to FI jail.

 

Danno74Z

[mark]

I don't mind tuning,(I have a guy that does it well) I don't mind the installation. I can do that well. I just really don't feel the need to learn all the ins and outs that are necessary to get this to run.

 

I really respect and admire the guys that are able to put this system on an engine and tune it.

 

Maybe if I were younger.........................

[speeder]

This is a joint project - I did the engine management and Scottie's doing the turbo install.

 

We're hoping low boost (7-8psi), careful tuning and alky injection will keep the stock internals together. That turbo is going to move lots of air even at low boost. The customer gave me a horsepower number and I sized the injectors accordingly, after asking, "Are you sure?"

 

CAS = crank angle sensor, the trigger wheel and magnetic pickup.

 

I would think that any system that gets the high voltage off the distributor would be an improvement, but maybe the Delteq doesn't preserve (or disupts) the original timing scheme. Those same GM DIS coils have been proven time and again to be able to support big power in Electromotive systems.

 

Again, the Megasquirt, or any programmable EFI, is done because more fuel/air flow than the OEM system can provide is required. Its benefit over other systems that program the stock PCM is that it is user programmable (no PROMS to be exchanged) over an almost infinite range (including positive manifold pressures) to handle fueling for any modifications done to the engine. Looking at the cost of a new Optispark, and the trouble they seem to cause, maybe the MS would be attractive to the LT1 owner who has the skills to do it. There is definitely a learning curve for the first-timer, however, and competent tuning ability is a must.

 

Unless an integrated setup with the fabricated crank angle sensor, wire harness, and precalibrated ECU are provided by a third party, This is definitely not a bolt-on system.

[jbc3]

There are many ways to skin a cat....

There is an adapter to allow one to run large injectors with the stock LT1 computer. http://www.acceleronics.com/ The Acceleronics Versafuler adapter will allow you to run huge low impedance injectors.

There are plenty of people running big horsepower with the stock computer, the MAF and both with and without ( Deltaq ) the complete opti. The down side of the stock computer is that it does not understand boost...but it's still very doable. The other problem is the stock computer can not manage the ignition past 7K RPMs. I have a friend that is running in excess of 20 lbs boost on his LT1. The MAF will max out (reading range) at ~4000 RPMS and the fuel is added in the power enrichment map.

I have had my stock optispark for well over 100K without any problems... and I spin my motor to nearly 7K frequently.... very frequently! I have heard people complain about the opti, but I have never had any issues. I have heard people say that the opti flys apart at high RPM... I have tried for over 10 years to blow one up... hasn't happened yet.

 

Jody