I'm scrapping my opti in favor of better spark control... and a Fast ecu. What's the best route to go in this area with the LT1's currently? I'm sure I'll get 101 people telling me to get that new thing that's out there that whoever made... if it works fine, but I want a broad range of opinions that's all.



Thanks
Chuck

 

Two options:

Dynaspark (very well built opti replacement)

LTCC (ditch opti and only use the optical portion as a crank position sensor and use 8 LS1 ignition coils, basically a conversion to coil pack per cylinder)

The latter is more expensive.

 

And now that we got those out of the way... we can figure out what the best way to go is with an aftermarket ECU. I don't want to run an opti, or anything made to replace the opti on a stock ecu. So what does it take to make a crank trigger msd setup work? Buy a set of LS1 coil packs and done dealin?


Thanks
Chuck

 

Even with a FAST (or a DFI or a MoTeC) you can not run sequential fuel injectors with only a crank trigger. You need cam position to set up sequential injection. You could run the FAST in bank-to-bank (batch fire) mode. Or there is a thread on Advanced Tech about a FAST setup that uses an eDIS 8-channel driver with 8 LS1 coils, a crank trigger, and a sensor and magnet set in the timing cover/cam sprocket for cam position. It was done by NEDyno. A "search" should turn up the post. I am not sure if anyone has it working yet, since I know "jimlab" was having problems getting the sensor and the magnet in the right postion on his 600+HP 396.

Then, after you ditch the Opti, you need to find a way to replace the functions that the stock PCM would normally provide.... it will not function without the low resolution (cam postion) signal from the Opti, so it won't turn on the fuel pump. And you need the stock PCM for the VSS/speedo, VATS, etc. If it a pure race car, you could ditch all that stuff.

Another option... I run the optical section of the Opti to feed cam and (psuedo) crank postion to a MoTeC M48Pro, with their IEX 8-channel ignition driver, and 8 LS1 coils. The worlds quickest LT1 used the same setup. I think that FAST has an option to use the Opti pulses also.

Once you get the high voltage function out of the Opti, it seems to eliminate a lot of the problems.........

8 LS1 coils mounted under radiator support

 

Ok, makes sense..... You think running the Opti with the Fast system will be fairly dependable? This motor will be making a minimum of 600 hp. So I need something that I can depend on. I don't quite understand what you did.... Could you explain that a little better?


Thanks
Chuck

 

the LTCC is basically the same thing that Fred just described in hte last option. the BIG advantage is that you still get to keep a full functioning stock PCM. why bother with 2 seperate computers when you can get away with the stocker? so instead of a MoTeC M48Pro, with their IEX 8-channel ignition driver and 8 LS1 coils... you just need the LTCC module and harness with 8 LS1 coils. usually the only reason ppl run an aftermarket ecm is if they are determined to spin the motor past 7k rpm... stock pcm spark maps only go to 7k rpm.

 

Yeah, I need the rpm's.... more than likely it's going to make peak power at 7500, so the stock ecu just isn't an option...


Thanks
Chuck

 

My setup now consists of an MSD digital CPC Hall-effect cam sync stub in the distributor hole in the back of my Hogan's intake, an MSD crank trigger, a FAST eDist, and LS1 coil packs. A Motec stub was also an option, but would have cost about three times as much as the MSD stub and still taken as long to receive.

Let's just say there were a number of problems with sending my front cover and timing set to NE Dyno and the service and parts we recieved and didn't receive from them, and leave it at that.

 

Using MSD Crank Trigger, and MSD Low Profile Crank Trigger Distributor, w/ EFI Cam Sync Sensor. FAST Sequential Management.

I also have a brand new MSD Small Diameter Distributor w/ Cam Sync that I won't be using of you decided to go this route. This unit will fit behind an LT* intake. My two intakes give me enough room to use the better 5" cap, and so I ended up not using the small diameter unit.

Good luck!