V8 S/C Idea......

scdtrd · #1 (**permalink**) 08-01-2003, 12:23 PM

Ok... running this past yall..... lets see what happens...

Ok, idea #1.

Remove the piggyback ECU and install a boost activated trigger switch that is adjustable for the 9th injector. "T" off the boost port for connection. When you hit a pre set boost level, lets say 3psi or 4psi.. click .. and the 9th injector is flowing.

Simple, cheap, easily done, and you have the stock ECU to boot.

Idea #2.

Find and remove from the piggyback ECU the timing controls for the engine. Put them BACK in the stock ECU and that way, you have the stock timing map, but all the added parameters for the piggyback to monitor for you.....

SCDTRD

Mudog715 · #2 (**permalink**) 08-01-2003, 05:22 PM

Quote:

Originally posted by scdtrd
Ok... running this past yall..... lets see what happens...

Ok, idea #1.

Remove the piggyback ECU and install a boost activated trigger switch that is adjustable for the 9th injector. "T" off the boost port for connection. When you hit a pre set boost level, lets say 3psi or 4psi.. click .. and the 9th injector is flowing.

Simple, cheap, easily done, and you have the stock ECU to boot.

Idea #2.

Find and remove from the piggyback ECU the timing controls for the engine. Put them BACK in the stock ECU and that way, you have the stock timing map, but all the added parameters for the piggyback to monitor for you.....
SCDTRD

Like many things in life, "it just ain't that simple."

#1: I'm pretty sure the 9th injector is pulse-width modulated like the others -- there is no "on" and "off," but instead many different levels in between. Further, I'm pretty sure the TRD piggyback has to shorten the stock injector pulse widths at the same time to keep it from getting too rich. It's a coordinated effort.

#2: The stock timing map is likely too agressive under boost to use safely without detonation. Some boost retard is probably necessary because of the combination of a supercharger on a relatively high-compression motor (stock SC applications rarely exceed 8:1 cr). However, I'm sure there is more timing to be had than what the TRD piggyback allows... The other problem is the TRD SC adds a "multiple spark" feature to the stock ignition, I imagine just by triggering each igniter several times after the initial firing. I don't think you could lose the TRD timing map without also loosing the "multiple spark" function. I don't know how beneficial it is, but I can't imagine them bothering to add it if it wasn't necessary.

stcj · #3 (**permalink**) 08-01-2003, 07:40 PM

I can only comment on the mutiple spark feature, this is a good thing. In by younger days racing cars, I put a MSD unit on my car. Wow, What a big differance. The idle smoothed out, fuel milage increased and obviously HP.

Dude Boy · #4 (**permalink**) 08-01-2003, 08:21 PM

Quote:

I put a MSD unit on my car. Wow, What a big differance. The idle smoothed out, fuel milage increased and obviously HP.

Those were kind of "after my time." The new ignition when I was young was "Transistorized" and breakerless, as well as CDI. What does MSD do to the life of spark plugs? Or is it a racing only application? Since the life of a plug depends on the intensity and duration of the spark, it seems like it would erode the electrodes pretty fast.

stcj · #5 (**permalink**) 08-01-2003, 08:58 PM

It did cause the plugs to wear out quicker, but at that time I didn't care.

Mudog715 · #6 (**permalink**) 08-01-2003, 09:17 PM

Quote:

Originally posted by stcj
I can only comment on the mutiple spark feature, this is a good thing. In by younger days racing cars, I put a MSD unit on my car. Wow, What a big differance. The idle smoothed out, fuel milage increased and obviously HP.

My buddy runs a MSD 6 on his Jeep CJ with a carb'ed AMC 360 V8 and it makes a noticable improvement on that motor.

Modern engines with tightly controlled A/F ratios and factory "high energy" ignitions, operated at "reasonable" speeds don't seem to benefit as much from the aftermarket ignitions. One of the magazines was following a shop buildup of a F350 with the EFI 460 (Ford TFI-IV ignition) and found no measurable power increases with MSD, Crane or Jacobs on that motor vs. the stock ignition. Perhaps at higher RPM's (above 5,000) the aftermarket systems have an advantage.

stcj · #7 (**permalink**) 08-01-2003, 09:45 PM

Modern engines with tightly controlled A/F ratios and factory "high energy" ignitions, operated at "reasonable" speeds don't seem to benefit as much from the aftermarket ignitions. One of the magazines was following a shop buildup of a F350 with the EFI 460 (Ford TFI-IV ignition) and found no measurable power increases with MSD, Crane or Jacobs on that motor vs. the stock ignition. Perhaps at higher RPM's (above 5,000) the aftermarket systems have an advantage. [/b][/quote]

I agree with you. Modern day engine management is far supirior to vintage stuff. The two cars I put ignition enhancers on was a '70 Olds Cutlass (not a 442) with a 455ci. The other car is a '69 GTO conv with a 400, which I still have. It has the MDS-6AL. That means it has rubber mounting grommets and changable RPM limitting chips. I used this MSD unit, because the GTO is a 4spd and has Nitrous Oxide. If I miss a shift