Secondary relay module questions - ZR-1 Net Registry Forums

-=Jeff=- · 07-12-2008

There is a post on CF as well, but I had some questions regarding the module.

in that other post, someone said the module was used 90-92 and 93-95 did no and it was in the ECM.. since the replacement ECM is the same for all years (although Kurt's website only states 90-94) then couldn't the module be eliminated and the wiring/harness/ PROM be made to work without the Relay module?

I am trying to understand the logic, if the 90 has the module, but I use a ECM that can be used in a 93 in my 90 and it works, I would think you could change something to eliminate the relay module if needed.

Now I could be all wrong ont he relay module as I am going by what I read in another post..

lbszr · 07-12-2008

I heard and thought the same thing

http://www.zr1netregistry.com/forum/...ead.php?t=5565

-=Jeff=- · 07-12-2008

Quote:

Originally Posted by lbszr

I heard and thought the same thing

http://www.zr1netregistry.com/forum/...ead.php?t=5565

THANKS!!!

Now THAT makes sense.. it was not eliminated just moved.. LOL

65ZR1 · 07-13-2008

The secondary injector modules were used for all years. However, the 90 model had a seperate knock module that was later integrated with the ECM. When I had a custom harness made for my 94 LT5 to allow it to run in a 65 coupe the company eliminated the modules and used a relay. They said it would work fine. This appears to make sense since the modules seem to be just an on/off switch. The pulse of the secondary injector is still controlled by the primary injector ground circuit though the ECM. I wasnt confident enough to try this route since I thought the general must have used a more expensive module for some reason. I guess when we cant find any then someone will give it a shot!

lbszr · 07-17-2008

Quote:

Originally Posted by 65ZR1

The secondary injector modules were used for all years. However, the 90 model had a seperate knock module that was later integrated with the ECM. When I had a custom harness made for my 94 LT5 to allow it to run in a 65 coupe the company eliminated the modules and used a relay. They said it would work fine. This appears to make sense since the modules seem to be just an on/off switch. The pulse of the secondary injector is still controlled by the primary injector ground circuit though the ECM. I wasnt confident enough to try this route since I thought the general must have used a more expensive module for some reason. I guess when we cant find any then someone will give it a shot!

Who made your harness? Might need to figure out a different ignition system someday also.

XfireZ51 · 07-18-2008

Quote:

Originally Posted by lbszr

Who made your harness? Might need to figure out a different ignition system someday also.

It would be interesting to adapt the LS coil packs to the LT-5. Some people suggest that the coil packs along with the short plug wires account for 25+ hp.

-=Jeff=- · 07-18-2008

Quote:

Originally Posted by XfireZ51

It would be interesting to adapt the LS coil packs to the LT-5. Some people suggest that the coil packs along with the short plug wires account for 25+ hp.

Yeah but if i did that kind of conversion I would install the coil packs under the plenum still..

I need to ook at the wiring but I bet it can be done.. depnding on the signal off of the crank sensor

Aurora40 · 07-18-2008

Quote:

Originally Posted by XfireZ51

Some people suggest that the coil packs along with the short plug wires account for 25+ hp.

Seriously? How do they account for such a suggestion?

FWIW, the Northstar went from coil packs to coil-on-plug (much more on-plug than the LSx) for the 2000MY. There was no huge power gain from that.

XfireZ51 · 07-18-2008

Quote:

Originally Posted by Aurora40

Seriously? How do they account for such a suggestion?

FWIW, the Northstar went from coil packs to coil-on-plug (much more on-plug than the LSx) for the 2000MY. There was no huge power gain from that.

Dwell time. Strength of the spark. Reduction of power loss due to cable inductance. Much more accurate timing due to significantly reduced latency. An old friend did this conversion on his GN.

Aurora40 · 07-19-2008

Quote:

Originally Posted by XfireZ51

Much more accurate timing due to significantly reduced latency.

Wouldn't this be about the same? Whether it's a plug wire or a regular electrical system wire, there's going to be about the same length either way. I don't think electricity travels more slowly in plug wires vs harness wires?

Anyway, I agree coil on plug (or coil near plug on the LSx motors) is definitely better. But 25hp better on a ~400hp motor? That just seems unlikely to me.

07-12-2008	#1
-=Jeff=- Join Date: Jul 2007 Location: Bartlett, IL Posts: 7,168	Secondary relay module questions There is a post on CF as well, but I had some questions regarding the module. in that other post, someone said the module was used 90-92 and 93-95 did no and it was in the ECM.. since the replacement ECM is the same for all years (although Kurt's website only states 90-94) then couldn't the module be eliminated and the wiring/harness/ PROM be made to work without the Relay module? I am trying to understand the logic, if the 90 has the module, but I use a ECM that can be used in a 93 in my 90 and it works, I would think you could change something to eliminate the relay module if needed. Now I could be all wrong ont he relay module as I am going by what I read in another post.. __________________ 1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback Late Model IH - Plenum Coilovers - 4.10s Shelby Series 1 - Wilwood Brakes Custom Interior NCM Lifetime Member #978

07-12-2008	#2
lbszr Join Date: Nov 2006 Location: dayton,ohio Posts: 424	Re: Secondary relay module questions I heard and thought the same thing http://www.zr1netregistry.com/forum/...ead.php?t=5565

07-13-2008	#4
65ZR1 Join Date: May 2006 Location: Canada Posts: 139	Re: Secondary relay module questions The secondary injector modules were used for all years. However, the 90 model had a seperate knock module that was later integrated with the ECM. When I had a custom harness made for my 94 LT5 to allow it to run in a 65 coupe the company eliminated the modules and used a relay. They said it would work fine. This appears to make sense since the modules seem to be just an on/off switch. The pulse of the secondary injector is still controlled by the primary injector ground circuit though the ECM. I wasnt confident enough to try this route since I thought the general must have used a more expensive module for some reason. I guess when we cant find any then someone will give it a shot!