Disable LS7 displacement on demand

[odiefords]

So the first question is when using the LS7 in a gtm do you have to disable the displacement on demand or any engine with that option?

[VRaptor SpeedWorks, LLC]

I'm guessing that to retain the DOD, you would have to use the LS7 and complete wiring harness from a C6 Corvette. I'm guessing that 99%, if not all guys running an LS7 in a GTM have most likely installed a crate engine/harness/ecu....which AFAIK, does not have DOD.

[Roger Reid]

I don't believe the LS7 came with the mechanicals of the displacement on demand (DOD). If there are program lines in the ECU I can only imagine they are disabled.

There are other GM engines that are set up for DOD. If the motor was mechanically set up for DOD, I would not not disable any part of the DOD except possibly the muffler valve.

Here are a few links to read.

http://www.z06vette.com/forums/f70/displacement-demand-109388/

http://www.superchevy.com/technical/engines_drivetrain/accessories_electronics/0405sc_gmdod/index.html

[odiefords]

I'm guessing that to retain the DOD, you would have to use the LS7 and complete wiring harness from a C6 Corvette. I'm guessing that 99%, if not all guys running an LS7 in a GTM have most likely installed a crate engine/harness/ecu....which AFAIK, does not have DOD.

What is AFAIK. That would make sense if they were using a crate engine. I meant if they were using a donor car. As I can tell all generation 4 ls engines have the d o d. In order to shut off or bypass the dod you would have to disassemble the engine and plug the oil ports to the lifters. Correct?

[crash]

AFAIK= As Far As I Know

odie-Please tell us what you know of the DOD system. I am unaware of it and my engine builder has not mentioned anything about it to me. We are working together and I am building the engine that will go on his dyno. I am using a different cam and valve springs, but the lifters and rockers are stock.

[crash]

OK. Looked into it a little further and if your valley cover has solenoids in it for pressure relief to valves, then you have the DOD system. My crate LS3 does not have this, and I don't think most LS3s will. The oil galley stanchions are there when you pull the valley cover off, but they go no where and are plugged by O ring seals on the valley cover.

[VRaptor SpeedWorks, LLC]

I meant if they were using a donor car. As I can tell all generation 4 ls engines have the d o d.

The GTM uses a C5 as a donor.....not a C6. The LS7 was not available on a C5.....therefore, I assume there is no such thing as a donor car with DOD, LS7 or Gen 4 LS engine. This is why I assumed we were talking about crate engines.

[93twotonegt]

Of the specific "LS" engines, only 1 has DOD, the LS4 that was used in the FWD Grand Prix GXPs and Impala/Monte Carlo SSs.

No Dod:
LS1, LS2, LS6, LS7, LS9, LQ4, LQ9, LSA, L92 (iffy on this one)

DoD:
LS4, L99, L76, LY5, LMG, LH6, LC9

Most of the DoD engines are truck engines, minus the LS4. The L76 and L99 are used in the base V8 Pontiac G8 and Chevy Camaro, respectively.

Hope that helps.

[odiefords]

I just got my book on ls engines. Most c6 engines have the dod. I guess you can bypass by pulling the intake plate and blocking the tubes that feed the lifters that cut off cylinders. Gmpp crates do not have the dod. Ill post the list of engines when off work. Just started reading on the throne this morning.

[odiefords]

The GTM uses a C5 as a donor.....not a C6. The LS7 was not available on a C5.....therefore, I assume there is no such thing as a donor car with DOD, LS7 or Gen 4 LS engine. This is why I assumed we were talking about crate engines.


I can't afford a crate ls7. I can find a donor car with a ls7, strip the engine harness and computor for half the cost and self the rest. Getting a 2000 -2004 donor car for gtm though, or going new.

[odiefords]

K. I just got home. What I found in this book "How to build and modify GM LS-Series engines By Joseph Potak


WITH DOD
GEN IV - 4.8/5.3 ALUM, LQ9 IRON, LS2,L76,L92LS3,LS9,LS7*


NON - DOD

ALL GEN III,
*GEN IV - LS7 - Has it but is not drilled for it.

They list that if it has DOD it can be plugged. Have to read more. Book has everything from 4.8- LS9 blocks, heads, cams, lifters, pistons. All types of brands and options. Good book so far. Bought it on ebay. Hope this helps.