Which Harness ECM to use LS1 or LS2

[SS Performance]

I'm building a bored and stroked LS2 that was resleeved for my 70 Camaro. Now it is 454. I'm using ported LS7 heads and either a Hi-Ram or Super Victor intake.

My question is should I get a LS1 harness and ECM or a LS2 ECM. The motor has the 24 tooth reluctor wheel so the early LS2 ECM would work.

Either harness would need to be modified for stand alone and I don't want to use drive by wire. The trans will be a T56 Magnum. Eventually I was planning to go with a Dakota Digital dash.

I have found several places that list which wires can be eliminated from the LS1 harness but haven't found any for the LS2.

What are the pro's and con's for each?

Any suggestion or advice would be appreciated.

Thanks
Craig

[ProServ]

If you want mechanical throttle with an OEM GM controller then you will have to use the Powertrain Control Module (PCM) used with the Gen III engines (LS1, LS6, LQ4, LQ9 etc.). These controllers are often referred to as the Warren PCMs. I would avoid the 1997-1998 model year PCMs.

You will want to get a PCM and a harness from a mechanical throttle vehicle so that the software in the PCM is already configured for a mechanical throttle and so you don't have to change as many wires in the harness.

The 1999-2002 Camaro and Firebird PCM and harness would likely be the best option. They were all mechanical throttle and manual transmission vehicles were available in fairly high quantities. The transmission/VSS speed sensor is also likely similar to your configuration (Corvette is different from the others for VSS sensor multipliers in the calibration due to the transmission location in the vehicle).

1999-2003 trucks would also work although most were automatic (so more wires to remove). After 2003 GM started phasing in electronic throttle on the trucks.

All C5 Corvettes are electronic throttle.

The other controller used with the 24x engines was the E40 controller (early Gen IV V8 engine equipped vehicles like the 2005 Corvette, 2005-2006 SSR/Trailblazer etc.) but this controller does not support mechanical throttle applications.

Not an automotive controller but the GM MEFI controller used in the marine and industrial engines can control the 24x engines and works with a mechanical throttle but since system is not used in any automotive production applications you aren't going to find any of them in the junk yards (unless boat junk yards exist). This is what was used in the early COPO Camaros. Some of those racers removed the MEFI system to switch to the Holley system so you might be able to find one of those systems for a fairly good price as well but keep in mind calibration options are more limited for the MEFI and companies/people with experience tuning that system are less common.


I'm building a bored and stroked LS2 that was resleeved for my 70 Camaro. Now it is 454. I'm using ported LS7 heads and either a Hi-Ram or Super Victor intake.

My question is should I get a LS1 harness and ECM or a LS2 ECM. The motor has the 24 tooth reluctor wheel so the early LS2 ECM would work.

Either harness would need to be modified for stand alone and I don't want to use drive by wire. The trans will be a T56 Magnum. Eventually I was planning to go with a Dakota Digital dash.

I have found several places that list which wires can be eliminated from the LS1 harness but haven't found any for the LS2.

What are the pro's and con's for each?

Any suggestion or advice would be appreciated.

Thanks
Craig

[Vince@Meanstreets]

I'm building a bored and stroked LS2 that was resleeved for my 70 Camaro. Now it is 454. I'm using ported LS7 heads and either a Hi-Ram or Super Victor intake.

My question is should I get a LS1 harness and ECM or a LS2 ECM. The motor has the 24 tooth reluctor wheel so the early LS2 ECM would work.

Either harness would need to be modified for stand alone and I don't want to use drive by wire. The trans will be a T56 Magnum. Eventually I was planning to go with a Dakota Digital dash.

I have found several places that list which wires can be eliminated from the LS1 harness but haven't found any for the LS2.

What are the pro's and con's for each?

Any suggestion or advice would be appreciated.

Thanks
Craig

We have been using PSI conversion harnesses and PCM's.

The common one on the LS2 swaps are the 411 pcm's. Also the 896.

https://www.psiconversion.com/products/standalone-wiring-harnesses/ls-car-24x/ls-t56-th350-700r4/

https://www.psiconversion.com/products/pcm-programming/ls-vortec-pcm-programming/

[6D9 Matt]

I also recommend PSI conversions, have one in my Camaro.

[SS Performance]

I also recommend PSI conversions, have one in my Camaro.

What did you do to hook up the gauges?

Are you using stock gauges or aftermarket or digital dash?

Thanks
Craig

[6D9 Matt]

I cant speak of specifics on install bc I had a buddy do it, but I have stock gauges (although about to install a DSE dash and Speedhut gauges).

[gnx7]

another thing to think about is once you buy the PSI harness, ECM, and pay for your tuner to do his thing.... Let's say the total is $1300.... And if you buy HP Tuners to tune/data log that is another $550+

You aren't very far away from buying a Holley HP, Megasquirt MS3Pro, or similar aftermarket EFI which has data logging, traction control, 2 step launch, automatic fuel compensation (add in up to 100% more fuel if needed), FlexFuel, multiple maps to choose from, etc. They include new harness and ECM for around $1800-2000.

The new MS3Pro Ultimate is about the same cost as the Holley HP and does what the Dominator unit allows at the HP price point. 100% made in the USA with lifetime warranty too.

I run the Holley HP in my road race RX-7 (LS7) and the Dominator in my LS9 turbo RX-7 (6.2 based LS9) and if the MS3Pro Ultimate was out when I built my cars... I would've run that.