LS7 Computer


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I am now looking at what ecm to drive my ls7 in my RCR. The motor is currently stock. I am upgrading ancillary parts an minor changes I am going to reverse the intake and have the parts for that. I have a remote water pump system going in, this will bring the motor forward in the chassis as is needed. I have aeromotive fuel rails. maybe some cf or fabricated valve covers. tuning wise I am considering a cam as well. but that would be it. I need to buy the wiring harness and ecm. I am considering a number of different systems. What did you come up with.
Hi Marc,

If you intend to use the DBW throttle body, I'd go with the GMPP LS7 ECU and harness kit which has the throttle included. The anticipated modifications should be handled by the ECU. Depending on the HP produced with the mods, you may want to upgrade the flow-rates of the injectors to match the 80% duty-cycle.
Doc is right. If you go drive by wire the GM stuff is the way to go. If you go cable you'll most likely have to go back to a 24 tooth reluctor and an older ECM in conjunction. If you want to know more about the cable setup send me a PM. I've got a modified N/A LS7 in a 94 RX7. Also go with a 50lb injector. It'll allow more room for modification before getting too close to its max duty cycle.

A couple of websites that might answer some of your questions

And...the DB-Cable option could include ECU's from FAST and others if you go that route. BTW, I have a FAST 102mm DBC throttle body NIB if needed as I went with a 105mm Williams DBW TB.


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I like the FAST config and would probably go with a cable option. I have a CTS-V and don't like the drive by wire. I find that it does not respond as quick nor does the motor back off quick enough for me. If feels like i am not in control. Doc may take you up on that TB. I have figured on needing to go with bigger injectors, but was hoping to do the engine mods after I got it going. Planned was injectors, cam, intake, maybe rocker arms.internals left alone as an LS-7 is pretty max'd out
...don't like the drive by wire. I find that it does not respond as quick nor does the motor back off quick enough for me. If feels like i am not in control.
Just curious and no experience on this set-up, but is there not edit software for the GM ECU that allows you to tailor the throttle tip-in and dashpot functions? There is no physical reason why a DBW can't be very direct if you can access and tailor these.

Cheers, Andrew

Mike Trusty

GT40s Supporter
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I have had Street Performance build a wiring harness for an LS7 and used their reprogrammed GM LS7 ECU. The wiring harness is very high quality and they will do whatever arrangement and lengths that you specify. I put an LS7 in a Pantera so you can tell it wasn't anywhere close to an off the shelf wiring harness.

Terry Oxandale

Skinny Man

If you swap out the LS7 injectors (assuming they are the 42 lb injectors), I'd be interested in them for my LS2.


I'll definitely have a set available in a couple of weeks (going to Cabo tomorrow). Never used from my crate engine.


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Thanks Guys!
Doc, I will be tracking this car and will probably have to go with a more gallons in the dry sump (moroso 2g) and probably the ARE oiling system to support that. I don't think that over stressing this motor with custom internals is too smart. At least til its a runner. I think that as is I will be fighting for traction even with slicks. These cars don't have the downforce to support the HP. Back in the late 60's when they banned these 7 liter prototypes was due to scary fast out of control cars made sense. The tires were harder, the wings and aero in its infancy, and a car that would do over 200 down the mulsanne and with either a touch of the brakes or rub of another car would be disasterous. Today we have better rubber better brakes and reliable 500-600hp motors. To try and track 800 to 1000hp right now would be foolish.
But I digress, a good ECM with programmable features will allow me the adaptability.

I will be taking my CTS to a tuner for some other issues and will see what I can do about the response time of the drive by wire system. I still am a believer in a big spring snapping the throttle closed, you know what I mean!