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Holley Terminator X Max in a C5 track car...

117 Views 7 Replies 4 Participants Last post by  autowiz
Hi all, Im seriously looking into the TMX kit for my 2002 C5 M6. Now I have an DBW LS3 530hp crate motor on order. I have several questions here...imagine that right?

1) Seems like I'll need a LS2 throttle body, that correct? If so, what MM size? Good vendor? I don't want a chinese knockoff either....

2) And a big one here is can I "piggy back" my new Term X to existing ECM/BCM to keep my dash gauges and power windows? If so, how does one piggy back?

Thanks Brian.....
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IMHO 0411 PCM is lightyears ahead of what is inside of any aftermarket EFI system today. This is primarily because of emission standards the manufacturer has to achieve that Holley never cared about.

Might I ask why are you considering this controller swap? There are 2 better ways you can go that will keep your vehicle's controller in place and happily communicating with all of the other vehicle modules.

1 - If you don't want to break open your new motor you can simply buy and install the Lingenfelter TRG-002 module. It is almost plug and play with your cam and crank sensors and then you have to connect ignition power and ground. This box will take in the 58x4x signal and output the 24x1x your gen III PCM is looking for. You can get that box here: Lingenfelter TRG-002 LSX Engine 58X To 24X Trigger Wheel Conv Control Module Kit

2 - alternatively and the correct and proper way to apply a gen IV engine to your gen III car is to open the engine when you get it and swap reluctors on the crank. Put a 24x wheel on the LS3 crankshaft and find you an early LS2 1x camshaft sprocket. Then you only need to extend your camshaft sensor harness to the front of the motor. And yes if you go that way the LS2 silver blade throttle body can be wired right in and the gen III TAC module will play with it just fine.

Also if you do keep the gen III controller you should try to keep the gen III MAP sensor. The LS3 intake has a larger hole and so you will want to replace the grommet on the MAP sensor with a thicker piece of hose so it is a tight fit. The gen IV map is a 1.25bar thing and the gen III controller is only 1 bar or 2 bar or 3 bar pending the OS we apply and so when we wire in the gen IV MAP to the gen III controller the end result is lost tuning resolution in breakpoints you never get to have.

The Holley controller will use a wideband and let you see outside 14:1-15:1 afr but it will only look at 1 bank and has no ability to trim seperately. Holley controllers also lack the factory calibrated knock sensors if we are trying to use those for power tuning. That Terminator X Max is a step up for up to a optispark driven engine controller but I feel like they are only better by that point for their reliability. Again in my opinion.

If you go with the X Max I do not think it matters if you use LS2 or LS3 throttle body. But you will live with warning lights on the dash and systems that don't work. Important systems like anti lock brakes and traction control that require a high speed connection with the engine controller for proper operation. But also the BCM and the vehicle's anti theft system. If the BCM and PCM can not shake hands then you will always have security lights on the dash.

FWIW I ran the TRG-002 box on my C5 for 7 years with the LSX376-B8. It never gave me a problem except a slightly longer cranking time which I attributed to the box needing to see a signal before it can send it out. And for this reason I wished I had opened the motor and just set it up to be a 24x and 1x motor. Which isn't extremely hard to do before the motor goes in the car.
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Wiz, your knowledge simply amazes me
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Wow, you understand these things! I should have given a little more background on the car and its purpose. I dont want to break open the new crate motor as that cancels the warranty, so Im gonna stick with 58x and all. The car is a track car only, so no ABS, traction control, A/C, anti-theft etc. I only need my windows to roll Open trailer and all.
The existing engine wiring harness is in rough shape as it caught fire, long story, but I want new wiring in the engine bay. I do wish to keep the existing engine gauge cluster as it works fine and I like it. And thanks Brian
If you know a better alternative to the holley X max im all ears for sure....
Also good point on the knock sensors as I did not know that....the crate motor is a 530HP LS3 and I actually want it detuned to 500...The drivetrain wont take more than 500hp until it ends up all over the track...
Autowiz what Torch said.
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If the factory harness is destroyed and you have no intentions of repairing it then that would kill the piggyback idea. And to be honest from what you are describing maybe that is better for you.

For the aftermarket EFI the Terminator X Max is about as good as you can do and I support you in your choices. Good calls, man. I have a couple suggestions of some supporting things to go with your build. I know it has a price to it and all but this is an easy button for getting yourself comfortable with the Terminator ECU's: GM LS & LT Standalone Tuning using Holley Terminator X (

The ECU's also come with a touchscreen, a small touchscreen and it is much better to use a laptop and the free Holley software that will let you play with maps and tables in a more meaningful way. There is a special USB cable that must be purchased separately for these communications. This cable plugs into the terminator ECU harness where the touchscreen plugs in and can be had right here: Holley EFI 558-443 Holley EFI CAN to USB Dongle - Communication Cable

I regret you will struggle with lost IPC functions but from what you are describing you have I really think you would do well with a Holley Pro Dash. For your C5 you will get the smaller 6.86" Pro Dash here: Holley EFI 553-112 Holley EFI 6.86" Pro Dash The Pro Dash also plugs in to the Terminator X harness where the touchscreen plugs in and the Pro Dash gets all it's sensor data from the Terminator X ECU over the can bus. So there is no extra wiring for coolant temp or oil pressure or tach input or vehicle speed if you want to use the vss from the Terminator X Max ECU. And you can add fuel level and turn signals and high beam indication, etc. The Pro Dash is it's own configurable controller and also comes with a host of general purpose input/output(G.P.I.O.) wires to play with so you can add any guage you want. Make you own even.

And you can get a specific bezel to mount that Pro Dash to your C5 right here: Mako Motorsports C5 Corvette Dash Display Kit - Enjuku Racing Parts, LLC

It's all money and it adds up quick but it all works together and the Pro Dash even offers GPS speedo so you get the most accurate speed reading no matter your tire sizes or gear ratio or calibrations, etc. And I can not say enough on the behalf of the good bunch of people at The Tuning School. They are a powerful knowledgebase to tap and their courses have helped me shine in my career. The price of these books are small in comparison to the level of comfort they bring to what is an otherwise new and uncomfortable place to be. And I am proud to brag on having this course in my tuning library.

Your power windows are run through the door modules. The door modules require a wake up signal from the BCM but the control is localized to the doors. Here is diagram of the power windows circuit for your C5..

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