Holley EFI tuning and wiring

[79 Camaro]

Andrew,

I'm putting together my winter project. 1987 C10 short box. On my engine stand I have a 2012 L92. Corvette LS3 intake and DBW throttle body. Texas Speed cam. 225I/230E .600 lift with 114 cam centerline. I've done this combo before with a TKO 600 and it worked well with the GM ECM.
The C10 project will have an automatic. I leaning towards a built 4L60E as I have done in the past with other LS swaps. The kicker is that as I understand on the 2012 L92 I will need a ECM for the trans (and specific for the 2012) and one for the L92. The early model 4L60E like a 2002 Camaro uses are easy to find around here. 2012 4L60E's not so much. Can the Holley system integrate the 2002 Camaro 4L60E to the 2012 L92?
I don't want to build something weird just like to know your thoughts.

[andrewb70]

Andrew,

I'm putting together my winter project. 1987 C10 short box. On my engine stand I have a 2012 L92. Corvette LS3 intake and DBW throttle body. Texas Speed cam. 225I/230E .600 lift with 114 cam centerline. I've done this combo before with a TKO 600 and it worked well with the GM ECM.
The C10 project will have an automatic. I leaning towards a built 4L60E as I have done in the past with other LS swaps. The kicker is that as I understand on the 2012 L92 I will need a ECM for the trans (and specific for the 2012) and one for the L92. The early model 4L60E like a 2002 Camaro uses are easy to find around here. 2012 4L60E's not so much. Can the Holley system integrate the 2002 Camaro 4L60E to the 2012 L92?
I don't want to build something weird just like to know your thoughts.

The short answer is, yes. Something like the Terminator X Max would support what you are trying to do. It will have DBW and trans control.

Andrew

[79 Camaro]

Andrew thanks for the reply. With my combo listed above could you do a mail order tune with the Holley system?

[andrewb70]

Andrew thanks for the reply. With my combo listed above could you do a mail order tune with the Holley system?

It's not so much "mail" order as it is remote tuning. I used software to dial into your laptop remotely while we talk on the phone. That's how I tune idle. Before that even starts, I build a base tune based on your engine combination. The short answer, is yes, I can definitely help you.

Andrew

[79 Camaro]

Thanks again for your reply. I'm a big LS guy but always used the stock GM stuff because my builds were fairly mild. This project is again fairly mild but I'm kind of mixing and matching different years of LS stuff. No one local does any tuning. Mid to late November the tear down will start. Unlike previous projects it will be a "patina" build of a CA no rust C10. So I'm thinking mid March I will need some help. Thanks again.

[andrewb70]

Thanks again for your reply. I'm a big LS guy but always used the stock GM stuff because my builds were fairly mild. This project is again fairly mild but I'm kind of mixing and matching different years of LS stuff. No one local does any tuning. Mid to late November the tear down will start. Unlike previous projects it will be a "patina" build of a CA no rust C10. So I'm thinking mid March I will need some help. Thanks again.

Get in touch sooner than later. I can help with wiring and maybe other parts selection.

Andrew

[Oldsmoboogie]

Hi Andrew, this is Erik with the ls swapped TransAm. I have been looking into the low fuel pressure issue and i was trying to power the fuel pump with the green wire in the main harness. After rereading the instructions i should use that wire to trigger a relay for the Areomotive 340 pump. I am loosing almost 6 volts by the time it gets back to the pump! Should i install a relay back by the tank or in the engine bay and run a 8 gauge wire back to the tank? Thank you for your patience as i work the bugs out of this car.

[andrewb70]

Hi Andrew, this is Erik with the ls swapped TransAm. I have been looking into the low fuel pressure issue and i was trying to power the fuel pump with the green wire in the main harness. After rereading the instructions i should use that wire to trigger a relay for the Areomotive 340 pump. I am loosing almost 6 volts by the time it gets back to the pump! Should i install a relay back by the tank or in the engine bay and run a 8 gauge wire back to the tank? Thank you for your patience as i work the bugs out of this car.

Where is the battery?

[Oldsmoboogie]

In the stock location.

[andrewb70]

In the stock location.

I suspect you have a poor connection somewhere. You should not be loosing that much voltage.

[carbuff]

I think he's saying that he's using the wire from the ECU to power the pump which, if I remember correctly, is something small like an 18 gauge or so. If that's the case, it's not surprising he would drop voltage at the pump. That wire isn't meant to power the pump, just trigger a relay.

Whether the relay is close to the battery or close to the pump shouldn't matter as long as the wiring in and out is appropriate gauge. 8 gauge seems a bit much, but a good 12 gauge should do.

Depending on the rest of your setup, I also like the VaporWerx fuel pump controller. It regulates the voltage to the pump to keep from over-running the pump. It does require an additional fuel pressure sensor (preferrably near the fuel rail although I had mine near the pump) and some wiring, but it's not hard.

[andrewb70]

I think he's saying that he's using the wire from the ECU to power the pump which, if I remember correctly, is something small like an 18 gauge or so. If that's the case, it's not surprising he would drop voltage at the pump. That wire isn't meant to power the pump, just trigger a relay.

Whether the relay is close to the battery or close to the pump shouldn't matter as long as the wiring in and out is appropriate gauge. 8 gauge seems a bit much, but a good 12 gauge should do.

Depending on the rest of your setup, I also like the VaporWerx fuel pump controller. It regulates the voltage to the pump to keep from over-running the pump. It does require an additional fuel pressure sensor (preferrably near the fuel rail although I had mine near the pump) and some wiring, but it's not hard.

Bryan,

While what you say is accurate for the HP and the Dominator systems, the Terminator X systems have a 12 gauge fuel pump wire and the ECU can power a pump directly as long as it is rated under 15 amps. Although, reading back through Oldsmoboogie's question, it is not clear which system he is using.

I also agree with you on the use of the VaporWerx system. I always recommend it for all my customers if they enlist my services before making purchase decisions.

Andrew

[carbuff]

Ah, I did not know that... I can see how that simplifies the install. As such, I agree, that kind of drop doesn't make sense unless it's a pump running at much higher current...

[dhutton]

That pump consumes at least 15 amps which is right at the Holley limit and who knows how much margin they have in their design. I would add a relay to adds margin. Back when I was an engineer we would derate something like that 25-50%. Location is not important so long as you use suitable sized wire on the relay.

Don

[andrewb70]

That pump consumes at least 15 amps which is right at the Holley limit and who knows how much margin they have in their design. I would add a relay to adds margin. Back when I was an engineer we would derate something like that 25-50%. Location is not important so long as you use suitable sized wire on the relay.

Don

Using a relay is never a bad idea.

[andrewb70]

Public Service Announcement for today:

For the love of God, please do not use a huge cable throttle body unless your engine combination absolute demands it, in the higher RPM range. And even then, carefully evaluate how your vehicle will be used and determine if a few extra HP are worth the tuning and drivability issues that these big throttle bodies cause! Be extra mindful if you have a manual transmission car, because they are especially vulnerable to the negative effects.

Andrew

[carbuff]

For the love of God, please do not use a huge cable throttle body unless your engine combination absolute demands it, in the higher RPM range.

Want to clarify this a bit? Are you saying not to use a huge throttle body in general, or that it's OK to use a huge one as long as it's DBW? What does RPM range have to do with it?

And what negative effects are you referring to?

And finally, I am guessing you are thinking about the LS front TB style and not referring to a more traditional 4-barrel style large TB in a single/dual plane intake?

Curious what you're running into and felt the need for the PSA about.

[andrewb70]

....Are you saying not to use a huge throttle body in general, or that it's OK to use a huge one as long as it's DBW?

Using a large DBW throttle body is fine, even two throttle bodies can be made to have good drivability characteristics as long as it is DBW. Case in point, my Cougar. I use two 87mm throttle bodies on a relatively mild 5.3L engine, with a manual transmission, and you can drive it around in stop and go traffic as easily as a new stock Camaro...or whatever...

What does RPM range have to do with it?

For NA (naturally aspirated) engines, the aiflow requirement is a simple calculation involving displacement, engine RPM, and VE (volumetric efficiency). Let's take for example a 6.2L engine and use 7000rpm and 100% VE, we get a maximum air requirement of about 738CFM. This value is actually inflated, because peak VE occurs at peak torque, not at maximum RPM. A LS3 90mm throttle body flow 1369cfm (https://accufabracing.com/cfm-air-flow). Clearly more than capable of a lot more HP than a stock, or even heavily modified LS3 would ever need.

And what negative effects are you referring to?

Negative effects include hard to control idle speed at a relatively appropriate level. Touchy throttle, which makes taking off from a stop in a smooth manner nearly impossible. Transient fueling challenges due to the non linear flow of a large TB, causing a very fast pressure drop inside the intake when the throttle is opened.

And finally, I am guessing you are thinking about the LS front TB style and not referring to a more traditional 4-barrel style large TB in a single/dual plane intake?

This applies to all engines and all intake manifold configurations. On a more traditional intake setup (single or dual plane) some of these issues are mitigated by the fact that the smaller bores of a 4 barrel throttle body have a more linear flow. Additionally, a progressive linkage can be used to limit airflow at low throttle opening.

Curious what you're running into and felt the need for the PSA about.

I am running into all of the above...LOL

Bottom line, it is hard to justify anything bigger than a 90mm (or 1000cfm 4 barrel style) throttle body for most NA applications, and if budget allows, using DBW is highly desirable.

Andrew

[carbuff]

For NA (naturally aspirated) engines, the aiflow requirement is a simple calculation involving displacement, engine RPM, and VE (volumetric efficiency). Let's take for example a 6.2L engine and use 7000rpm and 100% VE, we get a maximum air requirement of about 738CFM. This value is actually inflated, because peak VE occurs at peak torque, not at maximum RPM. A LS3 90mm throttle body flow 1369cfm (https://accufabracing.com/cfm-air-flow). Clearly more than capable of a lot more HP than a stock, or even heavily modified LS3 would ever need.

While I understand the math, my experience with TOW showed that the math doesn't always give you exactly what you need. I was running the highest-rated flowing 4150 style TB that I could find at 1550 cfm. It was 2 large blades with a center divider. I had a ported intake manifold which opened up the plenum and cleaned up transitions into the runners, so it was a good setup. I dynoed this on an engine dyno before installing into the car.

I also dynoed the engine with a 4500-style TB and different but similarly ported intake. This combination offered a much improved upper-rpm power that carried way better than the 1550 cfm 4150 did.

So in my opinion, the math isn't always the answer (of course how accurate the TB ratings are is always up for debate).

Negative effects include hard to control idle speed at a relatively appropriate level. Touchy throttle, which makes taking off from a stop in a smooth manner nearly impossible. Transient fueling challenges due to the non linear flow of a large TB, causing a very fast pressure drop inside the intake when the throttle is opened.

Yes, it took a good bit of work to smooth out the maps in my Holley also. The secondaries on my TB setup used a progressive linkage, and that was a bit tricky to tune, especially the AE tables when that secondary started opening.

Bottom line, it is hard to justify anything bigger than a 90mm (or 1000cfm 4 barrel style) throttle body for most NA applications, and if budget allows, using DBW is highly desirable.

Andrew

DBW would make things easier to tune in some sense I imagine, but I haven't tuned one myself. It was fun learning to tune the Holley, and fortunately the Holley platform makes it pretty easy (especially the helpful forums).

[andrewb70]

...

I also dynoed the engine with a 4500-style TB and different but similarly ported intake. This combination offered a much improved upper-rpm power that carried way better than the 1550 cfm 4150 did.

So in my opinion, the math isn't always the answer (of course how accurate the TB ratings are is always up for debate).

...

What was the power differential?

Andrew