2015.11.06 - UPDATE! - THE TERMINATOR VS. THE DOMINATOR!!!!
Pull up a chair and a tasty beverage... this is going to take a while.
As the header build started winding-down a few days ago, I was already thinking about the next steps that I needed to take to get the engine running. I've been thinking about EFI forever... and when Scotty built this engine for me in 2007 (Yes, it's really has been EIGHT YEARS!!!) I did a lot of research on EFI systems and decided that I wanted to use the Holley Dominator EFI system. This was in about 2010.... back then there weren't nearly as many choices in EFI as there are now, and almost nobody offered a solution with timing control or the ability to integrate the TCU controls into a single unit. The total package price was somewhere in the $3500-range by the time you bought the wideband O2 sensor upgrades, and all the extra wiring harnesses and correct TBI and injectors..... and that price didn't even include the fuel pump, filters or regulator!
Well time marches on..... technology evolves (and sometimes gets cheaper!) and so it goes with EFI design. Turns out, Holley released a system called "The Terminator" a few years ago that took all the best features of the piece-meal "Dominator" system and put it together as a package to simplify the whole process for consumers:
If you know much about the Dominator EFI system, it has a very distinctive (large) ECU housing to provide all of the EFI and Transmission Control functions. The new Terminator system uses the exact same ECU (literally the only difference according to the Holley rep is the sticker on the cover!) It also includes the 950CFM TBI unit with 80Lb injectors (good for 600HP) and a handheld touchscreen for programming and monitoring things. You can also plug in a "real" laptop and run their software if you really want to go above and beyond the "self learning" type stuff and tweak all the fuel and timing maps yourself. The systems all come with a wideband-O2 sensor now as standard which is good... and by adding a compatible distributor (like the MSD Pro-Billet EFI #8366) you can set up timing maps, advance curves and all sorts of fun stuff without ever opening up the dizzy to replace the advance springs, etc.
From what I've read, you can pick up 1 or 2 highway MPGs when you have computer controlled timing. That might not seem like much, but for a vehicle that might only get 7 or 8 MPG in the first place.... it's a huge improvement!
So... the bottom line to that whole story is that Terminator is the "new" Dominator System.... It's the same exact hardware (ECU/TCU and Software) bundled with the TBI and Touchscreen at a cheaper price than the Dominator system ever was.
DONE DEAL.
Here's where things start to get REALLY expensive....
"Might As Wells" are starting to creep into the engine a bit more deeply too. The motor is a fully-rebuilt 1996+ (Gen-VI) GM 502HO. This is an engine that was rated at 450HP and 550TQ... it's a completely forged bottom end (Crank, Rods and Pistons) and is actually the same rotating assembly used in their higher performance ZZ502 motors (the only differences are the cam and heads). When I had Scotty rebuild the motor, I wanted to focus on torque more than horsepower and I wanted it to be EFI friendly. At that time, I used the Comp Cams software (CamQuest6) to choose a cam that would work and we ended up with a VERY mild one.... what we didn't know at the time was that "EFI Friendly" in that software meant something that would work with GM factory EFI systems....NOT aftermarket tunable systems!!!
So ultimately we ended up trading about 50HP (down) in exchange for about 50LB/FT of TQ... 409HP/611TQ vs. 450Hp/550TQ
This all seemed to make sense at the time because I was obsessed about maximizing TQ at very low RPMs... but what I really wasn't thinking much about was the effect that low axle gearing (5.26s) and a 4-speed ATLAS transfercase (5.44:1) were also going to have on TQ delivery. In retrospect, it seems like the plan was a little off-base. What I really should have done was to allow the gearing (axles and transfercase) to do the job of providing earth-moving TQ.... and build a motor that could breathe better across a larger RPM range, with a nice strong mid-range and flat TQ curve across a wider powerband. Now, in the year 2015....THIS is what I am really looking for!
So.... I'm about to add an EFI system to an engine that was built 8 years ago, and has never had a drop of fuel, oil or coolant in it. If I wanted to make a few small changes....now would be the time to do it. Everything is clean and new, and it won't even make a mess or lose any fluids if I start pulling things apart a little...
The most obvious change to make is the cam. Obviously, the original selection was based on some bad assumptions and is SO mild that it really is giving away a lot of HP in an effort to pull good vacuum and keep factory EFI happy. Cams don't cost THAT much, so I can put in a new hydraulic roller cam with more lift and duration and still have a decent idle and pick up quite a bit of HP too. While I'm in there I can swap out the stamped steel rocker arms for a nicer set of steel roller rockers and pick up a little extra strength and get the clearance for the larger lift cam. Maybe a set of Magnum 1-piece pushrods too since it's unlikely that the originals will be the perfect length for a different combination of parts.
It's all feeling pretty good... and I haven't really blown the budget by adding a few extra engine parts to the EFI installation. But the one thing that isn't quite right about the new combination are the enormous rectangular-port iron heads (GM #14097088). They keep the compression ratio down to 8.75:1 and are really better suited to a high-RPM application where all that extra port size can actually be of value.
As before... time marches on..... technology evolves (and sometimes gets cheaper!) and so it goes with cylinder head design. For literally decades, the BBC crowd saw the rectangular-port heads as "the ultimate" design for power... but in 2015 things have changed. "Oval is the new Square"!!!
Engineers have figured out that you can get much better flow and port velocity with an oval port head than you ever could with a rectangular ported one. We are not talking about the old "peanut port" designs though... not all oval port heads are created equal. There does seem to be one particular standout from the crowd which seems supremely well-matched to the relatively low-compression 502HO pistons that I've got, and its called the Brodix RaceRite Oval (RRO)
Normally, you'd want a much larger combustion chamber volume, but since the 502HO leaves a lot more room above the piston (relatively shallow dome)... going with a smaller chamber is actually helpful. It can bump the compression up into about the 9.5:1 range and even though the ports are smaller, they flow a LOT better than the current rectangle-port ones do....and have better velocity at lower RPMs too. That means that even though my new cam would typically add HP up high and start to make the bottom-end TQ a little soggy.... these heads would actually keep the air moving well on the bottom-end so I don't have to give up my desire for a big, fat and flat TQ curve from idle to redline.
End Result?: The 502HO shortblock with the EFI, a new cam and these new Brodix heads should probably be in the 550HP/600TQ range...... that is a HUGE gain in HP (almost 150HP over the current setup) and the same TQ number, but probably spread out much flatter and a lot further up the RPM band than before.
It's all very tempting.... "Might As Wells" usually are. However, the decision to swap heads also creates some collateral damage:
1. I will need to buy a new intake manifold since mine is a rectangle port version, not oval.
2. My new headers were built with square-port flanges instead of oval, so I would have to throw them in the scrap pile and build a new set from scratch.
3. Just kidding.... I would only need to buy new flanges and redo the first 1.5" swaged segment on each primary tube to make it a "D" shape instead of square.... It's pretty straightforward since nothing is finish-welded yet.
So.....what should I do?
Part of me wants to just go for it and completely blow my budget, and part of me wants to start a "Go Fund Me" site and let fate decide how much (or how little) to change!!!
-G
Although 80 lbs off the heavy end of a rig is worth it too. 
