|Text and Photography By: Dr. Sean Michael|
GM 60° V6 Power Tricks: Solutions for Corralling More Horses
|The GM 2.8L V6 has been installed in many different makes and models which is surprising considering the virtually non-existant aftermarket support for it|
The GM 2.8L 60° V6 continues to challenge many off-road enthusiasts. A standard powerplant for S-10 pickups and Blazers, Jeep Cherokees and pickups, as well as Isuzu Troopers, this engine is truly everywhere. Surprisingly, there are relatively few aftermarket power solutions available. If your rig has this block, you may know what I mean and you may be ready for some new tricks. I've pooled the lessons I've learned personally with the myriad of solutions other Isuzu, Chevy, and Jeep owners have found. For good measure, I've also added some secrets from sports car enthusiasts I've corresponded with over the past three or four years.
The truck I did most of my experimenting on was a 1989 Isuzu Trooper. The Trooper first saw the 2.8L powerplant (an oxymoron on par with "military intelligence") in '89. I guess Isuzu learned something by waiting to see how the motor was incorporated into Jeeps and S10's, because they selected a throttle body injection system instead of a carb. Although easily mistaken for a two barrel carb at a glance, it remains a genuine Goodwrench part, along with the ECU that controls it
The advantage of having the GM motor, especially in an Isuzu, is that like so many things that wear the bow-tie, (and so few with the Isuzu badge) a healthy aftermarket caters to this motor. As a result I, like others, have been pleased to find that a bit of digging yields exciting results. To help put this information to work, I've organized it into a logical order in which the tricks can be applied -- I wish I had followed it. You may have already done some of these mods, and that's great. There is nothing particularly wrong with changing it up, however, I think you'll find that in this order you'll get a good initial bang for the buck, will address both ends of the motor, and will see some healthy gains. How much? All tricks combined should, with a conservative calculator, see your stable grow by four dozen ponies. That's pretty good for a motor rated for around 125 Hp stock. As for the real output you'll see that only the dyno really knows.
Trick #1: Turbo City, Holley or GM 4.3 TBI
|TBI taken from a GM 4.3L V6, which the 2.8's ECU can deal with just fine|
Short of a turbo -- or the twin-turbo setup that an acquaintance used on his 2.8L-equipped Datsun 510 -- the most notable gain to be had is from the addition of a high-flow throttle body. Good for approximately 20 hp, this simple 1-2 hour install goes a long way toward making your daily driver enjoyable, or at least less embarrassing. Mixing more air and fuel, and delivering them through larger throttle bores, the Holley 3210 provides an affordable option for many.
Turbo City reportedly makes a better product, and sells it at a better price. Their Hi-Flow TBI features some slick touches like air flow enhancement via shaved throttle body shafts. If not for the next option, this would be one to look at seriously. More affordable still, the TBI from a 4.3L GM V6 bolts right up. These throttle bodies are less than a hundred dollars at a good salvage yard, and the 2.8's ECU will handle the increased flow just fine. Turbo City's throttle body is actually built from the foundation of this GM model; they shave, tune, and polish it.
It only takes a few hours to install any of these throttle bodies, so the return on your effort is very high. These three throttle bodies are direct bolt-ups and provide excellent horsepower gains. In most cases, fuel economy will remain about the same if fuel pressure is well-regulated. With this sensitivity to fuel pressure, some have found it useful to install an adjustable fuel pressure regulator and even a pressure gauge in-line. The Holley, however, has a built-in adjustment screw.
Trick #2: Free Flow Exhaust
|Ceramic coating on the headers helps keep heat down under the hood, and keeps the headers looking great|
Exhaust options really help this little V6. A 2.25-2.5 inch diameter cat-back exhaust frees up exiting gases, letting the horses run. Two-inch pipe enhances crisp throttle response and provides top end gains. Many vehicles equipped with this motor can use headers from larger companies such as Pacesetter. Unfortunately, the Isuzus still lack a source for this important part, although CALMINI has a working prototype (be sure to contact them if your vote is for it to go into production). High mileage vehicles may benefit from replacing the stock catalytic converter with a free-flowing unit. Prices on these have really come down in recent years, and combined with new plumbing from the motor to the tip of the tailpipe, this will yield miles of smiles
Don't be fooled into thinking that you need a pre-fitted exhaust. Although available, they are often costly compared to the product a local muffler shop can provide. In either case, look for 16 gauge or thicker (smaller numbers are better) aluminized piping, minimal bends (only two bends are necessary from the cat back on '88-'91 Troopers), and an all-welded muffler with a lifetime guarantee.
After you've freed up your exhaust and got the TBI pumping more juice, you'll soon want to improve the air flow to the TBI. This will be descibed in Tricks 3 - 6. You'll also want to make sure you're not getting dirty air. Dirty air is bad - baaaaaad. Dirty refers both to particulates and to the smoothness and therefore the efficiency with which air flows into the motor. The Tornado product that most have heard of tries to smooth air flow and simultaneously mix fuel by routing it through directional fins. Although I have not found it to make any noticeable difference, I have been pleased with the results of a couple other tricks.
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