396 Stroker Motor Install - Pumping Up, Part 3

The real story here is our...        read full caption The real story here is our decision to use Evans NPG+. This will result in at least another 10 hp and probably over 20 hp due to the fact that we bumped up the compression ratio to take advantage of NPG's additional octane tolerance. By reducing or eliminating critical hot spots inside the combustion chamber, the potential for irregular ignition and detonation is reduced. This translates into increased octane tolerance, a more stable flame front and more horsepower. NPG+ is a non-aqueous coolant and cannot be mixed with water or other coolants, so most small-blocks need about 4 gallons to fill a coolant system. At $22.50 per gallon, you can expect to spend about $90 to change over to NPG+. The additional cost is offset by the fact that NPG+ is essentially a lifetime coolant (200,000 miles or 10 years) and it can be used effectively in most existing cooling systems without modification.

Getting all that heat out...        read full caption Getting all that heat out of our super-efficient Evans cooling system requires a pretty special fan system, and we don't think we've ever seen an aftermarket fan system as well-built as the Be-Cool unit (part No. 75007, $279). This dual 11-inch electric fan set-up is properly shrouded and produces 2750 cfm of airflow at 12.5 volts. It's basically the way the factory would build a fan if the car came with a 500-hp engine. We also found that the Be-Cool mounting brackets work perfectly on our Evans radiator.

In keeping with our high-tech...        read full caption In keeping with our high-tech thermal management philosophy, we sent our existing SLP 13/4-inch shorty headers (part No. 30003, $450) to Jet-Hot Coatings for their "Jet-Hot Sterling" coating process ($179). Jet-Hot was central to our goal of managing heat in the engine compartment and maximizing the effectiveness of our cooling system. The benefits for a high-powered street engine are less heat soak, lower intake air charge temperature, improved exhaust scavenging, resistance to rust and corrosion and improved looks. The Jet-Hot process consists of a thermal cleaning followed by blasting with an aluminum oxide media. The headers are coated inside and out, then cured at room temperature. This is followed by a 45-minute blast at 650F. The entire process is repeated again: coating, curing then baking. The final coating is an industry-leading three mils thick and is resistant to temperatures of up to 1350F.

In part two, we told you we...        read full caption In part two, we told you we weren't too happy with the quality of the cast SuperRam lid. We told ACCEL about our problem and they sent us this billet aluminum lid (part No. 74198). In these before and after photos you can see what an improvement the billet lid is. Thankfully, we won't have to chase down vacuum leaks from the SuperRam lid! As an added note, ACCEL told us that any customers who purchased a warped cast lid could trade it in at no charge for the billet lid.

Our new Evans coolant pump...        read full caption Our new Evans coolant pump pulley is visibly smaller in diameter than the factory pulley. This allows more coolant to be circulated in a shorter amount of time. Many pulley manufacturers make "underdrive" pulleys to reduce parasitic drag and increase horsepower, but the Evans pulley is "overdriven" to provide better cooling. According to Evans, this will result in more horsepower because, as an engineered system, we will have greater octane tolerance and superior heat management. Combined with our Evans NPG+ coolant, Evans coolant pump, Evans radiator, and Be Cool dual 11-inch electric fans, we should be able to do everything short of pull a 50-foot yacht up Mt. Everest.

Before dropping the 396 into...        read full caption Before dropping the 396 into Magnum TPI, Aaron Strope and technician Roger Creech installed our ATI flexplate (part No. 915533). As far as we know, ATI is the only manufacturer who makes an SFI-approved flexplate for neutral balance and a one-piece rear main seal. Both the ATI flexplate and our ATI balancer are designed to meet SFI specification 29.1, an NHRA requirement for cars running 10.99 and quicker. Strope also used ARP flexplate bolts (part No. 200.2902) which have a tensile strength of 190,000 psi. Often the flexplate and flexplate bolts are ignored, sometimes resulting in great harm to the driver*s health!

Okay, this is basically a...        read full caption Okay, this is basically a beauty shot, but for the real install, the headers were removed and fender covers were in place to keep things clean. According to Aaron Strope, "Installing the engine in one of these is a bitch. You've got to align the transmission dowel pins, center the torque converter and set the engine down in the motor mounts all at once. We usually install the motors without the trans in but we aren't using a lift today!"

Our Evans radiator has two...        read full caption Our Evans radiator has two rows of 1.25-inch tubing in a package designed to fit the tight confines of our 1988 Firebird. Now that we'll have over twice the power as a stock engine, the OEM radiator would be hard-pressed to pull all the extra heat out. Perhaps for a drag race-only application we could use the stock radiator, but Magnum TPI will have to serve duty in bumper-to-bumper traffic with the air-conditioner blasting.

After installing the Jet-Hot...        read full caption After installing the Jet-Hot coated SLP headers, Aaron primed the oiling system with a drill and adjusted the valves. With any hydraulic roller cam motor, the lifters need to be fully "charged" with oil to effect a true zero valve lash. If the lifters aren't primed, the valves may not close all the way with the engine running.

This is where things get slow...        read full caption This is where things get slow going. The process of putting a TPI motor back in a third-gen is fairly time-consuming if you want to get things right. Much of the work centered around cleaning 13 years of grime from the accessories, brackets, wiring harnesses and fuel lines. Since the motor looked spanking new, we were pretty much obligated to repaint all the pulleys, brackets and accessories where ever they were visible. We even ordered a new washer bottle and coolant overflow reservoir to complete the makeover. You'll notice that Strope took some photos before the original motor was removed (the small photo album on the radiator support). These helped the Strope crew route all the harnesses and hoses in the right place.

Yep, it's going to be a street...        read full caption Yep, it's going to be a street car so we'll need air conditioning! Aaron Strope has converted over all the a/c system's o-rings to HNBR o-rings to convert Magnum TPI over to R-134a refrigerant. The R-134a molecule is smaller than the old R-12 molecule, so old R-12 o-rings tend to let R-134a refrigerant leak past them. Also, R-134a causes the older o-ring seals to swell and deteriorate. Note that special R-134a quick disconnect adapters were also required for the conversion. At this point, Aaron is evacuating the system to check for leaks and to evaporate any condensation in the system.

During parts 1 and 2, we chronicled the construction of our 396 cubic-inch tuned port street/strip motor by the experts at Strope Speed Shop in Washington, Penn. During this time, we have marveled at the depth of knowledge shown by the crew at Strope's. They've put a lot of fuel-injected small-blocks together over the years and as it came crunch time to drop our powerplant into Magnum TPI their experience became readily apparent. As you will see, there is a lot to be done before we can crank this baby up. In this segment, the engine bay, harnesses, hoses, and reservoirs have been cleaned, painted, or replaced; a new dual-cat y-pipe has been fabricated; a completely new induction tract has been designed and fabricated; a larger radiator and high-output electric fans have been installed; and the air conditioning system has been updated to operate on R-134a refrigerant.

From an editorial standpoint, here's where we make tough decisions. Do we show every bolt and nut being turned with all the excitement of watching grass grow? Or do we cover the more salient technical concepts and let the reader work out the details? At this point it's worth mentioning that we've deviated so far from the factory TPI engineering that most reader's cars will not bare much resemblance to our project car unless they're copying it blow for blow. As a favor to you, we'll skip the microscopic detail and focus on key pieces of hardware and the problem-solving fabrication skills of Strope Speed Shop. We're guessing that even if you aren't building a Magnum TPI clone, much of the technical info--in particular the sidebar on the Evans cooling system--will help you no matter what type of third-gen you're working on.

Areas Of Note
Making big changes to a car of unknown origin that is 13 years old presents all sorts of problems. One of those problems we stepped into backwards was the exhaust system. Third-gen devotees are aware that 1988 F-bodies did not come with a dual-cat set-up from the factory. Since our car had been upgraded (jerry-rigged?) to dual-cat status before we purchased it, we elected to go dual-cat when we installed our complete SLP exhaust system last year (see "Primary Target," July 2000). This meant that our Hotchkis subframe connectors we ordered earlier this year (see "Better Than New!" July 2001) would not fit due to the fact that there is no such thing as a 1988 dual-cat 350 TPI application. To make a long story short, we decided to get the subframe connectors into the car while the engine was out. This necessitated that Strope build a new custom dual-cat y-pipe to fit around the subframe connectors. We can't emphasize chassis stiffness enough on a high-powered third-gen. Add the power without the chassis stiffness and you're asking for trouble! To this end, the folks at SLP (y-pipe) and Random Technologies (21/2-inch catalytic converters) ponied up fresh product to accommodate us. Thanks guys!

Coming to terms with all the extra heat generated by a 396 TPI motor requires some pretty high-tech solutions. One of the easiest for us was the decision to send our SLP 13/4-inch shorty headers off to Jet Hot for their Jet Hot Sterling coating process. Our stainless steel SLP units looked great when we installed them in July 2000, but like all uncoated headers, they became a visual mess pretty soon thereafter. The Jet Hot ceramic thermal barrier coating is applied both inside and outside the headers and can lower underhood temperatures by as much as 100 degrees. High levels of underhood heat can accelerate engine wear and wear on other underhood items such as ignition components. It also causes heat soak which elevates air charge temperature and robs power. Perhaps less important, Jet Hot Sterling looks super when you pop the hood for all your friends. With a nice mill like a stroked SuperRam 396, we can't have junky-looking headers can we? For $179, the Jet Hot Sterling coating is a pretty good deal, all things considered.

Up in the engine bay, the air conditioning was updated with HNBR o-rings and the schrader valves were replaced with R-134a quick-disconnect fittings. The a/c system was then evacuated, checked for leaks and charged. Our new Evans radiator was trial fit along with our Be Cool dual 11-inch electric fans. This required some creative repositioning of the a/c condenser and some modification of our OEM radiator sill plate. The tough part was leaving enough room between the 1000-cfm throttle body and the radiator for a new 3-inch induction pipe.

Strope's is still working out the details of a custom fabricated intake elbow and mass air sensor bracket. Third-gen TPIs built prior to 1990 all had mass airflow sensors so unless you're converting to an aftermarket speed density system (like we plan on later) you'll have to deal with a tight fit, particularly if you're using a SuperRam intake and/or own a Firebird. We're guessing that the dual-snorkel intake of an IROC or Z28 is much easier to work with compared to a Firebird. Also, more recently built speed-density cars will not be restricted to a 3-inch inlet like ours. This can really impact intake flow and thus horsepower on a larger engine.

As a side note, we have been particularly impressed with how Strope Speed Shop has been paying attention to the cosmetic element of this project. Ever since the spent factory motor was pulled, they have been continuously cleaning, painting, and generally sprucing up the engine compartment so that when the crown jewel arrived it would not look terribly out of place. As expensive as it is to build a bullet like this, it makes no sense not to do the cheap and free stuff. To this end, we ordered a new coolant overflow reservoir and a washer fluid bottle from the folks at Year One. We've also used approximately 10 cans of high-temp primer and spray paint on the engine, engine compartment, accessory brackets, pulleys, and other parts.

Prior to our most recent visit, Strope's fabricated a custom ground-level ram air system from steel sheet and tubing. This consists of a ground-level scoop which feeds a fenderwell box holding a conical K&N filter. Our prior arrangement consisted of this same filter hanging in the open fenderwell, a condition which resulted in a soaked filter and a burned mass air sensor element. The new set-up will supply the filter with cool air and keep the filter dry in the rain and slush.

Speaking of mass air sensors, our plan is to retain the stock MAF for the time being until we get our new Gen VII DFI and custom jumper harness from Fast Track Performance in Ferndale, Calif. The plan right now is to use the MAF with a custom PROM from Steve Cole at The Turbo Shop. Since many of you are curious about how far the stock computer can go (it's a lot less expensive than a stand-alone system!) we'd like to use a custom chip with the MAF sensor as a baseline. We do expect, however, at this power level that the MAF diameter will be an airflow restriction. There is obviously a price/performance trade-off; the question is, how big will the trade-off be? We hope to answer that question within the next two issues when we get our custom chip burned and dynoed, then get the wide-band DFI installed, tuned and dynoed.

Perhaps the most important thing we can cover in this installment is the cooling system. (See side bar, "Know Thy Enemy: Heat") With considerable deliberation, we chose the Evans NPG+ system at the very beginning of this engine project. This consisted primarily of Evans NPG+ coolant, but for us to get the most out of our SuperRam stroker mill we elected to go with the Evans high-volume coolant pump, overdrive pulley and radiator. By deciding this up front, Strope's was able to design more compression into the engine to take advantage of Evans' higher octane tolerance. If everything works according to plan, we will realize more horsepower at the rear wheels when we're done--all while using ordinary pump gas. The upshot to this is--without building a duplicate engine--we will never quite know exactly how much less horsepower we would have gotten with a half point less compression and a conventional cooling system. An educated guess would be 10 -15 rearwheel horsepower.

We had hoped to have Magnum TPI up and running by now, but there are a few things left to accomplish. The primary obstacle is the completion of the custom induction pipe, but we still have to install the radiator, wire the fans, hook up the ACCEL 300+ ignition, and tune on the dyno with our new TTS chip. We hope to have all these loose ends tied up for the March 2001 issue of GMHTP, so stay tuned.

Know Thy Enemy: Heat
The internal combustion engine has a love/hate relationship with heat. On one hand, heat is the source of all power, and on the other hand, it's a killer of engines. More precisely, we want maximum heat in the combustion chamber and we want relatively little heat everywhere else. Getting this to happen is far more difficult than it sounds. In fact, due to the laws of physics, no engine can be completely efficient.

The problem behind all the fuss is a concept known as entropy. It's most easily described as the migration of heat energy from hot regions to cooler ones. Entropy has been blamed for everything from the downfall of the Roman Empire, to the creation--and demise--of the universe. Pretty heavy stuff, but in the case of the IC engine, entropy is mostly to blame for the fact that mechanical efficiency will probably never, ever rise above 10 percent. That translates into roughly 90 percent of all the energy released from gasoline being wasted as heat. Ten percent sounds like a small amount, but when you turn it around, a one percent improvement in mechanical efficiency can equate to another 10 percent more horsepower at the flywheel--without any more fuel being consumed. Clearly, improving the efficiency of an IC engine is a worthwhile endeavor.

To help us with this technical challenge, we turned to Evans Cooling Systems. Their non-aqueous propylene glycol (NPG) coolant technology has helped racers, experimental aviators, boaters and operators of heavy diesel equipment for over 24 years. The concept behind Evans NPG+ is a simple one, but to really understand it, you must first forget everything you think you know about cooling systems.

The primary goal of any cooling system is to remove heat from the source, principally in and around the combustion chamber. Traditional systems do an okay job of this, but run into a snag along the way: the coolant itself becomes an impediment to heat transfer. As combustion chamber temperature increases, critical areas of the coolant jacket around the combustion chamber become so hot that the boundary at the coolant/metal interface becomes a layer of vapor bubbles. Imagine it as the bottom of a pan with boiling water. The layer of bubbles is like an insulating blanket that prevents heat from migrating into the coolant system.

As this insulating layer (called film boiling) becomes thicker and covers more surface area, the heat in the combustion chamber skyrockets. In particular, critical areas of the combustion chamber become ultra-hot and act as secondary sources of ignition, causing irregular combustion and detonation. Detonation is not only a power killer but an engine killer. Making matters worse, the thicker and broader the insulating layer of bubbles becomes, the greater the reduction in heat transfer and the more severe the detonation. It's literally a downward spiral that can bring a high-dollar engine to its knees in the blink of an eye. To combat this, many engine builders merely dial in a richer fuel mixture, use a high-octane race-only fuel, add extra ignition lead time or use a lower compression ratio. All of these fixes are, at their very best, costly, and at their worst, inefficient. And it's all because the coolant is incapable of staying in a liquid state around the combustion chamber!

To put a different spin on it, think of it like this: All these years engine builders have conceptually put cooling system technology in a box, labeled it "don't touch," and have ignored the potential gains. Evans has pulled cooling technology out of its "technological purgatory" and made some spectacular gains, much to the chagrin of traditional aftermarket cooling suppliers.

Simply put, Evans NPG+ doesn't use any water at all. As a result, it's boiling point is around 375*F, compared with 224*F (at zero pressure) for a typical 50/50 ethylene glycol water mix. At first glance, it sounds like an engine would be damaged by this high a temperature--and it would with a traditional 50/50 EGW mix. The reason for this is that motors with traditional EGW mixtures actually see much hotter localized combustion chamber temperatures due to the fact that heat migration into the coolant (from critical areas) is slow or nonexistent. An Evans NPG-equipped engine will not see the same localized combustion chamber heating, at say 230*F coolant temperature. In reality, even at a higher coolant temperature, the Evans NPG+ is moving much more heat out of the combustion chamber coolant jacket. As such, engines running Evan NPG+ are able to easily tolerate much higher coolant temperatures. This is one of the most confusing aspects of the Evans system and that is why customer education is such a key to realizing the full capability of Evans' technology.

Getting the heat away from the combustion chamber and into the cooling system is one thing, but getting it out of the cooling system and into the ambient environment is another problem altogether. Once the NPG+ coolant has done its job, an Evans coolant pump (part No. EP3122R) moves the coolant at a much faster rate than a standard pump. Evans NPG+ coolant does not use a thermostat, so the bypass line in the pump is plugged. Evans also adds an 8-vane impeller and an air bleed to their pumps. The air bleed (which would be practically useless with a water-based coolant) allows air pockets to be eliminated at initial start-up, thus improving the pump's efficiency further by totally eliminating cavitation.

This brings up another point about NPG+: since its heat of vaporization is 29 percent higher than an EGW mixture, vapor bubbles that do form on critical boundaries will be smaller and will condense back into fluid within the critical region and not in the radiator and coolant pump like with traditional EGW mixtures. This added benefit means that any coolant pump will be more efficient with NPG+ due to a lack of cavitation.

For Magnum TPI, we chose an Evans aluminum radiator (part No. 6582AE-BXX) with two rows of 1.25-inch tubing to get rid of all that heat. The Evans system does not require as much cap pressure (4-7 lbs.) due to the fact that NPG+ coolant does not need elevated pressure to remain a liquid. For this reason Evans supplies its street/strip radiators with a 7-lb. cap. Traditional systems require over twice as much pressure which can eventually lead to unnecessary system leaks.

For the final piece of our cooling system, we turned to another expert in the field of cooling technology, Be Cool. They provided us with one of their dual 11-inch electric fan systems (part No. 75007, $279). This unit provides an incredible 2750 cfm of airflow at a nominal 12.5 volts. This unit we're told is standard equipment on Lamborghini Countach and is frequently used to replace the factory fan set-up on road raced Dodge Vipers. Simply put, no other electric fan set-up provides as much airflow as the Be Cool unit. This has to do not only with the high-output of the fans themselves, but of the integrated shroud they're carried in. Proper shrouding so far has been an art mastered only by OEMs with large development budgets. This has finally changed with the Be Cool unit and we're happy to make it part of our project.

While cooling systems aren't the glamorous parts that cylinder heads and manifolds are, they are a valid means of improving efficiency, economy, power and longevity. To put a sharper point on it, we expect our Evans cooling system and Be Cool fans to pay big power dividends, perhaps as much as 25 horsepower. To take advantage of the octane tolerance and superior heat migration of Evans NPG+, we planned for our power dividend up front with a higher compression ratio. If all goes according to plan, we should be turning out 500 detonation-free flywheel horsepower on pump gas with the air conditioner on full blast!--J.H.

This image doesn't do justice...        read full caption This image doesn't do justice to all the work involved. Back in the July issue ("Better Than New!") we chronicled the installation of a complete Hotchkis third-gen suspension. We did not get a chance to install the Hotchkis subframe connectors due to our custom cat y-pipe which interfered. Strope decided that this was a good time to re-fabricate (from scratch) our y-pipe to accommodate the Hotchkis connectors. To do this, we went back to Random Technologies for some new 2.5-inch diameter converters and to SLP for a new y-pipe. Strope then fabricated the components into a new y-pipe after installing the Hotchkis subframe connectors.	The Hotchkis subframe connectors...        read full caption The Hotchkis subframe connectors connect at the front and the rear, but Strope tied both subframe connectors to the rocker moldings in several places along the side. This makes the subframe far more effective, an important consideration with the weight penalty that subframe connectors impose, i.e., if you're going to have them, they ought to work as well as possible.	Our earlier cold-air system...        read full caption Our earlier cold-air system installed by the previous owner left our K&N filter soaked and eventually caused our mass air sensor to fail. To improve on the situation, the Strope crew collectively designed this functional ram-air set-up which simultaneously keeps out water and feeds fresh air to a sealed box with a K&N filter just inside the fenderwell.
One of the final things Strope...        read full caption One of the final things Strope did on our most recent visit was to fabricate a custom air inlet. With the thicker Evans radiator and a SuperRam manifold pushing the throttle body closer to the radiator, there was not much space left to work with. Although the details are still being worked out, it looks like Strope will modify and re-use part of the OEM radiator sill plate and pass a three-inch diameter tube over to the custom ram-air box inside the fender well. Eventually, when we install our Gen VII DFI, we will replace the MAF and 3-inch pipe with a straight 4-pipe.	With the Be Cool dual 11-inch...        read full caption With the Be Cool dual 11-inch fans in place behind the Evans radiator it looks like there will be plenty of clearance for the serpentine belt system and the custom inlet pipe. The goal is to make everything look and function just as the factory might do it. All we can say is that the folks at Strope Speed Shop really sweat the details and things are going exactly the way we want them to.	In our next visit, we'll see...        read full caption In our next visit, we'll see how the finished engine compartment looks and we'll fire up the 396 in Magnum TPI for the first time using a custom computer chip from TTS! After we get our baseline dyno numbers, we may also begin working on our new Gen VII DFI from ACCEL--if we have time.