Kenne Bell's 2.1-Liter, Twin-Screw Blowzilla - Return of Foxzilla
Installing Kenny Bell's Fox Supercharger was a fun process
From the May, 2012 issue of 5.0 Mustang & Super Fords
By KJ Jones
Photography by KJ Jones
It really is amazing how fast '11-'12 Mustangs such as GTs, Boss 302s, Cobra Jets, and the recently unveiled '13 Shelby GT500 (yeah, the 'Stang with 650 factory horsepower) are moving our hobby forward at what seems like warp speed. However, while we've blathered about how bitchin' the newest 'Stangs are, the truth is, we'll remain dedicated to the Ponies that got this party started. The '79-'93 "Fox" Mustangs and the original 5.0-liter engines got us in this game, and we won't forget 'em.
Our continued commitment to pre-Coyote 'Stangs is one of main reasons why we occasionally embark on projects that harken us back to the early glory days of 'Stangbanging. The days when '86-'93 5.0 Mustangs were the talk of the town—and the catalysts for enthusiasts' magazines like this one to hit the presses.
Building on and improving a Fox 'Stang's OEM engine performance did not require much during this period. Naturally aspirated options ranged from basic (adding a CAI, deleting air conditioning and/or power steering, advancing timing) to a bit more involved (swapping cylinder heads, camshafts, and exhaust upgrades), and power-adder choices were really simple; you either bolted a supercharger on your Pony or shot it with nitrous oxide.
"Speed ain't cheap…How fast can you afford to go?" The phrase certainly rings true for most of us who enjoy the Mustang hobby. And for EFI Foxes, fortified aftermarket engine pieces and various custom treatments (brought forth by the really aggressive, elaborate 'adder setups that eventually came into play), ushered in a completely new performance price range for mods. However, while ultra-sophisticated supercharger and turbo systems have become today's hardware of choice for achieving 600-, 700-, and 800-plus horsepower in pushrod-5.0–based Mustangs, we still have a soft spot for the basic setups that preceded them.
Kenne Bell's 2.1-liter, twin-screw Blowzilla is one such system. In its heyday (the middle-to-late '90s), the stealth KB Blowzilla was the key to boosting many a stock or lightly modded street Mustang, as the blower and just a few additional components were the only pieces necessary for adding a gang of horsepower to a bone-stock Fox.
This is not our first test of Kenne Bell's entry-level Blowzilla; the '86-'93 kit (PN TS1000-GT; $3,099) was the subject of Chris Hemer's article in our April '99 issue. However, based on the number of '86-'93 cars we see on the road, at shows andat NMRA events, and on the Internet, it seems a subject worth revisiting.
At this point, solid, unmolested Fox-body 'Stangs are the absolute best candidates for our projects. While longtime enthusiasts may have run through several Ponies and many mods at this point, there are Mustangs out there that actually meet our stringent criteria.
Our friend Ricardo Topete of GTR High Performance was able to find one that's picture-perfect for this effort—Geoff Connors's virgin-stock '88 GT. The following photos, captions and dyno information detail the success of this reincarnated install/test project, performed by GTR's Ricardo, and Ken Christley, Technical Director at Kenne Bell.
We won't say Blowzilla is back, because it has always been available through Kenne Bell and its dealers. However, we will say the bolt-on supercharger system is still a great option for old-school, stock-Fox (and pushrod SN-95) owners or those who are just coming into the hobby by way of previously owned '86-'95 LXs and GTs.
When it comes to Fox-5.0 tech...
When it comes to Fox-5.0 tech projects, we couldn't ask for a better candidate than Geoff Connors' 100-percent factory-original (engine-wise) '88 Mustang GT. The OEM components are all there and fully functional on this ride, making it a great platform for a bolt-on power adder like the Kenne Bell Blowzilla 2.1-liter, as the supercharger is designed for bolting on street Ponies.
A fuel-system upgrade is required...
A fuel-system upgrade is required whenever power adders are infused on otherwise-stock 5.0 Mustangs. However, the upgrade isn't always elaborate, demanding bigger lines, regulators, and such. Adding a high-volume fuel pump like this Aeromotive Stealth 340 is perfect for applications like this, where boost will only be in the 6- to 8-pound range for now, but can be turned up much higher when Geoff replaces the stock bullet with a fully built engine.
The Kenne Bell Blowzilla 2.1L...
The Kenne Bell Blowzilla 2.1L system we're using (PN TS1000-GT; $3,099) comes pre-assembled, and features a 90mm throttle body flange and KB's less-restrictive Flowzilla inlet. The assembly bolts directly onto Ford Racing Performance Parts' GT-40 lower intake manifold (PN M-9461-B50; $150) using supplied hardware. Internally, the supercharger features two gear-driven rotors that turn in clockwise and counter-clockwise directions. The rotors intermesh in a screw-type fashion, which literally squeegees air from back-to-front, and discharges it through the top of the unit.
GTR technicians Eddie Zapata...
GTR technicians Eddie Zapata (right) and Pedro Tazsoldan remove the fuel tank in Geoff's '88 GT. The Stealth 340 is a drop-in replacement for a Mustang's original pump and does not require any additional pieces or exotic fabrication for installation.
While this procedure, and...
While this procedure, and all of the other install tasks associated with this project, can all be done by first-time do-it-yourself enthusiasts, we encourage you to leave it to shops like GTR if you're in any way apprehensive about taking it on in your driveway or home garage.
We weren't kidding when we...
We weren't kidding when we told you Geoff's Pony is stock as a rock. For those who have no idea what this piece is, it's the OEM air silencer from Geoff's '88 GT. The air silencer is one of the first stock pieces that is removed when a 5.0 Mustang is updated (with a cold-air-intake system).
We're following the old-school...
We're following the old-school script-writing ("burning") custom SCT calibrations onto a chip for the EEC-IV processor in Geoff's supercharged '88 GT. The chip contains all the timing and fuel commands for the blown 5.0.
Kenne Bell's tech director,...
Kenne Bell's tech director, Ken "I'm NOT the Ken in Kenne Bell Christley, performed all of the tuning and chip burning for our test. Our goal is to create calibrations that of course make power, but we also want the 'Stang to have good driveability and reliability with its Blowzilla 2.1-liter, with pump-, and higher-octane race fuel (when we're pouring the coals on).
The smallest pulley would...
The smallest pulley would undoubtedly yield ridiculous power, but we held off bolting that one on the virgin engine. Changing blower pulleys is an easy proposition, but the job requires using Kenne Bell's proprietary pulley wrench (PN SC3140).
One thing the folks at Kenne...
One thing the folks at Kenne Bell are not scared of doing when we work with them on dyno projects is making serious power. And, of course with a supercharger, boost is the key to achieving horsepower goals. Our test group of pulleys includes a 3-1/8-inch (included with the Blowzilla 2.1-liter system), 3-inch and 2-7/8-inch wheels, which are available for $69 each. We started with the largest wheel, and closed our project with the 3-inch piece. The smallest pulley would undoubtedly yield ridiculous power, but we held off bolting that one on the virgin engine. Changing blower pulleys is an easy proposition, but the job requires using Kenne Bell's proprietary pulley wrench (PN SC3140).
Since our blower is set up...
Since our blower is set up with the freer-flowing Flowzilla inlet, we called on Anderson Ford Motorsport's 4-inch Power Pipe (PN AF-0112A; $232.66) to support the system's high demand for increased air flow. On the flow bench, the big tube flows 1,147 cfm of air at 20.4 inches of water.
After disassembling such pieces...
After disassembling such pieces as the throttle linkage, intake-air tubing and distributor, and disconnecting all lines (fuel, water, etc) and connectors (injector harness, etc) that are associated with the stock intake manifold, Eddie removes the upper/lower intake assembly and preps the block for placement of the GT-40 lower manifold. The air conditioning system also is evacuated at this time, as its hard lines are modified during this installation.
Fel-Pro's 1250 intake gaskets...
Fel-Pro's 1250 intake gaskets are used to keep the intake sealed to the bone-stock heads.
A larger mass air housing...
A larger mass air housing is another component that we need for the bigger-air/bigger-fuel effort. This shot gives you a comparative look at the '88 5.0's original 55mm mass-air meter (left) and FRPP's 90mm Lightning unit (PN M-12579-L54; $199.95).
There are some pieces from...
There are some pieces from the stock lower intake that must be transferred onto the GT40. Ricardo makes the swap before installing the new manifold.
Kenne Bell provides all of...
Kenne Bell provides all of the fasteners required for bolting the intake down and securing the Blowzilla supercharger. We found that for the rearmost holes in the lower intake, installing studs makes aligning and dropping the new manifold much easier.
Since we're going big with...
Since we're going big with induction pieces for this installation (AFM Power Pipe, Accufab 90mm throttle body, 90mm Lightning mass air), we're also stepping up on the fuel side; swapping in 42-lb/hr injectors as replacements for the stock squirters. The larger air and fuel pieces are required for the higher boost pressures (12-18 psi) the blower is capable of producing when pullied accordingly.
This is the factory fuel-pressure...
This is the factory fuel-pressure regulator, which Ricardo modified for fitment after discovering a slight clearance conflict with the Flowzilla inlet tube (a phenolic spacer must be in place on the manifold if you're using an aftermarket regulator).
The "big" modification in...
The "big" modification in a Blowzilla installation involves cutting a section of the front A/C bracket, enlarging bolt holes, then removing a 3-inch section on the edge. This change is required, as it's the only way the bracket will be compatible with the supercharger's billet support bracket.
Ricardo and Pedro install...
Ricardo and Pedro install the Kenne Bell Blowzilla 2.1L on Geoff Connors's stock 'Stang. Once the blower is secured, such parts as the distributor, colder spark plugs and other completion hardware are reinstalled on the engine.
Here's a look at Blowzilla...
Here's a look at Blowzilla as it sits, fully installed on our test Pony. One of the beautiful things about this system is the fact that it actually clears the stock, flat hoods on '86-'93 Mustangs, and as you'll see in the accompanying sidebar, produces seriously stealthy steam.
Horse Sense: In this age of modular V-8 and new 5.0 engines, you're probably wondering why our spotlight for this report shines on a pushrod-5.0 power adder. The reason is simple: Despite their near-classic status at this point, '86-'95 Mustang LXs and GTs are still relevant. And the Ponies that are still fairly stock are perfect for adding bolt-ons like Blowzilla, which provide instant zoom for relatively modest coin.
With Kenne Bell's 2.1-liter Blowzilla supercharger bolted to the stock 5.0 engine in Geoff Connors' super-clean '88 GT, we proceeded to the Dynojet chassis dyno at GTR High Performance to create general and "max-effort" calibrations.
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Ken Christley (technical director at Kenne Bell) handled manipulation of the 'Stang's EEC-IV processor, using SCT's tuning software to create a custom chip that contains calibrations for VP's MS109 race fuel, as well as California-standard 91-octane gas.
As the data shows, the 5.0 in Geoff's 100,000-mile GT responded favorably to forced induction, and we're impressed with the performance gains. However, we have to note that the 9 psi of boost achieved during the initial post-install dyno hit is a bit of an anomaly. Technically, with the 3-7/8-inch pulley we used, boost should be barely above 6 psi.
While the combination produced 312 hp, we believe that a restriction caused by the stock 5.0's camshaft is the reason for the abnormality in boost. Basically, the supercharged air is being restricted in the intake manifold, and essentially not getting into the cylinders.
This graph details the anemic...
This graph details the anemic rear-wheel performance of our project GT, before installing Kenne Bell's Blowzilla 2.1-liter supercharger. Trust us, despite the 'Stang's age, its stock 5.0 is still putting out power and torque that's on par with the numbers these Ponies produced back in the late '80s. Thankfully, we've become accustomed to much-bigger steam since those days.
With nothing added beyond...
With nothing added beyond the Blowzilla and its supporting components (Aeromotive Stealth 340 fuel pump, bigger injectors, AFM Power Pipe, 90mm throttle body and 90mm mass air), the gain in performance is leaps and bounds beyond the GT's baseline. With the 3-1/8-inch pulley installed, the Kenne Bell generated a peak increase of nearly 120 horses, and almost 105 lb-ft of torque at the feet!
While we were pleased with...
While we were pleased with the numbers produced immediately after installing the blower (with the 3-7/8-inch pulley and 9 psi of boost), we agreed a "big pull" was needed to see how much additional power Geoff's Pony would put down with a smaller 3-inch wheel on Blowzilla's snout. The numbers are presented in the chart for clarity; power really starts climbing when you drop a smaller pulley on this Kenne Bell unit.
As we learned in a recent experiment (cylinder-head change) with Project T-top Coupe, while intake-air restrictions cause such boost increases, the engine isn't necessarily making more power. Thus the results of this experiment are great, considering the 5,500 rpm limit that the camshaft held us to.
Geoff's Mustang now has a considerable amount of power and especially rear-wheel torque, thanks to Blowzilla, and the cool thing is there's a ton of additional performance that can come from this blower package (it can be pullied for as much as 18 psi of boost), should Geoff decide to step up to a bigger, better engine in the future.
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