Insane Inline II Part 2 - Jp Magazine

Pete Trasborg Brand Manager, Jp

693HP! Last month we revisited the Insane Inline idea-for those of you playing catch-up, the idea is pretty simple. The six-cylinder Jeep engine is one of the stoutest factory engines out there, and it should be possible to build big power without the motor going pop.

693hp Inline 6 Jeep Engine westech Photo 31796670

So, we got together with 505 Performance and assembled a 5.0L inline-six Jeep engine. We started with an '04 block that had been hydrolocked, bored it out 0.060 over, and threw 505's 5.0L stroker kit at it. While bench racing, we came up with 600hp as our goal. We'd heard of Jeep engines that put down high 500hp figures, and we figured that three times the stock output would be something to brag about. Our first dyno pull at Westech Performance netted us 558hp/674 lb-ft without tuning, so we knew we were going to be close to our goals.

To get up to the numbers we were looking for we were prepared to go up to 30lbs of boost. At those boost levels, detonation can quickly kill an engine. In an effort to eliminate detonation, we coated the turbo with a C-186 coating from Streamline Custom Coatings to keep heat down, and ran a water-to-air intercooler to further reduce the temperature of the intake charge.

We hit a couple of snags along the way, but still blew the previous Jeep inline-six power levels out of the water. Not only that, but we are thinking of towing with this motor, thanks to its awesome torque down low and diesel-bashing power numbers. Follow along to see how we got 692hp and 777 lb-ft out of a regular Jeep engine.

insane Inline Ii dyno Chart Photo 26393042

Aftermath
After 40 dyno pulls and completely blowing through our power numbers, we decided at the end of the second day that we were happy. We had used 48 lb/hr injectors, which were running at 100% duty cycle at 570hp. To get to 693hp, we had to bump the fuel pressure way up (fortunately for Westech's dyno that wasn't a problem). However, we'd made a ton of pulls on the motor, and we just weren't sure how it would hold up to more. As it turns out, we needn't have worried. We took the motor back to 505 for an autopsy, and we could still see the crosshatching in the cylinder walls. Maybe with bigger injectors we could hit 800hp with this thing.

PhotosView Slideshow

In order to flow the air needed, we had to go outside the box on a few things. This prototype 70mm throttle body from F&B Performance is perched on a '99-and-up intake manifold that was coated with Cerakote by Streamline. We used 505 Performance's compressed graphite intake manifold gasket to keep the positive pressure from the turbo under control. The intake was gasket-matched to the head and throttle body.

We used a Pacesetter header for exhaust gasses and modified it to feed the turbo. The upper part of the header was coated with Cerakote, but the bottom part we just hit with some high-temp paint after we finished modifying it. The three-into-two-into-one design of the Pacesetter header made it a natural choice for our turbo'd engine.

We used an MSD coil and 6BTM ignition control module to ignite the mixture. In addition to the 6-series multiple spark and capacitive discharge, the BTM includes a built-in boost retard circuit to prevent detonation and can be adjusted from 1-degree per pound of boost to 3 degrees, up to a 15-degree maximum. We started off with a reserved 14-degree total timing and ended up at 25 degrees total for our big numbers.

There was no way a stock Jeep fuel injection system would do what we needed it to do, so we went with an Accel Dual Sync Distributor and Thruster EFI controller kit....

...The kit includes all the wiring to make the motor run using stock Jeep sensors, but gives infinite adjustability to things like timing and fuel delivery. We used a set of Mallory make-your-own wires to deliver spark.

We knew we were going to need a flywheel to bolt the engine to the dyno, so we went to Centerforce for one of its cast steel units. What none of us knew going into it was that none of the "normal" bellhousings that Westech has on the shelf would bolt to the Jeep engine....

...Fortunately, Scotty's Jeep Truck and 4x4 Auto Wreckers had the CJ T-18 we needed in stock and we were able to get the engine bolted up to the dyno with minimal fuss.

While the addition of the Snow Perfomance Stage 3 boost cooler got us 610hp, we ran out of turbo. Enter Comp Turbo with a CT3B ceramic ball bearing impeller. The same 70/84-sized turbo with better bearings from Comp Turbo gave us another 80hp.

Body Chassis Transmission Drivetrain Electrical Engine Suspension Brakes Wheels Tires Tech QA

Insane Inline II Part 2 - Jp Magazine

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