The Jeep Geek

The Jeep Geek's Blog
More Power

Resolutions Jeep Should Make

Having just finished his annual self-indulgent article on New Year resolutions, The Jeep Geek turns his attention to Chrysler. So how does The Jeep Geek get off telling Chrysler what they should do with Jeep? Well, two reasons:

  1. He talks to Jeep customers all day long and knows what they want. He is one himself and knows what he wants. Chrysler needs to spend more time with potential buyers to even better understand their wants and needs.
  2. Someone has to. There are product features and options that have been missing and are keenly desired.

First The Jeep Geek wants to put credit where credit is due. In the last two years, Jeep has climbed back to the top of the SUV market. This was done with some great products, most noteworthy are the Jeep Grand Cherokee and the Jeep Wrangler. The Grand Cherokee is the most awarded SUV in history and is truly a blend of elegant style and pure performance. Yes, The Jeep Geek is a fan. Then this year, Chrysler has fixed the only complaint with the Jeep Wrangler...they replaced the aging 3.8L (232Cubic Inch) V6 engine with the Pentastar giving us much more horsepower. Jeep’s quality has improved and is the top domestic brand for quality according to Consumer Reports (who have not been kind to Jeep in the past). All in all, they have done a tremendous job in a tough economy. But the competition is not sitting still and neither can Jeep.

So, The Jeep Geek’s list of resolutions for Jeep:

  • There is not a month that goes by when The Jeep Geek is not asked about a diesel Wrangler. The Pentastar engine takes some of the steam out of this request, but there are such significant advantages for the diesel engine. First, a diesel Wrangler already exists in Europe where emissions laws are as strict as here in the US. So what gives?? The diesel engine is very torquey at the low end where it is needed in off-roading. Fuel economy and fuel cost are both better for diesel and may provide some relief from government regulation that require improvements in Chrysler’s fleet. Finally, despite the improvement that the Pentastar engine provides, there is significant demand here in Boulder when many residents dream of converting french fry oil into diesel fuel. This could spark a large growth in the restaurant industry because of a demand for used cooking oil...think of all the jobs that this would create.
  • Build the JK8 at the factory. Recently The Jeep Geek wrote an article on the Jeep Wrangler pickup truck that we built. Mopar built a kit to convert a 4 door wrangler into the JK8. Overall a cool looking Wrangler, but this is an inefficient process resulting in a high price tag. Since the Wrangler is built using body on frame construction, it makes all this possible, but in reality it would be cheaper to build the JK8 at the factory than building a 4 door Wrangler. For example, the hard top is smaller saving money, there are only two door rather than four, saving money, there is no back seat saving money, the roll bar doesn’t have to extend all the way to the back, saving money. Overall a factory built JK8 could be built for less than the cost of the 4 door...and certainly for less than the cost of converting a 4 door to a JK8 at the dealership. So is there a market for a cheaper Jeep pickup truck. You bet, it would compete with small pickup truck offerings from the other manufacturers but would kick their butts off-road. If the JK8 kit was a market acceptance test, it was flawed. The cost to do in the field added $12,000 to the base price of the 4 door wrangler. Cost elasticity will put this $50,000 small pickup truck out of the mainstream market.
  • Lets refresh the Liberty. There is a mid-sized SUV market that the Liberty competes in, however the Liberty’s age is showing. It is getting harder to compete with an underpowered rolling box. Time to get the Pentastar engine and the Grand Cherokee’s 5 speed transmission into this unit (the 6 speed would even be better). Also, time for a re-design providing some nice shape to this unit. If Jeep does this with the same quality as the Grand Cherokee, then Toyota will not be able to sell a single Rav4. We need this product for 2013.
  • Next, build a version of the Grand Cherokee with three rows of seating. There is a market for this mini-van alternative here in Colorado where the snow makes a soccer mom’s (or Hockey mom’s) blood turn cold thinking about their precious cargo in a two wheel drive van.
  • Finally, lets advertise the Patriot and Compass a bit more. Last summer when Chrysler was running Compass advertising we sold a boat load of these great little SUVs. Stealth marketing just doesn’t work. The Jeep Geek guesses that Chrysler’s plan was to have the sales folks at their stores showcase these small SUVs to customers who show up at the showroom. The problem with that approach should seem obvious...the folks that show up at a Jeep store are looking for larger SUVs...you know, the kind that Jeep advertises. If someone is interested in a small SUV that is great on gas, they probably aren’t stumbling into a Jeep store. They go to a Subaru store where they are purchasing inferior product at a higher price. Subaru is the most popular car in Boulder Colorado...remember the residents here dream of converting french fry oil to diesel fuel...gives you a clue to our market. The fringe, however with the quality that Jeep puts into these small SUVs, they would crush Subaru if given nearly as much advertising as competition gets...help us help you.

OK, two days in a row of self-indulgent posts. The Jeep Geek will now rest from his labors and go back to more informative articles. If there are topics you would like to see covered, leave a comment. The Jeep Geek does read them.

As always, The Geek abides.

blogEntryTopper
Comments

6.4L Hemi Powered Wrangler

The Jeep Geek just test drove a 2011 Jeep Wrangler Unlimited Call of Duty Rubicon that we modified with a 6.4L Hemi engine. The Jeep store here tweaked the output to produce 500 horsepower, added some AEV accessories such as 4 1/2” lift, 35” tires, AEV wheels, AEV off-road bumpers and a Warn winch.

What a rush, The Jeep Geek was very impressed. The Jeep started with a wonderful throaty rumble giving a very satisfying feeling. At last a Jeep Wrangler with so much power that there was nothing on the road that he couldn’t pass. What a feeling. Acceleration was smooth, and accompanied by real head snap...don’t remove the head rests or you will experience whip-lash. The roar of this SRT8 engine was loud. So loud that it was almost distracting at around 50 miles per hour.

The Jeep Geek took one of his friends (who used to race Jeeps off-road) and his friend was duly impressed with the performance. This is likely the most powerful Wrangler in the US today. The Rubicon gearing delivered a tremendous amount of torque to the wheels even though they were very heavy Goodyear M/TR Kevlar 35” tires installed on black AEV wheels.

As can be seen in the photo at the top of this article, this unit looks as tough as it performs. Very muscular appearance with the AEV modifications adds to the excitement of this one-of-a-kind Jeep. Everything on this package says “get out of my way” including the exhaust roar.

The AEV lift performed just as The Jeep Geek expected with a smooth ride...just like the factory ride. Mrs. Geek had a little bit of trouble climbing up into this Wrangler, but once in, she was blown away by the power. She has consented to letting The Jeep Geek add some of the mods to his incoming Wrangler...lift, wheels, tires, bumpers tire carrier and such. The Jeep Geek doubts that he will be able to sneak the expense of a Hemi conversion to The Hummer Recovery Vehicle II. At least not in the near term. However with the new Pentastar engine, he doubts he will need such a boost.

So what would The Jeep Geek do differently to the 6.4L Hemi powered Wrangler? Well, he did notice a slight throttle lag from a dead stop, this is easily corrected by boosting the throttle voltage a bit to improve the throttle response. This won’t add any power, it will just deliver the power a little bit sooner when the accelerator is depressed...other than that, it was a perfect experience.

By the way, this Jeep is for sale. If you are interested in purchasing this one-of-a-kind Wrangler, drop The Jeep Geek a short message and he will get you pricing and details regarding the modifications.

blogEntryTopper

Comments

2012 Wranglers are Close

The Jeep Geek was poking around the tool that enables the Jeep store (where he works) to order vehicles from the factory. Lo-and-behold the 2012 Wranglers are available for order. Oh happy day. Barely able to contain himself, he had to check to see if the Bill of Materials showed the long awaited new engine. More on that subject in a minute.

Scarcely a day goes by when The Jeep Geek is asked about the new 2012s. This has gone on since last summer...when we were getting our first 2011s. What changes will be made...the answer...we just don’t know. Wranglers have been the top seller for Jeep as long as The Jeep Geek can remember...2011 stands in contrast. The 2011 Jeep Grand Cherokee has taken top spot. Two factors have contributed to this reversal. First, the Grand Cherokee was completely redesigned for 2011 and Chrysler did a stunningly good job. Every automotive magazine and reviewer agreed. It has won so many awards that it is hard to keep up with all of them. But this is not the chief reason for the reversal. The Jeep Wrangler sales have fallen dramatically. The market was ready for the new Pentastar engine in 2011 but Chrysler was not ready to ship this powerful engine, in the Wrangler, at that time. Potential customers decided to wait and see if the 2012 model would have this engine. Wrangler sales slowed significantly...for no other good reason. Yup, they slowed in a rising market.

The 2011 Jeep Wrangler market did not fall to zero, there were (and still remain) good reasons to purchase this very capable machine. One reason is to get out on the trails where the difference in horsepower is not an issue. The 200 horsepower of the current model is sufficient to move the Wrangler through almost any obstacle one might find out there...remember that speed on the trail is not a virtue.

The Hummer Recovery Vehicle (The Jeep Geek’s main ride) is a 2 door Rubicon. The Rubicon gearing together with the adaptive engine controller allows for very good acceleration and is able to handle highways, hill roads and the like just fine. The Jeep Geek is able to get his yayas out.

So why all the pent up demand for this new engine? Everyone wants just a bit more power from time to time in their vehicle. The Jeep Geek doubts that anything short of infinite power would satisfy everyone. Some forums’ users have labeled the 2011 Wrangler as severely underpowered...this just isn’t true. This is not a modified fuel racer...it is an off-road beast...the best on the planet for off-roading. In fact, nothing is better in bad weather on the road either. This is a mighty capable vehicle and should not be dismissed just because it might be better somehow. What vehicle can’t be improved? Do people use that same criteria when talking about other vehicles?

So back to the subject. The Bill of Materials list the 3.6L VVT engine and a new 5 speed automatic transmission as included in the new 2012 Wranglers. The 6 speed manual transmission is still an available option. The Jeep Geek can’t tell if there is any other change to the Wrangler based on the Bill of Materials. But in all likelihood there is not much else that has changed. The 2011 had a pretty extensive interior refresh in 2011, so it is unlikely that much will change here. The exterior won’t change much since the appearance of the Wrangler is iconic. Will a couple of body panels change shape? Possibly slightly, but uncertain.

Additional changes are that the Rubicon can be ordered with matching body colored hard top and body colored fenders (similar to the Sahara model). Colors that are available are White, Sahara Tan, Flame Red, Cherry Red, Natural Green, Cosmos Blue, Silver but at this time no Black...although that may change. Chrysler had a pigment supplier that was located in Japan and their production was halted due to the earthquake and tsunami earlier this year. More colors may become available once their production is restored.

So what should you do? Wait for the 2012 to get the new engine? Or purchase the 2011? Well the answer is, it depends. If you have a JK today...you might want to wait to upgrade. If you don’t, then the 2012 won’t be on lots until late September or October. This is the end of the off-road season...most Jeep trails are only open from July to October due to snow and snow melt. If you want to get off the pavement this summer, the 2011 Jeep Wrangler is a very satisfying vehicle that will let you get out and have fun in the great out doors.

Late September or October? Do you really have to wait that long to get one of the 2012s? No, you can order one today and it will probably be delivered in late August or early September. Dealers probably won’t see Wranglers in their inventory til later because of the pent up demand. Customer orders are prioritized over stock units. So most of the units that will be built in August will be customer (pre-sold) orders. It is likely that stock units will not be built until September. Those won’t arrive at dealers until late September or October. You can order today and be one of the first to receive these new units. The only hitch is that you won’t be able to test drive one before you order.

What can you do if you want the horsepower of the new units before the 2012s are available. Buy a 2011 and upgrade the engine power via one of the methods that The Jeep Geek wrote about earlier. You can read these articles in the archive section of this website.

As The Jeep Geek has written about, the key is getting torque to the wheels. The current 3.8L engine is a very torquey engine, even at low RPMs. The delivered torque can be improved by changing gear ratios, adding cold air intake and free flowing exhaust, or by bolting on a supercharger. All this can be accomplished easily and without voiding the factory warranty...of course, you can also swap the 3.8L V6 engine with a 5.8L VVT Hemi conversion that Pollard Jeep has done a number of times. This conversion will give you much more power than even the new Pentastar engine will provide.

Or you can just wait and see what the new units will be like. If it was The jeep Geek’s decision, he would buy now and enjoy the trails and see what the new engines were like next year.

blogEntryTopper

Comments

AEV is In the House

The Jeep Geek has always been impressed with Mopar upgrades for Wranglers for the simple reason that they are well thought through and just work well. He has not changed his mind despite this article. The Jeep Geek likes to have options, choices, you know...like most jeepers, he likes to break the rules sometimes and do something totally different.

A week ago, The Jeep Geek tested a wrangler that had been outfitted with a 3 1/2” lift, Hemi engine, off-road bumpers, heat reduction hood, side armor, 35 inch tires, off-road wheels. It was quite eye-opening.

Of course the Hemi engine provided a good deal of head snap as expected, The Jeep Geek still feels that this is a bit of overkill. What really impressed him was the suspension kit. The AEV 3 1/2” SC lift performed beautifully on the road. Most do not. Even the Mopar lifts show a bit more stiffness on the highway...not really uncomfortable, but noticeable. The engineering on the AEV lift allowed for a very smooth ride on the highway. The way the arm brackets are dropped, allow for the feel of a very long arm suspension, which puts the energy absorption of bumps into the springs and shocks, rather than the trailing arm link. Very clever. This combined with the progressive rate springs yields a ride that is as close to unmodified as The Jeep Geek has experienced. On the trail these lifts have proven themselves to be as capable as any on the market.

What The Jeep Geek appreciates is that this lift has the best ride on highway of any lift he is familiar with, and is as capable as the best off-road. It is able to use all the Electronic Stability Program functionality...just like the factory suspension. Another virtue of this lift is the price. While this lift is priced in the premium portion of the market, it is about the same price as the Mopar 2” lift, and the 4 1/2” version is much less than the 4 1/2” Mopar lift. It would not surprise The Jeep Geek if Mopar assigns a part number to this lift soon, as they have done to many of the other AEV products.

So, AEV is in the house. For all of you in the Boulder Colorado area, we are having a big event on Saturday June 18th. AEV, the JK krawlers group, and Pollard Jeep are putting on a Jeep show, swap meet, and various informational presentations. Come out and join in the fun. Meet other off-roaders so you can connect to some of their outings and get the most out of your rig.

If you are new to jeeping, this is a great opportunity to see what is going on, test drive some rigs, and get the information you need to make this hobby safe and fun. The Jeep Geek will see you there.

blogEntryTopper
Comments

Gears, Gears, Gears

Jeep performance is as much about gearing as it is engine horsepower. To improve vehicle performance the goal is to get more torque to the wheel...where it will be imparted to the ground. Traction does play a factor in all this...it does no good to stomp on the accelerator and spin the wheels...no power is imparted to the ground...speed is not attained. However, the primary issue is getting the power to the wheel.

The Jeep Geek has explained (in previous articles) how to improve the performance of the engine. In this article he will take a different approach to accomplish the goal of more power.

So a little basic math is involved...the Wrangler Sport (or Sahara for that matter) come with differential (final gear ratio) gear ratios of 3.21:1 What this means is that for every rotation of the tire the drive shaft rotates 3.21 times. The Rubicon has a final gear ratio of 4.11:1...this represents a 28% improvement in power (Torque) delivered to the wheels. Instead of 3.21 turns of the drive shaft causing one turn of the Rubicon’s wheel, it takes 4.11 turns of the drive shaft to turn the wheel once. This increase in torque is called the torque multiplication by gearing effect. This is why The Jeep Geek’s Rubicon is able to accelerate so rapidly...gearing...even though it has the same engine as a Sport.

In fact, the effect of this increase due to torque multiplication is the same as adding 60 horsepower to the Sport engine. (The standard 3.8LV6 engine in the Wrangler produces 208Hp...a 28% increase would be near 60Hp). Wow...gearing can really help energize a Wrangler. So is it possible to upgrade a wrangler gears with those with higher gear ratios? Yup...plenty of gear choices out there and you should consider this option. Especially if you are putting a lift kit on with oversized tires.

So if one adds larger tires (tires with a larger diameter) then this effect works against us because the tire must travel a larger distance for each revolution...this robs power. Adding a higher gear ratio can overcome that effect.

The Jeep Geek recommends that you increase the gear ratio of a Wrangler to 4.88:1 if you are running 35” tires. If you want to run 37” tires, then consider a jump to 5.13:1 gears. Both of these are widely available and will provide good power without unduly sacrificing fuel economy. It may be difficult to get these higher gear ratios into a Rubicon’s differential and still maintain the electronic locking differential functionality. It can be done, but the gears may not fully mesh...check with your local jeep technician.

Gearing may be the way to go if you are trying to boost power...especially if you have an automatic transmission powered Wrangler. In these units, the computer for the automatic transmission tends to de-tune the engine so some milder engine modifications don’t seem to unlock the engine potential.

A word of caution...if you change the gear ratio...be sure to have the odometer/speedometer adjusted to reflect this change. If you don’t you may find you are collecting speeding tickets...just a thought.
blogEntryTopper
Comments

Hemi Powered Wrangler

The Jeep Geek has written articles on improving the horsepower of the Wrangler engine...this one involves discarding the engine altogether and replacing it with a 5.7Liter Hemi...probably the most extreme modification in this area.

The Jeep store where The Jeep Geek works has such a modified 2011 Wrangler Unlimited with a Hemi engine and The Jeep Geek took it out for a short test drive (short for The Jeep Geek...also known as “The King of the Long Test Drives”).

First impressions were that this unit develops enough torque to give you a wonderful head snap when the accelerator is stomped on. The acceleration was smooth (as one would expect from the Hemi). There was the slightest torque steer to the right when The Jeep Geek stomped on the pedal while traveling at 45 miles per hour...nothing that can’t be dealt with, just a bit of a surprise.

It is expected that this unit produces 400 Hp because a cold air intake and cat-back exhaust was also added. The Jeep Geek has not dyno-tested this one.

The modifications were made in town here (Boulder Colorado) and Pollard Jeep provided the new Hemi engine, as well as the Wrangler.

So what is involved in this modification...well quite alot. The engine is replaced (obviously). The new engine is significantly more powerful than the previous engine, so the transmission must also be upgraded. Pollard Jeep used a Dodge Truck Heavy Duty Transmission (an automatic...see The Jeep Geek’s last post). The radiator must also be upgraded since this engine occupies more space in this smaller engine compartment. Pollard Jeep used a Griffin Radiator as well as some custom fabrication. Finally, the conversion requires a kit of stuff like Wiring harness, Pollution control module (PCM), mounting hardware, fuel lines, steering shaft relocation bracket, power steering high pressure hose, exhaust kit, A/C lines, basically bits-and-bobs as it were to make it all work. The Kit used here was the Burnsville Off-road (BOR) Conversion Kit. Simple right? Well, not really, but it is a wonderful result.

This conversion will set you back about $20,000...and Pollard Jeep keeps your old 3.8Liter engine and transmission. However the cost doesn’t end here...it will also cost you your warranty. Chrysler will not stand behind any of this. So once these modifications are performed, the warranty on the power-train is voided. Warranty should still cover basic stuff like power windows, radios and the like. But for those who don’t care about warranty, and have the need for speed...this may be the answer you have been looking for in the Wrangler.

So if you desire a large aggressive lift, 37” tires, and don’t want to pay the performance hit that you will take by making these mods, then consider the advantages of a Hemi conversion.
blogEntryTopper
Comments

Superchargers are Super

Superchargers are super...or are they? In this series of articles The Jeep Geek has attempted to show that there is more than one way to get more power from a 3.8L V6 powered Wrangler. In case you have missed any of the previous articles, there is a stage one upgrade that opens the breathing of the engine, a stage two that involves adding a supercharger, and possibly a stage 3 that involves replacing the 3.8L V6 with a Hemi engine. This is pretty extreme, but will result in maximum horsepower and torque.

So back to superchargers. The Jeep Geek likes this solution for several reasons. First, the Supercharger is not an extreme solution like a Hemi conversion (that involves replacing engine, transmission, possible transfer case, drive shafts, upgrading differentials, etc.). Second, the supercharger allows for the increase in power to result throughout the RPM curve...in other words, you get boost at the low end where you want more power. This is especially true for off-road use. Compared to a turbo-charger which provides the increase in power at higher RPMs, the super charger gives a flat (good) response throughout the range of engine speed.

So what makes a supercharger work? The Jeep Geek is glad you asked. Remember from yesterday’s article that adding cooler denser air enables a better burn in the cylinder...what what the supercharger does is pump air into the intake of the engine. Depending on the demand (pedal on the right...yup, gas pedal) it provides between 0 and 8 PSI of additional air pressure. It is dense and loaded with oxygen. It is also cooled by the inter-cooler which uses an additional radiator that is mounted in front of the main engine radiator. The pump runs on a belt that is driven by pulleys on the front of the engine...this means at idle it is driving air pressure and makes the boost available at low RPMs as discussed above.

A turbo-charger also provides additional air pressure, but runs by a turbine fan that is driven by exhaust gas on the output of the engine...this is generally not available at lower engine RPMs.

So why wouldn’t a person put a supercharger in their Wrangler? Well, the same issue exists with a supercharger as a cold air intake system, the intake is lower and this will impact river fording.

Also, there are some minor issues, first, it is still unclear if the addition of a supercharger will impact factory warranty. The Jeep Geek knows if the supercharger is not setup correctly and provides too much boost the engine will “lean out” and this will burn up the pistons. This repair is expensive and will not be covered by Chrysler. There is also a local issue which we may be able to resolve soon. Every two years here in Boulder County we have to have our vehicles’ emissions inspected. Part of that process has the technician (at the inspection station) open the hood and see if there are modifications to the engine. Modifications are OK if there is a sticker under the hood indicating that the manufacturer of the modifications has passed a certification for emissions. If there is no such sticker, hang it up...it will not pass and you will not be able to license it to drive it on the road. Many localities have similar inspections and they could be problematic.

The Jeep Geek would also like to point out that the installation of most supercharger kits (including his favorite...the Avenger) requires that a large hole be cut in the hood. This can be covered up with a hood scoop, but it won’t appeal to everyone and will require some body work (and associated expense) to make this look good.
blogEntryTopper
Comments

A Little More About Power

In yesterday’s article The Jeep Geek mentioned a stage one performance kit adds 20 Hp and 30 ft-lbs of torque. Subsequently he read in some forums comments that some folks have posted that indicated that they were less than satisfied at the performance gain they received by just bolting a cold air intake on. If this is all they did, The Jeep Geek is not surprised. Let me explain.

When you look at performance increases you have to take a systematic view of the problem you are trying to solve. By only adding one component you may not see anywhere near the performance gain that a manufacturer advertises for that component.

So are the manufacturers lying about their performance improvement numbers? Not specifically. What a manufacturer typically does is tests a population of their products (say around 10) on a number of Jeeps. They then either average the performance gains...or pick the best result and advertise that. If they bolt the product on a unit that is in need of a tune-up they will not get much gain...if they bolt it on a unit where the exhaust system is upgraded, or otherwise opened up a bit, then they get a better result.

So back to the issue of cold air intakes. They work pretty well, but only show gain if they are paired with other components. Think for a minute about the engine as an air pump. If you open the intake, but don’t open the output side, then you only move the tight spot from the front (intake) to the back (output). Any improvement in efficiency is limited by the restriction from other components.

No (or little) gain will come from just putting on a cold air intake system by itself. However when paired with a throttle body spacer and cat-back performance exhaust the improvements are noticeable.

So how does a cold air intake system actually work? There are a few effects that happen when they are added. First, the filters have more surface area and therefore provide less restriction to the air flow. Second the pipe leading from the filter to the throttle is smoother and provides less air turbulence to the air...turbulence slows the air flow. Third, it pulls the air from lower in the engine compartment where the air is a bit cooler. Cooler air is more dense and therefore has more oxygen so there is better combustion in the cylinder.
blogEntryTopper
Comments

The Hummer Recovery Vehicle

If you live in or near Boulder Colorado you may have actually seen The Jeep Geek roaring by you in the “Hummer Recovery Vehicle” (probably on his way to a Starbucks). Yes, roaring by...in a 2008 White Rubicon with the 3.8L V6 mini-van engine...a concession to the old school Jeepers out there.

So this will likely raise an eyebrow or two...this engine has more horsepower and more torque than the old 4.0L I6 engine. The Jeep Geek actually dyno tested this and can prove it. Sitting high on his office wall is a torque curve, measured at the rear wheel proving this audacious claim. So why does this vintage of Wrangler feel so sluggish? The Jeep Geek thinks it may be because the JKs are a thousand pounds heavier than the older TJs. acceleration is a function of power to weight ratio and the point in the torque curve where max power is developed.

What can be done to boost the torque and horsepower of the JK models? The Jeep Geek is glad you asked. There are a few things that can show a noticeable difference...short of a Hemi conversion...

Stage one is replacing the OEM air box with a cold air intake, adding a throttle body spacer and replacing the exhaust with a higher performance cat-back system. This is only worth doing on a manual transmission version of the JK as the automatic transmission computer tends to de-tune the engine controller thereby reducing the output. However on the manual transmission JKs we are seeing an increase of 30 ft-lbs and 20 Hp. These improvements were measured by The Jeep Geek at the rear wheel and can definitely be felt by even the most dull drivers.

Stage two is bolting on a super-charger. There are a number of kits out there, but caution is needed. Boost over 8lbs can cause damage to the engine...so only kits that have boost limiters should be considered. The Jeep Geek is aware of a kit that was developed here in Colorado (at altitude). The avenger supercharger kit includes an intercooled supercharger, larger injectors, and a complete engine software map. This kit will provide a greater than 50% increase in torque and horsepower making it a dramatic improvement in Jeep acceleration. You will have to cut a hole in the hood to make room for some of the components that are bolted high on the engine. Avenger makes a hood scoop to hide this hole, otherwise a good body shop should be able to fashion something that will look better.

The stage one upgrade will not impact the Jeep’s warranty, The Jeep Geek is still trying to get clarification from Chrysler on the stage two modification.

Costs for these mods:

Stage one is about $1750 installed with Mopar parts

Stage two is going to be around $5000 with some budget for a body shop to help make the hood scoop look good.

blogEntryTopper

Comments