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Anyone know of a supercharger for the 3.6l VVT.

15K views 17 replies 13 participants last post by  2014 LAREDO 
#1 ·
I looking at buying a 2011-2014 Grand Cherokee and to initially save some money I was thinking Id opt for the 6 and then do performance mods when finances allowed. Does anyone know of a bolt on supercharger for it, or another worthwhile mod?

Rss1211
 
#2 ·
You'd be better off getting the 5.7. Most superchargers i've seen start at $5,000. The 5.7 upgrade about $2,000, plus any savings in gas mileage will go out the window due to sc always on feature. Plus from what i've seen the 13-14 do not have tuning capabilities yet.

In the end you'll spend more getting a v6 then supercharging vs. just getting the 5.7 to begin with.

Just my .02
 
#5 ·
Well, to throw a wrench in your plans, consider this. Some say, because of the new 8spd tranny the 2014 v6 is similar to performance 0-60 as the 2011-2013 5.7. If the tranny makes that much difference on the v6 then you'll love it on the v8.

Just something to consider. Search performance differences.

BTW I got my '14 limited with v8, nav, 20" wheels, and tow package for $38k down from $43.5k msrp.
 
#17 ·
Well, to throw a wrench in your plans, consider this. Some say, because of the new 8spd tranny the 2014 v6 is similar to performance 0-60 as the 2011-2013 5.7. If the tranny makes that much difference on the v6 then you'll love it on the v8.

Just something to consider. Search performance differences.

BTW I got my '14 limited with v8, nav, 20" wheels, and tow package for $38k down from $43.5k msrp.
The V6 with the 8SPD in Sport Mode is pretty amazing. It'll get you in plenty of trouble.
 
#8 ·
The proper place for a supercharger is either at 20,000 feet or on a Diesel. While there have been some great supercharged engines (L67), they are not cheap to live with and supercharging a 3.6 would require quite different computer maps.

Heck, you can't even buy a lower temp thermostat for the Pentastar.
Have to disagree with you on this. A turbo is better on a diesel, and there are some really great supercharged engines. The problem is when its done to an engine not built for it. Too much strain on the internals and especially the crank snout. Ford has done well with the GT, GT 500 and the '00-'03 Cobra. Audi is running them on their V6 engines with great results. The Fords had some heat soak issues, but aftermarket units and intercoolers helped no problem. Seen many Cobras with over 800 Hp at the wheels with no internal engine mods. The GT and GT 500 are capable of over 1,000. The Audi V6 will embarrass a Hemi all day long. The S4 will beat a SRT Challenger with its 3.0 V6.
 
#7 ·
A few guys did a similar thing back with the '05-'12 Pathfinder came out. They bought the 4.0L V6 and bolted on superchargers.

Most of them ended up spending a bunch of cash, blowing up the motors after 60K miles...and buying the 5.6L V8 version. I don't think anyone over on that forum is still running forced induction.
 
#9 · (Edited)
I wanted to stay out of this debate. I have to agree with JohnC on this one. There are great supercharged engines, Audi to mention one manufacturer makes a monstrous 3 L V6 that will run circles around Hemi. I've driven the stock S4 and it is a dream.

I would entertain a supercharger myself, but one built for motorcycles only, with very little boost, which would only require hardware bolt-on not any internal work.

Audi is not the only manufacturer to use supercharged engines. The yester-year's Mercedes E55 AMG had a supercharged engine (as did a few others like C55). Nissan had used them on X-Terras.

the main problem with supercharging/turbocharging normally aspirated engines is that it is hard to do it right as an aftermarket add-on. Turbo or Supercharged factory engines have lower static compression (engine turned off, cranking on starter only) and thicker cylinder walls, pistons, valves, better heat dissipation and cooling etc. To properly and reliably supercharge engines using an aftermarket solution for an engine not designed specifically for one, it is very hard and will compromise reliability.

that being said, there are supercharger kits out there that provide a decent solution. They are expensive and not worth the trouble generally speaking. And yeah, there are kits for the 3.6 Pentastar, marketed for the Wrangler crowd.
 
#11 ·
Exactly. To properly supercharge a gas engine you need to start with something already built like a diesel. The other problem is well, dieseling (or detonation aka pre-ignition). To support max cyl pressures with boost and without detonation you need either 100+ octane (pure ethanol works well) or direct injection and cooling of the charge (intercooling).

All of this is also a factor of bore diameter and speed of flame front propagation. For this a spark located at the center of the chanber helps to avaoid developing a second (or more) combustion point. Lostsa small diameter cyl can support more boost than a few big ones.

You can play a lot but since I prefer street engines to run on 87 PON, the current Pentastar is pretty much at an upper limit and VVT on both intake and exhaust really helps. That some may be a touch over might be a cause of all of the cyl head failures. Will say that on the rare occasions I haul something heavy in hilly terrain on a hot day I plan to fill up with 89 PON.

So if you want to add a supercharger, go ahead. Just be aware that the reason to go to low compression pistons is twofold:
1st: to reduce the compression pressure to avoid detonation (but can control that with the boost)
2nd: to increase the chamber size to increase the mass of the charge you can pack in for a given max BMEP. (where the extra power comes from).
Many miss the second point.
 
#13 ·
Exactly. To properly supercharge a gas engine you need to start with something already built like a diesel. The other problem is well, dieseling (or detonation aka pre-ignition). To support max cyl pressures with boost and without detonation you need either 100+ octane (pure ethanol works well) or direct injection and cooling of the charge (intercooling).

All of this is also a factor of bore diameter and speed of flame front propagation. For this a spark located at the center of the chanber helps to avaoid developing a second (or more) combustion point. Lostsa small diameter cyl can support more boost than a few big ones.

You can play a lot but since I prefer street engines to run on 87 PON, the current Pentastar is pretty much at an upper limit and VVT on both intake and exhaust really helps. That some may be a touch over might be a cause of all of the cyl head failures. Will say that on the rare occasions I haul something heavy in hilly terrain on a hot day I plan to fill up with 89 PON.

So if you want to add a supercharger, go ahead. Just be aware that the reason to go to low compression pistons is twofold:
1st: to reduce the compression pressure to avoid detonation (but can control that with the boost)
2nd: to increase the chamber size to increase the mass of the charge you can pack in for a given max BMEP. (where the extra power comes from).
Many miss the second point.
You're over complicating it. Any street enginge does not need all of that. Just a good crank, rods and pistons matched to the proper compression and tune. Most NA engines use cast parts and powdered metal rods. Great for atmospheric pressure, but will fail somewhere over 10lbs. You could probably go to 14 or higher on a turbo and cast crank though. What you are stating really only applies to a high boost, high power build. I have a friend that has over 120,000 on his 4.6 3V mustang with 9.5 lbs. of boost. The SC went on around 15,000 miles.
 
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