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Unread 11-27-2014, 04:54 PM   #1
2008Me
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I need more power

My wifes 08 GC has the 4.7 in it and it's a turd in my opinion. It's got 118k on it and it's been a great vehicle just under powered in my opinion. The only sweet spot it has is between 4-4500 rpm then shifts and falls on it's face.
I'd like to go with a supercharger but unfortunately the 4.7 doesn't have a big following in the aftermarket world.
What have you done to squeeze more power out of your 4.7? As much as you're willing to spill your guts I want to hear about it. Buying another vehicle is out of the question because this one has been so good to my wife, boosting her confidence in the snow and never giving me a reason to have to work on it.
I should also add that I'm used to driving a 600 HP cummins daily but have stopped driving it as much as I used to and drive the jeep more now.
The only things done to it now are a flat panel k&n drop in, a flowmaster 40 series and deleted the resonator. Everything else is bone stock.

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Unread 11-27-2014, 06:12 PM   #2
technologic80
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I think the 4.7l moves ok, but I agree.. its lacking that "butt dyno" feel. However, I have noticed that Jeep puts a ton of torque management into the shifts. My last SUV (Gmc Envoy), I sent the PCM out for tuning, and was able to select how much torque mgmt I wanted left in. I opted for firm shifts. After the tune, the thing seriously felt like I had gained 50hp.

I would look for a tune, myself. And then open up the exhaust and then finish the project off with a good cold air intake. Those are all the low-hanging fruit for performance.
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Unread 11-27-2014, 06:27 PM   #3
caddydaddy
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I also recommend a tune, I'm surprised you didn't list one yet. I run a Hypertech Max Energy in my Escalade, since they don't make one for my Diesel Jeep. It made a noticeable difference in the Escalade!

Quite a good gain for your 4.7:

Max Energy Power Programmer - Part #52501
Performance Gains
Premium Octane: +47HP +51TQ
Regular Octane: +39HP +42TQ

Adjustable Features
Speedometer\Odometer Correction For Gears 2.82, 3.07, 3.21, 3.42, 3.55, 3.73, 3.92, 4.10, 4.56, 4.88 & 5.13
Speedometer\Odometer Correction For Tire Sizes 22.5 - 44 inches 1/4 inch increments
Top Speed Limiter 25 - 75 MPH in 5 MPH increments, 81 to 255 MPH to match speed rated tires
Rev Limit -500 to +500 RPM
Cooling Fans Stock, 180 degrees F, 195 degrees F
Return Back To Stock
DTCs Read and Clear
Internet Updateable
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Unread 11-27-2014, 09:03 PM   #4
modernblueWK
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I have exhaust on mine. You can hear the torque management when it shifts at WOT. Superchips might help a bit. Ive read that superchips really wakes up the 2nd gen 4.7.
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Unread 11-27-2014, 09:14 PM   #5
90grandoneer
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Good low restriction exhaust, custom headers (if you can find someone to build them), a Superchips Tuner with the Advanced Transmission Tuning Application, and advance the cams one tooth to move the power/torque range to a lower RPM. It'll never be like a stump pulling Cummins though. If you're used to driving one of those, no wonder you think the 4.7 is a slug. You could also look around for a nitrous oxide kit for the 4.7. Don't know if anyone makes a kit for it but, if they do, make sure they are adding enough fuel for the various "pills". Also, do this last, as otherwise you won't get the full benefit out of it.
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Unread 11-27-2014, 09:55 PM   #6
modernblueWK
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Nitrous? Lol no.
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Unread 11-27-2014, 10:17 PM   #7
2008Me
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I've looked at the manifolds on it and that's a sad excuse for one, I'm a hands on kinda guy hence the cummins. I would make a set of headers for her jeep if I thought it was feasible but with the cats on it still it seems kinda pointless to me. Has anyone knocked the cats out on your jeep? If so how did you bypass the O2 sensor? Spark plug non foulers?

Her jeep sounds awesome she gets complemented on it all the time. That was a Valentine's day present for her, some girls like roses.... Not my kinda girls. I can definitely hear the tq management crap doing it's job.

50hp and 50 tq seems like I'd be getting raped for almost $300 for a superchips programmer. I'd like to hear more about this advanced transmission tuning. I know making the transmission do it's job more efficiently can make it seem like power has been added just by the strategies.

I'm also kicking around the idea of making a CAI for it, not that I feel it would do much. I know the quality I can build things to is much better then the over priced junk most people buy. Personal preference again.

Moving the cam one tooth sounds like it may be my best bet but doing that and having a programmer would essentially be lying to the pcm and the jeep wouldn't have a clue what was really happening, correct?

All of my personal vehicles are and will be diesels, once you have one you'll understand. I know it will never be a 600hp cummins but hey a guy can try lol.

Nitrous is out of the equation. Though it would be a blast and comparable to my truck then with my right foot and my wifes. It would only be a matter of time until I got bigger and bigger nozzles....


Thanks for all the good input, I didn't expect so many good responses here this quickly.

Last edited by 2008Me; 11-27-2014 at 10:22 PM.. Reason: made my post more legible
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Unread 11-28-2014, 06:32 AM   #8
JeepN4KC
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I suppose it depends on what you're used to but no way I'd call the 4.7 a turd. Seems to me the 4.7 is a pretty quick and powerful package - especially the gains they made in the GenII in '08. With stock size tires the thing oughta run like a bat outta hell.

A tuner would definitely be worth looking into but look out for any and all HP and torque gain claims. The gains are nearly always seen at rpms that are approaching wot - which to me isn't much of a gain. I can already mash the gas to go quicker and faster.
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Unread 11-28-2014, 08:19 AM   #9
caddydaddy
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Quote:
Originally Posted by 2008Me View Post
50hp and 50 tq seems like I'd be getting raped for almost $300 for a superchips programmer.
Those are huge gains for the money! A cam swap would cost as much or more and you'd be lucky to get half that gain.
Before anything else, get a tune!
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Unread 11-28-2014, 08:27 AM   #10
caddydaddy
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Quote:
Originally Posted by JeepN4KC View Post
A tuner would definitely be worth looking into but look out for any and all HP and torque gain claims. The gains are nearly always seen at rpms that are approaching wot - which to me isn't much of a gain.
I don't know about others, but Hypertech shows what the gains are at different RPMs.

http://b.cdnbrm.com/images/info/hype...ee_command.pdf
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Unread 11-28-2014, 03:50 PM   #11
90grandoneer
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Quote:
Originally Posted by 2008Me View Post
I've looked at the manifolds on it and that's a sad excuse for one, I'm a hands on kinda guy hence the cummins. I would make a set of headers for her jeep if I thought it was feasible but with the cats on it still it seems kinda pointless to me. Has anyone knocked the cats out on your jeep? If so how did you bypass the O2 sensor? Spark plug non foulers?

Her jeep sounds awesome she gets complemented on it all the time. That was a Valentine's day present for her, some girls like roses.... Not my kinda girls. I can definitely hear the tq management crap doing it's job.

50hp and 50 tq seems like I'd be getting raped for almost $300 for a superchips programmer. I'd like to hear more about this advanced transmission tuning. I know making the transmission do it's job more efficiently can make it seem like power has been added just by the strategies.

I'm also kicking around the idea of making a CAI for it, not that I feel it would do much. I know the quality I can build things to is much better then the over priced junk most people buy. Personal preference again.

Moving the cam one tooth sounds like it may be my best bet but doing that and having a programmer would essentially be lying to the pcm and the jeep wouldn't have a clue what was really happening, correct?

All of my personal vehicles are and will be diesels, once you have one you'll understand. I know it will never be a 600hp cummins but hey a guy can try lol.

Nitrous is out of the equation. Though it would be a blast and comparable to my truck then with my right foot and my wifes. It would only be a matter of time until I got bigger and bigger nozzles....


Thanks for all the good input, I didn't expect so many good responses here this quickly.
You won't get 50/50 from a tuner, but you'd need the Superchips to get the ATT App. for the transmission. I've been running it for over 4 years in my 5.7 with the same transmission as in the 4.7 and, when properly set up, it's like a whole different transmission. I also have the Sonnax Line Pressure Booster in mine, which also helps a little. The ATT App. allows you to adjust up/down shift schedules and torque management any way you want.

A CAI won't do too much for you unless you can come up with a way to make the exhaust more efficient. An aftermarket CAI is a waste of $$$ IMO. First the engine, in relatively stock form, cannot ingest/exhaust as much air (CFM) as the stock setup is able to flow. I have an SRT airbox with an extra air inlet and it is more than adequate. A similar setup could easily be made for the 4.7. Just remove the drain cup at the bottom of the box and add a duct from it to somewhere behind the grill. Just be sure to put a small hole at the lowest point in order to retain your drain capability.

Moving the cam timing is a quick, relatively easy and inexpensive way of moving the power/torque range to a slightly lower RPM. The tuner will actually reprogram the computer, and advancing the cam has no adverse effect (at least on either of mine), with regard to engine operation. I've done it to both of my Hemi vehicles with aftermarket, high performance cams.....my WK, 2 degrees (total of 6 degrees), and my LX, 6 degrees (total of 10 degrees). The bottom end with the LX is much stronger with the 6 degree advance. The cams I am using in both have been around in the LX community for about 8 years and have been dyno proven to deliver about 50 hp. if a good, low restriction exhuast is also used. I also have custom, ceramic coated headers on my WK with a 3 in. custom straight through muffled exhaust. I don't know about the cats. on the 4.7, but the ones on the 5.7 are low restriction, "wire spun" units, according to my exhaust guy. He recommended I not change them, so I didn't. Total power increase on both of mine is approaching 100 hp which, IMO, is not bad for just bolt on and minor engine teardown....radiator, front cover, and valve covers/rocker arms.

Up to a 100 shot of nitrous works well on the 5.7's, but I don't know if/how it would do on a 4.7, due to the piston top ring land. I chose not to go with it, more because of limited space and the plumbing required if the tank is mounted in the rear. A buddy of mine used to run a 100 shot in his Hemi LX, and it would instantly knock a full second off his ET at the drags. Personally, not my cup of tea though.

It would be nice to come up with a way to get the power/torque from idle on up like the diesels, but I don't think that would be possible without bigger changes to cam timing and increasing the compression ratio. Even then I don't think it could match the diesel. I am at altitude and still run 87 non ethanol fuel in mine during the winter and alternate 87/91 in the summer, unless it's above 95* or I am going racing, at which time I run all 91. When at altitudes above about 5000 ft. I even run 85 without issue.
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Unread 11-28-2014, 05:53 PM   #12
Hendrix9
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Quote:
Originally Posted by 2008Me View Post
50hp and 50 tq seems like I'd be getting raped for almost $300 for a superchips programmer. I'd like to hear more about this advanced transmission tuning. I know making the transmission do it's job more efficiently can make it seem like power has been added just by the strategies.
Hate to tell you, but you almost positively won't get 50/50 from only a tuner. They all exaggerate on their gains. Even if they advertise with a dyno chart, those can so easily be tweaked to say what you want.

Since you were saying all your vehicles are diesels I'll let you in on a secret- making power normally aspirated gets expensive quick for moderate gains in power. (particularly when it's not a large displacement motor to begin with) It's nothing like a turbo gas/turbo diesel where you can easily bump up the power with a little extra fuel and boost.

I'd get the tuner for what minimal gains it might give you, and get the real benefit from transmission tuning.
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Unread 11-28-2014, 09:07 PM   #13
technologic80
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What ever happened to the simple days when you could buy or get your hands on one of your Uncle Bob's (the one with the mullet & pickup truck with the naked lady mudflaps) Mopar performance catalogs, buy some sweet level 2 fuel injectors, or 32lb or whatever idiotic fuel injectors I bought in my teens, for some ungodly amount of money, and put them on your car complete with a fartcan muffler, that would be good (not dyno proven - just garage BS talk) for 100hp?!?!

Geez, things are so complicated these days!

(Seriously though, I used to love modding Mopar 2.2/2.5 turbos in my teenage years! Those were the days of being able to fudge with stuff and not have 13 computers, 17 modules and a CAN bus watching your every move and screaming "HELP! TAMPER!" if you try to alter anything to make the car more FUN)
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Unread 11-29-2014, 12:49 PM   #14
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LOL, it's called "progress" and "electronic wizzardry" but, for us shade tree mechanics, it's nothing but a PITA. It was funny about 10 years ago when they just started putting the Hemi in LX vehicles. All of us on the forums were trying to figure out how to hack the computer and figure out how everything worked. The shop manual wasn't much help either, but I think, in the end, the folks on the forums had more "real world knowledge" about them the any of the stealers. Certainly not like working on old iron without all the gee whiz stuff on it.

I ended up buying an Autel MaxiDas DS708 diagnostic computer, just so I can half way stay on top of what's happening within the electronic jungles of my two Hemi vehicles. It's pretty amazing, and sometimes comes up with stuff I didn't even know had a possible problem. All minor stuff so far, and most are one time stored or historical codes that never repeat once cleared. Even after changing the battery I got two codes, one for steering angle sensor and another communications problem, due to the battery being disconnected. I usually run the auto scan of all electronic systems about once a month on both of them.
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Unread 11-30-2014, 11:20 AM   #15
Aclow33
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You'd be better off selling your wifes vehicle and buy one with a Hemi in it.

THEN.... sink money into it
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