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4.7HO Modding questions

37K views 15 replies 9 participants last post by  Gary Allen 
#1 ·
Hi,
New member here and would like to ask for some Jeep tuning advice for my 02 Grand Cherokee Overland with the 4.7HO engine. I would like to thank AdamJ for pointing me out to his forum. He had a similar Jeep that I saw from the jeepsunlimited forum that was tuned so I asked him about it.

So far the only mod for power I had done is the Magnaflow exhaust. I’m looking to add a little bit more HP and torque with the K&N cold air intake, a bigger throttle body and the Superchips tune. I’m hoping the combination of these 4 mods will give me a nice boost. I’m looking for general opinions on these mods. How much more power/torque can I expect? How will my Jeep behave, sound and feel? AdamJ did similar mods and sounds like he got a real nice boost (and ¼ mile time to prove it).

My questions regarding the specific parts:

K&N FIPK – Does it let more dirt into the engine being less restrictive? Is the main reason that it is much louder is because you’re getting rid of the resonator? Can it mess with the throttle body being an oily filter and why does it need to be oily to catch dirt?

Superchip 3875 – I’m using 93 gas already so I guess I would be getting a real boost with this tune. Any downside of this chip? I read that it optimizes shifts. Does this mean it gets rid of torque management? And if it does, what is the down side of it? More wear on the transmission and less smoothness? Does it only affect shifts under WOT?

Throttle Body – I’m thinking about getting either the F&B 70mm or the Fastman bored 68.5mm (save some cash). How does a larger throttle body help increase HP? Does it affect throttle response? Why would a too large TB actually decrease power?

Thanks and looking forward to replies.
 
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#3 ·
First off, welcome to the garage! I hope this board is as useful for you as it has been for me. So now on to your questions. I have a 04 WJ Freedom Edition with the h.o and I recently have added the parts you have in question. I have the K&N FIPK 57 series and the Superchips Flashpaq 3875. I ordered them online through airram.com for $560 shipped. As far as how much power, I'm not sure how much hp/torque my Jeep is putting to the wheels, but K&N claims 13hp gains on this engine, and Superchips claims a max of 21hp increase. I can definitely feel a difference. Especially with the tuner. The tuner increases the shift firmness and is very recognizable. Along with the mid range torque. Not to sure the intake benefits too much, seeing how the h.o stock intake is pretty non restrictive itself. But, I can tell you this, it sounds alot better and louder IMO. Both are worth the buy. As far as letting more dirt into the engine, not really sure yet, I've only had it about 2 weeks. And yes, the reason the intake is louder is because there is no longer a resonator. I know you clean the intake with oil but it doesn't require oil to catch dirt, and it shouldn't cause problems with the throttle body. And for the tuner, you are going to benefit most from the 91 octane tune. It has the highest hp/torque gains, and it increases shift firmness as I mentioned earlier. And yes, it only affects shifts under WOT. Regular shifts still feel the same. Shouldn't harm the transmission as long as you don't beat on it all the time. The only downside to the tuner, is the $ it will cost you to run 91+ octane. But since you already run 93, then shouldn't be a problem for you. :thumbsup:.As far as the throttle body, I'm still running the stocker for now, but I'm considering having mine bored to 70mm. The Superchips Flashpaq is not compatible with throttle bodies larger than 70mm. From what I have read, a larger throttle body increases hp and throttle response by increasing more air into the engine. The throttle body is part of the whole intake system, so therefor benefits by maximizing the airflow from the FIPK you will be adding. And yes, too large of a throttle body can decrease performance if not correctly tuned. The engines computer can not readjust for the added amount of increased air without a proper tune. I hope this helps. BTW only other mods I'm running are Flowmaster exhaust, and 180 thermostat.
 
#6 ·
I would go with the 70mm F&B or fastman. They are a work of art....plus dont pay that much for the fastman.....call and talk to Dan and tell him Scott from jeepgarage sent you and you want the $100 ported tb.
 
#8 ·
How serious are you about making power? include how wild it may get at some point. I have done just about everything that is able to be done at this point. If you want serious parts that can be built upon, get the F&B TB. They are works of functional art. I run the 72mm and I am trying to get a custom one made just for me. superchips is good for standard mods but SCT is better for people who want more. If you have the 4.7HO you need to be running premium fuel in it anyways despite the tune for optimum performance.
 
#10 ·
I run 93 gas already.

What is the SCT custom tune? I know it costs a lot more but what you get out of it? Do you take your jeep to a SCT dealer to get it tuned?
SCT is a handheld tuner much like superchips. Most of us use Sean AKA HEMIFEVER@aol.com (his contact info) to make our custom tunes. SCT can do whatever you want performance wise. You can tune for more gas mileage (which I don't think anyone really does) different tunes for different fuel grades, different mods from intake and exhaust to complete blower, turbo or nitrous applications without having anything extra other than a remapped PCM. It is able to have the tunes updated for every change made where superchips has basic canned tunes for generic mods. Superchips has an advanted only in tranny control at this point. There are other new cheap mods for tranny upgrades now that you don't have to dig into the tranny to get little benefits.
 
#12 ·
I also have the 4.7l HO and have been looking at getting a tuner for it way down the line. Need to get an exhaust for it first. Have been looking at the STC website, but couldn't find the one for the 4.7. Is there a specific one for it? If so could you please link it.

A couple questions regarding this tuner. You said it could hold multiple tunes on the device, is it pretty easy to switch between tunes. The Jeep is my wife's daily driver and i don't think that she should have that much power at all times and would like her to have a better MPG. My father also has an 05 WK with the HEMI, can he share the same tuner or would he have to purchase his own? Since the tuner I saw were expensive it would be easier if I could split the cost with someone else. These are just some questions that came up off the the top of my head and not sure if they are reasonable or even if they are applicable.
 
#14 ·
I also have the 4.7l HO and have been looking at getting a tuner for it way down the line. Need to get an exhaust for it first. Have been looking at the STC website, but couldn't find the one for the 4.7. Is there a specific one for it? If so could you please link it.

A couple questions regarding this tuner. You said it could hold multiple tunes on the device, is it pretty easy to switch between tunes. The Jeep is my wife's daily driver and i don't think that she should have that much power at all times and would like her to have a better MPG. My father also has an 05 WK with the HEMI, can he share the same tuner or would he have to purchase his own? Since the tuner I saw were expensive it would be easier if I could split the cost with someone else. These are just some questions that came up off the the top of my head and not sure if they are reasonable or even if they are applicable.
The tuners become VIN locked once used and can't be used on another vehicle until the first car gets put back to the stock tune. It holds 3 tunes plus the backed up stock tune on SCT. It is easy to change tunes but takes a few minutes to do.

Sean who sels and makes the tunes for SCT and Diablo can be reached at Hemifever@aol.com He can tell you if your vehicle is supported or not. The actual tuner for the 4.7 is a SCT 9550.
 
#13 ·
tuners can only be used on one Vehicle at a time......plus the 5.7 hemi 05 isnt covered by SCT. Diablo has a tuner for the 5.7 hemi
 
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