performance mods?

moose_1978 · **Posted:** Mon Dec 04, 2006 6:03 pm

I am looking into doing some stuff on my kj and wanted to know if the investment was worth it.I am looking to put a magnaflow exhaust on ,afe intake and a throttle body spacer.Will I even notice a differance?

streetKJ · **Posted:** Tue Dec 05, 2006 3:30 am

moose_1978 wrote:

I am looking into doing some stuff on my kj and wanted to know if the investment was worth it.I am looking to put a magnaflow exhaust on ,afe intake and a throttle body spacer.Will I even notice a differance?

Get an AEM intake and a Borla exhaust. (I dont trust AFE, and AEM has built their reputation on intakes) Throttle body spacers dont do squat. You can however get a larger throttle body by Fastman.

Once you get a cone type intake, you can do the $4 cold air intake mod I did.

http://www.lostjeeps.com/forum/phpBB3/vie ... hp?t=11748

With the intake and exhaust, you will notice a seat of the pants difference in throttle response, and you will have improved high end power noticable from 60-80mph accel and 80-100mph accel.

Badgts · **Posted:** Wed Dec 06, 2006 10:22 pm

moose_1978 wrote:

I am looking into doing some stuff on my kj and wanted to know if the investment was worth it.I am looking to put a magnaflow exhaust on ,afe intake and a throttle body spacer.Will I even notice a differance?

You list these mods in your sig??? Do you not have them already? The most you'll likely notice (from the seat of the pants) from all of these is more noise and slightly better gas mileage. If you are looking for speed, then nitrous will get you much more hp for the same $ you would spend on all that other stuff. The least cost effective of the list is prolly the spacer. The intake and exhaust will gain you some hp, but it will be minimal.

SavageUrge · **Posted:** Thu Dec 07, 2006 12:43 pm

Don't get a throttle body spacer! Do not waste your money. I only paid $19 for a brand new Power-Aid TBS on eBay, and it was a waste of $19. If you look at the inside diameter of the TBS, it is actually smaller than the ID of the throtle body, so tell me: how is this supposed to increase the air flow? I don't care what you tell me about the little spiral thingies in there, it's allowing less air into the throttle body. I plan on removing mine soon. Once the engine acclimated itself to the TBS my fuel mileage went to hell! I DO however recommend an intake such as the K&N FIPK (Fuel Injection Performance Kit). It sounds like I have a small supercharger under the hood the way it sucks air and I noticed a difference in gas mileage and throttle response. Hope this helps!

hallb4 · **Posted:** Thu Dec 07, 2006 1:08 pm

There have been multiple threads discussing the benefits of a new intake. I thought the conclusion was made that they dont actually help since the stock intake is so "free flow" already. I havent personally used or driven with one so I wouldnt know. If you were to rate these mods what whould be the order of cost\benefit? anyone? (I ask because I am in the same boat as moose)

streetKJ · **Posted:** Thu Dec 07, 2006 3:29 pm

hallb4 wrote:

There have been multiple threads discussing the benefits of a new intake. I thought the conclusion was made that they dont actually help since the stock intake is so "free flow" already. I havent personally used or driven with one so I wouldnt know. If you were to rate these mods what whould be the order of cost\benefit? anyone? (I ask because I am in the same boat as moose)

Trust me, the stock intake is not nearly as "free flowing" as an AEM cold air.

Look at the opening which leads to the stock airbox and look at all the kinks and bends the path of air has to go through. If you open up the throttle, the vacuum has to work harder to pull more air through that system. Getting a cold air intake will improve the response time, and you'll notice a difference in how quick it gets up to speed.

spoonplugger1 · **Posted:** Thu Dec 07, 2006 3:54 pm

4WD & SUV mag just did a Liberty this months mag, they got a whole 2 HP and 4 ft lb of torque. Awful expensive HP I'm thinking.

streetKJ · **Posted:** Thu Dec 07, 2006 5:07 pm

spoonplugger1 wrote:

4WD & SUV mag just did a Liberty this months mag, they got a whole 2 HP and 4 ft lb of torque. Awful expensive HP I'm thinking.

Drive one and you'll see :shock:

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

I haven't read the article. Can someone that has tell me if they reset the adaptives in the PCM and drove it at least a few days, but preferably a few weeks in between dyno runs? Makes a big difference after making a mod. Also, the peak power the 3.7 puts to the ground is limited by the torque management, so peak increase won't be very much without a flash. If you have a good match though, you can pick up some very noticeable increases in certain RPM ranges. You should also consider cold air. As much as you can afford. StreetKJ's $4 dollar cold air mod will make a nice increase when combined with a cone intake and cat-back exhaust. You can also do a ram-air like mine, but it's much more expensive. Also, when doing performance mods, you need to get a B&G flash for your PCM. It has the adaptives still turned on, so it will work with a stock setup, or with a mild cam, headers, cold air, and an exhaust. Once my headers are done, we're going to start working on the ported heads, 206 cams, and bigger injectors. It will be interesting to see if it can figure it out, or if it will need an adjustment. So far it's been perfect.

MikeD0106 · **Posted:** Thu Dec 07, 2006 11:55 pm

KY Liberty wrote:

Can someone that has tell me if they reset the adaptives in the PCM and drove it at least a few days, but preferably a few weeks in between dyno runs?

I haven't read it yet, but I'm gonna bet that they didn't get that detailed info in the article.

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

My guess is they did the base runs, then swapped the intake and exhaust and ran it again. If that's the case, I would expect very similar numbers.

moose_1978 wrote:

I am looking into doing some stuff on my kj and wanted to know if the investment was worth it.I am looking to put a magnaflow exhaust on ,afe intake and a throttle body spacer.Will I even notice a differance?

I would go with the new dry AEM or K&N FIPK instead of the AFE. I have the K&N, but it's 5 years old and I'm thinking about going to the AEM. Do streetKJ's $4 cold air mod. Get Dan to make a Fastman throttle body for you instead of using the spacer. I've heard good things about the Magnaflow, but I have the Borla dual, so I can't comment on it. Get your PCM flashed by B&G. You will like the combination. This should give you a nice increase for around $1k. After that it starts getting expensive.

DaveKJ02 · **Posted:** Fri Dec 08, 2006 9:51 pm

Look at the data from the people making the crap. Aftermarket air intakes dont do much for the KJ. Waste of money.

streetKJ · **Posted:** Fri Dec 08, 2006 10:08 pm

DaveKJ02 wrote:

Look at the data from the people making the crap. Aftermarket air intakes dont do much for the KJ. Waste of money.

I seriously beg to differ, and I have a feeling that it will be a continuous debate on the subject.

AEM has built their reputation on quality made intakes for every vehicle they do, and while you might feel that $200 or so is a waste of money because you're expecting substantial horsepower gains and in reality you're only freeing up existing horsepower, it's really not fair to say that an intake "doesnt do much" for the KJ.

For the people that buy them, an intake will improve throttle response, will draw colder, more dense air for better combustion, and give you that neat vacuum sound that while may only make your KJ SEEM more powerful, is merely ear candy nonetheless. The vacuum sound however, lets you know that air entering the intake is far less restricted and has a higher velocity to boot.

Moreover, depending on your driving style, a cold air intake will allow you to consume less gas because the KJ is more responsive and because the colder air it draws in is denser.

The only crappy intake is the one you buy on ebay. And any company that makes intakes for the KJ that tries to sell you a throttle body spacer is merely trying to take your money. AEM did the research and found that a TBS will add absolutely no performance benefit. That's a trustworthy company to me.

DaveKJ02 · **Posted:** Sat Dec 09, 2006 7:13 pm

streetKJ wrote:

I seriously beg to differ, and I have a feeling that it will be a continuous debate on the subject.

Beg to differ all you want. Here's the data from your brand. Not worth $300. ALL the aftermarket intakes show very little improvement on the KJ. The KJ's stock intake is a great design for flow and acts like a snorkel to boot. I wouldnt want an aftermarket just for that. They look like drinking straws for the engine.

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

DaveKJ02 wrote:

streetKJ wrote:

I seriously beg to differ, and I have a feeling that it will be a continuous debate on the subject.

Beg to differ all you want. Here's the data from your brand. Not worth $300. ALL the aftermarket intakes show very little improvement on the KJ. The KJ's stock intake is a great design for flow and acts like a snorkel to boot. I wouldnt want an aftermarket just for that. They look like drinking straws for the engine.

That's your opinion. Before you pass judgment for everyone, consider the fact that some people would never understand why you would spend alot more than that to fit bigger tires under yours. They just don't need it or want it. My opinion is that Jeeps are built, not bought. Just depends on what you want it to be. I'm running over $5k in performance mods in my Jeep's current configuration. That's not including the nitrous system since I don't have the bottle in it right now, and the other 3.7 motor that is in storage in my garage. It easily outruns even the KB supercharged Libby without the N2O. With it, it will leave it behind by over 2 seconds in the quarter. For the performance increase, and the look of shock when people ride in it :shock:

, my opinion is that it was worth it. I have a vehicle that I can carry computer equipment in for work. It goes through snow and ice like it's nothing for my ski trips. I can tow our enlosed trailer thats bigger than my Jeep at Interstate speeds with no problems. And everyone wants to know if I have the 4.7 or 5.7 that rides in it.

streetKJ · **Posted:** Sun Dec 10, 2006 12:33 am

DaveKJ02 wrote:

streetKJ wrote:

I seriously beg to differ, and I have a feeling that it will be a continuous debate on the subject.

Beg to differ all you want. Here's the data from your brand. Not worth $300. ALL the aftermarket intakes show very little improvement on the KJ. The KJ's stock intake is a great design for flow and acts like a snorkel to boot. I wouldnt want an aftermarket just for that. They look like drinking straws for the engine.

Lets get real here. If you spend $300 (I got mine for $230 shipped) and expect the kind of gains from a cold air intake as you would a nitrous oxide kit, then you're obviously barking up the wrong tree. Most of the people who buy an intake want one for their own reasons. They're not as concerned with maximizing the cost-to-improvement ratio as you are, but you really shouldn't disqualify it on costs alone. I know some people who drive Civics who spend three times the amount of our AEM intake for a measly 5 horsepower gain. Everything is relative to your budget. And like I keep saying, if you think the stock KJ intake is so great for flow, drive a KJ with and without an intake and tell me which responds better. Granted, the stock intake is better for offroading and fording water, but as I've said in my situation before --I would probably not wheel in those kinds of places at all, so an aftermarket intake suits my driving needs. And if you really care about an intake looking like a drinking straw for the engine, well then you've basically highlighted the purpose of the intake --to allow the engine to sip air easier.

And like KY Liberty said, its the novelty factor. All the friends I've told that I have an AEM intake in the Liberty always give that look of amazement that AEM actually makes a product for the KJ. They get a kick out of riding in it.

Why dont you have contention with the fact that cold air intakes improve throttle response and allow for better gas mileage?

wendell · **Posted:** Sun Dec 10, 2006 9:03 am

It's sorta funny, out of the five forums I belong to, the intake debate seems to rage on in all but one. On focaljet, noone denies that a cai intake is an improvement over the breadbox unservicable airbox thats comes stock. We had dyno day at the strip, the only dyno I've ever done, my focus picked up 6 hp at the wheels with a AEM cai, I had it in the truck still in the box. A guy helped me install it there. AEM claims 11 on the focus, but I got 6 with no tune, computer reset or anything. You do need the proper fuel, air ratio for full benifit, so a tune or at least having the computer reset is a plus. Also a fan on a dyno doesn't do a good job of simulating driving at 55 or 60 mph with the air being pushed into the intake at speed. I have intakes on all my vehicles but the kj and will soon have one on it. I enjoy modding, it's my hobby along with 4wheeling. If it did only produce 2 hp, thats 2 more than I had. Dyno's don't drive our jeeps, we do, nor can dyno's measure the thrill and excitment of having a new mod, hearing that turbo like sound, it's an awesome experience. Money wise, people don't think twice about spending 10.00 bucks on a 12 pack and peeing it out 20 minutes later. People waste money all the time, so why not waste some on something that can put a smile on your face and instill pride in your rig. It looks great under the hood, sounds awesome, better throttle response and better mpg, so where's the harm ? If you don't like them, don't buy it, but don't flame those who do, we have our reasons. I've put more money in the garder of a stripper when I was younger, than what an intake cost.

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

It's actually pretty simple at the level of mods most people are talking about here. If you just upgrade your intake or exhaust, you will get sound differences, and a slight change in performance. Add both for a little bit more. Bring some cold air to it for some more. You will still have the problem of the programming of the computer. Look at the dyno graph from AEM http://www.aempower.com/images/products/218303D_3-7L_tq.pdf

Pretty obvious where the torque management is kicking in. It should be a smooth arc with peak torque around 4000 rpm.

TheJawsOfDeath · **Joined:** Sun Nov 05, 2006 3:56 am **Posts:** 305

I've put CAI's on my last 3 vehicles and noticed a performance benefit in each instance (2 VW GTI's and a Dodge Stealth RT/TT). Yes they draw in more cold air than stock. As far as $ per HP I really dont give a crap, do it if you want. However, the fact that my Jeep is going to see muddy, wet, dusty, dirty conditions, I like the fact that the stock intake will keep that stuff out. The snorkel bit where It places the actual air inlet as high as possible is a great idea I think. I'm going to throw a K&N panel filter in my stock box and call it good.

DaveKJ02 · **Posted:** Tue Dec 12, 2006 6:48 pm

TheJawsOfDeath wrote:

I've put CAI's on my last 3 vehicles and noticed a performance benefit in each instance (2 VW GTI's and a Dodge Stealth RT/TT). Yes they draw in more cold air than stock. As far as $ per HP I really dont give a crap, do it if you want. However, the fact that my Jeep is going to see muddy, wet, dusty, dirty conditions, I like the fact that the stock intake will keep that stuff out. The snorkel bit where It places the actual air inlet as high as possible is a great idea I think. I'm going to throw a K&N panel filter in my stock box and call it good.

I wasnt dismissing CAI overall-on some vehicles they can make a significant difference. Fact is, for the KJ it's only a 1.8% (peak gain. The again, as someone pointed out, there's always NO2. :roll:

performance mods?

Who is online