Current Performance/Engine Modifications List
"Kolak" Ignition Upgrade
Purchased From: Kolak@aol.com
Price Paid: $165 Shipped
Date Purchased: 8/11/04
Date Installed: N/A
Impressions: My Jeep was in heavy need of a tune up, so instead of going with stock parts I figured if I need to replace them anyway, why not replace them something better. So I went to Nick, aka Kolak and ordered his 4.0 ignition upgrade, The �Kolak Ignition Upgrade� Consists of the following components.
- Magnecor KV85 Ignition Wires
- MSD High Output Replacement Coil
- Autolite Platinum Plugs
- Niehoff Heavy Duty US Made Brass Terminal Distributor Cap With Rotor
The parts are sitting in my room waiting to be installed and I will post my impressions of the mod once I have it installed.
Jeepers and Creepers 60mm Bored Out Throttle Body
Purchased From: www.jeepersandcreepers.com
Price Paid: $90 Shipped (After $125 Core Refund and $20 Blemish Discount)
Date Purchased: 8/15/04
Date Installed: 8/25/04
Impressions: I decided to get the J&C bored out throttle body to go with my K&N intake; I figured that I would feel the gains more with the combination of the two mods, rather than doing one then the other at a later point. I was originally going to go with a 62mm TB, but after some research found out that 60mm was fine and that 62mm would offer no real benefits unless I had plans to do internal engine mods (which I do not). What J&C does it takes a used throttle body off of a 4.0 Jeep, cleans it up and bores out the 55mm taper that is below the throttle plate. Then the whole TB is 60mm straight though and this in turn increases airflow and the amount of air that is let into the engine. J&C does not include the electronics (IAC and TPS sensors) on their throttles bodies because they could be in �questionable� quality. So you need to simply remove and reuse the sensors from your stock throttle body.
Yes I was a bit worried because I was getting a used throttle body, but I was relieved when I saw how well it was cleaned up, it looked much better than the one that was one my Jeep! J&C also gave me a $20 blemish discount. I am not 100% sure but I think that the �blemishes� that they are referring to are some slight imperfections where the TB was bored out. There where a few extremely shallow �pits� about the size of a needle point that where present under the throttle plate where the TB was bored out. J&C mentions in the instructions that �blemishes� will not affect performance in any way (and I don�t see how they could). And I have all done a bit of research and found out that these �pits� are a common and normal thing when boring out throttles bodies. I was surprised that they gave a discount for such a minor thing, they could have just as easily not and I would have never known.
I would like to mention how good of an experience I had with J&C. First off my TB was here in just under a week, and they are located across the country from me. Secondly I had a question about the TB before I installed it, it was missing something that my stock TB had, the raised bar that runs horizontally across the top of the TB plate (see this picture if you don�t know what I am talking about http://www.accuratepower.com/Jeep/Throttlebody.html) so I emailed J&C about it and James quickly got back to me reassuring me that the removal of the bar is a feature of the TB to improve airflow, and that it does not have any negative effects. The helpful people on the Jeeps Unlimited forums also said the same thing.
After the TB and FIPK where installed I noticed a whistling noise at certain RPM�s, it was not too loud and sounded petty cool but I first thought it might be an air leak, but then ruled that out after checking all my connections, plus the fact that are air leak noise would be present at all RPM�s. I again emailed J&C about this to make sure it was normal. Again James quickly got back to me saying that the K&N air filter �whistle� is a common thing, and that the bored out TB makes it more noticeable as it lets even more air into the engine. He also gave me a few things to try to get rid of the whistle; one was to rotate the filter 90 degrees. I also searched a bit on Jeeps Unlimited and indeed find out that the whistle is a common thing with the FIPK and or a bored TB. Now here is the thing that really surprised me, a bit later that day I checked my messages and James had left a message on my machine, basically saying what he wrote in the email, and telling me to call him if I had any more questions. Now to me that right there is good customer service! I would defiantly recommend J&C and would order from them again! For impressions on the install and performance scroll down the page a bit.
K&N FIPK Intake
Purchased From: www.crutchfield.com
Price Paid: $230 Shipped
Date Purchased: 8/23/04
Date Installed: 8/25/04
Impressions: After a long time of wondering if this mod was worth the money and after reading many other owners� options on it, I finally decided to go for it. I originally ordered the intake from Sounddomain.com for $225, but my order was backordered, so I canceled it and ordered it from Crutchfield.com instead. It was only $5 more (had free shipping) and they had only one left in stock, as after I ordered it, the site said it was on backorder! It shipped the same day I ordered it and was at my house two days later, talk about good service! The build quality of the K&N is top notch, everything fit perfectly and I had no problems with the install. Yes the kit is a bit expensive, but I think it is well designed and worth the money. For my impressions of the install, performance and sound see below.
Impressions of Installation, Performance and Sound Of The J&C TB and K&N FIPK
Since I installed these two mods together I decided to go over my impressions of the install, performance increase and the sound here. First off the install, it went smoothly, took about two hours and was a fun confidence booster for someone like me who has somewhat limited mechanical knowledge. The instructions for the FIPK where very detailed and easy to understand with good pictures, the instructions for the TB where decent enough, no pictures but they are not really needed as installing a TB, as it is pretty straight forward. One mistake I made during the install was I forgot to take the IAC�s o ring off of the stock throttle body, I realized this when everything was just about done, so I had to take the intake and TB back off to put the o ring in. J&C�s instructions mentioned this, and I had read it the night before, but I just totally forgot to check for it inside the TB at the time. Other than that the only other real �problem� that I ran into was trying to get the negative battery terminal undone (as recommended by the instructions to reset the ECU). I ended up not doing it the day of the install but instead played with it more the day after and finally got it off, and reset the computer.
Now the performance gains, I was a bit skeptical about these mods and whether or not I would be able to �feel� the difference that they made, well the short answer is yes, I can feel a difference. Throttle response is definitely much better, and makes the Jeep feel much livelier at any speed. I need less petal pressure to get me moving to the same speed that before would require more pressure. The Jeep holds gears much better now as well, and does not (nor do I feel the need to) have to kick down to a lower gear as much (except on the highway). Also the lag that I was experiencing around 2,000 RPM�s mainly in second gear is just about completely gone. Before if I would take a turn onto a street without slowing down enough for the tranny to downshift into first gear, when I would go to accelerate with the Jeep at around 2000 RPM�s It would just be really unresponsive and I would have to kick it down (or it would kick down itself) to first in order to get going, esp. if I was going up a hill! But know the Jeep moves right though that range with hardly any lag and it no longer kicks down nor do I need to kick it down. As for the acceleration increase, it is not huge but it is defiantly there, mostly off the line and when merging on the highway between 40 and 60. Off the line I get more of a pushed back feeling and the Jeep takes off quicker, and when merging on the highway if I am doing around 45 and kick the tranny down it gets up to 60-65 a bit quicker than before. Also if I punch it and kick the tranny down at any speed the Jeep gets going quicker and seems to push you back a bit (which could be the torque increase).
Then the sound, I had heard everyone who owned a FIPK say that it sounded great and even made their 4.0 sound like a V8 when it was floored. Even after hearing what everyone was saying I still did not think it would sound as good as it does. It really surprised me the first time I floored it. Up until about 3000 RPM�s it is silent but once over that it roars and gives the 4.0 a very nice deep hum, It really could pass as a V8. I cannot stop opening it up just to hear the sound it makes, it really does sound incredible! And the whistle it makes actually sounds cool too, it is not too loud to the point of being annoying and sometimes it makes the noise right after the Jeep shifts and the sound resembles a turbos blowoff valve. So overall for $320 where these two mods worth it? Yes! They did not make an earth shattering difference, but I did not expect them to, they did pretty much just as I expected, made a very noticeable difference in throttle response and a fairly slight but noticeable difference in acceleration as well. I am not looking to run fast quarter mile times with this vehicle, but I am looking to improve overall drivability and that is exactly what these mods did. Plus they added a great sound to my Jeep, something I have really been wanting. I would defiantly recommend the J&C TB and K&N FIPK!
�Kolak� Cat-and-Back Exhaust
Purchased From: Kolak@aol.com
Price Paid: $406 Shipped
Date Purchased: 3/18/05
Date Installed: 4/1/05
Impressions: So my exhaust finally gave, it got clogged, was leaking somewhere and needed to be replaced, I had been waiting for this day and it happened around the time I got my tax return, which was nice. I went to Nick (Kolak) and ordered infamous his cat-and-back setup which consists of the following.
- 2.5� Magnaflow/Car Sound Cat Converter (Part #94006)
- 2.5� Large Case Magnaflow Muffler (Part #12586)
- 2.5� Custom Made Mandrel Bent Tailpipe
- 3� Magnaflow Stainless Steel Exhaust Tip
I think all this for $406 shipped is a great deal, as most cat-backs alone (Borla, Gibson, ect.) go for around $350-400 before shipping. For the install I brought my Jeep to Lou�s Custom Exhaust in North Reading, besides installing my parts I also had them make me up a 2.5� down pipe. I think they did a very good job (check out the pics) and they only charged me $150 ($80 for the install, $70 for the down-pipe), you can also watch them while they do the work if you please, I would recommend them.
So how is the performance gain? So far it is great and very noticeable. Throttle response has improved a lot and I find my self-going 45-48 without noticing, because the same pedal pressure that used to get me to 40 now gets me there. There are some who say that a 2.5� diameter exhaust on the 4.0 will hurt low-end torque, I have found this to be untrue. In fact low-end torque has improved a lot, the Jeep is much quicker off the line now and throws you back a bit more. It also pulls a lot quicker/easier though the gears even at part throttle. Merging onto the highway is also better and I can do it much easier without needing to kick the tranny down a gear. On the highway part throttle acceleration is better and I can get from 70 to 85 for example easier, and kicking the tranny down really gets me up to speed. For anyone wondering the exhaust has made a bigger difference in throttle response/accleration than the throttle body/FIPK did. Overall drivability has improved a lot which is great and was just what I was hoping for.
How this system would sound had me really worried. I was also torn between the Magnaflow and the Flowmaster 70 series muffler. I went with the Magnaflow based on the fact that I had heard mixed things on Flowmasters with the I6, some people said they sounded good, but others said they sounded ricey, tinny, raspy or made their Jeep sound like a UPS truck, but most everyone with the Magnaflow seemed to be happy with it, plus I think its straight though design offers a bit better performance and since everyone has Flowmasters, they are becoming pretty generic. I wanted something a bit louder than stock that was deeper and more aggressive, but not something that was annoyingly loud or ricey sounding. When you start it up it sounds good, it is pretty quiet but noticeable and sporty sounding. At idle it is also quiet but has a bit of a sporty tone to it and you can tell it is there. It sounds really sweet in the 1,000-1,500 RPM range when first starting off or going slow though parking lots and such, it has a really nice deep mellow tone to it. I am really happy with the loudness level of the muffler, at cruising speeds on the streets and highway you can barely hear it. It really only becomes pretty loud around 2,000-3,000 RPM�s in the lower gears, the best way I can describe the sound it makes in that range is a deep hum, the hum sounds similar to the sound that the FIPK makes when you get on it, but it is a bit buzzy. On the highway when you are in overdrive and in the 2,000-3,000 RPM range you just hear a quiet but pleasant and deep mellow tone. Just accelerating though the gears at normal speed it is fairly quiet but you know its back there, It makes the Jeep sound like a sporty or tuned 6 cylinder rather than a wannabe V8 (something I didn�t want it so sound like). When you floor it you get a deep hum for a bit and then the FIPK takes over once the Jeep gets past 3,000 RPM�s, which is good because I did not want the sound of that to be drowned out, and since the muffler sounds similar to the FIPK the two blend together nicely. I had a friend drive my Jeep so I could hear how it sounded on the outside; I was very surprised to hear how good it sounded! In the low RPMs it sounded nice, quiet but had a tone to it and you knew it was not stock, and when he gave it some gas it sounded great, it was really deep and did not sound that buzzy like it does from the inside and it defiantly does not sound ricey at all. Overall I am pretty happy with the sound, I don�t think it sounds awesome and it does not compare to a nice healthy V8 sound (which I love), but you are never going to get a 6 to sound like an 8 so I would rather it sound like a sporty 6 than a wannabe 8. I am also really glad I got a pretty quiet muffler, yeah a loud one would be fun for a mouth or so, but then I could see it driving me crazy, but I can defiantly live with the Magnaflow, I still wonder how the Flow 70 would have sounded though, but then again if I got the Flow I would be wondering how the Mag sounded, so you cant win.
Performance Modifications/Engine Pictures
Future Performance/Engine Modifications List
Optima Red Top Battery (When My Current Battery Dies)
Mike Leach or Banks Header
Page 1: Intro/News and Updates
Page 2: Appearance/Exterior
Page 3: Performance/Engine (You Are Here)
Page 4: Suspension/Brakes
Page 5: Audio/Interior
Page 6: Off-road
Page 7: Misc.