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Performance Mods List
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=4&t=17536		 Page 1 of 2
Author:  KY Liberty [ Sat Feb 10, 2007 5:49 pm ]
Post subject:  Performance Mods List
Since I get so many questions about how to upgrade the performance of the 3.7, I thought it would be a good idea to post a list.

1. You need to stop the computer from limiting the power. Stock, it will measure the torque being generated, and plug that into a table that determines if it should retard the timing to reduce the power. You need a B&G PCM flash to correct this. It will also advance your timing, change your fuel curves, raise your rev limiter, and help your shifts. This upgrade can be used on a stock 3.7, or with an intake, exhaust, headers, and a mild cam upgrade. This is really the first upgrade you should do.

2. You need to get more, colder air into it. You need an upgraded throttle body from The Fastman. If you don't off road, or live in a dusty area, you can upgrade to a drop in filter, or a cone intake with a heat shield. You can use an off road bag on the cone in dusty areas or temporary off roading. Just don't go through very deep water. To get optimum performance from the cone filter, you need to at least do the $4 cold air intake mod. That is, use a flexible accordian style gutter drain pipe to bring cold air around the radiator. You can also get a ram air hood from Profinish-Proglass that will dump air right where the opening for the stock intake is if you remove the top curve from the snorkel. It can be enlarged, and will dump air right on top of where the cone filters sit, bringing so much air that it creates a small ram air effect. You can modify the heat shield, and create an increase in the ram air effect.

3. You need to get that additional air, and the increased fuel the computer will compensate with, out of the motor. JBA manufactures headers for the '05 Liberty and up. They are currently working on headers for the '01-'04. These headers will help scavenge some of the exhaust gasses. At least upgrade your muffler, and make sure you get rid of the slight decrease in diameter right by it. A complete cat back system can give you an additional increase.

4. You need to get the power to the ground. The stock 42rle and 45rfe automatic transmissions are set up to shift slow, and comfortable. This is bad for both performance and reliability. A Transgo shift kit will allow the valve body of the transmission to be modified. This will make it shift much quicker and firmer. The quicker shift means less slipping and less time being partially engaged in 2 gears during shifts. It also increases the line pressure and helps it lock up better. An upgraded torque converter from APS will increase the automatic transmission's effeciency to around the same as the manual transmission. Also the torque multiplication can be raised. The stall can be raised if you're interested in being able to launch.

5. You can go to 4.10 ring and pinion gears. This gives you a lower gear ratio and allows the motor to wind up the rpms quicker. The motor will be putting more power to the ground at the same speed, since it's at a higher rpm. This is helpful if you have gone to larger tires, to correct for the difference in diameter causing a power loss. With stock diameter tires, or only slightly larger, it will increase acceleration. You do pay for this though on the high end. There are aftermarket gears for the rear, but you need Mopar for the front, or the front end from a 4 cylinder Liberty.

6. You can upgrade the cams. The Fastman can make bigger cams for the 3.7. To make low rpm power, with a cam similar to the 4.7 HO, you can get some 200's. For mid to high rpm with a higher peak torque you can get some 206's. You could also get the heads ported while they're taken apart.

7. You can upgrade to custom pistons. The bore of the 3.7 pistons is the same as the 4.7 which there are aftermarket pistons for. Would not be difficult to make pistons for the longer stroked 3.7. This is necessary if you are going to run any kind of boost or nitrous. The rings are too high on the pistons and the ring land tends to chunk off.

8. You can add nitrous, a supercharger, or a turbo. This is very risky and should only be done on a built motor with forged pistons. More information on this will have to be in another post.

http://www.bgperformancepcm.com/
http://www.thefastman.com/Throttlebodies37.asp
http://www.apsprecision.com/
http://www.profinish-proglass.com/
http://www.krcperformance.com/krc/
http://www.transgo.com/
http://www.ring-pinion.com/
http://www.knfilters.com/
http://www.aempower.com/
Author:  unixxx [ Sun Feb 11, 2007 1:07 am ]
Post subject: 
Awesome; hopefully, I won't bug you as much anymore :lol:

KY Liberty, you should add this info to the Jeep Liberty Wikibook Performance page: http://en.wikibooks.org/wiki/Jeep_Liberty/Performance
Author:  Troysterr [ Sun Feb 11, 2007 1:54 am ]
Post subject: 
I don't plan to do any of the mods you mention, but it's a great read, anyway. Thanks.
Author:  KY Liberty [ Sun Feb 11, 2007 11:38 am ]
Post subject: 
Glad I could help. I've corrected a couple typos, and started adding links. If an admin could sticky this, people could post their performance mods and results to this thread and I'll go back in and add the additional info to the top post as it becomes available.
Author:  Hood297 [ Mon Feb 12, 2007 6:30 pm ]
Post subject: 
well my question is...

how much should we expect to get out of each of these mods (HP/Torque)?

and how much will it help/hinder our fuel economy?

most of my on road driving is between 40-60 how much will 4.10's hurt me on the highway?
Author:  JJsTJ [ Mon Feb 12, 2007 6:46 pm ]
Post subject: 
How many miles have you put on the shift kit so far? Drill the spacer and move balls around type kit right? Anything else to it?

HOw about valve springs and keepers? THought I had read those have caused problems? Yuo still running stockers? Also, ANy 1/4 mile blasts yet?
Author:  KY Liberty [ Mon Feb 12, 2007 8:41 pm ]
Post subject: 
Quote:
well my question is...

how much should we expect to get out of each of these mods (HP/Torque)?

and how much will it help/hinder our fuel economy?

most of my on road driving is between 40-60 how much will 4.10's hurt me on the highway?


Most of these mods make less than 5% difference by themselves. It's all about good combinations to get more air and fuel through the engine, and getting as much of it to the ground as possible. Sorry, I don't run it on the dyno after each mod at $100 an hour. As for fuel economy, it depends on if you get the common accumulation of lead in your right foot after doing performance mods. Any mod that makes it more efficient can help the fuel economy, but can easily be negated by lead foot, or by the cost of the mod versus buying gas. I don't think the 4.10's would hurt you very bad at 40-60. I'm running 245/65R17's with 4.10's and saw very little difference in that range. Between 65-75 I lost about 3 mpg though. I average about 0.5 mpg less in city driving now. Hopefull someone will chime in who is running MTR's and 4.10's for a definative answer.

Quote:
How many miles have you put on the shift kit so far? Drill the spacer and move balls around type kit right? Anything else to it?

HOw about valve springs and keepers? THought I had read those have caused problems? Yuo still running stockers? Also, ANy 1/4 mile blasts yet?


I've got about 10k miles on the HD-2 shift kit for the 45RFE. There's actually quite a bit to it. I really like it. It shifts like a sport truck now.

http://www.apsprecision.com/45RFE%20Shift%20Kit/45_545RFE%20Instructions.pdf

The internals of the heads are weak. I'll add more info about them to the top post. I had my heads machined, and rebuilt with new stock valves and springs a little less than 2 years ago when the new block went in it. They're already starting to make a little noise. I think I'm going to get a ported set of heads completely built when we do the 206's. The 206's come with a kit that replaces alot of it. When I blew up the race motor, it actually only scorched 2 cylinders, and burnt up 2 of the rings. The majority of damge, and the initial breakdown was in the heads. I haven't raced with the current motor, but it could touch the 13's with a good launch and a 75 shot before.
Author:  SS-Virus [ Thu Feb 22, 2007 2:45 am ]
Post subject: 
KY Liberty:
Thanks for the great info. But I need more help:

If I have 42RE transmission, what kind of mods. to be done to it? as I don't did this before, can you please give the direct links.

More questions to come :D
Author:  Boi1ermaker [ Thu Feb 22, 2007 4:51 am ]
Post subject: 
Quote:
If I have 42RE transmission, what kind of mods. to be done to it? as I don't did this before, can you please give the direct links.

TransGo supposedly has new shift kit for the 42rle:
http://www.lostjeeps.com/forum/phpBB3/vie ... hp?t=17401

and a torque converter seems to be in the works:
http://www.lostjeeps.com/forum/phpBB3/vie ... hp?t=17405

Since those threads seem to have died, I sent APS an email yesterday requesting more info...but haven't received a response yet.
Author:  DarbyWalters [ Thu Feb 22, 2007 8:56 am ]
Post subject: 
Now a Sticky...Good Work 8)
Author:  KY Liberty [ Thu Feb 22, 2007 9:32 am ]
Post subject: 
Boi1ermaker wrote:
Quote:
If I have 42RE transmission, what kind of mods. to be done to it? as I don't did this before, can you please give the direct links.

TransGo supposedly has new shift kit for the 42rle:
http://www.lostjeeps.com/forum/phpBB3/vie ... hp?t=17401

and a torque converter seems to be in the works:
http://www.lostjeeps.com/forum/phpBB3/vie ... hp?t=17405

Since those threads seem to have died, I sent APS an email yesterday requesting more info...but haven't received a response yet.


APS doesn't have the torque converter or shift kit for the 42rle listed on their site yet. They're both brand new. I've always gotten the best results by calling and talking to Wayne. He really knows his stuff.
Author:  Boi1ermaker [ Wed Mar 07, 2007 12:31 pm ]
Post subject:  B&G Flash
Just to follow up on my last post, once i talked to Wayne he got me the info i needed to place an order. Giving him a call is the way to go, he was very helpful and got my kit in the mail quickly.

KYLiberty, i've got a couple of questions about things that need to be done before a pcm is sent to B&G for a flash.

i think i read in another thread you picked up a new pcm from autozone. Would it be wrong to assume that a used pcm with the same part number as my current pcm will work (or is going used a bad idea)? How involved is the vin and key programming; does the dealership need to install the new pcm into the vehicle before programming?

thanks in advance.
Author:  KY Liberty [ Wed Mar 07, 2007 3:44 pm ]
Post subject: 
You need to get Autocraft to put your VIN on it. A dealership will have to program your keys if you have the security built into them. Otherwise it will only run for 2 seconds and die. After I got it back from B&G, I took mine to a small dealership, the 5 star dealership wouldn't even talk to me about it, and pulled my Liberty into one of their bays. I swapped the PCM's, and then they programmed the keys for me. They said they would have to charge me an extra $50 if they swapped the PCM's since they would have to pull the battery.
Author:  Boi1ermaker [ Wed Mar 07, 2007 6:49 pm ]
Post subject: 
Quote:
the 5 star dealership wouldn't even talk to me about it

That's what i was mostly concerned with. I've got an autozone, O'reilly's and an advanced within a mile, i can ask around and see if they'll write the vin into a pcm i bought used (i.e. not from them). There's a different service manager every time i take the KJ to the local dealership, there's no telling if they'll help me or turn me away.

Thanks again.
Author:  KY Liberty [ Wed Mar 07, 2007 7:38 pm ]
Post subject: 
I actually got my spare PCM from Autocraft, not Autozone. Sorry about the mistake in the last post. I corrected it. You might call B&G and see if they can write your VIN to the spare PCM for you also.
Author:  Boi1ermaker [ Wed Mar 07, 2007 8:35 pm ]
Post subject: 
no worries, i got it started by putting autozone in my original question. I planned on calling B&G anyway when i was ready for this mod, i'll just add it to my list of questions.
Author:  KY Liberty [ Fri Mar 09, 2007 7:27 pm ]
Post subject: 
The dealership can write your VIN to it also. You just have to find one that will do it for you. Usually the smaller dealerships are better for this, especially if you have a customized Jeep. They warned me that it resets everything though. So you don't want to get it done after being flashed.

You could get a dealership to write your VIN to it, and program your keys to it. Drive it hard for a month and let it learn. Then send it to B&G. That way it will have all the info in it already. Once you get it back from B&G, just install it and you're ready to go. Also, you have the stock PCM as a spare. :D
Author:  Boi1ermaker [ Fri Mar 09, 2007 8:08 pm ]
Post subject: 
Quote:
You could get a dealership to write your VIN to it, and program your keys to it. Drive it hard for a month and let it learn. Then send it to B&G. That way it will have all the info in it already. Once you get it back from B&G, just install it and you're ready to go. Also, you have the stock PCM as a spare.

That sounds like a plan. The jeep is in for an extended visit at the dealership for some warranty work (long story). But they didn't try to blame anything on the intake, and seemed pretty cool when i told them i planned on replacing the stock throttle body, among other things. I think i'll stop by on my way out in the morning tomorrow and see how they feel swapping out a pcm for me while they are at it.
Author:  Neatus [ Sat Apr 21, 2007 7:42 pm ]
Post subject: 
Who is Auto Craft and where can I find them. I looked on the web but I think I am getting their corporate site. I think I am on the right trail though. do they have a retail type site?
Author:  KY Liberty [ Sat Apr 21, 2007 8:33 pm ]
Post subject: 
The link to autocraftdirect.com doesn't seem to work anymore. The other link on my confirmation email is

http://www.worldautopartsdirect.com/

It still works.
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