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Posted: 8/19/2004 11:20:23 AM EST
I have a '95 Wrangler and I want to squeeze some more juice from the motor. I have the 4.0 inline 6 cylinder with a manual tranny. I have always heard good things about Jacobs electronics and I was thinking about getting their electrical upgrades. coil/ignition/wires etc. Anyone tried this before? I really like the fact that it is a matched set of everything.

Also I want to get a new exhaust system, but I want to keep it as quite as possible while still getting some power. I know these 2 dont go together but what will be be the best a quite result? Should I even mess with a header or do the stock manifold work good enough?
Link Posted: 8/19/2004 11:51:42 AM EST
stuff a small block in it................

updating the ignition will do just about jack shit for you. first, increase your exhaust flow (i.e. header, real exhaust) then work on your intake (i.e. high flow filter and cold air induction kit) THEN start playing with the other shit
Link Posted: 8/19/2004 11:53:39 AM EST
forgot to add about the exhaust

flowmasters are pretty damned quiet, go there. also, an engine with headers as opposed to stock manifolds, when on the same exhaust system will actually be quieter. all about smoother flow.............
Link Posted: 8/19/2004 11:59:04 AM EST
[Last Edit: 8/19/2004 11:59:43 AM EST by slo5oh]
See if Vortech sells a supercharger for it.

Otherwise +1

stuff a small block in it
Link Posted: 8/19/2004 12:07:53 PM EST
[Last Edit: 8/19/2004 12:11:09 PM EST by CR_OPSO]
Quick and inexpensive - K&N and a TBI spacer (Poweraide, I think) seemed to help my '98 4.0 with 80K miles on it. The exhaust was next on my list, but I sold it before I got around to it.

Oh - I also replaced all the normal stuff when I got it since the miles were pretty high (cap/rotor, plugs, plug wires, etc).

CR
Link Posted: 8/19/2004 12:09:12 PM EST

Originally Posted By Snorkel_Bob:
I have a '95 Wrangler and I want to squeeze some more juice from the motor. I have the 4.0 inline 6 cylinder with a manual tranny. I have always heard good things about Jacobs electronics and I was thinking about getting their electrical upgrades. coil/ignition/wires etc. Anyone tried this before? I really like the fact that it is a matched set of everything.

Also I want to get a new exhaust system, but I want to keep it as quite as possible while still getting some power. I know these 2 dont go together but what will be be the best a quite result? Should I even mess with a header or do the stock manifold work good enough?



Those improvements are so minor you will not notice them. Get a supercharger. Kenne Bell, Avenger, etc.
Link Posted: 8/19/2004 12:09:39 PM EST
Making more power isn't as easy as adding just one thing but a sum of all the mods together.

A more free flowing exhaust won't do much if you still have a restrictive intake and vice versa. Also adding more spark won't do much by itself if you don't add more fuel and air.

There are tons of Jeep I6 accessories and mods. Quite a few companies sell kits online.

Remap the ECU or add a chip, bigger injectors, a more free flowing exhaust and an aftermarket intake(if they make one) would be a decent combo for more power.
Link Posted: 8/19/2004 12:10:04 PM EST
well sure, do a basic tuneup on it if you haven't already!!!!!!! just don't spend 9000 dollars on trick ignition components because you won't even be able to tell the difference if you don't do any other modifications

also, jeeps are notorious for shit buildup in the fuel rail, take it and get it flushed and you'd be surprised at the difference, i was
Link Posted: 8/19/2004 12:12:06 PM EST
Small block if it's possible, upgrading ignitions only make a diff on HiPo motors and do dick on stock engines. I'd start off with a cold air intake, SS freeflowing catback exhaust system and new plugs, wires, cap and rotor does wonders. New fuel filter and a good engine flush helps too.
Link Posted: 8/19/2004 12:14:56 PM EST
My neighbor and good friend has a little newer Wrangler, his has the coil springs.

He installed the Jacobs ignition system, larger dia. exhaust and tail pipe, and a K&N filter. I don't remember if the intake snout is original or not. The filter is cone shaped and installed behind the right headlight. But both intake and exhaust manifold are stock. It's a great running Jeep. Hell, it thinks it's a sports car not a Jeep.

Really all he did was free up the intake and exhaust tracts and added a hotter ignition. I would recommend this same type of set up.
Link Posted: 8/19/2004 12:19:00 PM EST
Get a K&N FIPK or some other cold air intake; that'll help a lot.

There are several tuner chips out on the market (stay way from Jet, though)...they'll also help a bit.

There are several companies that manufature superchargers and I think turbochargers for them as well...that's a bit expensive, but it also works.

Or, you can do what a lot of rockcrawlers have done...and that is put a Corvette engine into the jeep. The conversions are out there. (Older Vettes...late 80's/early 90's vintage) That'll make the jeep scream
Link Posted: 8/19/2004 12:19:10 PM EST
Kinda O/T, but I know according to www.jeepsunlimited.com, a KJ with a chip loses power on a dyno.

May wanna mosey over there for engine/make/model specific information.
Link Posted: 8/19/2004 12:31:20 PM EST

Originally Posted By CavVet:
Kinda O/T, but I know according to www.jeepsunlimited.com, a KJ with a chip loses power on a dyno.

May wanna mosey over there for engine/make/model specific information.




Is that with other mods or just a chip by itself.
Link Posted: 8/19/2004 12:38:04 PM EST
well if you had the money? 383 stroker, turbo 350 tranny, atlas II transfer case, driveshafts(they will twist and break into believe me), gears. i put some of this stuff in my boss's 89 TJ it will ever bit fly, from a stop light it is sooo funny, gas on it and it will tote the front tires for a few feet. talking about making rice burners look like crap! well actually they are...
but my boss is a pharmacist, so hes has the $$$$
Link Posted: 8/19/2004 1:04:28 PM EST
Let me give you the cold reality of building engines and making power...

It costs big money and its not easy.

On a modern, well running engine, chips, exhaust, throttle body spacers, ignitions are not going to buy you any substantial horsepower gains. The only thing they are good for is separating you from your money. The only reason you will feel faster is because your wallet will be lighter.

In order to make your rig faster there is only one thing you need to do. Feed it more gas and air. You can do this the old fashioned way, with cubic inches or you can go with some form of forced induction.

Kenne Bell makes a supercharger that is very nice. Not sure if it is CA legal.

4.0 supercharger

Many posters also talked about engine swaps. In CA, to be legal you need an engine newer than the one you are replacing AND you need to retain all the emission. Any V-8 out of a Camaro or Caprice is an easy swap. M.O.R.E. makes engine mounts that bolt-in, so does Advance Adapters.

With any serious horsepower upgrades, you had better seriously evaluate the crappy tranny and axles that came stock on that Jeep. The horsepower available out of V-8 will rip the guts out of the stock stuff.

You didn't mention if you have gone to bigger tires already or not. If you have, its time to change your gears. Think 4.56 or so.

My Jeep setup? Chevy motor going into an NP435 and twin 44's, 4.10's and 35" BFG's

Good luck,

-Z

Link Posted: 8/19/2004 1:08:48 PM EST
Ding ding ding.... crimson trace is the winner.

Wanna feel like you have more power? Are you running oversize tires?

Re-gear to the appropriate ratio. You jeep probably came with 3.07's. That was a total compromise gearing for mileage. If you are running 31's-32's, 3.73's are great. 4.10's for 33's.

If you are running bigger than 33's, then there are too many other issues to look at than simple gearing.
Link Posted: 8/19/2004 1:09:28 PM EST
[Last Edit: 8/19/2004 1:12:01 PM EST by chrome1]
The 4.0 was and is a stout motor , but it will never be a HP monster . It was designed for
torque ( Which It Makes in a big flat band) . Aftermarket ignitions wont give you any noticeable seat of the pants gains . The real problem with many CJ/YJ's was that they are under geared .If you bumped up the tire size you only worsen the problem . The best way to improve scoot is a gear change . If you have the bucks ARB air lockers front and rear , sporting 4.11's and 31x10.50 LT15's . is damn near a perfect match for the engine/vehicle . While giving you great off road grunt and still do 75 mph in 5th gear without winding up the RPM's to the sky .

You could just do the gear swap , but the air lockers flat out kick ass in the rough stuff .
Link Posted: 8/19/2004 1:20:55 PM EST
Well turbos/super-charges and engine swaps are a no go. I just cant get into that boat right now with my only daily driver.
Im not looking for another 100 + ponies. I just want to make the most of the motor I ve got. I already have the K&N intake cone filter. This was my first choice as the intake of air is the limit to making power on any engine.
Just wondering if the Jacobs is worth the money. I had used Accel products on my El Camino and liked what it did. But I have heard Jacobs stuff is much better.

Plus I like talkin to you guys here, more chances to get into a gun conversation
Link Posted: 8/19/2004 1:32:32 PM EST

Originally Posted By chrome1:
The 4.0 was and is a stout motor , but it will never be a HP monster . It was designed for
torque ( Which It Makes in a big flat band) . Aftermarket ignitions wont give you any noticeable seat of the pants gains . The real problem with many CJ/YJ's was that they are under geared .If you bumped up the tire size you only worsen the problem . The best way to improve scoot is a gear change . If you have the bucks ARB air lockers front and rear , sporting 4.11's and 31x10.50 LT15's . is damn near a perfect match for the engine/vehicle . While giving you great off road grunt and still do 75 mph in 5th gear without winding up the RPM's to the sky .

You could just do the gear swap , but the air lockers flat out kick ass in the rough stuff .



The flat torque band is a function of the I6 design. My Ford 300 I6 has the same properties.

The gear swap is also a good idea, I swapped the 3.08s out for 4.10s and wish I had went with 4.56s in my F150.

The gear swap totally changed my truck, it had some balls. Balls enough to shear the extension housing transmission mount in half.


Link Posted: 8/19/2004 1:33:56 PM EST
Given what you are telling us, the best you can do for that motor is to let it run like it was DESIGNED to.

Give it fresh, properly gapped plugs; new OEM spark plug cables, check timing and distributor advance. That's the best you can hope for.

Again, that other crap is just jerking yourself off, for VERY little gain.

-Z
Link Posted: 8/19/2004 2:28:18 PM EST

Originally Posted By chrome1:
The 4.0 was and is a stout motor , but it will never be a HP monster . It was designed for
torque ( Which It Makes in a big flat band) . Aftermarket ignitions wont give you any noticeable seat of the pants gains . The real problem with many CJ/YJ's was that they are under geared .If you bumped up the tire size you only worsen the problem . The best way to improve scoot is a gear change .



You speak the truth, brother.


If you have the bucks ARB air lockers front and rear


Whoa nelly! Now, lockers are nice, but they wont have anything to do with this issue. Lets keep it clear and simple. You DONT run lockers on the street, and while they help offroad traction, they arent related to HP gains....


sporting 4.11's and 31x10.50 LT15's . is damn near a perfect match for the engine/vehicle


Seems a bit low to me. Good for crawling... but I'd rather see a 3.73 for a 31" tire on a 4.0/AX15/NP231 combo. Personal opinion at that point tho, I will give you that.


You could just do the gear swap , but the air lockers flat out kick ass in the rough stuff .



Aw, just get lock-rite's if all you are gonna do is run 31's! Air lockers are for the big boys. You must own a Rubi.
Link Posted: 8/19/2004 2:36:14 PM EST
When it comes to making HP, think of an engine as a big air pump, the more air you can make flow through with the least effort the more HP you will make.
Link Posted: 8/19/2004 2:44:09 PM EST
[Last Edit: 8/19/2004 2:46:06 PM EST by Cableman]
You need a stroker kit for that inline 6 - turns the 4.0 to a 4.7 liter with 260+ hp and 350+-ft lbs
Cost is $2000 for the kit.

www.rockcrawler.com/techreports/stroker40/index.asp
Link Posted: 8/19/2004 2:50:35 PM EST

Originally Posted By Crimson_Trace:
Given what you are telling us, the best you can do for that motor is to let it run like it was DESIGNED to.

Give it fresh, properly gapped plugs; new OEM spark plug cables, check timing and distributor advance. That's the best you can hope for.

Again, that other crap is just jerking yourself off, for VERY little gain.

-Z



+1 to Crimson_Trace.. I'd hazard a guess that playing too much with gearing, forced induction, or aftermarket engines will greatly affect the reliability of the vehicle for "daily driver" duties. You start getting into gearhead mods, you WILL start getting into gearhead (read: spectacular and/or bizarre) failures. My recommendation would be to address the abovementioned maintainance tips and work towards optimal use of what you got. I learned that the hard way with an '89 Bronco that had (and still has, 2 owners later) a real talent for sucking funds. The worst lesson included a field trip.. Me sittin on the side of a road in bumfuck PA for about 9 hours with melted plug wires, but we're not even gonna go there.
Link Posted: 8/19/2004 2:56:45 PM EST
Buy the Banks set up. I forget the name of it, but it has headers, exhaust and intake. Then buy a chip and re gear. Or just get a small block.
Link Posted: 8/19/2004 2:59:00 PM EST

Originally Posted By CR_OPSO:
Quick and inexpensive - K&N and a TBI spacer (Poweraide, I think) seemed to help my '98 4.0 with 80K miles on it. The exhaust was next on my list, but I sold it before I got around to it.

Oh - I also replaced all the normal stuff when I got it since the miles were pretty high (cap/rotor, plugs, plug wires, etc).

CR




I second the K&N FIPK with the larger throttle body..the spacer was worthless. I also upgraded the ignition system with a Kolak ignition system. You find it on Jeeps Unlimited.com. Magnecor wires, new brass contact rotor, MSD coil, new thermostat. My '96 ZJ gets up and moves..I have 160 k miles on it too. The quickness is night & day of what it was before.
Link Posted: 8/19/2004 2:59:28 PM EST
I'm stuffing a 455 Pontiac in mine!
Link Posted: 8/19/2004 3:05:35 PM EST

Originally Posted By Combat_Jack:
Buy the Banks set up. I forget the name of it, but it has headers, exhaust and intake. Then buy a chip and re gear. Or just get a small block.



JCWhittney.com has that kit I believe.

Where a pic of this jeep?
Link Posted: 8/19/2004 3:14:05 PM EST
Is this what you are looking to do???



MT???
Link Posted: 8/19/2004 3:29:12 PM EST
[Last Edit: 8/19/2004 3:32:21 PM EST by 3-gun]
Take a look at this site. www.hescosc.com. Lee Hurley is the owner in Birmingham al. No one better when it comes to a Jeep.

Do over!
Link Posted: 8/19/2004 3:59:14 PM EST
[Last Edit: 8/19/2004 4:12:23 PM EST by Lion_Dog]
IIRC, 2003 Hunting Season I came across an article outlining a NET 25-35 HP boost for about $1000 on Jeep Cherokee 4.0

If I find it I'll try to post it.

ETA: And you can do it in three incremental stages.
Link Posted: 8/19/2004 4:05:41 PM EST

Originally Posted By Cableman:
You need a stroker kit for that inline 6 - turns the 4.0 to a 4.7 liter with 260+ hp and 350+-ft lbs
Cost is $2000 for the kit.

www.rockcrawler.com/techreports/stroker40/index.asp



One of my friends at work is doing a stroker build on a 4.0 for an XJ. He has an old XJ, and he bought (I think) the newer HO 4.0 to do the stroker build on.

I follow his build because my '88 XJ/4.0 has over 300k miles, and someday it may need a new engine (although I think I'll have to replace the Peugeot BA-10 tranny first, I'm thinking NV 4500 . . .).
Link Posted: 8/19/2004 4:07:31 PM EST
Another friend had a 2.5L I-4 XJ. He put in a (I think) 318 Dodge V-8. Veeeery expensive build, should have bought the 4.0 and did the stroker instead (IMO).
Link Posted: 8/19/2004 4:14:45 PM EST


There she is, but now she has 33x12.50 BFG mud terrains.
I know gears should be the first thing I do. Im just holding off till my buddy finds me a Rubicon that got smashed. He owns a wrecking yard/tow business. I want the Dana 44's off of one.

Anyone know of a place that has OEM dash panels for the Jeeps? Ive searched around but all I find is aftermarket accessories.
Link Posted: 8/19/2004 6:09:17 PM EST

Originally Posted By Snorkel_Bob:
www.imagestation.com/picture/sraid43/p3fbd1e3f8bc3d30f1add160bdade8f75/fce9a19b.jpg

There she is, but now she has 33x12.50 BFG mud terrains.
I know gears should be the first thing I do. Im just holding off till my buddy finds me a Rubicon that got smashed. He owns a wrecking yard/tow business. I want the Dana 44's off of one.

Anyone know of a place that has OEM dash panels for the Jeeps? Ive searched around but all I find is aftermarket accessories.



Your problem is your 33" tires. Thats it in a nutshell. You cant even use 5th gear with those 3.07's. That gear ratio was designed for 30" tires, and even then it was applied for the best mileage.... not power in mind. Many stock Jeep owners with stock tire sizes and 3.07's complain about their 5th gear and poor accelleration performance on the street.

I understand tho, you dont want to regear if you are going to upgrade the axles.... and if you do any serious wheeling the Dana 35 will not hold up.

Screw all that other crap. Gearing is what you need to get back that performance, and 4.10's are perfect for that size. If you think you might ever run bigger (35's), go with 4.56's.

Also, keep in mind, if you ever get in water a lot... those K&N kits are bad news, unless you also buy the K&N wrap designed for water crossings. Stock or snorkel is so much better for offroad use. K&N's are for mall crawlers.
Link Posted: 8/19/2004 8:28:28 PM EST
Well I dont mess with water all that much, we only get average 10 inches a year here. But I am in a heavy farming area and with all the dust in the air stock air filters get clogged pretty quick. K&N gave me some more power and let me clean it pretty easy.

I was actually thinking about 3.73's just so I can keep some freeway miles. I dont crawl this beast that much. But I dont want to bog down in 5th like I am right now.
Does anyone have the equation for figureing out final drive gear ratios? I had it lying aorund but I cant find it now. Does putting 4.10's give you a final drive ratio that is comparable to stock?
Link Posted: 8/19/2004 8:33:39 PM EST
Buy the axles off a 2.5L equipped YJ, it comes with 4.1 gears. You can bolt them on in your driveway. They are geared right for your 33s. This is the same axle gear ratio as the Rubicon Dana 44.
Link Posted: 8/20/2004 10:46:19 AM EST

Originally Posted By Snorkel_Bob:
Well I dont mess with water all that much, we only get average 10 inches a year here. But I am in a heavy farming area and with all the dust in the air stock air filters get clogged pretty quick. K&N gave me some more power and let me clean it pretty easy.

I was actually thinking about 3.73's just so I can keep some freeway miles. I dont crawl this beast that much. But I dont want to bog down in 5th like I am right now.
Does anyone have the equation for figureing out final drive gear ratios? I had it lying aorund but I cant find it now. Does putting 4.10's give you a final drive ratio that is comparable to stock?



3.73's wont be enough, and you will be sorry with 33's, even on the highway. Trust me. You want 4.10's.

You could buy someones TJ axles from a 2.5L like Jack stated.... but you would still have a Dana35, which is weak. However, if you dont wheel a lot or hard, and you dont lock the Dana 35 axle with a locker, then it is plenty strong for your needs, and I wouldnt wait around for a Dana44. You can find 4.10 gearing easily, used.... but it would be easier to swap axle for axle, I think.... and cheaper, cause you can sell your axles, or keep the axle shafts for trail spares.
Link Posted: 8/20/2004 11:09:49 AM EST
Whoa, whoa, whoa... slow the heck down.

Gears.
With 33" tires and 4.56 gears you are running 2100 rpms at 60 mph. 2450rpm @ 70
With 33" tires and 4.10 gears you are running 1900 rpms at 60 mph. 2200rpm @ 70
With 33" tires and 3.73 gears you are running 1700 rpms at 60 mph. 2000rpm @ 70

This assumes your tranny has the .75 OD, which is does.

So you need to be honest about how fast you really want to go on the street. The lower gears make a big difference off-road.

Here is a link so you can do the ratios yourself:
gear ratio calculator

As for axles, you are on the right track. The stock axles, expecially the rear, are junk and not worth putting money into.

Here's a couple options for you:

1) Wait for the 44s out of a Rubicon or upline TJ. These will be VERY expensive as it was a rare option and they are in high demand.

2) Pull an 8.8 inch rear out of an Explorer or other compact Ford pickup.

3) Wagoneer 44s or 30s make excellent swap candidates for the front. Although you will have to get it retubed on one side to get the pumpkin to the left (wrong) side.

-Z
Link Posted: 8/20/2004 11:47:21 AM EST

Originally Posted By Snorkel_Bob:
Well I dont mess with water all that much, we only get average 10 inches a year here. But I am in a heavy farming area and with all the dust in the air stock air filters get clogged pretty quick. K&N gave me some more power and let me clean it pretty easy.

I was actually thinking about 3.73's just so I can keep some freeway miles. I dont crawl this beast that much. But I dont want to bog down in 5th like I am right now.
Does anyone have the equation for figureing out final drive gear ratios? I had it lying aorund but I cant find it now. Does putting 4.10's give you a final drive ratio that is comparable to stock?




K&Ns are pretty risky is high dust areas. I used K&Ns until I realized that I will be money ahead by using paper filters rather than risk cylinder scoring.

Paper filters every oil change are very cheap in comparison.

There's a forum dedicated to everything including oil and air filters. There's quite a bit of negative feedback on K&Ns and those same style filters.

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