I need cheep power

[thedarkprince]

I want more power, I want to keep my wallet fatter than empty. I have a 99 with the auto tranny and 4wd. I dont offroad much with it, but more power and gas milage. I would pull searches but I really dont know what to search for!

 

[Purple]

header
exhaust
62mm throttle body
throttle body spacer

not necesarily in that order....
but before you search for all these items on naxja....
get yourself a cold intake mod and a k&n filter that will help it work/breathe better

 

[WB9YZU]

I want more power, I want to keep my wallet fatter than empty. I have a 99 with the auto tranny and 4wd. I dont offroad much with it, but more power and gas milage. I would pull searches but I really dont know what to search for!

Generally speaking power and gas milage are opposing values.

Power:
Tune up
Better header ( I hear Borla makes a good one), cat back exhaust (Borla, Flowmaster)
Cold air intake system (K&N)
Synthetic oil
Fuel system/computer upgrades

Gas milage:
Tune up
Synthetic oil (same reason as above)
Tires to correct pressure, and a "non-agressive" tread "AT"
Midgrade fuel (not the cheap low test stuff)

Use crappy "Champion" plugs and you will get Crappy performance. Use something like a NGK "V" Power plug. Use "Standard Ignition" Cap/Rotor with the Brass terminals. Use Good wires! Autolite 7mm, Accel... No bubble pack crap.
The synthetic oil will let you run a lower viscosity than you would think with the SAME protection which helps reduce windage losses. A typical example would be a 5-20W instead of a 10-30W.

 

[Dr. Dyno]

You'll find all you need to know and some at http://www.jeep4.0performance.4mg.com

 

[Chancer]

You want to get more power out of a jeep AND want to keep your wallet fat?

That's the Holy Grail, my friend - we're all trying to find it!

In fact, owning a jeep and not spending much money is in itself an oxymoron... :bawl:

You might want to search this forum for 5-90's posts - he knows his stuff. Especially see the thread on NOS - penny for penny, it has to give the best return, even if you run the risk of shafting your engine in the long term.

 

[Dr. Dyno]

You want to get more power out of a jeep AND want to keep your wallet fat?

That's the Holy Grail, my friend - we're all trying to find it!

If you can fabricate some of the mods yourself, that'll save you a bunch of $$$ and you can still enjoy the benefits. Here's some examples as they apply to the performance mods that I've done to my own Jeep:

1. My homebrew FIPK $60, K&N FIPK $250. Money saved $190.
2. My machine shop bored 62mm TB with home-made oversize throttle plate $40, Accurate Power 62mm bored TB $200. Money saved $160.
3. Homebrew MAP adjuster $9, Turbo City MAP adjuster $95. Money saved $86.
4. Homebrew oil catch can $3, Greddy oil catch can $95. Money saved $92.

Total money saved by doing homebrew mods $528!!

...and here's the ultimate one:
My homebrew 4.6L stroker engine $1136, Golen Engine Service 4.6L stroker long block $3300. Money saved a whopping $2164!!!!!!
YEEHAW.

 

[XJ_ranger]

4. Homebrew oil catch can $3, Greddy oil catch can $95. Money saved $92.

what is that one all about?

 

[Dr. Dyno]

Here's my oil catch can write-up:

http://www.angelfire.com/my/fan/Catch_can.html

 

[Bloose]

Generally speaking power and gas milage are opposing values.
[\quote]

Not at all. Increasing te efficience of the combustion process increases power, reduces fuel consumption, and reduces emmisions.

Power:
Tune up
Better header ( I hear Borla makes a good one), cat back exhaust (Borla, Flowmaster)
Cold air intake system (K&N)
Synthetic oil
Fuel system/computer upgrades

Gas milage:
Tune up
Synthetic oil (same reason as above)
Tires to correct pressure, and a "non-agressive" tread "AT"
Midgrade fuel (not the cheap low test stuff)

Use crappy "Champion" plugs and you will get Crappy performance. Use something like a NGK "V" Power plug. Use "Standard Ignition" Cap/Rotor with the Brass terminals. Use Good wires! Autolite 7mm, Accel... No bubble pack crap.
The synthetic oil will let you run a lower viscosity than you would think with the SAME protection which helps reduce windage losses. A typical example would be a 5-20W instead of a 10-30W.

I agree with most of what is here except,

Running higher octane fuel will not increase power or lower fuel consumption, it will only lighten your wallet. Higher octane fuel conains no more specific energy than lower octain fuel and will produce no benefit in a motor that does not require it. In fact it can reduce fuel economy because it has more resistance to igniting. The catch is that if you have detonation then you do need to go up in fuel grades. Also many vehicles have knock sensors that will retard timing if knock is experienced but I don't believe the 4.0 has one. With the compression the 4.0L has standard fuel should be no problem. If knock is experiences a combustion cleaner is more likely a better fix than higher octane fuel.

When using synthetic I would stay with the recommended viscosity. You should still see some advantage over regular oil from it's better lubrication and better pumpability.

Champion spark plugs do suck but they do thier job just fine. I wouldn't buy them because there are better made plugs for the same money. I would not buy fancy plugs in hopes of better fuel mileage. You can run platinums for longer life but their higher price may negate any benefit. Just run some Autolite's or AC's and change them at the recommended service intervals.

B-loose

 

[thedarkprince]

I typically run either 89 or 91 octane (low and mid here in vermont) and will run 93 once a month or so for the slight cleaning effect. So heres my plan after looking at yalls comments. I'll run mobil1 on the next oil change, make a homebrew cone filter deal with a K&N, replace the cap, rotor, wires and plugs, throw an aluminum heatshield between the EX and INT manifolds, maybe build an oil catcher, and eventually get a custom ex manifold, wrap it with the heat wrap stuff, and run a 2.5" exhaust to the muffler where I pull it out to dual (I love dual exhausts, the look mainly) on either side of the class 3 hitch so it looks tight, then maybe bore out the TB (can this be done with a dremel or RA air grinder?)

 

[Bloose]

I typically run either 89 or 91 octane (low and mid here in vermont) and will run 93 once a month or so for the slight cleaning effect. So heres my plan after looking at yalls comments. I'll run mobil1 on the next oil change, make a homebrew cone filter deal with a K&N, replace the cap, rotor, wires and plugs, throw an aluminum heatshield between the EX and INT manifolds, maybe build an oil catcher, and eventually get a custom ex manifold, wrap it with the heat wrap stuff, and run a 2.5" exhaust to the muffler where I pull it out to dual (I love dual exhausts, the look mainly) on either side of the class 3 hitch so it looks tight, then maybe bore out the TB (can this be done with a dremel or RA air grinder?)

Premium has no additional cleaning affect. All fuel has detergents, they just advertise them for premium and not regular even though they both contain it.

You cannot bore the TB with any kind of hand held device. The bore needs to be precision, plus you need to make or buy a larger butterfly. The price they are charging for bored TB's is rediculas but you will need access to a mill to do it yourself. For the butterfly a lathe and possibly a surface grinder would be needed. Every thing else you are planning sounds pretty good to me.

I think a cool way to do the exhaust would be to have 2 manifolds (1 for each 3 cyl's) much like the later 4.0l's but tube instead of cast, then run 2 smaller pipes (maybe 2") to an x and out to 2 mufflers and 2 exaust pipes. I would think this would create a very free flowing exhaust while giving you good scavaging for low end. At the very end you could go up the 2.25" or 2.5" so you have a nice looking exit. For the mufflers you could do 2 Dyno Max bullet race mufflers or even a dual inlet/outlet style muffler.

B-loose

 

[Bloose]

Here's my oil catch can write-up:

http://www.angelfire.com/my/fan/Catch_can.html

I really like this idea Dyno! I'm thinking of doing it on my '68 Ford. I change the breathers every year because they fill with oil. Also, I run 2 breathers and no PCV to keep the oil out of the intake. Running a PCV actually increases HP because you get a better ring seal if you have a negitive pressure in the crank case. But oil in the intake charge negates most of that benefit. I've been looking for a solution and now I thing I've found it. Of course there is no way I'll use and old soup can but other than that it looks like a great solution.

B-loose

 

[Bloose]

Premium has no additional cleaning affect. All fuel has detergents, they just advertise them for premium and not regular even though they both contain it.

You cannot bore the TB with any kind of hand held device. The bore needs to be precision, plus you need to make or buy a larger butterfly. The price they are charging for bored TB's is rediculas but you will need access to a mill to do it yourself. For the butterfly a lathe and possibly a surface grinder would be needed. Every thing else you are planning sounds pretty good to me.

I think a cool way to do the exhaust would be to have 2 manifolds (1 for each 3 cyl's) much like the later 4.0l's but tube instead of cast, then run 2 smaller pipes (maybe 2") to an x and out to 2 mufflers and 2 exaust pipes. I would think this would create a very free flowing exhaust while giving you good scavaging for low end. At the very end you could go up the 2.25" or 2.5" so you have a nice looking exit. For the mufflers you could do 2 Dyno Max bullet race mufflers or even a dual inlet/outlet style muffler.

B-loose

Forgot, You would also have to run 2 cats. Could probably work that out too, but you'd be running low on space.

B

 

[nuttinbuttmudd]

You want to get more power out of a jeep AND want to keep your wallet fat?

That's the Holy Grail, my friend - we're all trying to find it!

In fact, owning a jeep and not spending much money is in itself an oxymoron... :bawl:

You might want to search this forum for 5-90's posts - he knows his stuff. Especially see the thread on NOS - penny for penny, it has to give the best return, even if you run the risk of shafting your engine in the long term.

J Just
E empty
E every
P Pocket

 

[thedarkprince]

Bloose, I doubt I will run two of everything on the exhaust, too much work, too many fittings, and I doubt it would be all kinds of emissions legal. but a muffler with single entry and dual outlets, run one over to the other side and throw some chrome tips on them. either that or angle them out behind the rear wheels or in front of them, but I definately wanna run it single till the muffler, one bank, one main pipe

 

[Bloose]

Bloose, I doubt I will run two of everything on the exhaust, too much work, too many fittings, and I doubt it would be all kinds of emissions legal. but a muffler with single entry and dual outlets, run one over to the other side and throw some chrome tips on them. either that or angle them out behind the rear wheels or in front of them, but I definately wanna run it single till the muffler, one bank, one main pipe

I didn't figure you would want to, but I think it would be an interesting system. I had a BMW 530I years ago and that's pretty much what they did. With the exception that they ran to a single muffler at the rear of the vehicle. I think the earlier or maybe it was the later 528 ran two pipes all the way back. To be honest I think the only complication would be dual cats.

One of the conundrums with an exhaust for the XJ is getting it to flow for the top end while getting it to scavange well for the bottom. Go too big and you lose the low end. Go too small and you lose the top. A true dual with an X pipe would likely satisfy both ends.

Again though, it's likely a lot of work and I understand not going to a system like that.

B

B-loose

 

[thedarkprince]

I'm still a bit of a n00b on this whole exhaust thing, would you mind explaining what scavaging is? I understand top end flow, but how the low end stuff and backpressure works is currently a mystery, if its a real boon (without boring the TB to improve flow IN that is) then I might consider it

 

[Bloose]

Back pressure is never a good thing. It keeps the exhaust charge from completely exiting the cylinder and thus reduces power as the cylinder cannot fully fill with a fresh charge. That being said a system that is too large will not create a scavaging affect. Scavaging is where the exhaust flowing through the system actually pulls the exhaust from a port when an exhaust valve opens. This phenomenon is what makes full length headers work so well. The long tubes create a nice free flowing system. Then in the collector it creates a high velocity exhaust flow that helps scavange exhaust from a port with an open valve. Thus creating "back pressure" is not the idea but creating good velocity, scavaging, and flow in the system is the name of the game. An X pipe in a dual exhaust system further helps scavaging as it creates a more continuous scavaging flow in both exhaust pipes.

Does this make sense?

B

 

[jeepcherokee95]

Ok, I looked through my "research material" and did not find the writeup on exhaust but someone did an excellent job on a writeup recently giving pipe sizes and tech info on why this set-up is better than that ect...

If someone finds it could you please post it here?

Next question:

I am trying to make the best flowing exhaust with stock manifold (I can't afford a new manifold) I am after MPG NOT HP!

My thoughts are this; go from the exhaust outlet into 2.5" to the hi-flo cat, through the cat to a flowmaster40 muffler then go 2.25 out to the tailpipe.

Would this work or do I need to stay at 2.25 all the way?

If I were going to do the dual I would just make a "Y" pipe right out of the hi-flo cat and go into the dual mufflers but with any dual system on any I-6 I think that it would be too free flowing and you would loose low end torque, response and even mileage - just my opinion.

JC95

 

[Dr. Dyno]

. Of course there is no way I'll use and old soup can but other than that it looks like a great solution.

Hey, what's wrong with an old soup can? A Campbell's soup can does the job very well. You can spray paint it on the outside in your favourite colour to make it look good, or even powder coat it if you feel that way inclined.