trying to get a lil' more power

[LilRhodyXJ]

i have 2000 xj 4.0 with a k&n air intake, magnaflow hiflow cat, a flowmster 40, and rustys tail pipe.. it has pretty good power but i drive on the highway eeryday and i'm looking for a little more power to get me through the insane traffic of route 95...

i was looking at a banks or a thorley header plus a jeepers creepers bored tb.. wondering if they were worth it and any suggestions you may have for other power increases.. don't have he money to stroke, s/c, or boost my 4.0

thanks for your suggestions

[BrettM]

http://www.jeep4.0performance.4mg.com/

[j99xj]

Get lower gears, (numerically higher). 4:10s do good. That will give you the kick your looking for. It will lower gas mileage but will increase torque multiplication to the rear wheel giving you more power to the ground via higher rpms.

[Dr. Dyno]

i have 2000 xj 4.0 with a k&n air intake, magnaflow hiflow cat, a flowmster 40, and rustys tail pipe.. it has pretty good power but i drive on the highway eeryday and i'm looking for a little more power to get me through the insane traffic of route 95...

i was looking at a banks or a thorley header plus a jeepers creepers bored tb.. wondering if they were worth it and any suggestions you may have for other power increases.. don't have he money to stroke, s/c, or boost my 4.0

thanks for your suggestions

The Thorley header with a custom made 2.5" downpipe would be a worthwhile addition. You can get a 62mm bored TB cheaply from ebay. Don't bother with a TB spacer 'cause you won't have enough underhood clearance if you combine it with the K&N FIPK.

[LilRhodyXJ]

i can only find the doug thorley headers to 99 mines an 00

[scoobyxj]

As long as you don't have the precats on the header the 99 will work. If you can fab up a mount for the coil packs you can get a 96-98 head. Have a valve job done on it, and yea haw.

[raypla]

http://www.thefastman.com/Throttlebodies40.asp Great product and customer service. Cheapest prices around :yelclap:

[LilRhodyXJ]

so is this fast man throttle body the one to go with?... i've been lookin around and the RE one is rediculously expensive but the jeepers creepers one got a good write up and its only $115.... also will a bored tb kill my gas mileage?

[OUG]

I've never had any experience with Jeepers Creepers but reading this xj forum a lot of people have mentioned his name in a non positive tone.

[Beej]

The Jeepers & Creepers TB is a stock unit that has been bored out to a uniform 60mm. In other words, if you just remove the material below the blade on your own TB, you will have the same thing they sell on their site. The one above is a true 62mm bored out unit. It will be a flow improvement on over the stocker. The RE is considerably more pricey, but again its a true 62mm bore. Folks have adapted mustang TB's and tealcherokee has mated a massive Taurus SHO TB to his machine. That size bore will require milling of the intake manifold TB mount to accommodate the larger bore...

[MogifiedXJ]

You shouldn't go any bigger than a 62mm throttle body on your stock cherokee. You can use a tb larger than 62mm of another car and adapt it to fit and modify your intake, but I think it would hender you more than it would help. You could try to find a local machine shop willing to bore your old tb out. There is a company that sells 62mm brass butterflys for the do it yourselfer, but for the life of me I can't think who it is.

[LilRhodyXJ]

i still have a couple of question but these tbs are startin to make sense
1.is this tb (the fastman) the one to go with?
2.will my k&n fipk still be usable?
3.gas mileage on bored tb better worse or same?
4.and back to the gearing comment... since i dont have boatloads of money could i regear my rear end to 4.10s and as long as i always have it in 2wd not damage the front end or do i have to do both no matter what?

[fdsa487]

You get a lil' power and you fiend for more.

[Beej]

i still have a couple of question but these tbs are startin to make sense
1.is this tb (the fastman) the one to go with?
2.will my k&n fipk still be usable?
3.gas mileage on bored tb better worse or same?
4.and back to the gearing comment... since i dont have boatloads of money could i regear my rear end to 4.10s and as long as i always have it in 2wd not damage the front end or do i have to do both no matter what?

1. its the same as boring out your stock throttle body, which you can probably do yourself or at least have done for you, for considerably less money. So its up to you. Its cheaper than the larger bore TB's but does not offer the same inlet sizing.

2. yes, it should still be usable with either the 62mm or the fastman one (60mm), since both versions are bored stock versions. The OD of the inlet does not change size.

3. should be the same, except that you may become Prince Heavyfoot with your newfound power and will then work your jeep harder giving you worse mileage than before.

4. you can only regear the rear axle if you remove your front driveshaft. With no driveshaft in place, the axles can be geared differently. This way you can get one done and then save up to get the other done later. Don't drive with different gearing from front to back with both driveshafts connected.

HTH...

[LilRhodyXJ]

i have 31s at 3.5"of lift, looking to add two inches of lift and mayb go wih 32s.. soo lets say i put in 4.10s and got a header and d-pipe for a little more power would it be relatively faster... i kno that sounds weird but right now i have stock 3.55s with the 31s and its really not that bad, only difference is acceleration is slower and if i need to merge or go quick on the highway it will hit almost 3 grand before nailin' overdrive... im just lookin to get that extra oomf back... but i need it for highway use so 4.56 would not be smart..

[j99xj]

Even if you have the ideal gear ratio for the tires your running you will still be slower than stock because big tires weigh more and have more "moment of inertia".

The "moment of inertia" not only makes it harder for the engine to accelerate the vehicle but it also makes the brakes work harder to overcome that extra interia to slow the vehicle.

Go for 4.10s.

[LilRhodyXJ]

what is a good company to go with for gears... on rocky-road outfitters they have us gear/yukon $159 for D30 and $185 for the 8.25...worth it??
also to i need a carrier for my front axle its an extra $49?

[LilRhodyXJ]

also kind of opposite from power i was wondering are the cross drilled rotors an d hawk performance brake pads worth it because im going to need new pads soon, was just wondering what u fellas prefer for brake upgrades

[LilRhodyXJ]

???

[sjx40250]

I got an extra TB and had it milled out to 60. What a difference! Throttle response was much better and Milage did improve except when.... Throttle response was much better!

I changed back after a year and a half when it would not pass emissions testing. The testing changed so I think I will swap and run it through again. The problem was that NOx and HCO was way over with the 60. Don't really know if this makes sense or not! Might need bigger injectors and hotter plugs. Oh yeah I alread talked about that today!:doh:

[XJoshua]

also kind of opposite from power i was wondering are the cross drilled rotors an d hawk performance brake pads worth it because im going to need new pads soon, was just wondering what u fellas prefer for brake upgrades

Get the hawk pads. Cross drilled or slotted brake rotors are just a scam to get ricers to think their cars are bad ass. Some cars do come stock with them, but by having your rotors drilled or slotted you loose brake power since there is less meterial to grab onto. Also the slots are meant to evacuate brake dust and gasses. Many newer brake pads dont create large amounts of brake gas.

So stay with you stock rotors, or upgrade to the biggest rotor you can fit inside the wheels.

[Beej]

Get the hawk pads. Cross drilled or slotted brake rotors are just a scam to get ricers to think their cars are bad ass. Some cars do come stock with them, but by having your rotors drilled or slotted you loose brake power since there is less meterial to grab onto. Also the slots are meant to evacuate brake dust and gasses. Many newer brake pads dont create large amounts of brake gas.

So stay with you stock rotors, or upgrade to the biggest rotor you can fit inside the wheels. Agreed, kinda. Slotted/crossdrilled rotors do not cause you to lose braking power. Crossdrilling was first done about 40 years ago in an attempt to reduce the gas layer that reduced friction between the pad and the disc due to outgassing of the pad materials. As said above, modern pads do not outgas as much, so in all but really high performance applications, they can be cosmetic in nature. Slotting helps vent gases and brakepad materials and helps to prevent vitrification of the pads in high performance applications. They are impractical for everyday use though, as they wear the pads down much faster.

In your case LilRhody, to improve your braking, consider going to larger rotors up front, like a WJ conversion or something. And do a disc brake conversion in the rear. There are a few writeups out there for both...

[LilRhodyXJ]

are those hawk pads worth it for 60 a pair?

[SCW]

Get the hawk pads. Cross drilled or slotted brake rotors are just a scam to get ricers to think their cars are bad ass. Some cars do come stock with them, but by having your rotors drilled or slotted you loose brake power since there is less meterial to grab onto. Also the slots are meant to evacuate brake dust and gasses. Many newer brake pads dont create large amounts of brake gas.

So stay with you stock rotors, or upgrade to the biggest rotor you can fit inside the wheels.

The amount of material is irrelevant, but the location of the "grab" is paramount. Friction is NOT a factor of surface area, so having larger pad footprint won't gain anything. The difference is having the calipers grab as far away from the centerline of the wheel as possible, but get too far without increasing the power of the calipers (improved booster) and performance can actually go down.

I'm bored, so here goes. Torque is force*distance. Your wheels spin with a certain amount of torque on them depending on the speed and weight of the vehicle. To stop the torque from the brake must = torque from the vehicles movement.

As T =F*D, you get larger tires and the mass and velocity of the vehicle place that much more torque to the centerline of the wheels (which is why you would regear, it takes more torque to turn them in the first place). To stop, you have two choices, increase the distance of the braking force from the centerline of the wheels, or increase the braking force. When you get bigger rotors you are moving the application of force further from the centerline and increasing brake torque, as long as the calipers are also grabbing further away. If the rotor just fits up into the caliper further and the pad grabs at the same place, gains will be minimal, like none.

[LilRhodyXJ]

makes sense but how di i fix that without paying crazy amounts of money ZJ disc conversion worth it? and is it expensive?

[SCW]

makes sense but how di i fix that without paying crazy amounts of money ZJ disc conversion worth it? and is it expensive?

Instead of a new rotor (increased distance) look at increasing the force applied to the brake pads. Use a 95-96 booster for example.

I have decided to skip over the 95-96 booster and go straight to hydroboost. I've pretty well sorted out what I need but the budget was shot before I spent $300 on a new rifle scope today. This winter I hope to be converted over to hydroboost and rear disk brakes, but that's pretty spendy overall. I figure over $500 as a midrange guess but up to $800 if things go poorly. I haven't decided if I'll get different rotors up front, it depends on cost mostly. I really like the setup GoJeep has for sale but not the price.

[LilRhodyXJ]

i dont even have close to that amount of money...is there anything cheaper that will help a little..im not concerned really that bad i've leanred to drive it but around my town its no biggy its when i drive up to school on the highway at the 65 mph speed limit and then driving around the campus which is in "the big city" people drive like nut bags and the traffic is terrible so it gets a lil hairy.. the jeeps got 89000 on it and it has never had new brakes... so what should i do?

[Beej]

i dont even have close to that amount of money...is there anything cheaper that will help a little..im not concerned really that bad i've leanred to drive it but around my town its no biggy its when i drive up to school on the highway at the 65 mph speed limit and then driving around the campus which is in "the big city" people drive like nut bags and the traffic is terrible so it gets a lil hairy.. the jeeps got 89000 on it and it has never had new brakes... so what should i do? If you're just doing regular street driving, then just replace the pads regularly with OEM's. They will do the job while you save up to do a conversion. The rear disc conversion is not terribly expensive, you should be able to do it for under 200 USD...

[SCW]

i dont even have close to that amount of money...is there anything cheaper that will help a little..im not concerned really that bad i've leanred to drive it but around my town its no biggy its when i drive up to school on the highway at the 65 mph speed limit and then driving around the campus which is in "the big city" people drive like nut bags and the traffic is terrible so it gets a lil hairy.. the jeeps got 89000 on it and it has never had new brakes... so what should i do?

Your profile says you have a 2000? New booster won't help. Like Beej says, rear brakes won't be too bad at a junkyard, maybe as much as $200 on the outside after new pads and fluid, etc. Maybe as little as 1/2 that.

Good luck-

[BrettM]

Instead of a new rotor (increased distance) look at increasing the force applied to the brake pads. Use a 95-96 booster for example.

I have decided to skip over the 95-96 booster and go straight to hydroboost. I've pretty well sorted out what I need but the budget was shot before I spent $300 on a new rifle scope today. This winter I hope to be converted over to hydroboost and rear disk brakes, but that's pretty spendy overall. I figure over $500 as a midrange guess but up to $800 if things go poorly. I haven't decided if I'll get different rotors up front, it depends on cost mostly. I really like the setup GoJeep has for sale but not the price.
Can you direct me to any good resources you've came accross for hydroboost?

[SCW]

Can you direct me to any good resources you've came accross for hydroboost?

Well, we have now hijacked this thread for our own purposes :D


I searched the crud out of it here and didn't get very far. Google had a few nuggets scattered around, but Pirate was a veritable gold mine. I'm not a red-start member so I had to search Pirate using Google (in the google search bar type "hydroboost site: www.pirate4x4.com and it will search for that term only on Pirate).

Here is the single best resource there. This should keep anyone busy for the rest of the day learning about hydroboost-

http://www.pirate4x4.com/forum/showthread.php?t=305103


For me the first step will be getting a second steering pump and rebuilding it for more performance, possibly adding a cooler at the same time.

Vanco sells a really nice setup for about $700 that has everything you would need but it's just way beyond what I think I can pay. I have seen a LOT of hydroboost boosters with master cylinders sell on Ebay in the $100 range- brand new. Ford parts are significantly more desired than Chevy among those who know hydroboost, but I don't know why. I'll have a local place make up some pressure lines for me, it should be pretty cut-and-dried for me because I'm not running hydrosteering. If you are you may want to work with Vanco, it places a lot of demand on the pump and he has worked out the details. I will get his high-output pump if I don't like my rebuilt OEM pump, his is $150.

[LilRhodyXJ]

what exactly do i need to pull off a Zj and what do i need to replace or buy extra to put it on my xj?