Questions from a new guy

[Bargain Box]

Hello everyone, my name is Brandon and I've been messing around with Jeeps for years. This is my third one. I took a break from 4x4 for 15 years and played with race cars. I'm back! I bought my 99 TJ a few months ago and it need a little TLC. It's about ready for the trail but I had a few questions to see what input this community had to offer. Thanks in advance and happy to be here!

1. Wheels - It currently has 15x7 ProComp La Paz alloy wheels with 33x12.5 Mickey Thompson Baja ATZ tires. Since these are so skinny I want to go up to wider rim. Should I be on an 8 or a 10 to have the best footprint and reduce risk of pooping off the bead under low air pressure with this size tire?
2. Running hot at high speed - I've read a lot of other post and can't seem to find the answer. I run at 195 when idling for long periods or at speeds under 50-60mph. If I go over 60mph it slowly creeps to 215 to 220. It does not matter what the ambient air temp is, if it's cooler out it takes longer to heat up. As soon as i slow down it cools down pretty quick. When I got the jeep the cooling system was in bad shape. I have already replaced the radiator, hoses, water pump, tstat housing, tstat with a 195, and radiator cap. The fan clutch works fine. I do have a barricade bumper and winch in front of the grill. Thoughts? Could it be related to problem 3 below?
3. Lack of power - 5th is unusable going up hills and if it's steeper fourth won't get it done either. I have the stock 3.07 gears and an AX-15. I did already replace the spark plugs, wires, cap, and rotor because they were not in good shape. It improved a good bit after that but still struggling. Gummed up intake and valves? Plugged cat?

 

[Jerry Bransford]

First, a big welcome to WTF! Go with 15x8 for your wheels, 15x10 is too wide once you air down for offroading which can allow the bead to unseat more easily. Insure they have the proper 3.75" to 4" of backspacing. Pay no attention to their 'offset' measurement which is different from backspacing.

Then the engine is supposed to run at or close to 210-215, both sitting and on the highway. By yours idling at 195 that indicates someone installed the incorrect 165 or 180 degree thermostat, it should be a 195 degree NON-failsafe thermostat. Plus the engine computer is programmed around the temperatures the correct 195 degree thermostat will cause the engine to run at.

Your 3.07 gears are the sole reason your Jeep has a lack of power with your 33" tires, they're causing your engine rpms to be too low which reduces how much power the engine can develop. Regearing both axles to 4.56 will get the rpms where they should be which will totally and completely restore your power. And yes 4.56 will produce the proper highway rpms, they will not be excessive.

 

[Claytone]

3. Your 3.07 gears are killing your power. It’s expensive but 4.56ish is probably what you need.

Jerry beat me to it

 

[hear]

2. Running hot at high speed - I've read a lot of other post and can't seem to find the answer. I run at 195 when idling for long periods or at speeds under 50-60mph. If I go over 60mph it slowly creeps to 215 to 220. It does not matter what the ambient air temp is, if it's cooler out it takes longer to heat up. As soon as i slow down it cools down pretty quick. When I got the jeep the cooling system was in bad shape. I have already replaced the radiator, hoses, water pump, tstat housing, tstat with a 195, and radiator cap. The fan clutch works fine. I do have a barricade bumper and winch in front of the grill. Thoughts? Could it be related to problem 3 below?

I have the exact same problem. Well, mine will get up to 230 if I let it (live reading off the OBDII reader), but slowing down cools it back down pretty quickly. I've asked about it here, but not gotten any takers for whatever reason. Last time I had it up to that speed for any length of time it was about 100F, but slowing down brought it down to about 212-215 within about 5 minutes. Would love to know what the cause is & how to correct it.

I'm running the same size tires on a 8" rim, that seems to be a pretty standard recommendation for off-road use.

 

[JMT]

Hello everyone, my name is Brandon and I've been messing around with Jeeps for years. This is my third one. I took a break from 4x4 for 15 years and played with race cars. I'm back! I bought my 99 TJ a few months ago and it need a little TLC. It's about ready for the trail but I had a few questions to see what input this community had to offer. Thanks in advance and happy to be here!

1. Wheels - It currently has 15x7 ProComp La Paz alloy wheels with 33x12.5 Mickey Thompson Baja ATZ tires. Since these are so skinny I want to go up to wider rim. Should I be on an 8 or a 10 to have the best footprint and reduce risk of pooping off the bead under low air pressure with this size tire?
2. Running hot at high speed - I've read a lot of other post and can't seem to find the answer. I run at 195 when idling for long periods or at speeds under 50-60mph. If I go over 60mph it slowly creeps to 215 to 220. It does not matter what the ambient air temp is, if it's cooler out it takes longer to heat up. As soon as i slow down it cools down pretty quick. When I got the jeep the cooling system was in bad shape. I have already replaced the radiator, hoses, water pump, tstat housing, tstat with a 195, and radiator cap. The fan clutch works fine. I do have a barricade bumper and winch in front of the grill. Thoughts? Could it be related to problem 3 below?
3. Lack of power - 5th is unusable going up hills and if it's steeper fourth won't get it done either. I have the stock 3.07 gears and an AX-15. I did already replace the spark plugs, wires, cap, and rotor because they were not in good shape. It improved a good bit after that but still struggling. Gummed up intake and valves? Plugged cat?

Everything sounds good except 3. You’ll want to re-gear. The 307’s are crap gearing with any transmission, the 4.0, and 33’s

If you do want a wider wheel, 8” is perfect.

 

[Jerry Bransford]

I have the exact same problem. Well, mine will get up to 230 if I let it (live reading off the OBDII reader), but slowing down cools it back down pretty quickly. I've asked about it here, but not gotten any takers for whatever reason. Last time I had it up to that speed for any length of time it was about 100F, but slowing down brought it down to about 212-215 within about 5 minutes. Would love to know what the cause is & how to correct it.

Confused about the 100f above. What temperature did it get up to? Are you running an aftermarket/store brand radiator?

 

[hear]

Confused about the 100f above. What temperature did it get up to? Are you running an aftermarket/store brand radiator?

It was 100F outside, driving ~65-70. Factory radiator (as far as I can tell), fan shroud in place, new (functioning) fan clutch, replaced water pump & t-stat about a year ago, flushed the system at that time. Zero heating/cooling problems outside of the temp climbing at higher speeds. Slowing down brings the temp back down.

Even sitting STOPPED in traffic with it being 100F outside does not cause the temp to increase, in fact, there is one spot on US75 coming into Durant, OK where you'll be doing 70ish and then you get to the casino stoplight and it can be dead stopped, which I would think would be the worst scenario for me-- running hot, and then no air movement on a really hot day. But it comes right back down to the 212-215 range.

It feels like maybe it's a fan problem at higher speeds, not sure what else it could be. Open to ideas obviously.

 

[Vasq]

1) normally I would absolutly suggest the 15x8" wheel, but lately I've seen a lot of talk about the 15" rim selection for tires is dwindling as manufactures move to the more common 17" wheel size. SO if you're also in need of tires, might be worth it in the long run to jump to a 17x8" rim?

2) everyone's got you covered there.

3) It's all the gears like most have said. 3.07 is the worst, if 33's are the tire size you're sticking with, it's time for 4.56 gears

4) Welcome!!

 

[Bargain Box]

First, a big welcome to WTF! Go with 15x8 for your wheels, 15x10 is too wide once you air down for offroading which can allow the bead to unseat more easily. Insure they have the proper 3.75" to 4" of backspacing. Pay no attention to their 'offset' measurement which is different from backspacing.

Then the engine is supposed to run at or close to 210-215, both sitting and on the highway. By yours idling at 195 that indicates someone installed the incorrect 165 or 180 degree thermostat, it should be a 195 degree NON-failsafe thermostat. Plus the engine computer is programmed around the temperatures the correct 195 degree thermostat will cause the engine to run at.

Your 3.07 gears are the sole reason your Jeep has a lack of power with your 33" tires, they're causing your engine rpms to be too low which reduces how much power the engine can develop. Regearing both axles to 4.56 will get the rpms where they should be which will totally and completely restore your power. And yes 4.56 will produce the proper highway rpms, they will not be excessive.

Thanks for the info Jerry. I figured gearing was causing most of it but I was worried about having 3k or more rpms at 70mph on the highway with a gear above 4.10 or so. I need it to be streetable because i live in central NC and the closest trails are 2hrs away and the mountains are 3.5-5.5hrs depending on where I go. My thermostat was incorrect when i bought it (165) but it now has a new thermostat that is 195. The needle is just below 210 so I threw out the 195 number. I need to drive around with my OBD app and see what it tells me. 15x8 is what I had in the past and was curious as to why someone would put the 15x7 on it.

 

[Bargain Box]

1) normally I would absolutly suggest the 15x8" wheel, but lately I've seen a lot of talk about the 15" rim selection for tires is dwindling as manufactures move to the more common 17" wheel size. SO if you're also in need of tires, might be worth it in the long run to jump to a 17x8" rim?

2) everyone's got you covered there.

3) It's all the gears like most have said. 3.07 is the worst, if 33's are the tire size you're sticking with, it's time for 4.56 gears

4) Welcome!!

I have not had a 17 suggested before. My tires are in great shape so I wasn't considering that. I'm going to get the basic steelies for it so I'll probably just go with 15x8 for now since it's a budget vehicle/toy that gets very low miles.

 

[Vasq]

I have not had a 17 suggested before. My tires are in great shape so I wasn't considering that. I'm going to get the basic steelies for it so I'll probably just go with 15x8 for now since it's a budget vehicle/toy that gets very low miles.

I honestly haven't really suggested it before haha. I've just been noticing lately that the 15" tire selection is being phased out by some manufactures it seems. At least in the sizes we all seem to want lol

a 15x8" steelie will do you just fine

 

[Bargain Box]

Thanks for all the info and warm welcoming. I have been reading through a lot of the forums on here and it's a great community with a lot of information so I joined. Glad to be here. Based on other threads and the answers I received here, below is the plan.

1. Buy some steelies that are 15x8, cheaper the better. Then sell my La Paz alloys. I know I'm sacrificing some weight but it's not a drag car anyway!
2. Will do some testing with my OBD app and make sure I'm within the ranges discussed. Doesn't seem to be a concern.
3. I want to put in some lunch box lockers (probably torq). I will look into gearing to a higher gear at that time. The factory carrier doesn't support 4.10 and up does it?

In case you didn't gather from my handle, this is a bottom of the barrel budget build. The only parts I bought noteworthy brands on where the ones that mattered. Everything else was either already on it when I bought it or is the cheapest thing I can find. I'm capable of doing most of the work myself so cost stays low.

 

[thekidwithquestions]

Hello and welcome to the forum, I as well am in NC
Depending on where you live, id love to help you out with any tj related projects you decide to do
Edit; I see your username is theebaytj, are you by chance near the ocean?

 

[Bargain Box]

Hello and welcome to the forum, I as well am in NC
Depending on where you live, id love to help you out with any tj related projects you decide to do
Edit; I see your username is theebaytj, are you by chance near the ocean?

I'm in the Raleigh area. And my handle is "the ebay TJ". It's a budget build so that's where I've bought and sold a lot. We jokingly called it that one time and it stuck.

 

[thekidwithquestions]

I'm in the Raleigh area. And my handle is "the ebay TJ". It's a budget build so that's where I've bought and sold a lot. We jokingly called it that one time and it stuck.

ahh I gothcha, im in wake forest

 

[Bargain Box]

ahh I gothcha, im in wake forest

Where do you usually go for adventure? Maybe we can meet up sometime.

 

[thekidwithquestions]

Where do you usually go for adventure? Maybe we can meet up sometime.

that'd be cool, i've been to Uwharrie once and it was fun, I went on the easy trails since it was my first time

 

[fwgump]

First, a big welcome to WTF! Go with 15x8 for your wheels, 15x10 is too wide once you air down for offroading which can allow the bead to unseat more easily. Insure they have the proper 3.75" to 4" of backspacing. Pay no attention to their 'offset' measurement which is different from backspacing.

Then the engine is supposed to run at or close to 210-215, both sitting and on the highway. By yours idling at 195 that indicates someone installed the incorrect 165 or 180 degree thermostat, it should be a 195 degree NON-failsafe thermostat. Plus the engine computer is programmed around the temperatures the correct 195 degree thermostat will cause the engine to run at.

Your 3.07 gears are the sole reason your Jeep has a lack of power with your 33" tires, they're causing your engine rpms to be too low which reduces how much power the engine can develop. Regearing both axles to 4.56 will get the rpms where they should be which will totally and completely restore your power. And yes 4.56 will produce the proper highway rpms, they will not be excessive.

Alright Jerry... You seem to have the right answers. I have just bought my wife a 1997 tj with 2.5L I we have new 255/75 R17 jeep wheels I have the same issues as everyone else her daily driver short distance back roads and we would like to do some wheeling 4.88 gearing? Thnx

 

[Vasq]

Alright Jerry... You seem to have the right answers. I have just bought my wife a 1997 tj with 2.5L I we have new 255/75 R17 jeep wheels I have the same issues as everyone else her daily driver short distance back roads and we would like to do some wheeling 4.88 gearing? Thnx

https://wranglertjforum.com/threads...angler-tj-lj-and-other-re-gearing-faqs.17063/

 

[Ron505]

Welcome EbayTJ!