TheGhost45
New member
It reduces heat alot flex a lite claims a 30 degree drop in heat levels so it gives the engine alot more power! 
I'm going to get an aluminum rad and electric fan.
I'm going to get an aluminum rad and electric fan.
2.5 vs. 4.0
- Thread starter jeeptjon37's
- Start date
quicksand97
New member
I was also thinking of electric fan. hey what about a regular non electric flex fan? anybody have any experience or feedback on that?
TheGhost45
New member
Are you talking about a belt driven fan?
quicksand97
New member
Yes Sir a belt driven flex fan, wondering the pros and cons, if anyone knows
TheGhost45
New member
Bad compared to an electric fan, a belt driven fan uses power to cool the engine bay where as an electric fan costs a little more and runs off the battery as to a belt driven which runs off the engine, I say get an electric.
quicksand97
New member
Cool, I will save more money and go for electric. Thanks
TheGhost45
New member
Great idea! Super glad to hear it man go with a flex a lite, they make a great one!
go with a flex a lite, they make a great one!
quicksand97
New member
Yea that will be my last mod, electric fan. Got everything else under the hood. She runs pretty good for a 4 Banger. Then I will focus more on skid plates and rock sliders
superj
Active member
do you do lots of off roading where you are scraping stuff? i always think of buying that stuff but i don't off road so it would just be weight using extra gas for me. just like a lift and big tires. i had it all on my cherokee but the once a year i went off road wasn't worth the loss of gas mileage the rest of the year. my good ol 87 wrangler will stay pretty stock and just look cool all blacked out (minus the rims)
quicksand97
New member
You know I dont do alot of offroading, but would like to in the future. But I do get your point loud and clear. I do think of things in and out, just like you are saying. What does it look like? Does it have a purpose? How often? How much does it wiegh? Will it rust? etc, etc,etc. Its like having a winch, driving it around all year long in all the elements. I am actualy thinking of light sliders with a functional step. Maybe home made from aluminum to my own specs. Light wieght, ground clearance, rust proof, step, and light duty protection. I will just try to avoid rocks, maybe. Time will tell. Take care
Jpwheeling2000
New member
Well I guess he could have been spinning he's in the snow, doesn't take much to do that, I own a 2.5L don't bother in getting it, its way under powered and if you put bigger tires on, your going to really slow down. All I've been doing, is trying to create more power from this Engine, I've made allot of mistakes, I've tried Chips, don't bother, I've tried better spark plug set-ups, there a waste the only true given that worked for me is a Cold Air intake set up, I've tried a few the one that worked best was AEM it's called Brute Force, there using there newest Air Filter, it's tough and only needs water from the tap to clean it. I got rid of my Stock Fan, tried Flex-aLight, that one never worked right for me, always came on, I've forgotten which company I went with. As yo can see I've done allot just get some horse power, don't even think of getting a Four, I forgot sense I Put my left kit on and 33's I get Horrible gas Milage.
TheGhost45
New member
Re gear then your complaining about your power loss and all these add Ons youve wasted your money on. Invest some money in deeper gears your power loss you'll gain back, I'm trying to find 4.10's out of a 2.5 to slide under my 4.0 so I regain the power I'm going to lose with the bigger tires. You say you have 33's the swap your gears out for 4.88's whatever power you lost will come right back and your gas mileage will improve. Gearing = everything. Theres 1000's of guys that will tell you that.
Dittrich31
New member
I have a quick side note Everyone says 4.88 in the 2.5 but what about 4.88 in the 4.0.
The reason why im asking is i want to do an axle swap with my already regeared axles to a 4.0 because it is looking like my jeep may not recover this time
The reason why im asking is i want to do an axle swap with my already regeared axles to a 4.0 because it is looking like my jeep may not recover this time
tjlboise
New member
I have a 90 YJ with a 2.5 that I THOUGHT had the stock 4.10 gearing, but now im not so sure anymore. The freeway lacks big time, if im doing anything over 60 mph, but when I get off road, she turns into a raging monster. If I crawl down underneath and look at the diff cover, will that tell me what kind of gearing I have? If not, how do I find out?
TheGhost45
New member
What size tires will you be on that 4.0L your sliding your axles under?
There should be a tag stamped into the metal on your axle that should tell you, or you could drain all the fluid put of it get a piece of chalk and mark a spot on the big gear then turn it and count all the teeth. Theres some conversion you can do to find put it exactly (can't remember what my teacher showed me, have to ask again Monday) but every 2.5 came from the factory with 4.10 gears. What year is it and what size tires and lift are you running?
There should be a tag stamped into the metal on your axle that should tell you, or you could drain all the fluid put of it get a piece of chalk and mark a spot on the big gear then turn it and count all the teeth. Theres some conversion you can do to find put it exactly (can't remember what my teacher showed me, have to ask again Monday) but every 2.5 came from the factory with 4.10 gears. What year is it and what size tires and lift are you running?
JohnnyO
New member
Eh, just jack up the rear, put it in neutral, make one chalk mark at 6 o'clock on the tire and another one across the bottom of the diff to the driveshaft. Lay underneath and count how many times the driveshaft rotates while a friend spins the tire around one time. It'll be close enough. If the diff doesn't have a tag on it any more.
I think the biggest thing is something no one has talked about. When changing your tire size you really need to change your speedo / speed sensor to fix the input to your computer. Without fixing your vehicle runs like garbage, get crappy gas mileage and just all around tends to **** you off.
TheGhost45
New member
Alot of people don't change the speedo gear and have no problems?
superj
Active member
all it does is mess up your calculations when figuring mileage if you forget to factor in the percentage change. thats why so many people think they are getting horrible gas mileage, they forget to factor in the percentage of change from the tires being different. instead of your tire turning 1000 times per mile, it now only turns 878 times (just using imaginative numbers) so your odometer is showing you only get 150 miles per tank instead of 200 so it looks like you are getting horrible mileage. in reality, you are probably getting 18 instead of 20, or something close like that
E-Fan conversions are really good for several reasons.. as noted above, they can actually give you some better performance being this:
the fan is not driven 100% of the time by the engine (disregard fan clutch engagement, it still spins)
Engagement is 100% when the fan is "on"
Engagement can be selectable (water crossings - off, towing up hill forced on, etc) whiloe I do have to add, highway speeds, fan should remain auto based on temp, just as the factory fan clutch is designed
Overall HP gains can be quantified (but really not noticable)
Myths are easily confirmed:
E-Fans = 15% HP gains - NOT, maybe 2 or 3 (doesn't run all the time)
MGP gains - negligable...laws of conservation of energy (Einstein)
Cooler - only if the fan can move more than the factory setup, I guaruntee, factory engineers had the thermal dynamics figured pretty well
Easy gimme on E-Fan conversions:
Less space, better cooling efficiency when designed correctly, and easy failure diagnosis, not to mentin the advantages of the manual control for off road.
