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General Forums => The Mess Hall => Topic started by: colorado_jeeper on February 08, 2010, 10:32:18 AM
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Here is what I have:
'97 TJ 2.5, 5-Speed, 4" lift with 33x12.50, AIRAID cold air intake, Throttle body spacer, Jet stage 1 chip, Cat-back exhaust, everything else is stock.
What I Need:
I need more power without going broke. More specifically, higher speeds and higher-end HP. What else can I do to increase power without spending thousands of dollars. Electric fan? Header? 62mm throttle body? Re-Gear? Any suggestions, links, advice, or don'ts would be greatly appreciated.
Thanks.
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Here is what I have:
'97 TJ 2.5, 5-Speed, 4" lift with 33x12.50, AIRAID cold air intake, Throttle body spacer, Jet stage 1 chip, Cat-back exhaust, everything else is stock.
What I Need:
I need more power without going broke. More specifically, higher speeds and higher-end HP. What else can I do to increase power without spending thousands of dollars. Electric fan? Header? 62mm throttle body? Re-Gear? Any suggestions, links, advice, or don'ts would be greatly appreciated.
Thanks.
all that you mentioned and if you do the header might as well go with a high-flow cat and muffler. make sure your airraid CAI is actually pulling cold air and not hot air from under the hood. A perf cam would probably be the next thing that comes to mind. Re-gearing won't give you more HP but it will make better use of it at the wheels and in your case (same as mine with 33s and 4.10) you should go with 4.88s as it will bring the final ratio back to stock level. i would do it in this order
1. 4.0L or 62mm t/b (first one is cheaper)
2. 4.88 R&P front/rear
3. e-fan
4. perf exhaust
5. perf cam
i put the t/b on top since it's the easiest mod. e-fan is good but you won't get blown away by the gains (the other 2 are more significant). exhaust and cam are more expensive, i think you can make 2 to 5 HP on the exhaust and probably at least 10HP with the perf cam (depending on which kind you get).
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Gearing is the biggest single improvement.
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Gearing then Engine swap...
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Thanks! Another question if you don't mind:
If I re-gear, should i just spend the extra $$ and put in a locker since it'll be open and worked on? would that be easier regardless of the cost? or would it be just as easy to put in a locker after the 4.88's are in?
Thanks again.
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Thanks! Another question if you don't mind:
If I re-gear, should i just spend the extra $$ and put in a locker since it'll be open and worked on? would that be easier regardless of the cost? or would it be just as easy to put in a locker after the 4.88's are in?
Thanks again.
There should be no labor on the locker if you have it installed as the carrier will have to come out and the ring gear removed anyway. So if you can swing a locker then there shouldn't be any additional cost other then the locker itself.
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I had the gears done in my sons 94yj. 4:88's both axles and a locker in the rear, one of the best things done to the money pit. The one thing to think about though is to get your speedometer recalibrated afterwards. You will see more speed with the new gears, but your power curve will fix itself with the speedo gear. But will tell you the locker is a different drive than without, not bad but different.
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I put ARB's front and rear when I regeared (I also installed alloy axles while at it). If you can afford them, the ARB's are, in my opinion, the best lockers out there. Ox are pretty good as well, but I prefer air actuated to cable actuated (just personal preference; both work great). In any case, I regeared when I had 31's, and I felt the Jeep lacking power before, and LOVED it afterwards (I could cruise in 5th all day long!). Then I stepped up to 33's MT's and I now wish I could go to 5.13 gears. It's not horrible, but it's not like 31's and 4.88. The reason for the power "drop" (even though numerically you are back to stock level) is that you now have much more rolling resistance and wind resistance, which is not considered in the math...
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I put ARB's front and rear when I regeared (I also installed alloy axles while at it). If you can afford them, the ARB's are, in my opinion, the best lockers out there. Ox are pretty good as well, but I prefer air actuated to cable actuated (just personal preference; both work great). In any case, I regeared when I had 31's, and I felt the Jeep lacking power before, and LOVED it afterwards (I could cruise in 5th all day long!). Then I stepped up to 33's MT's and I now wish I could go to 5.13 gears. It's not horrible, but it's not like 31's and 4.88. The reason for the power "drop" (even though numerically you are back to stock level) is that you now have much more rolling resistance and wind resistance, which is not considered in the math...
JFYI OX lockers are available with cable, air or electric actuation.
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I'm still not sold on OX. They don't have the history like Detroit and ARB's or the networks.
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Also get a throttle body spacer, it helps, I posted a reply in the internet deal section with throttle body spacers for $30-35 each shipped.
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My bad I didn't read you already have a spacer
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Thanks for all of the suggestions. Another question:
Is a 4.0 throttle body a direct bolt on, or are there any modifications needed? Also, would I re-use my current sensors on the new TB?
Thanks.
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http://4bangerjp.com/forums/index.php/topic,8.0.html (http://4bangerjp.com/forums/index.php/topic,8.0.html) Here is a link to the FAQ section thread on this.
On my YJ, It was simple bolt on and off stuff, and unplug and plug in stuff. Although all I changed was the AIS motor, never could manage to force the Throttle position sensor off so gave up on swapping the TPS (throttle position sensor).
You can get technical work in this by boring out the intake hole to match the new throttle body bore diameter (I have yet to work up the courage for to do this part and I am happy with the performance I have now and dont want to push my luck). Hope this helps
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Thanks for all of the suggestions. Another question:
Is a 4.0 throttle body a direct bolt on, or are there any modifications needed? Also, would I re-use my current sensors on the new TB?
Thanks.
this is based on the info i have for my YJ:
you need the IAC valve motor and housing from the 2.5L t/b
you need the tps from the 2.5L tb (although some said that the tps is the same - in my case the part numbers were different so i went ahead and swap that as well - you might want to check on yours and see if they have the same p/n then you don't need to swap them).
if you have a map sensor on your t/b, i think that is the same but to make sure you can compare the p/n on the 2 of them (don't see why they would be different, should be both 1 bar map sensors).
the 4.0L t/b has the same diameter on the bottom as the intake manifold so I didn't need to bore out the intake, not sure if that's the case with the TJ - if you have a bored out 4.0L t/b (they are usually about 60mm on the bottom) or larger t/b then you should enlarge the intake manifold opening as well for best results.
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Just installed the 4.0 TB I got off ebay. It was from a 96-98 cherokee/wrangler, that's how it was listed. I did have to use all of the sensors from my 2.5 due to different connector styles. Otherwise, it was a direct bolt-on and the intake manifold itself is big enough for it. I did notice a difference in power at higher speeds, which is what I was after. Now all I have to do is either get a new spacer, or try and bore out the one I already have...
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Buy a big, old sail boat and sell the jeep. Vs. a 4banger CJ/YJ/TJ, you'll spend less money taking care of the boat :lol: Kidding.
Gearing -- here's a good Jp magazine piece:
http://www.jpmagazine.com/techarticles/drivetrain/axletech/154_0909_gearing_for_power/index.html
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Gearing -- here's a good Jp magazine piece:
http://www.jpmagazine.com/techarticles/drivetrain/axletech/154_0909_gearing_for_power/index.html
$350 for a 4.0l throttle body form a junkyard :yikes: i don't what to know what kinda junkyard they go to.
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$350 for a 4.0l throttle body form a junkyard :yikes: i don't what to know what kinda junkyard they go to.
it's a tbi, must have something to do with it. not sure if it's a direct swap either, the 2.5L TBI is 44mm at the bottom (below the butterfly), they mentioned 58mm which is quite a bit larger.
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i paid $40, with shipping for my 4.0 tb. the intake manifold on my jeep is big enough for the 4.0, so no extra work necessary.
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$350 for a 4.0l throttle body form a junkyard :yikes: i don't what to know what kinda junkyard they go to.
Didn't see that. The 62mm one I got off ebay a few years back only ran me around $100.
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Didn't see that. The 62mm one I got off ebay a few years back only ran me around $100.
i paid $40, with shipping for my 4.0 tb. the intake manifold on my jeep is big enough for the 4.0, so no extra work necessary.
it's TBI, they come with an injector and the FPR on them - still $350 is quite a bit but they are more expensive than the MPFI t/b
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it's TBI, they come with an injector and the FPR on them - still $350 is quite a bit but they are more expensive than the MPFI t/b
The way I'm reading it, the performance parts and 58mm TB went on the '95 yj. On the second YJ -- the '89 with the tbi 2.5 -- he ended up doing just a axle gear change and didn't change the TB or anything else.
So, to me, it reads like he paid $350 for a junkyard 58mm tb for the '95 mpfi 2.5.
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the 2.5L TBI is 44mm at the bottom (below the butterfly), they mentioned 58mm which is quite a bit larger.
where did you find the opening size of the 2.5l tbi? I've never found it anywhere when searching.
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where did you find the opening size of the 2.5l tbi? I've never found it anywhere when searching.
i got one and measured it. working on getting an oversized one done, it is 52mm on the outside on the narrowest section, so the most i can get out of it is 50mm - still about 30% improvement on the cross section. I got that bored out but i need a matching butterfly now.
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i got one and measured it. working on getting an oversized one done, it is 52mm on the outside on the narrowest section, so the most i can get out of it is 50mm - still about 30% improvement on the cross section. I got that bored out but i need a matching butterfly now.
definitely looking forward to some pics and details of that... so you are making tbi mods now rather than working on your supercharger? got a jeep lined up to test it?
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definitely looking forward to some pics and details of that... so you are making tbi mods now rather than working on your supercharger? got a jeep lined up to test it?
i'm waiting for warmer weather. was working on the adjustable fpr and i figured i'll see if i can get the tbi enlarged (found a t/b at the junkyard) - just as an exercise. not sure if there's any interest in it, i have had one of the 64mm t/b for sale but no takers yet and so far i am spending - just having fun i guess. If it turns out good i'll post it in the garage sale.
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The way I'm reading it, the performance parts and 58mm TB went on the '95 yj. On the second YJ -- the '89 with the tbi 2.5 -- he ended up doing just a axle gear change and didn't change the TB or anything else.
So, to me, it reads like he paid $350 for a junkyard 58mm tb for the '95 mpfi 2.5.
interesting, the 4.0L from what i remember is 55mm at the bottom, i'll measure it later today. But to your point that is a lot of cash for a t/b, you can most likely buy a brand new one for that money so not sure what they are smoking (maybe that t/b came with a matching 58mm bong ready to go).
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i'm waiting for warmer weather.
I thought you were having the warmest weather in the last 100 years or something like that? :pot: ;)
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I thought you were having the warmest weather in the last 100 years or something like that? :pot: ;)
for this time of the year, doesn't mean i'm down at the beach sunbathing
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for this time of the year, doesn't mean i'm down at the beach sunbathing
:lol:
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i just got a 4.0 throttle body for under $50 with shipping included off eBay. it's been cleaned and comes with gaskets and sensors et al.