4bangerjp.com
General Forums => The Mess Hall => Topic started by: bigchelis on March 27, 2008, 06:37:02 PM
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I just purchased my first Wrangler: a 97 TJ with 4in superlift kit, 33's w/alloy crome wheels, 4:88 gears, automatic lockers, and already I installed the air raid cold air intake along with the spacer.
Next,
1. 4.0 tb
2. tauras electric fan
3. full exaust
Has anyone dynod their rig to get a true meassure of hp, tq increase. After all this work if I get 20hp I would be happy.
Example my 01 cobra dynod 271 stock, but catback with x-pipe it went up to 292hp at the wheels.
I was wondering if anyone has actually proven Hp increases, even if they are at WOT which likely no one drives a jeep that way anyway.
Thanks,
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I have the same set up 97 with 33's, 4.88's and everything you plan to do plus a chip and don't know if I would claim 20 HP? It helped but who knows what the actual horse power is, doesn't really matter. It will go off road though. Your still not going to be happy with off the line power, especially if your other vehicle is a Cobra.
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This is from JP Magazine...
(http://i46.photobucket.com/albums/f138/jfrabat/Jeep/JPMagazine4bangerarticle.jpg)
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Thank you all for the info! If power will not improve much, how about the power curb?
Also, I know from going through 3 stroker cobra engines, 3 full exaust combos, and 3 cam options on my cobra that although HP and TQ may not increase you can effectively change the power curb.
ex: One of my cobra engines went from 300hp at 5k rpm and peaked out at 6700rpm at 368hp, but upon cam and exaust change I lost considerable HP. I got 300Hp at 3k rpm and peaked at 6100rpm at 345hp. Huge difference in street driving. The car felt extremely quicker and I was incredibly pleased.
Consequently; I want to know if anyone has altered the power curb, im sure if you could increase the low rpm power the everyday street driving would be amazing. I woud welcome the loss of high end power for added power low in the rpm curb anyday, especially on my Jeep.
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The problem I've run into is that when you start tweaking the power band, you end up either adding more horse power to the top end at the cost of having less torque down low. The opposite is also true. I've had more torque down low at the cost of more top end horses. Currently, the engine runs out of torque around 4000rpm. I did have it where I could rev to 5000rpm freely but that was at a cost of low end torque. Under 40mph, my Jeep is pretty peppy if you keep the RPM's up even with 35's and only 4.56's.
I'd say short of going even lower in gears, a Turbo would be the next best thing. Small things like an electric fan, exhausts etc. will help you fine tune the powerband but it won't make up for any big differences. Proper gearing is very important on a 4banger. I should be running 5.38's or 5.89's with my tires.
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... Proper gearing is very important on a 4banger. I should be running 5.38's or 5.89's with my tires.
I run 4.88's and 35's for a bit. It was barely adequate. I have driven a TJ with 5.38's and 35's. I did alright. I love the 5.89 and 35 combo in my YJ!
I am not really a HP or torque junkie because I have a minimum of 3,600 HP to play with at work. I can drag close to a million lbs at 80 mph all day long... 16 cylinders just make everything else seem weak. :naughty:
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will 4.56s be adequate for running 33's or should i go to 4.88s ??
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will 4.56s be adequate for running 33's or should i go to 4.88s ??
I'd run no less then 4.88's if you're even going to go with a gear change. The difference between 4.11 and 4.56's isn't that much. Still even 4.88's are just adequate. They'll make a big difference if you're used to 4.11's and 33's though.
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i have 3:73 right now. so should i still go ahead and go 4.88 then?
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i have 3:73 right now. so should i still go ahead and go 4.88 then?
You have an auto? I'd probably still go with 4.88's, if ti was me. For 33's you'd be about stock and then some by going with 5.13's on a manual. Since you don't have a OD gear, you'll want to be slightly higher if you do a lot of freeways.
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heh..I have 4:10s and 31s..oh ya all factory gearing. :biggrin: I could use a little more power when I'm 5th, most of the time have to downshift into 4th on a windy day.
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so im confused u think i should go with the 4.88s but if i do alot of drivin of the freeway i should go with 4.56? yea its an auto, it sucks :ass:
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so im confused u think i should go with the 4.88s but if i do alot of drivin of the freeway i should go with 4.56? yea its an auto, it sucks :ass:
http://4bangerjp.com/forums/index.php?topic=173
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5.38 gears? Can you even cruise down the highway with those? I have 35's and stock 3.73's and I turn around 2600 rpm at 70 mph.
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33" tires, 4.56 gears equals 3000 rpm at 70mph is a nice gearing to me
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5.38 gears? Can you even cruise down the highway with those? I have 35's and stock 3.73's and I turn around 2600 rpm at 70 mph.
Here ya' go...
http://www.csgnetwork.com/rpmcalc.html (http://www.csgnetwork.com/rpmcalc.html)
35 + 5.89 @ 60 mph = 3300 rpm. That is figuring a final output of 1.1. Obviously, that changes if you still have a 5th gear.
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yea....I usually don't question Jeffy one bit, but that chart gearing seems a little too low for me as well. It may give you the optimal power band, but not sure how comfortable it would be for highway driving. Based on where I'm at right now with 4.10's and 31's, I think the 4.88's will keep me at the same right or only slightly worst with 35's (and the added weight of my axles and armor). I'm willing to give up a tiny bit of power so I don't have to re-gear when I throw in a new engine....hopefully next year!!
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heh..I have 4:10s and 31s..oh ya all factory gearing. :biggrin: I could use a little more power when I'm 5th, most of the time have to downshift into 4th on a windy day.
That makes 2 of us!
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That makes 2 of us!
I have had a 4.0 throttle body for almost a year now and have just been to lazy to install it. I need to do that, isn't it true you get a little more power in 5th?
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I did not notice any real difference with a 4.0L throttle body. It might be worth 2-4 horsepower that you will never really feel. It is when you add a header, free flowing exhaust, better air intake, electric fan, and a throttle body you might feel a small difference.
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5.38 gears? Can you even cruise down the highway with those? I have 35's and stock 3.73's and I turn around 2600 rpm at 70 mph.
yea....I usually don't question Jeffy one bit, but that chart gearing seems a little too low for me as well. It may give you the optimal power band, but not sure how comfortable it would be for highway driving. Based on where I'm at right now with 4.10's and 31's, I think the 4.88's will keep me at the same right or only slightly worst with 35's (and the added weight of my axles and armor). I'm willing to give up a tiny bit of power so I don't have to re-gear when I throw in a new engine....hopefully next year!!
Doubters? :twofingers:
Here are charts with RPM's and vehicle speeds. The sweet spot for the engine is anywhere between 2700-3500RPM. Around 3300RPM is probably the best since you won't fall too low when going up hills and such. BTW: these are for a 5-speed AX-5. You can see 4th is pretty much useless with the 3.73's as well as 5th. 3rd is a bit too short at 3300 but you could rev it to 3500RPM and get it to 65mph at least.
(http://i4.photobucket.com/albums/y118/yokomura/4BangerJP/manuals/373b.jpg)(http://i4.photobucket.com/albums/y118/yokomura/4BangerJP/manuals/373.jpg)
(http://i4.photobucket.com/albums/y118/yokomura/4BangerJP/manuals/538b.jpg)(http://i4.photobucket.com/albums/y118/yokomura/4BangerJP/manuals/538.jpg)
Here's a stock Manual:
(http://i4.photobucket.com/albums/y118/yokomura/4BangerJP/manuals/411b.jpg)(http://i4.photobucket.com/albums/y118/yokomura/4BangerJP/manuals/411.jpg)
Here's a stock Auto:
(http://i4.photobucket.com/albums/y118/yokomura/4BangerJP/manuals/auto.jpg)(http://i4.photobucket.com/albums/y118/yokomura/4BangerJP/manuals/autob.jpg)
Now what gear ratio seems to get an auto back to stock?
(http://i4.photobucket.com/albums/y118/yokomura/4BangerJP/manuals/auto35.jpg)(http://i4.photobucket.com/albums/y118/yokomura/4BangerJP/manuals/auto35b.jpg)
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Jeffy,
Your auto with 4.88:1 is a little weird! I think you may need a new tranny!!! :blbl:
Felipe
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Doubters? :twofingers:
:drink: :beers:
Hehe... 5th gear is over rated. My YJ never liked it and tossed the stupid little snap ring at the end of the gear cluster several times. I live in Albuquerque, so 5th would be useless. It was nearly useless in Texas with more atmosphere. I figure that I really ought not be kicking a trail rig down the road at much over the posted speed limit anyways... Something red and on 35's usually turns heads without adding low flying...
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Oops, I forgot to mention that somewhere along the way, I did the math on 27 inch tires and 4.10s and came up with 5.89 as being a similar power band for 37's... Guess what size my next tires will be? :thumb:
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I personally need to be able to cruise at 70 mph on the freeway in Detroit. You get run over if you don't. I also don't like the idea of buzzing the motor at 3500 rpm for an hour or more down the freeway. I do however think I need a little more gear than the 3.73. I am keeping my eye out at the boneyard for an 8.8 with 4.10's.
My turbo also makes plenty of torque, so I don't need as much gear either though. On the trail 4-low works just fine.
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I have an auto with 33's and 4.88 gears. There is a good chance that when I upgrade my lockers I will be putting 5.38's in it.
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I personally need to be able to cruise at 70 mph on the freeway in Detroit. You get run over if you don't. I also don't like the idea of buzzing the motor at 3500 rpm for an hour or more down the freeway. I do however think I need a little more gear than the 3.73. I am keeping my eye out at the boneyard for an 8.8 with 4.10's.
My turbo also makes plenty of torque, so I don't need as much gear either though. On the trail 4-low works just fine.
You hit the nail on the head there....people forget that we have a speed limit of 70 here...which means the average is probably around 80.....Jeffy is just sitting in CA traffic half the time.... :stick:
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You hit the nail on the head there....people forget that we have a speed limit of 70 here...which means the average is probably around 80.....Jeffy is just sitting in CA traffic half the time.... :stick:
The difference is that with more torque and hp, you can flub the ratio a bit more. Changing gearing ignores the engine. If you have more torque can subsequently, run a higher ratio then you normally would since you have a lot more torque available at any given RPM.
Out here on I-5 the speed limit is 70mph but you'll still get SUV's trucking at 80mph. Although some go faster. I still wouldn't want to drive a lifted Jeep at 80mph though. I have and it's not fun. A good gust of wind will still shove you around.
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I think mine will ride a lot better once modded....I'll definitely have a lower center of gravity with the new axles....and the long-arm should ride a little better...also adding a new steering box to tighten things up....
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How do you think you will get a lower center of gravity with different axles? You are going from 31" tires to 35 " tires or bigger seems to that raises the center of gravity unless you use these highline fenders and hack the rear wheel wells it will sit higher than it does now. Sure a good long arm lift kit helps handling , but then wider tires and the rims to make them fit tend to make the front want to follow grooves in the road more. Wanna have fun try to swerve for somebody that cuts in your lane on the freeway at 75- 80 mph gives new meaning to white knuckling it :gimp:
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The new axles weigh A LOT more than the old ones..... :thumb:
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Still doesn't affect the cog, it just makes it heavier makes for a bigger slurpy in the gas tank :'(
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Still doesn't affect the cog, it just makes it heavier makes for a bigger slurpy in the gas tank :'(
yes it would????????
You don't have to know anything about axles, jeeps, etc. just take some low-level physics or something and you'll know, more weight lower on a beam (or brick in the case of a jeep) means a lower COG. Going into jeeps and lifting, it's unsprung weight, which means more weight staying directly parallel to the ground (it ignores body roll, because it's not part of the body y'know?), and therefore, a more stable driving platform. Also, I believe moz is putting full width axles? That means wider track base, and, again, a more stable platform... He'll still have to deal with finding grooves in the road, but hey, it's a tradeoff I guess?