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Unread 06-17-2013, 10:07 PM   #1
dbhale
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Engine upgrades for my ZJ anybody???

I want to get some more horsies for my beloved vehicle but do not know where to start.

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Unread 06-17-2013, 10:08 PM   #2
WhiteOut
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Don't bother. Change the gearing instead.
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Unread 06-17-2013, 10:19 PM   #3
dbhale
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Oo ok didn't think of that, thanks,
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Unread 06-18-2013, 10:17 AM   #4
rgreen
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no, hughes engines air gap intake manifold, 1.7 rockers, sct tune... i would know, my jeep ran a 13.7 in the 1/4... all this was done on a stock bottom end w/ 135,xxx miles on it.
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Unread 06-18-2013, 10:38 AM   #5
PolkaPower
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Quote:
Originally Posted by rgreen View Post
no, hughes engines air gap intake manifold, 1.7 rockers, sct tune... i would know, my jeep ran a 13.7 in the 1/4... all this was done on a stock bottom end w/ 135,xxx miles on it.
Well you can't do that with a 4.0 which is what he has plus is doesn't make sense to increase HP to make up for gearing. You gear it right then add the HP.
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Unread 06-18-2013, 07:03 PM   #6
underpowered
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best way to add HP. remove 4.0, install gm LSx.

but to add it to the 4.0, trying to polish a turd. you may get it to shine, but the shimmer is quick to tarnish.
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Unread 06-18-2013, 08:58 PM   #7
rgreen
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Quote:
Originally Posted by PolkaPower View Post
Well you can't do that with a 4.0 which is what he has plus is doesn't make sense to increase HP to make up for gearing. You gear it right then add the HP.
first i didn't see where it said it was a 4.0L, also you can get a turbo kit for this engine. as for gearing it all depends on what your purpose is with the jeep, street or offroad. my jeep was on the the stock 3.73 gears.
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Unread 06-18-2013, 09:15 PM   #8
PolkaPower
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Quote:
Originally Posted by rgreen View Post
first i didn't see where it said it was a 4.0L, also you can get a turbo kit for this engine. as for gearing it all depends on what your purpose is with the jeep, street or offroad. my jeep was on the the stock 3.73 gears.
Info is in his profile. 4.0's came with 3:55 gears with a few in 3:73 if specified. Tire/rim size matters with gears and he's running 31's(also in profile) so to get it back in stock range he needs 4:11. If you want more grunt off the line taller gears are it.

4:11's would have been better for the v8's too but 3:73's are better for the highway mileage.

Search for TurboTPI He did a custom inexpensive turbo for his 4.0.
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Unread 06-19-2013, 07:47 AM   #9
1slo_camaro
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theres a ton of things you can really. comes down to money, knowledge and time. you could:

build a 4.7 stroker
swap in a LSx
find a 5.9 driveline and swap in

or if you want just a little more throttle you could start probably with a tune-up, a lot of people dont realize how crappy their vehicle runs until they install new plugs, wires, cap, rotor, coil, new O2s and seafoam the engine and injector cleaner....

after a tune-up for the 4.0 i threw on 703 injectors, 60mm TB, 99+ intake, and a header and that seemed to have a little better throttle response. i dont have the money to throw in gears along with the 4.0 i dont want to build up my 30/35 when i plan on swapping axles down the road so ill just let them be right now, im not going over 33s for awhile so for what i do they are just fine. but the intake and TB are what seemed to help the most after a good tune up
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Unread 06-19-2013, 09:20 AM   #10
Jeeples
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99+ Intake manifold swap, bored TB, header (I had a Pacesetter on my '94 Wrangler and it was a great replacement for the stock manifold), high flow cat, exhaust and '703 injectors would make a nice difference for about $1k, assuming you do all the install work yourself. You can get some nice roller rockers from Yella Terra, but they cost $texas.

Other than that, you'll want to regear, but that can cost substantially more if you don't do it yourself. Being that you're only running 31's, I would do what I mentioned first and wait until you know what tire size you ultimately want to run before regearing.
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Unread 06-19-2013, 09:27 AM   #11
JohnnyZJ
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gearing will utilize what power your existing motor has.

i can't wait to run 4.88s and 33s. be a rocket. i'll roast civics

you can add all sorts of stuff to your motor for better horsepower. but the added power still only comes at higher RPM. its torque that drives your motor at lower RPM; and all that crap won't increase it much. so if your motor is still chugging along at 2000rpm the only difference you will 'feel' is the one you manifest in your mind to try and justify all the money you just spent.

only way to get more ponies out of a 4L is to go internal; aka stroke it.

unless you really, truly feel the engineers at Jeep that designed a motor that can easily go half a million miles (the venerable 4L) 'missed' something when building the motor to make it stronger, and more reliable.

but hey, who am I right?
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