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General Forums => The Mess Hall => Topic started by: mack90 on February 09, 2008, 05:47:23 PM

Title: Will I have decent acceleration?
Post by: mack90 on February 09, 2008, 05:47:23 PM
I have a big pile of stuff ready to put on my 1998 manual tranny 4 banger jeep, and was just wondering what I should expect.  4.88 gears, 33x12.5 tires, winch body armor tire carrier, kilby skid, jeeperman side bars, electric cooling fan, firepower ignition, freeflow cat/exhaust.  This is a little weight, should I expect no acceleration at all with these added?  I have a dana 44 axle I could put in too.  How much weight difference is the 44 over the 35?
Title: Re: Will I have decent acceleration?
Post by: Jeffy on February 09, 2008, 06:28:53 PM
I have a big pile of stuff ready to put on my 1998 manual tranny 4 banger jeep, and was just wondering what I should expect.  4.88 gears, 33x12.5 tires, winch body armor tire carrier, kilby skid, jeeperman side bars, electric cooling fan, firepower ignition, freeflow cat/exhaust.  This is a little weight, should I expect no acceleration at all with these added?  I have a dana 44 axle I could put in too.  How much weight difference is the 44 over the 35?

The gears will help A LOT.  That's going to be your #1 upgrade.  Even with all the extra weight, it should be OK.  I'd go ahead and install the D44 if you're going to be doing gears anyway.  You'll probably see a larger drop in performance from poor gearing and poor aerodynamics then with added weight.
Title: Re: Will I have decent acceleration?
Post by: mack90 on February 09, 2008, 07:03:45 PM
Thanks for the info.  I am building this jeep for a life long farm/play vehicle.  I noted taking my rubicon out to the farm it would really suck down some fuel.....so now a four cylinder.  Any idea on fuel economy with this set-up?
Title: Re: Will I have decent acceleration?
Post by: Jeffy on February 09, 2008, 07:20:08 PM
Thanks for the info.  I am building this jeep for a life long farm/play vehicle.  I noted taking my rubicon out to the farm it would really suck down some fuel.....so now a four cylinder.  Any idea on fuel economy with this set-up?

That really depends on what your jepe currently gets and how you drive it.  I get around 16-18mpg with my 35's normally.  If I keep the speeds down to 60-65mph on the highway and follow behind a large truck, I can still get into the 20's.
Title: Re: Will I have decent acceleration?
Post by: Bounty Hunter on February 09, 2008, 07:57:29 PM
With 33" and 4.88's your power and mileage will be down just a little bit from stock, but liveable.
Title: Re: Will I have decent acceleration?
Post by: garydubf on February 09, 2008, 10:52:14 PM
I'm Get 16-18 and hit 20 on long flat drives w/out a e-fan.  4.88's and Heavy ass 35 Toyo's.  Power wise is relitively close to stock but in a head wind forget passing or keeping up with the flow of traffic.  Short of super charging I really don't think that you'll ever be pleased with the power out put of the 2.5 without some major mechanical mods and at least 5.13's.  If I had it to do all over again with the same money I'd save for the V8 swap and dana 44's, which is the direction I'm going now. :confused:
Title: Re: Will I have decent acceleration?
Post by: bestos on February 11, 2008, 01:44:16 PM
u getting aluminum wheels or steelies,

rotational mass is a factor, aluminum is less than steelies.

steelies slow my acceleration
Title: Re: Will I have decent acceleration?
Post by: cmgorman94 on February 11, 2008, 02:24:41 PM
I have 35s and 4.88s, I usually get around 16 mpg.  If you have a D44, either put it in or give it to me.  If you have the better axle, why not use it?
Title: Re: Will I have decent acceleration?
Post by: jfrabat on February 11, 2008, 02:34:57 PM
I have 35s and 4.88s, I usually get around 16 mpg.  If you have a D44, either put it in or give it to me.  If you have the better axle, why not use it?

cmgorman94, I disagree with your evaluation; I think he should give it to ME!!!   :clap: :fitz:
Title: Re: Will I have decent acceleration?
Post by: mack90 on February 12, 2008, 10:52:15 AM
Thanks for the information.  I was hoping to get 18ish with 33's and 4.88's.  The main thing I wanted was better fuel economy at the farm which is usually around 10mph driving.  My rubicon would go through a 3/4 a tank a day at the farm.
Title: Re: Will I have decent acceleration?
Post by: dexetr30 on February 12, 2008, 11:06:14 AM
Doesn't matter if it's a 2.5 or a 4.0, Jeeps are not economy cars. The 4 banger doesn't do much better than the 6 when it comes to mpg.
Title: Re: Will I have decent acceleration?
Post by: bestos on February 13, 2008, 05:47:17 AM
like i said above, i hope you are getting aluminum wheels, that will save the mpg some.
Title: Re: Will I have decent acceleration?
Post by: mack90 on February 13, 2008, 08:06:16 AM
My plan is aluminum 33 10.50's for the street, have a set of 33 12.50 swampers on beadlocks for the farm.  I was basing the mileage on the 4 cylinder getting better economy in town than the six.  I'm hoping it will apply at lower speeds at the farm too.
Title: Re: Will I have decent acceleration?
Post by: Jeffy on February 13, 2008, 01:13:07 PM
My plan is aluminum 33 10.50's for the street, have a set of 33 12.50 swampers on beadlocks for the farm.  I was basing the mileage on the 4 cylinder getting better economy in town than the six.  I'm hoping it will apply at lower speeds at the farm too.

If you keep the speed down it should do a bit better then a comparable 6.  When you start driving faster say over 55mph, you are at a big disadvantage because of the lack of available torque from the engine.  Wind resistance starts becoming a factor at around 40mph and grows exponentially as the speeds increase.  Then is when you're flooring it to keep speed and that just kills your mileage.  This is why proper gearing is important especially so for the I4.
Title: Re: Will I have decent acceleration?
Post by: BOOGIE444 on February 15, 2008, 09:05:28 AM
I have 33 x 12.5 and 4.88, no other mods that add weight though.  My performance is almost identical to stock.
Title: Re: Will I have decent acceleration?
Post by: neale_rs on February 15, 2008, 09:11:46 AM
I have 4.56 gears and plan to upgrade to 33s soon.  Based on previous posts it seems 4.88 is ideal, but how bad will 4.56 be on road?
Title: Re: Will I have decent acceleration?
Post by: Bounty Hunter on February 16, 2008, 09:50:43 AM
4.56 won't be too bad on the road.

A small switch from 4.56 to 4.88 wouldn't be worth the time and money in my opinion. 
Title: Re: Will I have decent acceleration?
Post by: Jeffy on February 16, 2008, 11:15:47 AM
I agree, it's not worth it to go from 4.56's to 4.88's unless you're installing the gears yourself so there is no labor.  The difference is around 2-300RPM which can make a difference but is pretty small unless you do not plan on going any larger ever.You will not recoupe any labor costs by selling the old gears which is usually half the cost.

Only reason I geared to 4.56's was because back then, 4.88's weren't on the market.  I also installed them myself so the cost of changing gears was minimal ($408).  I've thought about gearing lower but it's just not worth it.  I'd rather gear to 5.38's and leave the front till I swap it out but by then I might just swap both axles out and start over.

I do know someone who went from 4.56's to 4.88's and liked the difference but the law of diminishing returns really rears it's ugly head.
Title: Re: Will I have decent acceleration?
Post by: neale_rs on February 18, 2008, 08:34:10 AM
When  I regeared I was thinking of going with a 2.5 OME lift and 31s but then got caught up in the bigger is better trend and now think 33s is the way to go  :biggrin:.  It's not a daily driver so the on road performance isn't critical.  Also, I'll hold off on the 4.0 throttle body and ignition upgrade until after the 33s so that I can feel I got some power back (have to manage my psychology to avoid spending too much)!  Thanks for the opinions.