gutless YJ

Re: ride

berettajeep said:
Tampering with the emissions is illegal :roll:

Maybe so, but that little 2.5L with no cat will still put less fumes in the air then some of these huge SUV's that are flooding the roads.

Gut the cat.

I really liked my 4 banger in my '92 YJ. I too did alot of the little mods & gutted the cat, but I think I got the most gain from the electric fan conversion. I could easily maintain 5th gear on inclines if I got the speed up over 65-70 beforehand. Real long steep grades would be the exception. With 32's I had her pretty close to how she ran stock. I should mention that I didn't have power steering, which may have been a big benefit.

I wish I still had it.
 

My '94 YJ with 31x10 Mud Kings does okay on flatland in 5th, and depending on the speed, it works ok on hills, too. If I'm at 55-60, I have to downshift to go uphill, but anything over 65 will go ahead and pull up a hill without downshifting. The only mod I've done is to pull the restrictor out of the intake tube. That little mod put me from 16mpg up to 21 mpg, and definitely added some ponies.
 
The Mopar Performance cam made a big difference, mostly at 2500+ rpm where the 4banger is happier anyway. It revs up quicker and is a little more free revving at very high rpm, seems it's happier wound up tight. I had to change out valve springs to accomodate the additional valve lift. Got the Cam from Ebay brand new for $35 from a dealership, since Mopar Performance has discontinued the cams. Valve springs and retainers were another $80 or so.

My cam came from Koller Dodge in Naperville, IL, but I think they ran out a long time ago. They're scarce now, but you can still get performance cams from Clifford, Comp, and other cam manufacturers.

For me it's not just one mod to the 2.5L that makes it more livable, but a combination of all the mods. Most mods compliment each other very well. One of these days I'll be building an adjustible MAP sensor to fine tune the air/fuel ratio to better suit the mods.

I'll plug the 4Bangers United forum here, seems like a good time. Lot of 4banger specific info and jeepers who know a lot about it.
 
sicnic, (Great name!) :D

I am going to play the Devil's Advocate here, if for no other reason than to spark some discussion. :twisted:

Physics and math are our friends.

As an approximation, your little Jeep engine must produce almost nine times the power to propel your Jeepy at 60 MPH as is required to propel your Jeepy at 30 MPH.

Power required varies as the cube of the vehicle speed ratio: doubling the vehicle speed equates to 2 X 2 X 2 = 8. Add in misc. other losses and the approximation becomes 9.

This is why all those intake-exhaust accessories -- if they actually work, and provide small horsepower increases -- are of little practical value at highway speed.

The power required increases geometrically, while the power increases provided by common catalog-type accessories (assuming they actually work) are small and linear. A geometric series will always overtake a linear series.

All those air intake/exhaust goodies might have some value at low vehicle-high engine speeds, but at highways speeds -- forget it.

Other accessories? There is no free lunch -- in life or in physics. The electrical power required to run an electric fan must come from somewhere. That electrical power comes from the alternator. The horsepower required to spin the alternator comes from the engine. More alternator loading, as might be required by the addition of an electric fan, the more engine horsepower required to spin the alternator (When the electrical cooling fan is running).

Your headlights, on low-beam, consume very approximately two engine horsepower. I would guess, without taking the trouble to look it up, that an electric fan would consume roughly the same amount of horsepower. The horsepower gain of an electrical fan, if any; therefore, is the difference in horsepower required to spin a conventional belt driven fan Vs. the horsepower required to spin an electrically driven fan.

With modern declutching belt-driven fans and/or flexible fan blades, the horsepower gain achieved by the substitution of an electric fan will be minimal and of little consequence at highway speeds. It is interesting to factor in here that at highway speeds, most vehicles won't require an engine cooling fan of either type.

Proving once again the Hot Rodders first two Commandments:

(1) Thou shalt not believe that there is a substitute for cubic-inches.

(2) Thou shalt believe that, all other things being equal, the vehicle with the better horsepower to weight ratio wins.

Sad to say, sicnik, but if you want to use 5th gear (overdrive) while going uphill, without lugging the engine, you'll need a bigger engine.

As I mentioned at the beginning of this post, I am playing the D-A here. The above is, however, my take on the situation. Others might well disagree.

I hope those who disagree will chime-in with opposing facts, as opposed to unquantifiable seat-of-the-pants impressions.

Regards,

Gadget

PS: BTW -- you have hills in Kansas? :shock: Does Dorothy know? :wink:
 

4.0 HO

I've just given up on 5th gear, dont need it, jeep does better with out it. after all the stuff I replaced the other day I've increased my MPG from 15 to 17, not much but at $2.03 a gallon it helps. to answer your question inspector YES there are hills in Kansas, you shouldnt believe everything you see on TV. bellieve it or not it dont start getting flat until you get past Ft. Riley which means Kansas is only half flat.
 
Inspector Gadget wrote:
Physics and math are our friends.

Mrs. Mud says, "NOT MINE!!" I, of course, disagree - isn't that what marriage is all about?

Your headlights, on low-beam, consume very approximately two engine horsepower.

Gadget, I think you've hit on my problem (see: gutless TJ post)!!! I guess listening to my John Prine CD's at earbleed level probably robs me of, oh, 20-30HP! No wonder I can't climb hills. :lol:

(1) Thou shalt not believe that there is a substitute for cubic-inches.

Love that quote and, of course, I believe it........but I've been in denial.
 
Gadget, go put your Jeep in fourth gear and take off from a dead stop......how about from 30mph, will your Jeep push that tall gear from 30mph? It accelerates alot faster from 60mph, in that gear, than it does from 30mph doesn't it? You don't have enough power to push that tall of a gear at that low of a speed, but at the higher speed the engine makes plenty of power to push it.

Do the physics take into account the gear ratio and the fact that the engines power varies with rpm?


Thou shalt not believe that there is a substitute for cubic-inches.

Ahhh, the favorite saying of someone who runs a big block engine. It's only true if both engines are operating at the same volumetric efficiency. I've seen too many small block cars take the money from big block cars that I know it's not just a matter of size.
 

IG, how's more current draw on the electrical system cause a drag on the engine and use more HP? I've often wondered how varying electrical loads affect the alternator and it's power taken from the engine.
 
Yes, Toto, there are hills in Kansas...we also have indoor plumbing now.

L14-2.jpg


That is in far eastern Kansas, on my farm. I'll be spending the weekend camping there next week. I live near Wichita, where it is mostly flatland. Go much further west and it's so flat you can see into next week. Around here, most of the hills are either overpasses or the occasional climb up out of a river basin.
 
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