Upgrade experience?

Hey all. Great site with lots of technical help. I've got a 73 a CJ 5 resto-mod that I've worked over for about 8 years. Phase 1 was a frame off rebuild. Phase 2 was dialing in some issues, particularly for safety and drivability. Phase 3 will involve some major mechanical upgrades. I'd like to know others experiences with the following plans.

What I have today:

73 cj5
Glass tub and fenders
Rebuilt, bored 258. Howell TBI conversion. Clifford headers
T14 with Dana 20
44 rear and 30 front. I think they are original, but the rear track is narrower, which makes me wonder. I've got G2 spacers on the rear so the track is the same.
OEM replacement springs. Upgraded shackles with 1/2 lift
1 inch body lift to fit the glass tub
SSBC disc conversion on the front.
Power steering upgrade.
Retro sound model 2. Kenwood 1200w amp. 4 x focal 6 inch and an 11 inch sub under the seat.
10.50 x 15 x 32 TSL swampers on procomp allows
Adco sway bars front and rear
Good wiring all around, battery, etc
Heavy duty steering linkage with procomp stabilizer
Plain old Monroe heavy duty shocks
KC hilites

The jeep behaves pretty good. The swampers softened up the ride, but it is still pretty rough
The t14 has been rebuilt, but it still isn't a very smooth. Getting into 3rd clunks a bit
My Dana 20 has the 2wd low option, meaning it is probably in need of a rebuild.
The gauges are spotty. I guess on fuel level.
It stops, but not very quickly, even with the discs.

I use the jeep to putt putt around. Beach, bar hop and every now and then a mud hole. No crawling, Louisiana is flat and muddy. Top down on country roads with a special lady friend. That sort of thing.

Here is what I'm thinking about:

Pocket flares to trim the tub. The 32s rub on the back
Yj spring conversion. There are some nice kits. Any comments on how they ride? I was thinking of going OME 2.5 inch lift. Any recommendations on shocks. I'd like to smooth it out some. Do I need the lift? I don't really want a tall ride due to roll over concerns.
The t14 is driving me nuts. It is slow off the line and I'm turning a lot of rpms at 60 mph. Worst of all worlds. The Dana 20 needs to be rebuilt. I was thinking a t18 or nv435. I'd like something with an overdrive though. I may go with a Novak set up already put together. I'm worried about drive shaft angles, etc. especially if I do the yj conversion.
Power brake conversion would be nice I think. I do want a ride that is safe.
Custom bumpers and a winch on front. Tire carrier on back.
14 gallon fuel tank. I run out after 100 miles right now.
The speed hut gauges look nice and I think are really cool at night
Turn the exhaust to the side to keep fumes out of the cab. Maybe an open exhaust
The spacers on the rear axles bother me, I worry about them failing while I'm going down the highway.
I really would like to install lockers at some point. Just seems a jeep needs them.

Any advice comments are appreciated. What would you do first?


Im in no hurry. I've got years to do all this.

 

Complete overview of the jeep is needed yet its best to focus on one problem at time.
Fix the main issue them move on.

Looks like the gearing is the main complaint.
Changing transmissions will have zero effect on the Final Drive Ratio.
What Differential Ratio are you running ?
Sounds like you have the optional (1972-1975) 4.27 differential gear sets.
258 suggests you need relatively high FDR to attain highway cruise speed at engines maximum torque velocity.
You should seriously consider installing either 3.73 or 3.54 differential gear sets.
While your at it you can also install your preferred traction devices.

If the transmission performance or its gearing remains a problem you can upgrade that next.
Same goes for the transfer case.
If you go to 3.73 FDR or 3.54 FDR you may want to consider Tera low gear sets in the transfer case.
The transmission and transfer case gearing should be considered as a combination along with all other available gear selections.

 

On the braking issue, if you don't have power assist, use organic, not metallic pads. They work much better than metallics if you don't have power brakes.

 

I don't trust a CJ5 to drive fast. Better to get an other toy, and keep te CJ5 for ballads.

 

They are organic. The conversion was set up for no power assist from the start.

 

I think it may have the 4.27. I always assumed 3.73 because it is a very basic jeep. At 55 mph it is turning a lot of rpm. Don't know exactly how much, but it is wound up. 10 mpg is what I average and I can pretty much ride around in 3rd gear in all situations.

 

The 4.27 axles are pretty desirable, if you have them. If you were local, I would trade you straight across for my 3.73s.

4.27s, especially with 32" tires, should be fine on the highway. if you've never owned a Jeep, you may be overly sensitive to the engine and drivetrain noise. 60 mph with 4.27 gears and 32s is only 2690 RPM. That's not excessive, even for the low-reving 258.

If you are only making 10 mpg, something is wrong with your driving style or the Jeep. If I kept the speed down, I would expect low teens or even 15-16 mpg, especially with the Howell TBI and headers.

What's your hot idle oil pressure? Hot cruise? Compression?

The factory fuel tank capacity is 14 gal, IIRC.

The T-14 is an easy if slow shifter. If it clunks going into gear, it needs refreshing. Why do you think the transfer case is worn out? Is it noisy? Just because you can find 2LO does not mean anything.

Sounds like you ahve a lot to work with ... I would definitely get what's there functioning 100% before I thought about upgrades.

 

Also - likely the Jeep was delivered with the H78-15 Polyglas tires, which are about 28 inches tall. Realize that, with 32" tall tires and an indicated 60 mph, that's actually about 70 mph (60 * 32/28 = 68.6).

Maybe you'll want to get a tachometer and see how fast you are going from the engine RPM. You can also check your indicated speed with the speed from a GPS or cell phone GPS app, or time a measured mile at a specific speed. All those will give you an idea of how fast you are actually going at some indicated speed.

 

The 32s we're put on a week ago. With the weather, I haven't driven it enough to know how it is working. I've had an81 cj7, 92 wrangler, 01 tj. Probably half a million miles behind the 4.2/4.0 Six, so I'm very familiar with the engine. This t14 is new for me though, and it is not a very good transmission. Shifts very slow and not very smooth. I've had it rebuilt twice at this point - once with the original rebuild and again last year. Figuring out what is in the differential is a good start though.

 

Wat part of Louisiana?

 

Lafayette

 

If I'm not mistaken the maximum torque for the stock AMC 258 is right at 1800 RPM.
So 1800 becomes the maximum efficient RPM range for this particular engine to operate.
Anything above 1800 RPM is going to provide more HP but will yield no more torque.
So going above 1800 rpm only serves to increase vehicle speed and will shorten the engines service life.
Yet it will not shorten the 258 engine service life any more than any other engine operating at the same range.
That's why I claim the 258 is ideal with high ratio differential gears.
Problem is that installing tall differential gears will also serve to increase the crawl ratio.
It's a matter of synchronizing the engines optimum RPM range with the proper gear ratios.

 

Well, I don't know how you define screaming. It is what it is. My J10 pickup turns faster than that at 65 on the highway. It's noisy, but it's fine. A lot of the noise comes from the fixed fan, and the thin rubber floor mats provide little sound insulation. It has a quiet exhaust, which exits at the back of the truck, well back from the cabin. A 258 in good condition should be able to turn that speed all day and night.

This may or may not be ideal. It takes power to lift the vehicle over hills and overcome wind resistance (a mighty barrier), and power is proportional to engine speed. But you'd like to have the lower gearing to provide more force at the rear wheels at low speeds. It's always a compromise.

You might want to put some insulation on the floor, to dampen the noise from the tires and drive train. Helps a lot. I had two layers of jute padding under carpets in my '73 CJ-5, with quiet factory exhaust. 4.27 axles and 75-80 on the highway, no problem. Probably was not a good idea to drive that fast, but most of the noise came from the flapping soft top, not from the engine.

 

Why is peak torque most efficient? I'm not convinced that it is.

 

If you look at a Dynamometer chart you will see two things.
The Torque curve and the HP curve for that particular engine.
The HP always increases as the RPM increases.
The Torque reaches it's peak at a much slower crankshaft velocity.
Available Torque typically takes a dive after maximum torque has been reached.
At that specific RPM, maximum work is derived per volume of fuel being consumed.

Most stock automotive engines develope maximum torque anywhere from 1600 to 3200 RPM.
Some diesel engines and a very few gasoline engines will develope maximum torque output as low as 1200 RPM.

This becomes the topic of RANGING.
Ranging encompasses both "crankshaft velocity" (RPM) and all drivetrain gear ratios.

I

 

Here is an example of the Torque and HP curves I am referring to:
http://cj3b.info/Tech/EngineDyno.html

This particular engine puts out maximum Torque at 2200 RPM.
Likewise it will promote maximum efficiency when at 2200 RPM.

Maximum Torque is directly observable via the senses.
Try accelerating the vehicle when operating from various RPMS.
Maximum G force is felt when accelerating from the maximum torque output.

 

With all due respect Ken, you aren't telling me anything new, except for using the term "ranging."

I understand that hp is torque times rpm. Torque is angular force and f=ma, so the more torque the faster the acceleration. Power is energy per unit time, or said differently, your rate of energy utilization. Power is what you need to overcome drag and move the car forward. Drag can come from many sources, including hills, rotating friction and wind resistance. The less power you need to move the car a given distance, the more efficient the conversion of fuel is.

So why is peak torque the most efficient operating point? I don't see any physical argument for why that should be so. Maybe you could point to some references about ranging?

Sorry if I'm beating up on you here, but this is of interest to me and I'd like to learn more.

 

Tim, I sure don't take any offense to any of my claims.
In fact I'm happy that others are serious interested regardless of their conclusions.
Specifically no one else I know of but me has ever claimed the peak torque output to be the most efficient output for a particular engine setup.
We really need to start up a separate topic for this as it could become quite involved.

Jeep Ranging is a compound series of drivetrain concepts that is fully dependent on ones comprehension of engine design/analysis and more.

Engine design, concepts, analysis and comparison becomes an extremely in depth topic all on its own.
We must fully understand all that before we can ever hope to benefit from the topic that I call "Ranging".

I'll start another topic .....