Best option for increasing HP?

[4x4junkie]

I'll toss in another vote for 4.56 gears since you mentioned the possibility of going to 33" tires (and also given your concerns about power).

I have 33" tires with 4.10 gears on my '94 4.0L w/5-speed stick... It's what I would call adequate, but nothing more. From the beginning I wished I had done 4.56, but with the high cost of regearing, never could justify doing it all over again just to go from 4.10 to 4.56). At 65MPH it shows maybe a hair under 2200 RPM in 5th. 4.56 would put it closer to 2400 @ 65MPH.

If you stay with the 31s though, then yeah 4.10 gears.

 

[Shran]

Build it for what you want to end up with, rather than continually putting bandaids on stuff to make it better. It hurts to regear axles more than once.

Even with appropriate gears you may find it lacking. Franklin's advice about getting a bigger truck is sound... I know you don't want to... but just speaking from experience here, I built my "overland" rig out of a '92 Explorer and I feel that I've just maxed out what the RBV platform is capable of, at least with the stock drivetrain. There is a significant amount of additional weight with the roof rack & equipment, awning, bumpers, winch, skid plates, 15 gallon water tank, fridge, camping gear... plus passengers & gas. I've only got 30x9.50x15 tires on it, and 4.10 gears, and it's seriously a turd when I'm fully loaded. Keeping up with highway speeds is hard.

 

[holyford86]

Build it for what you want to end up with, rather than continually putting bandaids on stuff to make it better. It hurts to regear axles more than once.

Even with appropriate gears you may find it lacking. Franklin's advice about getting a bigger truck is sound... I know you don't want to... but just speaking from experience here, I built my "overland" rig out of a '92 Explorer and I feel that I've just maxed out what the RBV platform is capable of, at least with the stock drivetrain. There is a significant amount of additional weight with the roof rack & equipment, awning, bumpers, winch, skid plates, 15 gallon water tank, fridge, camping gear... plus passengers & gas. I've only got 30x9.50x15 tires on it, and 4.10 gears, and it's seriously a turd when I'm fully loaded. Keeping up with highway speeds is hard.

I've got a 4.0 swapped 86 long bed with 4.56 gears and 33s, along with a bunch of other stuff added to it, which increased weight, it's adequate while not towing a trailer but with even the smallest one, about 50mph was about all I could do going up any sort of grade. Cue hand built supercharger adapter and 6 psi, now it's got adequate power but I'm at the absolute limit of the drivetrain, I also understand doing this sort of mod is outside of the skillset of many. I've done this only because of the sentimental value the truck has to me, that's it. If you are running at or near the gvwr of the truck and would like to keep up with traffic, something larger may be a better choice and your fuel economy and reliability would most likely be better.

 

[idontknowwhatimdoing]

Thanks shran and hf86, you're absolutely correct. I do realize there are limitations to such a small truck. Everything matters when exploring mods, It will only take so much. I was hoping there were some options to help me balance the performance and capabilities, but it I am going to have to live within it's small truck limits, or spend a lot over time in appropriate bites to absolutely max out what it's able to take. At heart I guess I am just a gear junkie, like having the biggest and baddest. I've multiple tents, bags, pads, harnesses, enough rope and cord to fix a mile long canyon, etc... And water, extra fuel, food, etc... Even though it's just me, being equipped for weeks of dirt roads and hiking and canyons is a noticable load. Not excessive, but noticable. And to add even, say, front (with winch) and rear off-road bumpers with fuel mounts would add to that already noticable load. But I love, absolutely love, the truck! I know it. I have zero qualms or worries anytime I hit that dirt. I've had 6+ years now of worry free performance with a bone stock truck other than a minor lift to accommodate the 31" tires. And I like the compact profile.

Again, thanks for bearing with me, and especially for all the advice and comments, this has really helped me see what is really important and what is just desired.
Or maybe I'll start hitting those progressive slots hard, win the mega millions. Then I could afford to build a really bad ass rig! That sounds like a reasonable plan.

 

[Shran]

I've got a 4.0 swapped 86 long bed with 4.56 gears and 33s, along with a bunch of other stuff added to it, which increased weight, it's adequate while not towing a trailer but with even the smallest one, about 50mph was about all I could do going up any sort of grade. Cue hand built supercharger adapter and 6 psi, now it's got adequate power but I'm at the absolute limit of the drivetrain, I also understand doing this sort of mod is outside of the skillset of many. I've done this only because of the sentimental value the truck has to me, that's it. If you are running at or near the gvwr of the truck and would like to keep up with traffic, something larger may be a better choice and your fuel economy and reliability would most likely be better.

I would go that route if it wasn't something I intended to drive across the country. Custom stuff in that scenario is sometimes not a good thing if I have to track down oddball parts.

I would love to do a supercharged 4.0, maybe I will on my stepside truck someday!

 

[holyford86]

I would go that route if it wasn't something I intended to drive across the country. Custom stuff in that scenario is sometimes not a good thing if I have to track down oddball parts.

I would love to do a supercharged 4.0, maybe I will on my stepside truck someday!

In my case, I wouldnt hesitate to drive across the country, the parts I used are all factory parts for relatively common stuff other than the custom made adapters whicch are unlikely to fail, and if they do, are made from mild steel so they would be easy to repair.

 

[gaz]

@idontknowwhatimdoing ,
If you actually want more power, as mentioned above there is more power, performance and economy in these engines. If you have an engine in good mechanical condition, consider optimizing it's EFFICIENCY.

There are three areas that these respond well to:
1) increased compression ratio, for each full point if compression increase you can expect 6hp.
2) complete balance of the entire bottom end, this will yield a 10% increase in performance (hp, tq and economy).
3) improving the air flow in the top end (performance valve job, verify the valve seats and seals are serviceable, flow bench port work to heads/intakes, custom cam regrind, insure valve train is in top shape)

If you compliment all three areas with a suitable exhaust, good fuel and keep it tuned well, you can expect +60hp/+50tq and much better fuel economy (due to the improvys in the hp to weight ratio).

In the end it will not be a race car or a race engine but it will be capable of using less resources to do more work...after all, it's a truck.

NOTES:
• removing the crankcase driven fan for an electric fan will reduce the load felt by this engine and let it make the same amount of power, more efficiently (you will see improved fuel economy).
• any extra measure spent keeping this power plant cool is worth it's weight in Au. An engine oil cooler is a very economic way to help keep it running at designed operational temperature.
• if you know that you will need more than 210ho/270tq, considering a different engine may be a more cost effective route.