I have a '97 Wrangler and I want to run dunes. I expect to port the heads and mabe improve the valve train. I will air down the tires of course. What do I need to do to run dunes in my stock vehicle? I expect that lower gears 4.88/5.38 would be nice with my ax15 and 31" tires. I realize that the vehicle weighs 3850 lbs which makes this magical thinking. Mabe my jeep needs to loose some weight.

Cant get 5.38 gears for your dana 35/30 combo. 4:88's would get you torque, but not much topend with 31's. Unless you get a port polish for free, i think your money would be better spend on a chip, header, throttle body spacer :shaking: I'd just go out their, air down and mash into the throttle...that sounds like a good time.

i think your money would be better spend on a chip, header, throttle body spacer.

...:shaking:

OK, or just drop a 5.7 in it.

Cant get 5.38 gears for your dana 35/30 combo. 4:88's would get you torque, but not much topend with 31's. Unless you get a port polish for free, i think your money would be better spend on a chip, header, throttle body spacer :shaking: I'd just go out their, air down and mash into the throttle...that sounds like a good time.

Oh boy. The chip is a waste of cash. The headers, a cam and a throttle body with more fuel pressure always works wonders.

Unless you get a port polish for free, i think your money would be better spend on a chip, header, throttle body spacer

I wouldn't bother with the header. The others will make an improvement.


I run the dunes in 2WD high in my TJ with 35's (4.56's). Get some sand tires (or mild paddles) and go. 4.10's will be all you need with a 31" tire. (If you have stock 3.73's use those) You don't need the torque in the dunes. You aren't crawling.

I have Borla exaust manafolds. So with paddels and 200 hp I should be able to get through the dunes? This little 4 liter should really breath with better ports and the newer intake manafold. I might just go for it with my 3.07:1 gears and 31" tires, which is what I really want to do. I want to run up Test Hill at Gordon's Well.

For what its worth, 200 hp seems optimistic. I have not seen a header make that type of power. Mine lays down a whopping 134 (or 138) at the tires.

Drop the pressure to 8-10 psi and let her rip. With a 31 you should be able to get some wheel speed going.

Look on Dezertrangers.com as the ranger guys often have mild sand tires and rims in your size and bolt pattern on the cheap. Wider would help with floatation. Taller might require some gear work.

If you want any respectable power for the dunes you really need to consider doing a stroker or a v8 swap. And crawler gearing behind 31" tires will get you nowheres. You want wheel speed, you can't be topping out gears or you will be stuck ALOT. You can avoid this if you have an auto. But if you have a stick you need to keep the gearing somewhat higher and get some horsepower.

THeres nothing that you will do to a stock 4.0 that will net you any serious gains short of doing a full stroker kit. Even then the more radical they get, the less reliable they get also. For any serious horsepower, I would consider doing the V8 swap if you can afford it.

Your only real choices are:
Stroker with a mid range cam
V-8
Forced induction on the 4.0

All those bolt on "Go fast Parts":shaking: really don't amount to big gains. You can throw every bolt on part to your 4.0, then you close to the price of doing any of the 3 mentioned above.

Is this a dune only jeep? I have a 4 banger, 33s, and stock 410. I run low range and use all the gears. And do what I do DRIVE IT LIKE ITS A RENTAL:)

Is this a dune only jeep? I have a 4 banger, 33s, and stock 410. I run low range and use all the gears. And do what I do DRIVE IT LIKE ITS A RENTAL:)

While posters like this are always fun to watch in real life, don't do this.:laughing:

Is this a dune only jeep? I have a 4 banger, 33s, and stock 410. I run low range and use all the gears. And do what I do DRIVE IT LIKE ITS A RENTAL:)

I second this 100%
The best times Ive ever had in the dunes were in my 4 cyl YJ in Low (2.72) and on the rev limiter and mashing the crud out of it. Busted motor mounts, bent axle tubes, torn off oil filter, you name it.
But then thats why its in the driveway in pieces waiting for new life.

just air down and go have fun. you'll be amazed where it will go. watch out though, that Dana 35 is gonna bend. no matter what ya do.:D

so save your money for a new rear end.

I run the dune's here in california pismo and Glamis 4-6 times a year. I have had my yj with 4.0 and 4.10 gears running 33" bfgs. My jeep goes up comp hill and olds. You have to air down. I run 7-9 psi. the guys I go with all have v8's in their jeeps and I am on their ass all the time. You would be surprissed!!!!!! Air down and put it in 4Lo and go. I usually run 3-4 gear on must of the dunes. some times 5th in big bowls..... I love it. Someday when I break the 4.0 I am going 5.7 with 700r4 and a dana 44 in the rear and maybe some paddles. Be carefull not to hit the WHOOOP-DEEEE-DOOOOOO's To hard. you will bend/break something (DANA 35)....... have fun.

BTW. I have been flogging my 4.0 for about 4 years out on the dunes. and All I have broke has been U-joints. that was before the SYE and DC drive shaft.

"Your only real choices are:
Stroker with a mid range cam
V-8
Forced induction on the 4.0"

I would invest my energies into the ports and the intake manafold. I think that with a die grinder there can be gains in air flow, and of course I would find one of the later intakes. I would increase fuel pressure and mabe get larger injectors with new valve train. You say stroker with mid range cam. Is that to keep the horsepower at lower rpms? Is 8000 rpm too high on a balanced 4 liter and 6.30:1 gears? It would top nearly 150 mph.

"Your only real choices are:
Stroker with a mid range cam
V-8
Forced induction on the 4.0"

I would invest my energies into the ports and the intake manafold. I think that with a die grinder there can be gains in air flow, and of course I would find one of the later intakes. I would increase fuel pressure and mabe get larger injectors with new valve train. You say stroker with mid range cam. Is that to keep the horsepower at lower rpms? Is 8000 rpm too high on a balanced 4 liter and 6.30:1 gears? It would top nearly 150 mph.

I assume we are talking a 4.0 here. So with that being said you can try to run a later model intake I think its like 00'+ as they have better flow and design characteristics but you won't see that many gains. Basically what Jpfrk2001 said are your only real options if you want to gain any significant HP. The stock TJ head and intake already flow pretty damn good to begin with.

Mid range cam would make the powerband a little lower on the 4.0, instead of higher in the RPMs like it is stock. 8k RPMs is way too high. With 6.30 gears you would have a top speed of about 98 mph +/- mph with gearing that low and your engine would be screaming at the red-line. Thats also assuming you have axles big enough to install gears that tall, your stock ones won't.

"Your only real choices are:
Stroker with a mid range cam
V-8
Forced induction on the 4.0"

I would invest my energies into the ports and the intake manafold. I think that with a die grinder there can be gains in air flow, and of course I would find one of the later intakes. I would increase fuel pressure and mabe get larger injectors with new valve train. You say stroker with mid range cam. Is that to keep the horsepower at lower rpms? Is 8000 rpm too high on a balanced 4 liter and 6.30:1 gears? It would top nearly 150 mph.

I assume we are talking a 4.0 here. So with that being said you can try to run a later model intake I think its like 00'+ as they have better flow and design characteristics but you won't see that many gains. Basically what Jpfrk2001 said are your only real options if you want to gain any significant HP. The stock TJ head and intake already flow pretty damn good to begin with.

Mid range cam would make the powerband a little lower on the 4.0, instead of higher in the RPMs like it is stock. 8k RPMs is way too high. With 6.30 gears you would have a top speed of about 98 mph +/- mph with gearing that low and your engine would be screaming at the red-line. Thats also assuming you have axles big enough to install gears that tall, your stock ones won't.

98x.79x6.3x336
______________=5287 rpm
31

so yes your right, if I run out of breath at 5287 rpm my top speed would be 98 mph. I was thinking I could get my intake, heads and exuast to breath to 430 hp at 8000 rpm. Is that way more than the heads can support or is that rpm unreasonable?

150x.79x6.3x336
_______________=8092 rpm
31

98x.79x6.3x336
______________=5287 rpm
31

so yes your right, if I run out of breath at 5287 rpm my top speed would be 98 mph. I was thinking I could get my intake, heads and exuast to breath to 430 hp at 8000 rpm. Is that way more than the heads can support or is that rpm unreasonable?

150x.79x6.3x336
_______________=8092 rpm
31

Use this to calculate your gearing and engine RPMs. You can change your tranny, t-case, gearing etc etc and even compare setups. Its a really great tool.

http://www.grimmjeeper.com/gears.html

As for 430 hp and 8000 RPMs I think that IF you could get that kind of horsepower and performance from a 4.0, not only could it be borderline unreliable, the cost alone for you to do this would probably equal a whole VERY nicely beefed up V8/tranny/t-case swap. If you run that kind of HP your stock tranny and t-case, hell even the axles won't hold up, so theres even more cost ontop of the engine building costs. 400 HP is also pretty obscene for a SWB jeep with small tires.

You won't be able to reach that high of horsepower just by balancing the rotating assembly, porting and polishing the heads and giving it a intake upgrade. That motor will peter out long before it gets to 8k RPMs. You will probably have to run a combination of....race fuel mix, run high compression pistons, port/polish the heads (probably custom head work for clearance issues, valves, springs etc.), install one hell of a cam plus lifters, stroke it or turbocharge it, if not both, upgrade the fuel system to a bigger fuel pump and bigger injectors, the exhaust will probably be too restrictive, and you will have to burn a custom chip for the fuel injection ratios. Then you need to scrap your tranny for a beefier one, this will require expensive adapters, this goes for the T-case as well, your axles will shit the bed as soon as they hook up, If you build a stronger set yourself they are mildly expensive, if you have them built or bought, a set of axles runs anywheres from 5k-10k alone. Speak with jpfrk2001, he's running a high HP blown 4.0 to see what hes running for HP numbers and if he's had any issues thus far.

I'm not bashing your build, but there have been guys on here who have tried it before and everyone of them was disappointed in the end. If you are set on doing it, more power too you. But you can gain alot more for alot less. What you are trying to attain costs some $$BIG MONEY$$ using the engine as a base.

A little side question have you ever been in a Jeep with even 300 hp or 250? Its pretty damn snotty. HP goes along way in a Jeep as opposed to other full size 4x4s

Air down and have fun.
The sand is quite dif than dirt you will need to keep airing down till you can get around.
1 or 2 psi makes a big dif in sand.
Running the dunes at night is soooo much more fun than the daytime.

Waynoka, OK open 24/7

Air down and have fun.
The sand is quite dif than dirt you will need to keep airing down till you can get around.
1 or 2 psi makes a big dif in sand.
Running the dunes at night is soooo much more fun than the daytime.

Waynoka, OK open 24/7

X2
Go have some fun with what you got. If you still feel the need for speed and you can afford a $50,000 sand duner Jeep go for it -after you get some experience in what you have now. Just my .02

36X SX's, aired down to 2-3psi in the back and 6-8psi in the front.
4.56 gears

It's sand, your engine will do fine on it's own. When I play in sand my engine spends a LOT of time between 4,000 and 5,500rpms just doing stupid shit.

Stupidist (and of course coolest) so far was climbing a 30' or so vertical sand wall.

36X SX's, aired down to 2-3psi in the back and 6-8psi in the front.
4.56 gears

It's sand, your engine will do fine on it's own. When I play in sand my engine spends a LOT of time between 4,000 and 5,500rpms just doing stupid shit.

Stupidist (and of course coolest) so far was climbing a 30' or so vertical sand wall.

LIAR!!!!! sand can only pile up at an angle of repose of about 30-35* beyotch!!! :flipoff2:

This is one hell of a hill climb that I always liked watching, from the Norwegian side of the world :flipoff2:

http://www.youtube.com/watch?v=XxcXgaVRCLU

You can have tons of fun totally stock. 3.07 gears in the sand are the only place they do alright. As many others have said AIR DOWN. Start under 8 lbs and go as low as you dare. 3 lbs is a good stoping point. Always have a good tow strap. Good tow points front and rear. The other nice thing to have is a way to air up when your finished. So on board air or powertank is a way to spend your cash before engine mods. Spend some time when you get to the dune talking to the old timers to see what work and what doesnt. Just like every where else tires are next. For sand the wide the better. Let us know when you return how it went.