Best engine upgrades for the cost?

[Jerry Bransford]

Awesome Jerry, thanks! If I were ever considering 35’s (I have plenty of room for them) would you say go ahead and go with the 5.38’s (even though I’d be running them w/ 33’s for now) or stick with the 5.13’s? If I’m gonna do gears I’m gonna go ahead and do lockers at the same time...do you recommend a certain gear/ locker combo (brand/size wise) or a spool, welded etc? My LJ is NOT a Rubi.

5.13 is as low as you can go with your non-Rubicon front Dana 30. 5.13 is still better than 4.88 for 35's like my present TJ originally came with. Eaton E-Lockers would be a good choice of selectable locker for either or both axles.

 

[04 LJ]

5.13 is as low as you can go with your non-Rubicon front Dana 30. 5.13 is still better than 4.88 for 35's like my present TJ originally came with. Eaton E-Lockers would be a good choice of selectable locker for either or both axles.

Thanks for the knowledge. I have the stock Dana 44 in the rear. For light to moderate wheeling do you often see an advantage in upgrading the front axle before doing a locker? How about the rear 44? Any trussing type mods, etc. If we’re highjacking this thread just pm me. Thanks!

 

[rasband]

Thanks for the knowledge. I have the stock Dana 44 in the rear. For light to moderate wheeling do you often see an advantage in upgrading the front axle before doing a locker? How about the rear 44? Any trussing type mods, etc. If we’re highjacking this thread just pm me. Thanks!

Upgrading the axle shafts (chromoly) at some point would probably be good, but if your usage skews on the lighter side of off-road you’ll probably be okay.

 

[Jerry Bransford]

Thanks for the knowledge. I have the stock Dana 44 in the rear. For light to moderate wheeling do you often see an advantage in upgrading the front axle before doing a locker? How about the rear 44? Any trussing type mods, etc. If we’re highjacking this thread just pm me. Thanks!

You can install a front locker into your stock front axle with 33's. If you get to 35's it'd be a good idea to upgrade the front shafts with direct replacement 27 spline 4340 axle shafts. The stock rear Dana 44 is up to 35's and a locker for reasonable/common wheeling scenarios.

 

[Rescue6]

Terminal velocity in neutral on the long downhill into Silverthorne is about 73mph, last I checked.

I’ll give it a shot next time I’m up there in the jeep myself. Hahaha

 

[D M]

For 35's with your 42RLE automatic transmission, you definitely need 5.38 gears. Not even 4.88 is enough. Yes I know 5.38 may seem like too much gear and it would be for most other transmissions but it's what your particular transmission needs. I had 4.88 in my TJ with 35's with the same transmission and it was a dog. I regeared from that 4.88 to 5.38 last year and it does much better on the highway now. Even my mpg went up after installing the 5.38 gears from under 12 mpg to over 14 mpg.

Dang thats a nice increase. I have 33s on my tj with 3:73 on the nv3550 and like you said, yeah its a absolute dog on the freeway, barely going to 5th unless im literally going 62+mph I plan to do 4:56 in the future

 

[Flivver250]

I have 33's with the NV3550 and 4:56 gears. Still a tad gutless in 5th. If I ever have to change one of the gears, I'll probably just swap both for 4:88s and call it a day.

 

[chino1969]

I personally believe Sea Foam is today's snake oil. Rarely of benefit due to virtually all US gasolines having more than enough cleaning additives to keep things clean.

Agreed. The claims for Sea Foam reminds me of the old tonics sold by hucksters out of the back of covered wagons. 'Good for rheumatiz, snake bite, woman problems, headache, gout, near sightedness, hearing loss, constipation, and much much more. Useful as a lineament for animal and human alike'. Don't forget Slick 50 and other modern snake oils.

 

[xxdabroxx]

I believe a tune is the best and easiest mod. I have been playing around with mine and must say the difference in performance is obvious. Short of forced induction or internal mods, I believe a good tune is the most significant of mods. I am basing this on results others have seen on various bolt ons.

Here is my inquiry to Flyin Ryan's tune. It was a bit more expensive than I remebered. I bought the Syked software for $365.

View attachment 85271

Is this on a stock engine though or does it have stuff done to it? 15hp is pretty good if that is all stock. I've kept my Jeep engine stock on purpose as I hate dealing with CA smog and CARB approval stickers.

 

[Shawn of the farm]

@Chris sorry for an ignorant question. You mention the long tube headers on a few posts and I want to better understand.

I went to American racing and they have a with and without cat option. Is it eliminating the cat completely? From their picture, it looks like they go from the double cat to a single and then straight back.

Probably some questions that should be directed at American racing but figured you mentioned it a few times so might have the info off the top of your head.

My pipes are rusted and my engine is literally a ticking time bomb. Huge lifter tick. I am planning an engine rebuild or upgrade to a stroker and am trying to get all my things lined up so I can make this as smooth as possible with as little downtime. So since I have to unbolt it anyway I figure the exhaust could be upgraded at the same time.

So my questions is this.

#1
If I am going to upgrade/replace the exhaust do I get the TJ 4.0L Jeep Long System with cats to stay close to stock operations? In their picture, it looks like it has the 4 sensor spots and it looks like it has a single cat at the collector.
#2
I would couple this with a 3" cat back exhaust system to finish the system off right?

Thanks for all the good info. Also I am reading up on your stroker posts. I think that is the direction I want to go.

Cheers

 

[TheBoogieman]

Best engine upgrade for the cost ever! I confirmed the HP and MPG gains on my new Butt Dyno.

 

[TheBoogieman]

 

[Chris]

@Chris sorry for an ignorant question. You mention the long tube headers on a few posts and I want to better understand.

I went to American racing and they have a with and without cat option. Is it eliminating the cat completely? From their picture, it looks like they go from the double cat to a single and then straight back.

Probably some questions that should be directed at American racing but figured you mentioned it a few times so might have the info off the top of your head.

My pipes are rusted and my engine is literally a ticking time bomb. Huge lifter tick. I am planning an engine rebuild or upgrade to a stroker and am trying to get all my things lined up so I can make this as smooth as possible with as little downtime. So since I have to unbolt it anyway I figure the exhaust could be upgraded at the same time.

So my questions is this.

#1
If I am going to upgrade/replace the exhaust do I get the TJ 4.0L Jeep Long System with cats to stay close to stock operations? In their picture, it looks like it has the 4 sensor spots and it looks like it has a single cat at the collector.
#2
I would couple this with a 3" cat back exhaust system to finish the system off right?

Thanks for all the good info. Also I am reading up on your stroker posts. I think that is the direction I want to go.

Cheers

Yes, the cat-less option eliminates the cats entirely.

You'll be able to make a bit more power without the cats, but if you live in a place that does inspections, you'll need them, so ultimately it's up to you. Where I live there are no emissions or inspections, so I don't need the cats.

A 3" cutback system is way too big for a TJ by far. That is what you should be running on a high powered turbo engine or something, not a TJ. For a TJ I believe the exhaust diameter is 2.25".

 

[Shawn of the farm]

A 3" cutback system is way too big for a TJ by far. That is what you should be running on a high powered turbo engine or something, not a TJ. For a TJ I believe the exhaust diameter is 2.25".

Thanks Chris

I’m clear on the cat option now but looking at the product page it looks like thy only have A 3” option at this time. So based on not running a turbo or any thing I should keep looking for a different set up it sounds like.
Maybe they used to have a smaller option?
Thanks again.

 

[Chris]

Thanks Chris

I’m clear on the cat option now but looking at the product page it looks like thy only have A 3” option at this time. So based on not running a turbo or any thing I should keep looking for a different set up it sounds like.
Maybe they used to have a smaller option?
Thanks again.

You know, I'm not entirely sure about that. Give Nick a call and ask him, he's super friendly and easy to get ahold of. The TJ stock system is definitely not 3". In the worst case scenario you'd need a 3" to 2.25" (I believe that's what it is) conversion piece, but that's no big deal at all.

It's unfortunate that there really is no other gull long tube system other than this one and the aFe, but the aFe isn't as good of a design (though still better than almost everything else on the market).

 

[TJRick]

Thanks. Due to that particular transmission's stupid-deep .69 Overdrive ratio you need to gear the axles to a lower ratio than would be typical for a given size tire. At a MINIMUM 4.88 would semi-work but 5.13 would be the best all-around highway and offroad ratio. 5.13 would just get the rpms up to where they should be for cruising at 67-70 mph. It'd lug much of the time with only 4.88.

Interesting. So are you saying that if you have an overdrive transmission, you would choose your gear ratio based off of the final overdrive gear ratio?

I always thought that the overdrive gear is for highway cruising only? Why wouldn't you choose your rear gear ratio based on the third gear ratio where it is 1:1?

 

[Jerry Bransford]

Interesting. So are you saying that if you have an overdrive transmission, you would choose your gear ratio based off of the final overdrive gear ratio?

I always thought that the overdrive gear is for highway cruising only? Why wouldn't you choose your rear gear ratio based on the third gear ratio where it is 1:1?

Because if you don't the engine will lug on the highway at cruising rpms with the 42RLE transmission. It's more important to gear correctly for the highway unless you trailer your Jeep everywhere.

 

[jjvw]

Interesting. So are you saying that if you have an overdrive transmission, you would choose your gear ratio based off of the final overdrive gear ratio?

I always thought that the overdrive gear is for highway cruising only? Why wouldn't you choose your rear gear ratio based on the third gear ratio where it is 1:1?

I don't see why this wouldn't be true for any vehicle.

 

[Mikeythemikster]

Best bang for the buck without rebuilding is edlebrock head and roller rockers

 

[Tioga river Rat]

Interesting. So are you saying that if you have an overdrive transmission, you would choose your gear ratio based off of the final overdrive gear ratio?

I always thought that the overdrive gear is for highway cruising only? Why wouldn't you choose your rear gear ratio based on the third gear ratio where it is 1:1?

TJRick, that's how I always geared all my trucks and jeeps, I never used overdrive unless I was running around 63+ mph. I see you live in S.C where abouts?