Ethan94

So, I've got a little bit of a power problem with my 2.5l up long semi steep hills that I'm tired of. And besides a 4.0 swap what would be other options without major modifications to the engine bay? I'd like to get a good mix of decent mpg and biggest power possible. As this is my DD. And I'm sure I'd need to swap out my ax5 as well. Any suggestions for a new manual trans?

EDIT: it's an 87 xj. Stock setup for now (RE 3.5" to come). On 28's

88whitecomanche

What is your current set up? All stock?
Or lifted with big tires?
Gears would be the best help regarding more power before swapping any engine...

texastaz38

Without any other modifications, I would suggest re-gearing. If your running bigger tires and haven't regeared, your shooting yourself in the foot. We need more information on your current setup to make an intelligent discussion, i.e., tires, lift, etc.

My 2.5L is far from being a beast motor but re-geared is adequate.

Just my .02 worth.

Happy Jeepin'

Ethan94

Currently stock, it came with 215's I put 28 inch 235's on it. But I will be getting a RE 3.5" lift on it some time soon hopefully.

ALSO FORGOT TO ADD ITS AN 87 XJ

Ethan94

i kind of want it to be sleeper to show up all the rice rockets, but I'd be happy with being able to go up a grade at speed and when a big rig gets in the fast lane not take 10-20 seconds to get back up to 55 pedal all the way down. The engine was rebuilt and has less than 2,000 miles on it. And I figure if I could get an engine with about the same mpg (16.7 average to work) and a lot more power why not?

is it possible to put a modern engine in without a lot of issues? I mean modern V8's get better mpg so if I could stuff a new engine in get more power and mpg then I think I should spend the extra money

any suggestions on a new gear ratio? And is there anything else to change or modify to get more power out of the 2.5?

Cummins93

The only way to keep that 2.5 and make it put out some power is with a turbocharger.

Ethan94

regeared and turbocharged any idea what kind of power I'd be getting?

most of the ones I see are for 2.5l yj's would those work?

what would be the one to get and give me the most power or are they all the same?

Cummins93

With 10 psi on an appropriately sized compressor and turbine you may be able to hit 200 at the crank. You will need a few things though.

Turbo, turbo manifold (no one makes one...yet) turbo downpipe, wideband sensor, boost gauge, tuner ( I am guessing MS is the only way for a renix?) , blow off valve, wastegate if you go external, charge pipes, injectors, oil feed and drain lines. Intercooler would be nice. Laptop. Colder plugs. Many misc. Parts that you need along the way.


Skills you will need.
Tuning experience, welding and fabrication, how to size a turbo compressor, a healthy understanding of how ignition happens in a turbocharged engine. OR a large amount of money that you would like to pay someone to put a large amount of money into a 2.5 amc motor.

Ethan94

I'm young and dumb so I'd have to go the cash route. How much cash we talking about to get it done?

4BangerDanger

For $3000 you could drop in a stroker:

http://www.shop.505performance.com/p...&categoryId=34

Obviously pricey, but it would be completely bolt-in.

Cummins93

Go look up each of the things I listed and make an expense sheet. Let's say you use a td04 16g as your turbo. Let's also assume that the only welder you can find charges you $1000 to make a log manifold. List off everything you will need at the prices you find.

mschi772

Well, I'll be the one to offer-up my favorite engine alternative. Buick 3800 swap. Good used 3800's are everywhere; the biggest hurdle, and it's not a small one, is getting the parts and fabrication to actually mount the thing and mate it to a transmission, but Novak has good information in that regard.

Cummins93

Chris Dunham had done a srt4 2.4 turbo swap in a TJ. I don't know what trans bell housing or adapter was used. From what I can tell he used the SRT NGC ecu for factory engine mgmt. I've been running 20 psi out of the stock 15g turbo for years now on my SRT without any issues other than blowing off a charge pipe every now and again.

Charlie Foxtrot

Another way forward: The 2.5 amc engine in the xj is cast to mate to a bell housing designed to mate to a GM engine. (This is a result of AMC/Jeep buying engines from GM, then making their own, but still using the bell housing/trans that mates to a GM). I believe this opens the door on a lot of bolt up options including a 4.3l V6 from a chev/gmc pick up. There are a lot of these 4.3 V6s in the bone yard. They run well, develop enough passing power that my old lady routinely gets tickets in her k1500, and last a looooong time (my OL has 250k and is still running fast). If you look around you should be able to find one cheap, find swap info/parts easily online, and using a little creativity, you should be running down the road.

Outlaw Star

The SBC 4.3L uses a 90° bellhousing pattern while the 2.5L uses the 60° bellhousing pattern. So the 4.3L will not bolt onto the 2.5L transmission.

I have the 2.5L but bored and stroked off of the 505 performance's 2.9L design. 187HP/215TQ (My own cam design and custom pistons)