DeltaOP4

I have a 1995 xj with a 4.0 and would like to know what you guys would reccomend doing to get a bit more power. Mostly just to be able to get to cruising speed a bit easier. Takes forever to get from 55 to 65 unless i floor it lol. Not looking for any heavy engine work because I dont know enough to do something like a stroker and refuse to pay people to work on my car unless I absoloutely have to. So far im thinking loud exhaust and a throttle body spacer

GreenXJ98

Here's an article about what works and what doesn't. http://www.fourwheeler.com/how-to/en...ing-true-lies/

Rogue4x4

Both worthless. Save your money on that stuff. Best advice I can give you is do all your normal maintenance, tune-up, fluids, and the like, to get it in peak condition, then I would do an injector upgrade, cowl intake, and bored throttle body. As far as bolt on pep goes, that's about it. You might get a bit more from an exhaust overhaul, but you would probably need a new header and larger diameter pipe, and if you're gonna do all that, might as well port and polish the head, if you want to squeeze as much out of it as you can, but our rides aren't tuners. If you want more power, there's no replacement for displacement....

salad

What's wrong with your XJ that you can't gain 10 MPH in the middle of the power band? Sounds like you need to "get back factory oomph"

Rogue4x4

Exactly.

DeltaOP4

Could it have something to do with a chop job exhaust that doesnt have any pipe after the muffler? (Flowmaster super 44) Looking at getting that redone as soon as possible. As far as general upkeep im pretty on top of that. Other than the jacked muffler the only thing ive done is add a 3 inch lift and have 31 inch tires.

Ianf406

Did you regear?

Rere1992

That's just what a jeep is. Other than maintenance and putting deeper gears in your axles, that's what the 4.0s got. A buddy of mine did gain some power back after he swapped his transmission when he blew it. It had 230k on it and got one with 1xxk on it. He felt the difference. Sometimes old parts just lose their touch.

Rere1992

I also wouldn't bother re-gearing till you get larger tires, and match the gears to the tires.

Rogue4x4

Now, see....this is info we need to give you good answers. When you modify your ride, you change everything.
This.
Agreed. If you're gonna go bigger in the future, buy the appropriate gears then. If not, check the tables out there to find your optimal ratio, and regear.

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

DeltaOP4

I guess i didn't know that you should re gear with tires as "small" as 31's. Im 18 and really only started wrenching about say six months ago so ive got a lot to learn but am willing! Think re gearing would help that much? And as far as older parts losing their touch i only have 91 k on it.

salad

Yes, but even with stock gears on only 31s it shouldn't be that bad to make the thing scoot. What catch-up maintenance have you done on it?

Ianf406

While I doubt it is all that substantial, It certainly makes a difference. Is yours a manual or automatic?

The muffler situation cant be helpful but being as the top of the line system is only worth a few ponies, it has to be pretty minimal. I once ripped my exhaust off from the down pipe back on the trail and aside from it being incredibly annoying, actually felt like I had gained a tiny bit of power.

Every time you add weight ( larger/more aggressive tires- beefier suspension components etc.) without adding power, it is going to slow you down a tiny bit. Combine that with a gearing issue and it can certainly make a difference. I doubt that at 90k you have any serious powertrain issues. You might try a tune-up if you haven't.

Rogue4x4

This will make a difference....if you have a manual, you can just swap axles from an auto, and gain a bit

Also, as far as your mileage, just make sure you have all your routine maintenance done. Plugs, wires, cap, rotor, fresh oil and filter, all other fluids topped or replaced, tire inflation to correct pressures, cooling system in good shape, proper alignment, etc, etc....a basic tune-up goes a long way.

pbiancardi

I had the same question as OP, I was thinking adding headers, CAI, and high flow cat, does that make sense or dont bother?