[Mick-Harvey]

I have been searching this site looking for mods for horsepower. But most seem to be going loud. I have 2 kids under 6 and this will be a camping/skiing rig. Looking for lots of horsepower but keeping cabin noise moderate. Off shelf cold air intakes for her seem to nonexistent and exhaust seem to focus on noise vs HP. Dont care about fuel economy, just looking to climb the altitude towing a camper or weekend of ski gear. Looks for advise with some miles on them, not brand new mods. Have a moderate budget so can't go nutty but not going cheap either. Thanks for everyone's advise and previous knowledge I have gained
Oh, I put 2" lift running 29's so HP should go farther

 

[Gluckmysock]

Hello, Welcome.

Lots of horsepower? Hmmm. Short of rebuilding the engine (stroker), not many options for big bolt on horsepower boost.

Need some info about your rig? Transmission? Transfer case? Axle ratio? How many miles?

I'm pretty sure you have a Renix engine. Hopefully, someone will chime in with a link to a bunch of Renix tips.

 

[Mick-Harvey]

Sorry been a while. Working on other projects. “Lots”, not meaning 50-100 more; but bang for buck more. Everything is stock but 2” lift and slightly bigger tires. It is the 4 speed auto. Wondering if 5 speed would help climb the mountains better as well. Just went last weekend and cruising at 70 and went down to 45 before I manually shifted it to 3 to get rpms over 2k and start getting mph back. It’s a DOG!!! Also heard of bolt on electronic gearing with remote switch but it’s about $2k. Need to do something. 18 wheelers are passing me ?

 

[Mick-Harvey]

Oh. Yes renix and 222k. Burns a little oil but Lucas oil fixed that so she’s solid now!
Thanks all replies

 

[Gluckmysock]

Sorry been a while. Working on other projects. “Lots”, not meaning 50-100 more; but bang for buck more. Everything is stock but 2” lift and slightly bigger tires. It is the 4 speed auto. Wondering if 5 speed would help climb the mountains better as well. Just went last weekend and cruising at 70 and went down to 45 before I manually shifted it to 3 to get rpms over 2k and start getting mph back. It’s a DOG!!! Also heard of bolt on electronic gearing with remote switch but it’s about $2k. Need to do something. 18 wheelers are passing me ?

Electronic bolt on gearing?? Never heard of it? Got any more info?? op::mfpopcorn:

Read and try this for a start.

Cruisers Renix Tips

 

[Mick-Harvey]

company is Gear Vendors. I haven't looked into it at all, but have a buddy has it on his hot rod and said doesn't see why couldnt work for my xj. just big bucks

Gluckmysock, DUDE!! thanks man for the link, man, i can never find **** on here searching. sorry if was repeating info, but can never find myself. must be searching with wrong words. Thanks again. I'll get right on those, hell of a list.
thanks
report back

 

[Mick-Harvey]

 

[4.3L XJ]

company is Gear Vendors. I haven't looked into it at all, but have a buddy has it on his hot rod and said doesn't see why couldnt work for my xj. just big bucks

Gluckmysock, DUDE!! thanks man for the link, man, i can never find **** on here searching. sorry if was repeating info, but can never find myself. must be searching with wrong words. Thanks again. I'll get right on those, hell of a list.
thanks
report back

I had a smaller version I put on the back of a Ford toploader. Allowed me to split gears as well as have an overdrive. I let the kids shift it, they loved it

 

[Gluckmysock]

company is Gear Vendors. I haven't looked into it at all, but have a buddy has it on his hot rod and said doesn't see why couldnt work for my xj. just big bucks

Gluckmysock, DUDE!! thanks man for the link, man, i can never find **** on here searching. sorry if was repeating info, but can never find myself. must be searching with wrong words. Thanks again. I'll get right on those, hell of a list.
thanks
report back

Learn something new every day:
" Fact is, when you are in 4X4 there is very little desire to use GearSplitting and overdrive unless you are racing (and we do make the in-between kit for that purpose), it’s 2wd where the benefits of overdrive and additional gears are most needed. All our kits bolt directly to the rear of the transfer case and are electronically locked out during 4X4 operation." From Www.Gearvendors.com

Welcome to the Stone Pearl White Cherokee club!!

 

[DOWNSY]

With the overall drivetrain length of the XJ and the driveline problems they already have with mild lifts adding an extra gearbox into the mix isn't going to help any of those things. That gearvendors setup isn't even offered for Jeeps, I'm guessing because it looks like it adds a foot and a half to the driveline so you would have no room for a driveshaft

 

[DOWNSY]

Here is a picture showing it attached to the back of a T-case. Just eyeballing it that looks like it would be right at or past the pinion yoke in an XJ.

 

[lawagoneer]

The '89 4.0 is the RENIX version of the motor. As such it has a different head and intake than the later 4.0s. The interesting thing is it has the same torque and arguably a better torque curve with it being flatter and occurring earlier. Also horsepower wise the HO only beats out the RENIX at upper rpms. Typically they get better fuel milage because of this difference. Cold air intake have limited effects of increasing hp but can be easily made from parts store parts. Exhaust side there are several cat-back exhausts that help without being too loud. There is also a header that helps. You'll be hard pressed to exceed 200hp on a healthy RENIX and at 222k and burning oil yours is tired. A stroker is probably the best money spent in you situation.

Here's a pick of my home built CAI on my 89 RENIX XJ.

 

[Mick-Harvey]

that is very possible there isnt much room for this set up. havent looked into it, just sounded like what i was looking for
The more I think about it and drive it, the more I think it is gears. I think the HP is fine, just need one or 2 more gears. in 4th (OD) it does fine on most roads. Once i hit the big hills of tahoe it just dies to 45, I wait for rpms to get to 2k before dropping to 3rd manually and then the speed goes back up until top of hill. so sounds like the power is there, just need a gear between 3&4.
I have opened up the exhaust with new cat and muffler from magnaflow

 

[lawagoneer]

Nice looking rig by the way. XJs are very sensitive to tire size changes. I'm assuming you have 3.55 gears stock. You may want to look into changing you gears to 3.73 or 4.11s. That should pick up the climbing power you're looking for.

 

[Mick-Harvey]

Yes, stock
I was thinking about that, that is an option.
Do you know what speed gives you what rpms?
65mph gives a nice 2,000 at this time. if 65 gives about 2,500 not sure what to do that. Might to talk to folks and see what it doing. see if worth it.
is a good idea though
thanks

 

[Mick-Harvey]

BUT, no way could drop to 3rd on highway with those gears, would be SCREAMING.
i would think
hmmm

 

[Gluckmysock]

Just spitballing here. The newer heads benefit from the "horseshoe" intake. I don't know if it's any option on the renix. But if your gonna give it more air you gotta give it more exhaust, aka a header.
My 96 is an HO and was stock with an aw4 and 3.55's. I ran 31's for years with this setup. I now have 33's and 4.56 gears. I swapped the Speedo gear to reflect the change but got the one for 35's cause those will be my next tires. Anyhow. According to my Speedo I'm at 65 and 2250. It will downshift from OD pretty quick. But hold 50 on mountain roads with little effort. Ok. Enough self gratification. ?

Have you adjusted the "TV" cable? Fuel filter? I have heard royal purple oil, #rollseyes, can reduce friction in your gears and increase horsepower. That being said, how old is the oil in your diffs? Make sure your brakes are in good shape and properly adjusted. Dragging brakes will rob HP. If you have the vacuum disconnect on your front axle, is it working?