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View Full Version : Straight Pipe drawbacks/Cams?/Best headlights?/Vacuum actuator delete?



Trapped_Echo
10-05-2016, 05:41 PM
Hey guys, brand new to this site, so far, loving it!

So I've been running my 91xj straight piped (no muffler or cat) for about a month and a half now, haven't really noticed any issues, but I am concerned if I do it for too long that it could cause some. Any insight on that?

I've also been wanting to put a nice lopey cam in it, I know I'll need new springs, valves and push rods, and probably some other items. If you done a cam swap, any details/ideas/advice would be great!

My headlights are fairly bright, but when it snows I CAN'T SEE A DARN THING! What type of lights would help this issue? I also drive through fog at times, and can't exactly afford lights bars or kc style lights for the blue and red covers at the moment.

And last thing for now is the Vacuum actuator. I don't like it. It's a royal pain trying to find the right lines for it (I have the Laredo model). I spent hours at pick n pull trying to find the right lines, and had 0 luck, so I'm over it, but I need it fixed before winter strikes. How would I go about swapping over to a cable system or something?

Thank you everyone in advance, any advice, tips, tricks, ideas, etc. is much appreciated!

prerunner1982
10-05-2016, 05:58 PM
Have always been told the engine needs some back pressure from the exhaust... I don't know how true that is.

Can't help on the whole cam swap. Sorry.

Headlights... you might look into upgrading the wiring harness. LMC truck has one for about $25 that will increase the stock headlight output. http://www.lmctruck.com/icatalog/cc/full.aspx?Page=103 I believe it would be the 36-3280. Mudderoy runs them on his so he should know for sure.

Central Axle disconnect. YOu can buy cable operated actuators, you can bolt it in the locked position or you can replace the axle shaft with a one piece shaft off a later Dana 30 front axle and make a block off plate for the hole.

http://www.fourwheeler.com/how-to/transmission-drivetrain/154-0904-dana-30-vacume-disconnect/

Trapped_Echo
10-05-2016, 06:03 PM
Thanks man, I'll look into those! As far as the back pressure, I've heard the same thing, but I'm getting better mpg and power, so I'm not sure. haha

4.3LXJ
10-05-2016, 06:44 PM
Do you still have an O2 sensor? You need one. I have heard of people getting away without one for awhile, but the computer will eventually give up on it and kind of quit.

CAD can be eliminated or just shimmed over permanently. I shimmed mine over permanently years ago and not had any problems

Is your light problem in snow from too much glare?

Trapped_Echo
10-05-2016, 06:58 PM
Do you still have an O2 sensor? You need one. I have heard of people getting away without one for awhile, but the computer will eventually give up on it and kind of quit.

CAD can be eliminated or just shimmed over permanently. I shimmed mine over permanently years ago and not had any problems

Is your light problem in snow from too much glare?
No 02 sensor, or I DEFINITELY would have fixed it. And yeah, the glare is terrible. It's like driving towards the sun with no glasses.

4.3LXJ
10-05-2016, 07:02 PM
The O2 sensor gives data to your ECM so it can determine the right fuel/air mixture. I am going to suggest installing one. The headlight thing is likely a problem many of us would face. Headlights are getting brighter, but this is not good in a storm. If you have an H4 conversion, you might look into E code light buckets that cut off the light above the light at low beam This will reduce the glare

Trapped_Echo
10-05-2016, 07:07 PM
Were you talking about an 02 in the back half of the exhaust? Cause I didn't have one of those, but I do have one in the headers. Sorry, I should've said that before hand.
And as far as headlights, I wanted to get these. http://www.topgearautosport.com/part/A128SVY3199/Jeep_Cherokee_1979-2001_Blue_LED_Black_Sealed_Beam_Projector_Headligh t.html?gclid=CjwKEAjwydK_BRDK34GenvLB61YSJACZ8da3g fa12G41ZGcAWR4x16PXz8zWfW0XX6wl5j-vXdmXdRoCmWfw_wcB

cpttuna
10-05-2016, 07:27 PM
LMC Truck # 36-3580

4.3LXJ
10-05-2016, 10:14 PM
As long as they have a good cut off that should work

denverd1
10-06-2016, 10:36 AM
inspected and daily driven? not sure about your 91, but my 98 has a composite fuel tank - i.e. its plastic. If your exhaust is cut off where mine was (right after the cat), your exhaust is getting dangerously close to the tank. IIRC, older XJs had metal tanks so this may not be an issue. What WILL be an issue is getting it inspected. maybe different laws in NV, not sure. I'd still want a turn down that goes past rear axle to keep your fuel cool. Can vapor lock and cause other issues. Wait, your carb'd right? Still wouldn't want my fuel tank getting hot for obvious reasons.

The 4.0 cam profile is a pretty good one. unless you drastically change cam lift, you're not going to see a lot of gain from a mild cam swap. Better gains are founds opening up intake and exhaust to take advantage of the cam profile you have. If you want a .6" lift cam, then like you said, stiffer 3 piece valve springs at a minimum. Other mods would depend on how miles are on the head, at 250K new valve seats and a valve job would probably be money well spent. no need for new pushrods. If you go with an aggressive cam, an aftermarket head might make sense to take advantage of your new flow capacity. stock head doesn't port very well either. So keep that in mind when your picking a cam.

for that downstream O2 sensor, haven't run one in mine for years. cranks up every time.