I plan on doing Magnaflow downturn in place of stock and downturn. JP magazine says 5-15 hp gain with a catback system but says nothing about not having one at all. Isn't the loop over the axle restrictive ? Or does having a catback system increase velocity enough that it gives more power gains over not having one at all? Will I see a gain in hp over having piping over the axle? Will I lose torque due to decreased air velocity ? Noticeable gains ?

 

I am just looking for anyway to make my Cherokee less slow..... Nowhere near as quick as my old 2wd XJ, I think the 31s are the main factor.... But I have 4.10s which should make up for it but don't.

 

the only noticeable gain will be noise in the cabin

have you looked into a cold air intake, injector upgrade or bored throttle body?

 

Yes I have Turbo City Rock It cai and am having a 99 intake manifold and throttle body ported as well as the higher pressure 99 injectors installed... Also have Jet Stage two that I will install when all of it is in.

 

Mine has a lot of in cabin noise. It's not as bad as when I first did it but it's got better, it sounds fine when it's really warned up. By it sounds a little throatier, when it's cold and you romp on it, but I have a 10 series fm if I could I would have out a full pipe to the back

 

Going to probably use old tip and have it come out the side, in front of the back right wheel but in front of the leaf spring then. I did not mean to upload that picture, I clicked the wrong one on my iPhone lol

 

actually, the ICE needs some backpressure. While having too many bends will restrict the airflow, not having any exhaust (straight pipe) will actually make the performance worse. Now, dumping the exhaust right after the cat, might not be so bad. But its not going to be a noticeable difference. Now, if you do a whole complete header back system with magnaflow high flow cat will give you more low end torque. What you want is a lot of torque. Torque is what gets you going, horsepower is what keeps you there. Think of it like a diesel, 650ftlbs of torque and 300hp will pull a house off the foundation. So, the best ways to improve your get up and go, is #1-gearing, #2-good exhaust system, #3-good intake system (a filter on a piece of pipe in the engine bay is not a cold air intake system) you must seal it off from the heat of the engine bay and have adiquate airflow to the filter. Now, anything that will restrict the airflow into the engine will cause power loss. The easier the engine can breathe, the harder it can work. I know it sounds kinda contradictory, but thats just the way it works. lol

 

I ran a cherrybomb muffler (pos) with a downturn right before the axle. It was a little loud inside on the highway (droning) and made exhaust gasses disperse all around the vehicle. It also seemed to hurt the torque on it. It just didn't have same pep off the line. I then put on a glasspack "muffler" and a new tailpipe (that goes back like normal) and it was a lot more torquey off the line. Could've been the glasspack, but I really think it was the tailpipe.

 

[quote="DieselD"]

I ran a cherrybomb muffler (pos) with a downturn right before the axle. It was a little loud inside on the highway (droning) and made exhaust gasses disperse all around the vehicle. It also seemed to hurt the torque on it. It just didn't have same pep off the line. I then put

 

ive also heard that dumping the exhaust out under the body helps rust out the floor and everything else.....ive got a gibson cat back exhaust and the magnaflow hi-flow cat and built a k&n intake with a helix throttle body spacer. i notice a good difference in torque and get-up.....just another thing to think about.

 

Its not back pressure you want, but rather scavenging. You want the air out as fast as possible, scavenging helps pull the old are out of the cylinders so you can get cool clean fresh air in.

 

You quoted me but didn't say anything. Lol

 

The drone is what made me change mine back to running a pipe out the back.

 

My Xj has a Magnaflow exhaust and I cut off the tailpipe right before the rear axle. It's definitely got a loud/noticeable drone to it when driving, and it's even more obnoxious and WAY worse when the doors are off! Can barely carry on a conversation inside at any speed.. and talk to someone in the car next to you at a stop light? Ha, good luck lol. I'm planning on bringing out out the side and see if it gets a little better atleast.

 

That would put a good amount of heat on your tire.