Header Question -Tune?

Reply Subscribe

Thread Tools

Search this Thread

Apr 2, 2013 | 06:42 AM

#16

w-stev29

Junior Member

Joined: Feb 2011

Posts: 49

Likes: 0

From: Near Wilmington, NC

Year: 1996

Model: Cherokee

Engine: 4.0L

Adding a header the vehicle along higher flow exhaust system including cat will not keep the O2's from doing their job. Long as the new cat is doing its job the rear O2 will read correctly. As far as the front O2 there is enough adjustment in the ECU to allow for increased flow and injector pulse without turning on a CEL. I used to work on performance parts for various vehicles. I have never had a problem with Jeeps having an issue with bolt-on mods.

Apr 2, 2013 | 07:13 AM

#17

salad

Herp Derp Jerp

Joined: Nov 2011

Posts: 18,251

Likes: 17

From: Parham, ON

Year: 1999

Model: Cherokee

Engine: 4.0L OBD-II

Quote:

Originally Posted by s346k

they are called "bolt ons" because they literally bolt on. not because of how they affect the engine. I'd like to see someone verify with a wideband what actually happens when doing mods like this, just to see. as stated earlier, putting bolt ons on my ls1 car took it from a solid 12.8 afr @ wot to 14.7 at only 2800 rpm. bolt ons or not that is not safe or right. the lean condition also caused 8* spark knock. also all below 3k rpm.

In a 4.0 you bolt it up an you're done. The engine cant flow enough air without assistance and the ECU does a pretty good job at maintaining 14.7:1 AFR. If you feel it necessary you could always unplug your MAP lol. These are not performance engines... International Harvester bought a few of the last model.

Apr 2, 2013 | 07:47 AM

#18

s346k

CF Veteran

Joined: Feb 2012

Posts: 2,282

Likes: 18

From: central IN

Year: 1997

Engine: 4.0

I am only saying I don't know how much the o2s will compensate. no kne seems to know or has verified any mods w a wideband. guess I could do it haha. I have a wideband and leaky manifold