• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Difference in years?

skinny_pedal

NAXJA Forum User
Location
BonneyLake
So what changed on the 4.0l from 87-91. Cause browsing through my quadtrec catalog it appears that they don't make any aftermarket goodies for the early engine. Im wanting to get header to replace my cracked manifold but looks like everything is 91 and newer. What gives?
 
There's a lot of differences. In 91 they went to fuel injection and the HO motors. Do you know what engine you have, we don't? Info goes a long way.
 
Engine "goodies" dont do much for the 4.0, Replacing a cracked header would be about the only reason to worry about it. Post up your info (engine, year, trans, etc) and some Renix guru will be along to help you shortly.
 
There's a lot of differences. In 91 they went to fuel injection and the HO motors. Do you know what engine you have, we don't? Info goes a long way.

They were fuel injected before the HO motor too. The big difference with respect to the intake and exhaust is the head was revised for the HO version of the engine, and the ports changed a bit.
 
Big differences 87-90 to 91: engine management changed from Renix to OBDI, EGR system eliminated, HP increase, o2 sensor moved from header to downpipe.

And there lies the rub for the header: the Renix header has two bungs--one for the EGR tube and one for the o2 sensor, the 91 and up HO headers have no bungs, or nobungus for short.

So, what are your choices? Well, you can pay a lot of money for a "performance" header for a Renix--Pacesetter makes one--or you can purchase a 91+ HO header and install a couple of bungs.

I think the best header out there, not a performance item, is the APN: http://www.ineedparts.com/index.php?target=products&product_id=15343 but if you buy one don't use the gasket that comes with it, buy a quality gasket locally.

As lawsoncl stated there never was a 4.0 non-fuel injected engine in the XJ from the factory.

You will get more "bang for your buck" with a stock header and a performance CAT-back exhaust system.
 
Big differences 87-90 to 91: engine management changed from Renix to OBDI, EGR system eliminated, HP increase, o2 sensor moved from header to downpipe.

And there lies the rub for the header: the Renix header has two bungs--one for the EGR tube and one for the o2 sensor, the 91 and up HO headers have no bungs, or nobungus for short.

So, what are your choices? Well, you can pay a lot of money for a "performance" header for a Renix--Pacesetter makes one--or you can purchase a 91+ HO header and install a couple of bungs.

I think the best header out there, not a performance item, is the APN: http://www.ineedparts.com/index.php?target=products&product_id=15343 but if you buy one don't use the gasket that comes with it, buy a quality gasket locally.

As lawsoncl stated there never was a 4.0 non-fuel injected engine in the XJ from the factory.

You will get more "bang for your buck" with a stock header and a performance CAT-back exhaust system.


Thanks. Im not trying to get more horsepower but if Im going to replace the manifold I figured id do a header. Now I know the difference. Thanks
 
Yeah.

Technically, the stock 4.0 exhaust IS a header rather than an exhaust manifold, the defining factor being individual runners for each cylinder in a header and shared runners in a manifold.

While the stock headers in the 4.0 are a long way from being a tuned performance exhaust they still do a pretty good job for an engine like the 4.0s design.
 
Back
Top