99+ intake and Banks lookalike install on 97 I-6

Okay, here goes.

Only problem I had was with #6 intake manifold casting and #6 exhaust tube interference... I clearanced for about 1/8"+ space between them with my die grinder for about 1/16"+ on bottom of intake and flattening exhaust tube about same using a 1 1/2" socket and hammer on exhaust tube in 3 places about 3/8" apart. You can see pics at: http://www.wiedenman.com/pub/intake/

As for mileage/power differences... not sure. I live at 4000' and am now in SoCal. Engine is stronger here anyway. Add a 3.5" lift and 32's a couple days before intake/exhaust and ..... I think it's stronger on bottom end power. This weekend I'm going to Death Valley, so can give a more objective answer.

I'm curious as to how well this works out for you. I've got a complete 99 intake out in the garage and I've debated just selling it vs installing it on my 97.

btw, very nice inlay craftsmanship on your website there. :sunshine:

JEEPZZ said:

I'm curious as to how well this works out for you. I've got a complete 99 intake out in the garage and I've debated just selling it vs installing it on my 97.

btw, very nice inlay craftsmanship on your website there. :sunshine:

Click to expand...

After I spent 3 days wheeling in Death Valley I say it works well. I got 18.5 mpg driving 70 - 80 mph on my 97 going to and from the park. Mileage when wheeling was less of course. Road to and from have grades of 7-8% and power with the lift and tires feels like it did with stock intake and exhaust on stock tires and no lift. Trip was on 265/75 MTs

Then I drove from SoCal to central Montana following a loaded trailer average 60 mph and 22.9 mpg for 1400 miles on stock wheels and 235/75r15 street tires.

When driven under same conditions before I got 21 mpg. Most of the time these kind of changes don't have reasonable A - B testing. Even mine is not a controlled environment, but is best I could do. I did not change anything else. Throttle body, injectors, spark plugs, wires, cat, muffler, etc. are all unchanged.

I was very careful NOT make any other changes in engine! Only other mod for trip with 22.9 mpg was 3" F>R lift. (If anything, the lift should hurt and no way it could improve mileage) Keep in mind, following an 84' Suburban with a 350 pulling a 7000 lb trailer means much more economical driving for ZJ then most drivers drive. The 22.4 mpg includes 2 hours of being stuck in traffic in Mojave Desert moving 10 miles too... and idling when stopped every hour to check trailer and stretch. (cruise control on suburban died)

I've studied this extensively and reports are mixed. A few have said they actually lost mileage. Some say little or no difference. Some say they got an improvement.

Bottom line from what I've found is that biggest improvement is in cruising speed torque. You can hold speed on grades easier in the 1800-2500rpm range. gojeep is Australian driving an XJ with 99+ intake with exhaust mods and does lots of Outback driving. He got same kind of low end power improvement I got.

Also check out http://go.jeep-xj.info/HowtoIntakeManifold1.htm gojeep is on and JeepsUnlimited.

Here's a link to conversion and dyno run on a modified 4.0: http://www.mallcrawlin.com/forum/showthread.php?t=6355
Dyno runs were at 3000+ rpm. Not real world rpm range for me. Almost all of my driving is well below that. Cruising is 1900-2200 rpm.

Here's another link:
http://www.naxja.org/forum/showthread.php?t=73552

Good luck