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JeepPirate 06-12-2013 07:50 PM

Is the inner fender necessary?
2 Attachment(s)
I attached a couple blurry pics but I installed the xrc steel fender flares over the weekend. The inner fenders are not reuseable bc I ruined them. The install instructions implied that they were not necessary but the more I look at the exposed
areas I'm questioning it. I know metal cloak has an answer to this problem but was curious if anyone has ran like this for a little while.

ronjenx 06-12-2013 09:06 PM

On and off road the inner liners protect the engine bay components from water/dirt/mud/debris.

They may not be needed in a rock crawling situation.

On the road, they help with engine cooling, as they prevent most of the air pushed into the wheel wells from entering the engine bay, thereby allowing more air to pass through the radiator fins. You may not see a problem until you are approaching the limits of the cooling system's capacity to remove heat from the water.

RockyClymer 06-12-2013 09:34 PM

ditto, if all you do is trailer your vehicle for rock crawling...probably not, but in an every day situation or off road general, yes, they protect the engine bay from nasty stuff and keep water out of places it should not be.

1222 06-12-2013 10:01 PM


Originally Posted by JeepPirate (Post 15554302)
...The inner fenders are not reuseable bc I ruined them...

Sorry but I had to laugh but I applaud your honesty. I have to agree with what was posted above and even if I didnít, with them removed the look is horrible. Hope you can find a solution on the cheap.

spyder6 06-12-2013 10:29 PM

When I put my tube fenders on the first thing I did was rip those retarded liners out of the front and rear fender wells and throw them in the trash

SubAtomicGenius 06-13-2013 03:35 AM

I've got the front ones trimmed for the Poison Spyder flares, but I took the rear ones out. Everything is bedlined/epoxied/rust checked in the back

JeepPirate 06-13-2013 06:40 AM

Thank you for all the responses. My plan is to have the rear line x'ed. I can't believe all the protecting the front liners did from what you all are describing. The jeep is my second vehicle that sees a fair share of on road time and some off road time but no mud. I was just basically curious if I could get by like it is on the front for a while until I find something to put back on there.

spedly 06-13-2013 06:54 AM

I haven''t had fender liners in 2 years. Hasn't hurt the jeep a bit.

spyder6 06-13-2013 07:23 AM

Ill also add that I didn't run fender liners in my tj for 5 years. It's still rolling around somewhere without them

They're silly

JeepAddOnsChris 06-13-2013 07:35 AM

^^ This.

Completely unnecessary.

Don't believe me? Go through a mud puddle or look at the engine after a hard rain and driving through it. It's going to be wet. The electrical components are already pretty well protected.

What they're good for:

A little sound deadening.
Protection against gravel being thrown up and pinging the sheet metal in the rear.
Keeps the engine a bit cleaner. Not totally. Just some.
Good for being in the way when you're wanting to reroute something lower in the engine bay.
Great for trapping salt and chemicals and introducing rust areas.

Used rubberized undecoating or bedliner on the exposed sheet metal and you won't have problems.

GauchoMark 06-13-2013 07:44 AM

If you need a new set of inners, just check a junkyard. Or, I just removed my flares and inners to replace with metalcloak stuff, so I have a full set too.

While I agree with inners not really being "necessary", I bought the MC inners with my fenders for 2 reasons - to dress it up a little and to help with air flow - inside the engine compartment and aerodynamics. They help from those standpoints, but not for keeping the engine clean.

spyder6 06-13-2013 07:53 AM

The front wells arnt a high pressure zone if you run a narrow bumper, the aerodynamic standpoint is moot. If anything due to the tires creating a neutral pressure area, it increases cooling efficiency at speed due to pressure equalization

GauchoMark 06-13-2013 07:58 AM

I meant aerodynamics from a handling/noise perspective. I felt that on the highway without the inners it was a lot more flighty in crosswinds/turbulence. Definitely seemed windier by noise.

As far as cooling, yeah, high speed isn't an issue. I was thinking more at low speed cooling

spyder6 06-13-2013 08:33 AM

The electric fan (at least the 3.6) flows an unreasonable amount of air. I don't expect cooling to ever be an issue.

jwmbishop 06-13-2013 11:56 AM


Originally Posted by spyder6 (Post 15555991)
The electric fan (at least the 3.6) flows an unreasonable amount of air. I don't expect cooling to ever be an issue.

Even the best fan can't force air into a pressure that's already higher than the pressure created by the fan. Case in point - we had a 69 Camaro super stocker running round tracks - both dirt and asphalt. Since the dirt required turning RIGHT (cross steering during left turn corner slide) we had to cut the tire well back 7". That raised the underhood pressure and we saw a 10 degree increase in temp (from 225 to 235) - as well as less nose weight at speed - so had to run two fenders - one for dirt and one for asphalt (of course that said it WAS a engine driven fan and we ran about 900 RPM difference at the two tracks). One thing to note though - as air resistance increases - so does the amperage draw of the fan motor - adding more air under the hood through the fenders will raise the pressure and thus draw - and of course that shortens the life of the fan!

Side flow does not really come into ground effect equations noticeably until around 60ish - under that only frontal changes makes big differences.

The JK is arguably not that extreme - so the liner would not be a horribly bad thing to ditch. But as the temp gauge on the dash does NOT display actual temp - only a computer display of whether current temp is in "expected" normal range - based on the operating and computer parameters - so you would have no way of knowing you are running warmer unless you have installed a separate non oem gauge (or a live display on a handheld code scanner). I Have used an infra red and seen temps (at the radiator inlet tank header) of 195-205 always with the dash gauge straight up on the normal line.

I would have no worries running without them - but when I do start modding there I will use something - I don't like road water (or more precisely the fine grit that comes with it and thus gets in all the wiring harness, connectors etc.) getting under the hood! The factory pieces ARE repairable with a fiberglass repair kit - just rough the surface, lay the mat and one coat of resin (do the bond work where it won't show as much - engine side for example) along any tears cuts or breaks.

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