Inner fenders

[Hollow65]

Are they necessary? Mine are rusted and I'm thinking of ditching them. I read through some threads but they all got sidetracked and never answered the auestion. Saw some cool builds though. I don't have any ignition or anything mounted to them. Like super73 asked will the front hold up at 130mph without them?

[71Dragtruck]

Yes will hold up fine, just be prepared for all the small rocks you will be cleaning out of every nook and cranny.

[Hollow65]

Thanks for the reply. I'm hoping to drop the temps under the hood also.

[BR3W CITY]

I just pulled mine out

You Tube

[68racer]

Removing the inner fenders can make the cooling worse. The air pressure in the engine compartment is increased so the radiator does not see enough airflow.

[BR3W CITY]

I've actually seen that mentioned in a few places, but I'm not sure the jury is exactly out on that. While its true that uncontrolled air under the vehicle can alter the under hood pressure, we'd have to actually know what path that air is taking. Depending on the truck (body, stance/ride height etc), this can vary hugely.

At low speed, this isn't an issue since the fans should be able to direct enough air themselves to cool the heatload. The additional outside air, the free-er movement of the air, and the lack of 34lbs of sheetmetal would improve engine temps and heatsoak under those conditions.

At speed, its possible the additional air coming in from the wheel openings could create pressure (or at least turbulence) causing the natural flow through the front grill opening to be altered. We would have to know the pressure differential and flow to see for sure what was occurring at say 40-100mph. At least from what I've seen of the 40's-70's trucks, there isn't a natural rear exit for the air aside from into the firewall and down, so I'm not sure how effective their air management is to start with.

If there were a positive pressure issue at hand, then you'd probably consider looking to alter the front air dam to move more air out and around instead of under.

[Hollow65]

I have a 4" cowl hood which I bet lets more air out than it draws in. I'll rip the fender wells off and if it runs hotter I'll put em back. Wouldn't be the first mistake I've made on the truck.
Thanks for the input guys.

[Kyle@FTP]

If you really want to see how it effects your cooling and airflow, buy some pink ribbon and duct tape at home depot. tape it in 6" strips in strategic locations in the engine compartment and film it with a go pro.

Back when I worked in offroad racing we had some engineers from a indy team come out and do cooling testing with us. When they told me their method I almost crapped myself. So easy and so cheap. Keep it simple. You need the air to move across the radiator the exit the engine bay.

If you are worried about weight then ditch them. If you drive it the 5 days a year SD gets rain then I would leave them in.

[Hollow65]

Driving in the rain is dangerous. I'm not worried about the weather or weight really.