Piston Slap: SUV Edition

by Robert Farago

Published: March 6th, 2009

TTAC reader JG writes:

Sajeev, do I have a question for you! Knowing the roads (and potholes) of Houston (like I know you do) here goes. I own a 2001 Ford Explorer 4-door. My pregnant wife curses the ride every time she’s in the car (whether it’s moving, or not). I have recently replaced the tires, which helped a little and ball joints up front. I’d love to get out of this car into something safer, but it’s not an option for a few more years. Is there anything I can do to improve the ride quality? I know I’m dealing with limited options with the solid rear axle, but there has to be something, right?

Sajeev writes:

I see two quick fixes: put several bags of mulch in the cargo area, or hack the muffler and run a straight pipe. (You can get away with it in Texas.) The mulch takes the bite off the leaf springs, and a large amount of ride quality comes from the rear suspension, fuel economy penalty be damned. But the straight pipe ensures your wife will never complain about the Explorer’s terrible ride. Ever.

But seriously: check/replace your shocks, especially the rears. Explorers with air shocks do ride nicer than the regular model, which shows you can fix this oxcart rear suspension. If they are original, consider replacing them no matter what: the fluid (whatever is left) inside the shocks is more like maple syrup by now

TTAC’s own Stein X Leikanger writes:

I really like the original Jeep Cherokee and am comfortable with the 1993-1996 version, except for the fact that most don’t have an airbag, and if they do, it’s only for the driver. Which is kind of selfish.

The car share I’m using doesn’t like my hunting dog(s), and I’m going to need a Jeep (I say that as if it’s a bad thing.) So here’s my question: apart from the other upgrades I’ll do to the car (suspension, engine tweaks, up country reinforcement and raising, etc) – can I retrofit the 1997 passenger airbag into a 1996 model year Cherokee Limited, 4.0L HO? It will already have the driver airbag installed.

And would that be legal? Will it be approved?

Sajeev writes:

Now that you mention it, the amendment to the “Federal Motor Vehicle Safety Standard 208” in the 1980s is quite self-centered. Or aimed at the perpetually lonely.

Back to your question: the 1997-newer models had a redesigned dashboard and steering wheel. That is, the driver’s side airbag might have changed too, in accordance to the “de-powered” regulations that brought USA systems more in-line with Euro regulations. So you’d need another wheel, dash, and probably a new dashboard wiring harness. And who knows: maybe a rewiring of the dash-to-chassis wiring harness too. Which may cause brightly colored warning lights a plenty. Ouch.

I’d recommend you get a stateside 1997 Cherokee and have the seller put an older front fascia in the cargo hole before it enters the shipping container. Or forget about your personal feelings for your passengers.

But I have a line on a 2001 Ford Explorer with dual airbags and a wikkid straight pipe exhaust in my hometown. For cheap: just wait about two months for the seller’s wife to contact me. I’ll even drive it to the Port of Houston for immediate shipping to Europe.

[Email your automotive queries to sajeev.mehta@thetruthaboutcars.com]

Robert Farago

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2 of 32 comments

Sajeev Mehta on Mar 07, 2009
Ferrygeist : Yikes…physics. Okay, I’m way in the deep end here, but assuming the ballast is secured to the chassis, then the accelerated mass of that ballast would be diffused (is there a better physics term for this?) through the entire multi-thousand pound structure…wouldn’t it? And also in that case, wouldn't a loaded vehicle fare better in a collision with another vehicle...because more inertia is transferred to the other vehicle and now (with the ballast) there is more of it?

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Rpn453 on Mar 09, 2009
Mehta: And also in that case, wouldn’t a loaded vehicle fare better in a collision with another vehicle…because more inertia is transferred to the other vehicle and now (with the ballast) there is more of it? The more heavily loaded vehicle would slow less and impart more energy on the other vehicle, so the reduced deceleration may be helpful to the loaded vehicles occupants. But the loaded vehicle will also have to absorb more energy in the impact, which could result in more structural deformation. If the deformation is low enough that it does not contribute to injury by causing passenger compartment intrusion, then more weight will help the passengers of the loaded vehicle while causing more harm to the other vehicle. If the collision is severe enough that the passenger compartment deforms, then the weight will increase the degree of deformation. In my collision, an extra few hundred pounds in the trunk or back seat may have been enough to finish me off.

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