Development of the Body, Suspension, and Steering of the Chrysler LH Cars
(Dodge Intrepid, Chrysler Concorde, Eagle Vision)
The code name for Chrysler’s revolutionary large cars (LH), which some jokingly called “Last Hope,” could, if the press releases are to be believed, have stood for “leveraged handling.”
The 1993 Dodge Intrepid, Chrysler Concorde, and Eagle Vision all easily out-handled large domestic sedans in their classes. Chrysler claimed, and critics agreed, that they may have been the most balanced-handling four-door sedans America had ever produced for the mid-size, medium-price market segment.
While some aspects of handling are subjective, “Some parameters such as roll angle and maximum lateral acceleration can be measured," said Mark Pedersen, senior vehicle dynamics engineer on Chrysler’s Large Car Platform Team. “But that doesn’t mean we sacrificed ride to get better handling. Actually, we raised the level of both with these vehicles. I’d say the cars [have] a couple of orders of magnitude improvement in handling and maybe a single order of magnitude improvement in ride quality.”
Engineers benchmarked two top-tier cars in the same segment for each LH, with the primary targets being the Ford Taurus and Nissan Maxima. The Acura Legend, Toyota Camry, Lexus ES300, and the BMW 5 Series were secondary targets.
Intrepid, Concorde and Vision had three levels of suspension, depending on model:
BASE: Developed for an entry-level vehicle that has a sporty handling feel, as good as Taurus or Lumina, and better in several respects.
TOURING: Better than Legend or Maxima in any handling parameter.
PERFORMANCE: To rival the likes of BMW 5 Series, Audi 100, and Mercedes S.
The base suspension was only used in the Intrepid and Concorde. Both had the Touring Package an option, while Intrepid buyers could opt for the Performance Package. The Vision has the Touring standard with the Performance Package optional.
LH’s power rack-and-pinion steering design had a ratio of 1 7:1 and felt more “connected” than previous American cars, with a neutral feel. It had a tighter feel with somewhat higher turning effort than normal, but was still easy to use.
Despite its 113-inch wheelbase and 62-inch track, the curb-to-curb turning diameter on LH was only 37.6 feet, less than many competitive cars with smaller overall dimensions.
A good part of this is due to the longitudinal, forward-mounting of both engine and transaxle, which avoids having the transaxle interfere with the left front wheel well. The LH design provided more space for the wheels to turn.
The sturdy body structure of all three LH models (torsionally, the stiffest Chrysler had ever built) also helped. Pederson said that “Intrepid, Concorde and Vision will be among the most ’shake-free’ cars on the road today. Only a few of the most expensive German models can compare.”
LH cars used larger tires than most sedans in its class, too. Pederson pointed out that the larger sizes gave more capacity for ride and handling alike.
LH’s hydroelastic engine mounts, fitted to an isolated engine cradle, cut vibration in the body of the car. When the car hit bumps, the mounts permitted slight engine shifting, dampening the shocks.
The front suspension design separated the directional motions of the bushings (fore/aft and laterally). Pederson pointd out that fore/aft motions should be soft to avoid harshness from bumps, but lateral motions should be firm to avoid having the outer wall move inboard.
Thus, the LH chassis design had a strut at all four corners. The front suspension used a rubber-isolated fore/aft "tension strut" while the lateral link had a stiff inner pivot bushing. Similar measures were taken in the rear.
The suspension was fully independent at all four wheels, unique to any Chrysler car larger than the Horizon/Omni series.
Body and safety features - Dodge, Chrysler, Eagle
Safety features included anti-lock brakes, traction control, standard dual air bags for both driver and front-seat passengers, an integrated child restraint seat, collapsible steering column, more comfortable and effective shoulder restraints that adjust to the height of the occupant, and improved seat-mounting structures.
The body structure of Dodge Intrepid, Chrysler Concorde, and Plymouth Vision was stiff but light, as a result of extensive structural analysis by Chrysler’s supercomputer. “These are the strongest body structures we’ve ever had on a Chrysler car,” contended Dennis Renneker, executive engineer for Large Car Body-In-White and Chassis.
The body structure goals were world-class front-to-rear torsional rigidity with no torsional bending in the middle; the smaller Nissan Maxima was the benchmark for both. Glenn Gardner, general manager of LH platform engineering, said that it was a challenge because Maxima had a smaller wheelbase and a narrower track. He pointed out that the LH cars were 25% stronger, torsionally, than the Maxima.
The engineers did a great deal of computer simulation in crash/collision development, so that the actual car passed Chrysler’s barrier test on its first attempt. They analyzed crush on the front, sides, and back.
The longitudinal, “north-south” engine mounting helped, by allowing straight-through underbody rails without a bend (to get over the transmission). Gardner said the bend was “a natural place for the rail to buckle and collapse on frontal impact ... With one bent rail, if it collapses, the vehicle may twist and collapse on the driver’s side. Straight rails provide a uniform crush and make it easier to manage frontal impact.”
Renneker said that there was some concern over moving the LH’s rear wheels closer to the corners of the car. “It was a tough challenge, particularly with regard to the air bag systems. We had to be doubly sure the sensors would go off at exactly the right impact speeds and also that the deployment of the air bags had the right trajectory.”
The standard airbags on the Dodge Intrepid, Chrysler Concorde, and Eagle Vision were the first to vent inflating gases through the fabric instead of through vent holes, thereby reducing smoke in the car and localized hot spots. A gas release system allowed full deployment before impact with the passenger, according to Donald Goodwin, executive engineer of Interior Engineering for the LH Platform Team. The passenger-size airbag deployed in 1/20 of a second.
Lower surfaces of the instrument panel functioned as a knee bolsters in frontal impacts to restrain the occupants’ lower extremities against excessive forward motion.
The optional integrated child seat feature was a helpful feature (and far safer than the typical belt-attached child seat), and included a booster for children between 45 and sixty pounds by using the base of the child seat and the regular seat back.
First Generation Chrysler LH Series Information at Allpar
- Main first-generation Dodge Intrepid, Chrysler Concorde / New Yorker / LHS, and Eagle Vision page
- Performance upgrades and common repairs
- Dodge Intrepid, Chrysler Concorde, and Eagle Vision styling development
- Climate control and engine cooling systems
- LH body shell and suspension: performance, comfort, and safety
- Interview about LH packaging and design with G. Glenn Gardner
- Interview about LH design with Francois Castaing
- Definition and advantages of cab forward (how cab forward was developed, and an interview with Tom Gale.)
- 80-mpg Intrepids: ESX and ESX-2
- Design and manufacturing process for the LH series: innovations in the engineering and involvement process
- Step-by-step guide to repairing the LH steering
- Step-by-step guide to replacing the hub and bearing
- Components: 3.3 liter and 3.5 liter V6 engines • Four-speed automatic transmission
- Dodge Intrepid, Chrysler Concorde/New Yorker/LHS, Eagle Vision Specifications