How Far It Can Go! Improving the Ride Comfort of a Kei Car ~ Suzuki Lapin HE22S Installation of Custom-Made Suspension Plus Springs ~

This Lapin, which is about to undergo its second shock absorber replacement at 13 years old, has exceeded 130,000 kilometers in mileage.

2009 model CBA-HE22S K6A Turbo CVT 4WD, mileage: 132,000km

The slight engine oil seepage that began at around 90,000 kilometers has become completely unnoticeable thanks to the mysterious effect of the popular additive Maruyama Molybdenum Kansai region limited edition GX200, and there is no oil consumption typical of high-mileage kei cars.

Now that it has exceeded 100,000 kilometers, I think the engine is in its prime condition.

This Lapin underwent a suspension refresh about 6 years ago, at 60,000 kilometers.

Car Character and Shock Absorbers 2 (Suzuki Lapin CBA-HE22S, Ride Comfort Improvement)

Aiming for a tight, crisp suspension for this compact kei car, we chose shock absorbers with slightly higher damping force, the KYB NewSR Special.

KYB absorbers have excellent durability, so the owner drove about 70,000 kilometers without feeling a major change in performance, but decided to refresh the suspension again at the time of the vehicle inspection.

The main refresh is replacing with the same KYB NewSR Special, but this time we’re making a new attempt to change the coil spring specifications. Since we’re looking for a type not available on the market, we asked Suspension Plus, a company we have a good relationship with, to design and produce a custom-made product.

With driving performance as the top priority, we requested a slight lift by increasing the compression stroke.

Excessive lifting would make the car unstable due to a higher center of gravity, but a moderate lift should create a depth similar to increased suspension capacity. It also matches the 4WD vehicle’s character and looks good aesthetically.

Now,

What I find most amazing about Suspension Plus is how simple the custom order process is.

There may be other companies that take on one-off spring production, but they require the client (requester) to provide detailed specifications.

I’m not a coil spring specialist, so design is very difficult, and I would certainly waste a lot of time and money on trial and error before reaching the desired specifications.

This time, my order was simply “Please lift it by 15mm with a focus on ride comfort.” *1

Custom springs can be selected from color samples. After consulting with the customer, we chose white for strong contrast with the body, and additionally requested zinc (zinc powder) coating for high rust prevention as an option.

Here’s a comparison with the normal front springs.

The number of coils is half a turn more, and I think the secret ingredient might be that the top coil has narrower spacing between lines.

Next is the rear side. These also have narrower line spacing at both ends.

The spring rate designed for both front and rear is slightly higher than normal.

I had thought that prioritizing ride comfort meant lowering the rate, but Suspension Plus proposed the opposite. The overall balance of the design, not just the rate alone, must be important.

The KYB NewSR Special used for 70,000 kilometers had no oil leakage, but there was some gas “leakage” inside. There is a difference in the repulsive force of the rod when compared to new ones, though there was no difference between left and right.

We installed them together with wear parts to be replaced simultaneously, such as upper mounts and spring seats.

This is not limited to this suspension maintenance where the vehicle height (static angle of the suspension arm) changes, but 1G tightening is a very important process. After carefully performing this, we check and adjust the alignment.

After driving for a while, the various parts will settle in and the vehicle height will probably drop a few millimeters, so it should settle at the requested lift amount.

We achieved the desired style and immediately took it for a test drive.

The previous combination of normal springs + KYB NewSR Special had a very nice compact feel typical of kei cars, but this specification has completely transformed into a high-quality, substantial ride that’s uncharacteristic of kei cars. It made me want to give this special specification the trendy name “Lapin Cross.”

I’m looking forward to hearing the customer’s impressions after delivery.

*1. However, Suspension Plus requires measurement of the actual vehicle and provision of the normal spring itself.