Testing Feal 441 Suspension for the B13 Sentra SE-R!

An inside look at the Feal 441 Suspension for the B13 Sentra SE-R!

by Mike Kojima

 

The original B13 Sentra SE-R has always held a dear spot in many of our hearts. Produced from 1991 to 1994, the SE-R combined the lightweight shell of the Sentra coupe with the sparkling performance of the beloved SR20DE engine. For its time, the SE-R offered a great performance bang for the buck, and to this day, it has scores of hardcore devotees who treasure them.

The Achilles heel of the SE-R has always been its suspension. Struts with very limited travel, rear suspension that binds and front suspension that has a ton of bumpsteer in the geometry make the car difficult to get to handle really well, especially if it has been lowered. Compared to its contemporaries like the Honda Civics, handling has always been a problem with the SE-R.

The biggest problem standing in the way when trying to make the SE-R handle right is a lack of wheel travel. Lower the car 1.5″ and you are close to sitting on the bump stops, especially in the front. If the car rolls over onto the bump stops in a turn, it goes into instant grinding understeer. 

New shorter struts are the answer, but the problem with the SE-R is that it was a low production volume car. Even though the car has legions of fanatical followers, their numbers are still pretty thin. So thin, that no major suspension company has ever committed to making anything good for the car. There are a few Chinese companies that make some low quality stuff, but these do not work very well. So the only choices were custom short struts that were available at one time but not anymore. The fact is there are few companies willing to make something trick for a low volume car built 25 years ago.

Martin was in the process of rebuilding the well-worn suspension and brakes of his treasured daily driver SE-R, and his existing suspension was pretty hammered. Martin's car had a homebrew set up, which for a time was the best you could build for the B13 Sentra. In the front, Koni Yellow shocks for a A32 Maxima were set into some shortened modified stock strut housings that were altered to take a threaded sleeve, allowing the use of Eibach 300 in/lb ERS race springs. In the rear, Koni red shocks were used with some custom Hyperco springs that fit the stock perch. These were made for the SE-R forum on a group buy many years ago, and they came with a 200 in/lb rate. These springs are twice as stiff as stock which helps when you don't have much travel! 

Anyway, Martin's suspension was worn out and we needed a suitable replacement. After searching for a long time, the only company we found that we were comfortable with using was Feal Suspension. Feal is owned and operated by Formula Drift pro driver Aurimas “Odi” Bakchis.  We have known and competed with Odi for years and can vouch that he is a man well acquainted with suspension technology.

 

Every set of Feal shocks are assembled and calibrated in the USA, right in Feal's SoCal office by Odi and his staff. This also provides a lot of opportunities to order your Feal Suspension with custom spring rates and valving. Odi has a lot of experience with nearly all genres of Motorsports and can make recommendations for your custom set up or build to your spec as well. 

A set of Feal Suspension starts as this knockdown kit that Feal has made for them to their spec in Asia. Now don't let that scare you, most suppliers of high-end dampers also have many or all of their internals made in Asia, as well as many Asian factories are ISO certified and can produce world-class quality parts.

Odi has gone through a great deal of effort to assure that the parts used in Feal suspension are top notch with all of his parts built with a high grade of material and tight tolerances. Odi himself has made many trips to Asia to work hand and hand with his suppliers to get the quality up to his standard. 

 

The kit contains all of the parts needed to assemble a set of Feal coilovers. The coilovers are hand assembled with special care being taken with the valve piston assembly to assure adherence to tight specs for the damping curve. 
 

A build starts with a visual inspection of all components. Then the parts to build the valve piston are pulled according to the bill of material. The washers shown lying in front of the pistons are actually the shims that make up the “Christmas Tree” of the shocks valving.  

Feal uses a deflected disc system for their valves. A deflected disc system works by stacking up layers of thin washers or shims in a closely specified way. When fluid flows through the piston's orifices, it must deflect the shim stack to flow through. The thickness and number of shims along with their diameter controls how the shim stack bends and thus how fluid flows through the pistons. 

By varying the amount, thickness, and diameter of the Christmas Tree shims, the amount of damping and the shape of the damping curve can be closely controlled. Feal tunes each shock by using the shims for the desired damping. 

 

The main body of the Feal's coilover is this tube. Most shock companies don't pay a lot of attention to the tubes' tolerances, but the tolerances are critical for consistency in damping and to keep the amount of shaft play under control. 

Feal uses seamless DOM tubing to make their tubes. DOM means drawn over mandrel, and this manufacturing process refines the metals' grain structure and makes for a stronger tube with more consistent dimensions. As a final step, Feal has their tube honed for final control of the ID, a step usually only really high-end shock manufacturers use. 

 

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