Lotus Esprit V8/S4S Momo Steering Wheel Upgrade

This modification is purely aesthetic, absolutely no performance enhancement reasons for this one. It simply looks great!  The only reason we did this is because, as you may be aware, there is little room in the Esprit cabin, especially when getting in and out. Well we found a Momo steering in our beloved Blue,  Nappa Leather, with a flat bottom for better access. We could not resist buying it. They actually come in a variety of colored leather.

Available Momo Steering Wheels "Apache" Styling

The Official Lotus Momo Steering Wheel Boss, Spline & Horn Spring Assembly

One very important item is the steering wheel adapter or boss. After talking to Lotus and scouring parts manuals, we actually got a Lotus Part Number for the Steering Wheel Boss/Adapter that is fitted to the GT 350 in the UK and Europe. It turns out that this is a combination of five parts. The Steering Wheel Hub, (Lotus Part Number A082H4082S)  The Steering Wheel Boss and Spline Assembly, (Lotus Part Number A082H6056S) The Horn Bush,   (Lotus Part Number C100H8029F)  The Spring-Horn Pin,  (Lotus Part Number A100H6050F) The Horn Pin,  (Lotus Part Number A082H4085F) The Horn Ring Push Connection, (I do not have a part number for this but it is item 10,   in section 32.05 Page 1 of the Lotus V8 Parts Manual, your dealer should be able to get it for you) You will not find the part numbers in any manuals, they are listed TBA. Not any we could get our hands on anyway. Lotus say this setup willfit any 6 screw Momo wheel, but is exclusively for "Track Use". (The standard disclaimer).

Removing the SIR GM Style Steering Wheel Assembly

WARNING! - The SIR (Air Bag) is an explosive device, be very careful when handling upon removal, and DISCONNECT THE BATTERY.

This is very easy to do. The tricky bit is telling the SIR Computer that it still has a Drivers Side Air Bag, when in fact it hasn't. Otherwise the SIR light stays on, on the dash.

• Loosen the 4 Torx bolts on the back of the stock steering wheel. You cannot remove them as they are retained by an internal clip
• Carefully pull the SIR assembly out of the wheel center
• Disconnect the electrical connector from the SIR assembly. (Make sue that the automatic shorting pins have closed down on the SIR connectors. (The SIR assembly has a protective system that shorts the electrical activator pins out, you can see them if you look at the plug on the SIR. Using a HIGH IMPEDANCE Ohm Meter it should read 0 Ohms. DO NOT PUT A HIGH CURRENT VOLTAGE ON THESE PINS, IT WILL EXPLODE!)
• Disconnect the horn connector
• Loosen the the center spline lock nut and remove it with it's large washer
• Carefully pull the steering wheel off the spline, sliding the SIR and Horn electrical connectors through the wheel
• This will reveal the spline and the SIR Bus assembly

Now to the tricky bit. you will have to get a 2 Ohm resistor and place it into the car side of the SIR electrical connector. The Resistor MUST be exactly 2 Ohm, NOT 1.8 Ohm or 2.1 Ohm. The Wattage is not really a concern, although any thing over 1/2" Watt is recommended. We used a 1 Watt 2 Ohm Wire Wound Resistor. All that has to be done is the wires on the resistor bent into shape so they fit snug into the connector. The tape the lot up with black electrical tape, and we are done.

SIR Bypass Resistor

Installing The New Steering Wheel and Adapter

After all of the above explaining and experimenting was complete, we decided to go with the real Lotus Parts.  It took quite a time to locate part numbers for all the actual bits that would be required. They are as follows:

• Momo Steering Wheel Hub - A082H4082S
• Momo Steering Wheel Boss and Spline Assembly - A082H6056H
• Horn Pin - A082H4085F
• Horn Push - C100H0029F
• Spring-Horn Pin - A100H6050F
• Horn Ring - We retro fitted an Izuzu Impulse part. (Call Lotus for the Lotus Part Number, V8 Parts Manual Section 32.05 Page 1 Item 10 )

Once you have got all these bits, you will do the following:

Remove The SIR Bus Assembly

• Remove the upper and lower steering column shrouds (there are five screws, two for the top and three for the bottom shroud
• Using masking tape, tape the SIR Bus assembly together to stop it rotating on it's Bus, in the NEUTRAL POSITION
• Loosen the four small screws on the Bus Assembly
• Remove the assembly with the nylon indicator reset ring
• Remove the SIR Bus Assembly Plug from the socket under the dash (it has three contacts). You will need to remove two black tie wraps holding the wires to the steering column
• Insert the 2 Ohm Resistor (as mentioned above, in the Steering Removal instructions) into the appropriate connectors on the SIR/Horn Socket under the dash, where the SIR Bus Assembly was plugged into. Tape the Resistor into place with electrical tape
• You will notice another connector on the socket under the dash, this is for the Horn, and will be used later

Installing The New Hub, Boss and Horn Push Assembly

• Bolt the Boss to the Hub with the 4 Allen bolts provided with the Boss
• Assemble the Horn Ring to the Hub using some silicone rubber, and two small screws. We tapped the existing holes in the hub out to the nearest size, any two small English or Metric screws or even self tapping screws would suffice. Pass the horn wire through the hole provided in the hub itself. Let the silicone dry over night. If you get (and pay for) the real Lotus part, it should come with screws, and fit snug
• Insert the Nylon Horn Push into the hole in the Steering Column. It is dead center of the column. You will need to gently hammer it into place, it is a snug fit
• Insert the Horn Push Spring into the Nylon Horn Push
• Using a 1/16" Drill, drill a small hole in the rear of the Horn Pin, about 1/4" deep and be careful to keep it centered
• Solder a 12" length of wire to the Horn Pin
• Insert the pin (and wire) into the Nylon Horn Push through the Spring, so it moves back and forth easily on the spring.  This will be sprung against the Horn Ring on the Hub
• Crimp a SMALL spade male connector to the loose end of the 12" length of wire AFTER IT IS INSERTED INTO THE NYLON HORN PUSH
• Insert the small spade connector into the spare connector in the socket under the dash
• Tie Wrap the wires to the steering column as needed, we use 1 large tie wrap

Installing The New Steering Wheel

• Straighten the steering column so the front wheels are dead straight. You will end up doing this a few times...... we did
• Slide the Steering Wheel Boss and Adapter assembly on to the spline. Be careful not to damage the spline in the Boss. There is a mark on the back of the adapter that reads "TOP" make sure it is at 12 O'clock
• Place the large washer and lock nut (as removed from the original steering wheel) on the spline and tighten. This does not need to be really tight, 1/8th of a turn, once resistance is felt is adequate.  DO NOT OVERTIGHTEN THIS NUT
• Connect the Horn wire from the Hub and Boss, to the wire (Red) from the new Momo Wheel
• Crimp a round lug connector to the other (Black) wire from the Momo Wheel. We used one that fit exactly round one of the six countersunk retaining screws that came with the Momo Wheel. This will be the Ground Lug for the Horn
• Insert the lowest retaining screw (6 O'clock) through the wheel and through the ground lug, then loosely screw it into the boss, holding the wheel all the time. Be careful not to scratch the new wheel center
• Very carefully, tighten the retaining screw and adjust the ground lug so it is vertical to the wheel, and the wire does not foul the seating of the steering wheel
• Insert the 12 O'clock retaining screw and tighten it. These screws need not be really tight. DO NOT OVER TIGHTEN THEM
• Test the Horn (it works with the ignition off)
• Drive the car to see if the steering wheel is straight, if it is not, you will need to remove the 2 steering wheel retaining screws, undo the lock nut, put the steering wheel back on with two screws in the 9 O'clock and 3 O'clock positions, Pull the hub off the steering column, and re-adjust it's position. This is what we had to keep doing a couple of times, until we got it right
• When all is well, put the rest of the retaining screws in the wheel
• Replace the bottom and top steering column shrouds
• Admire your new (expensive, thanks to Lotus) steering wheel

Congratulations! You now have a VERY TRICK looking Momo Race Quality steering wheel on your Esprit.

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