I thought that "The One Stop Shop" compiling all information under one roof would be nice to have.
Would you please post technical data, tips, specifications, dimensions, reworks, etc.
I"ll start with some specs for different versions of UN1 specimen:
> The initial Lotus unit - UN1-016 had a Torque Limit set at 315 Nm (232 lb.ft).
This Version used different Crown Wheel & Pinion Material compared to most other Renault Applications (except Alpine, which had a different direction of rotation). Differential also had 4 Pinions like the Alpine & some of the Agriculture Units
(UN1-023 and UN1-024).The Lotus Version also had extra Dowels in the bell housing joint to further control bending.
>The UN1-026 (known as the High Torque Box) had new Casings which were stronger to reduce Bending under the increased Torque. The Main Fixing Bolt Size & Torque was also increased. There were some revised bearings and retaining plates introduced at that time. The Torque Limit was increased to 400 Nm (295 lb.ft)
> When the V8 came along (UN1-027), it carried over all the 026 features. Plus, there were also updates to the shaft machining & gear assembly procedures as well as well as the revised 5th gear ratio, synchro was added on reverse.
> For the GT3 (UN1-028) we changed 3rd gear the Final Drive Ratio to suit the Engine Performance. This revised Final Drive Ratio came with a lower Renault torque limit of 300 Nm (220 lb.ft).
The Gearboxes had to use a specific lubricant to eliminate Severe Crown Wheel & Pinion wear (Mobil SHC-630M... no longer produced, or Castrol TAF-X... also recently discontinued by Castrol).This was introduced during the initial development testing. The standard Renault lubricant (Elf Trans elf TRX) did not give enough protection due to the Load and Heat produced by the rapid Esprit Turbo Engine Torque rise.
> At all times the gear ratios used in the Lotus application were standard Renault, but the Lotus Crown Wheel and Pinion used upgraded materials. The Renault CWP parts will fit, but they're not as strong.
The main problem was in the stiffness of the Transmission Casing and the loading on the Crown Wheel & Pinion. The Lotus versions of the Renault UN1 Transaxles are the strongest variants available. The only thing that comes close is the later Renault Alpine GTA UN1-019, but it has a different direction of rotation and different final drive Ratio.
> The UN1-013 from the Renault 21 Turbo would provide some of the gears (not 3rd, 5th or final drive) and synchros suitable for the GT3.
An original Esprit Renault UN1-016 is standard in the non-SE and the SE.
The high-torque box started in 1993... 1993.5 SE and the S4 in Oct 93.
Just by looking, the shift translator is on the left side, and there should be an ID tag, or stamping, on the gearbox.
Esprit Original .... UN1-016 ... Started with first Renault equipped Esprits
... 1988 DOM / ROW intro
... 1989 Federal intro, non-ChargeCooled, and SE.
... With 0.8205 5th gear ratio (0.8205 x 3.89 final = 3.1917:1 overall). Left side shift translator, 315 Nm (232 lb.ft) torque rating
Esprit Hi-Tork ... UN1-026 ... 1993 intro (1993.5 SE and the S4 in Oct 93)
... Stronger case with new castings
... RIGHT side shift translator
... 400 Nm (295 lb.ft) torque rating
Esprit V8 ....... UN1-027 ... 1996 intro, for the most part carried over 026 features
... V8 bell housing - does not share 4-cyl bolt pattern
... Higher 5th ratio (0.76)(0.76 x 3.89 = 2.9564:1 overall)
... Synchro-ed reverse
... LEFT side shift translator
... 1998, modified cross shaft for DIRECT CABLE shifter, no translator.
... Minor durability improvements w/ Sport 350 intro.
... 400 Nm (295 lb.ft) torque rating
Esprit GT3 ......... UN1-028 ... 1998, for the most part like 027
... With lower third & final drive ratios (1.41 & 4.11 ??)
... With higher 5th gear ratio (.076)(0.76 x 4.11 = 3.1236:1 overall)
... 4.11 CWP ratio not suitable for torque of 910 or V8
... CWP is Renault parts, not as strong as Lotus 3.89 CWP
... 300 Nm (220 lb.ft) torque rating due to a weaker CWP
Would you please post technical data, tips, specifications, dimensions, reworks, etc.
I"ll start with some specs for different versions of UN1 specimen:
UN1/xxx
> The initial Lotus unit - UN1-016 had a Torque Limit set at 315 Nm (232 lb.ft).
This Version used different Crown Wheel & Pinion Material compared to most other Renault Applications (except Alpine, which had a different direction of rotation). Differential also had 4 Pinions like the Alpine & some of the Agriculture Units
(UN1-023 and UN1-024).The Lotus Version also had extra Dowels in the bell housing joint to further control bending.
>The UN1-026 (known as the High Torque Box) had new Casings which were stronger to reduce Bending under the increased Torque. The Main Fixing Bolt Size & Torque was also increased. There were some revised bearings and retaining plates introduced at that time. The Torque Limit was increased to 400 Nm (295 lb.ft)
> When the V8 came along (UN1-027), it carried over all the 026 features. Plus, there were also updates to the shaft machining & gear assembly procedures as well as well as the revised 5th gear ratio, synchro was added on reverse.
> For the GT3 (UN1-028) we changed 3rd gear the Final Drive Ratio to suit the Engine Performance. This revised Final Drive Ratio came with a lower Renault torque limit of 300 Nm (220 lb.ft).
The Gearboxes had to use a specific lubricant to eliminate Severe Crown Wheel & Pinion wear (Mobil SHC-630M... no longer produced, or Castrol TAF-X... also recently discontinued by Castrol).This was introduced during the initial development testing. The standard Renault lubricant (Elf Trans elf TRX) did not give enough protection due to the Load and Heat produced by the rapid Esprit Turbo Engine Torque rise.
> At all times the gear ratios used in the Lotus application were standard Renault, but the Lotus Crown Wheel and Pinion used upgraded materials. The Renault CWP parts will fit, but they're not as strong.
The main problem was in the stiffness of the Transmission Casing and the loading on the Crown Wheel & Pinion. The Lotus versions of the Renault UN1 Transaxles are the strongest variants available. The only thing that comes close is the later Renault Alpine GTA UN1-019, but it has a different direction of rotation and different final drive Ratio.
> The UN1-013 from the Renault 21 Turbo would provide some of the gears (not 3rd, 5th or final drive) and synchros suitable for the GT3.
An original Esprit Renault UN1-016 is standard in the non-SE and the SE.
The high-torque box started in 1993... 1993.5 SE and the S4 in Oct 93.
Just by looking, the shift translator is on the left side, and there should be an ID tag, or stamping, on the gearbox.
Esprit Original .... UN1-016 ... Started with first Renault equipped Esprits
... 1988 DOM / ROW intro
... 1989 Federal intro, non-ChargeCooled, and SE.
... With 0.8205 5th gear ratio (0.8205 x 3.89 final = 3.1917:1 overall). Left side shift translator, 315 Nm (232 lb.ft) torque rating
Esprit Hi-Tork ... UN1-026 ... 1993 intro (1993.5 SE and the S4 in Oct 93)
... Stronger case with new castings
... RIGHT side shift translator
... 400 Nm (295 lb.ft) torque rating
Esprit V8 ....... UN1-027 ... 1996 intro, for the most part carried over 026 features
... V8 bell housing - does not share 4-cyl bolt pattern
... Higher 5th ratio (0.76)(0.76 x 3.89 = 2.9564:1 overall)
... Synchro-ed reverse
... LEFT side shift translator
... 1998, modified cross shaft for DIRECT CABLE shifter, no translator.
... Minor durability improvements w/ Sport 350 intro.
... 400 Nm (295 lb.ft) torque rating
Esprit GT3 ......... UN1-028 ... 1998, for the most part like 027
... With lower third & final drive ratios (1.41 & 4.11 ??)
... With higher 5th gear ratio (.076)(0.76 x 4.11 = 3.1236:1 overall)
... 4.11 CWP ratio not suitable for torque of 910 or V8
... CWP is Renault parts, not as strong as Lotus 3.89 CWP
... 300 Nm (220 lb.ft) torque rating due to a weaker CWP
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