JP - check out
Lotus Forum - Lotus Talk. There's a guy there who has developed a better CW&P for the C35. The quaife LSD is also highly recommended.
.
YEP, you have to talk to Mr.D on Lotus Talk!
In 2014, he has identified the reason for the inherent weakness of the C35 tranny CWP, if used amid-ship with clock-wise rotating engines (as seen from the front). Maserati engine, which has a mid-ship location, rotates counter-clock wise and C35 transmission has CWP "flipped" to the opposite side. It has NO such a problem like Esprit.
Why OEM (Citroen DS/SM) CWP in Esprit configuration is inherently weak?
Originally, Citroen C35 gearbox was designed to run in the opposite direction on Citroen DS and SM (forward location). For Lotus Esprit configuration the whole gearbox was "flipped around" and placed behind the engine, thus all gears and the CWP is running "backwards" !
Ideally, the pinion gear should rotate the crown wheel on the drive side of the tooth. If however, the pinion rotates the CW on the coast side, strength of the gear set can be
reduced by as much as 20%. Therefore, the CWP on Esprit cars is weak in forward drive and its strength is much better in overrun!
Similar situation exists on the front Land Rover differential, which KAM,
http://www.kamdiffs.com/products-2/diff-ratio/
was able to resolve by installing a reverse cut CWP. As it is mentioned on KAM website, in the OEM front axle of the Land Rover, the OE gear set is running “backwards”, being driven on the coast side of the teeth rather than the driven side and as such is weaker. So, the reverse cut gears were required for this configuration!
Mr.D has a new, reverse spiral CWP design completed and has been competitively quoting it now.
Prices are scattered widely. One would have to order minimum of 10 pairs to make this project economically feasible. Thus, initiating a Group Buy initiative is the only way to accomplish this project. For details see:
https://www.lotustalk.com/forums/f164/citroen-g-box-crown-wheel-pinion-350506/index10.html
Comparing to the original Citroen CW+P, new design addresses several critical deficiencies of the old OE parts.
It offers:
- reversed direction of the spiral - to correct the OE design and apply force to the correct flank of the tooth (see posts 53-60)
- larger tooth pitch resulting in increased thickness (30% strength increase)
- revised, more robust pinion gear tooth design
- better final ratio of 1:4.286 (vs 1:4.375), which improves the top speed in gear (more "peppy")
- aerospace grade alloy steel ( as used on critical aircraft engine gears/shafts)
Here are some gear/traction calculations:
*******************************
Final Gear Ratio….: 4.286
Tire Size………....….: 275-40-18
Max Power RPM…..: 6000
Limit RPM……….....: 7100
*******************************
*********************
Gear..Ratio…Compound ratio
*********************
1 ….2.930 …....12.558
2 ….1.940 …...…8.315
3 ….1.320 …...…5.658
4 ….0.970 …..….4.157
5 ….0.760 …..….3.257
***************************************
Gear.MPH/1000....MPH @6000…MPH @7100rpm
***************************************
1 …..........6.32…....…….38……...........…….45
2 .......…...9.54…....…….57……...........…… 68
3 …........14.02…....…….84……..........…...100
4 ........…19.09.…….....115………............136
5 ........…24.36…...…...146………............173 MPH
************************************************** *****
MPH………………………RPM (in Gears)
************************************************** *****
…….......…1….…...…2…...…..3…......…4…….....…5
************************************************** *****
. 5……...791….…524…..…357....….262….....205
10…...1583…..1048…....713….....524….....411
15…...2374…..1572…..1070….....786…...…616
20…...3165…..2096…..1426…...1048…...…821
25…...3957…..2620…..1783…...1310…...1026
30…...4748…..3144…..2139…...1572…...1232
35…...5539…..3668…..2496…...1834…...1437
40…...6331…..4192…..2852…...2096…...1642
45…...7122…..4716.….3209…...2358…...1847
50………....…….5240…..3565…...2620……2053
55………....…….5764…..3922…...2882……2258
60………....…….6288…..4278…...3144……2463
65………....…….6812…..4635…...3406……2668
70………….........…..…....….4991….3668…...2874
75………………........………5348….3930…...3079
80…………………............…5704….4192…...3284
85……………………........…6061….4454…...3490
90……………………........…6417….4716…...3695
95…………………........……6774….4978…...3900
100…………….…......…….7130….5240…...4105
105…………………........……………..5502…...4311
110………………………........………..5764...…4516
115……………………….........……….6026..….4721
120……………………….........……….6288…...4926
125……………………….........……….6550…...5132
130……………………….........…….…6812...…5337
135………………………….........…….7074…...5542
140………………………………....................…...5747
145…………………………………...............……5953
150………………………………...............………6158
155………………………………...............………6363
160…………………………………...............……6568
165…………………………………...............……6774
170…………………………………..............….…6979
175………………………………..............….…....7184
************************************************** *****
Gear Change RPM drop (change @6000) RPM drop (change @7100)
************************************************** ***********
1 ->2…......…-2027 (To 3973).(19.60%)..........……-2399 (To 4701)
2 ->3…......…-1918 (To 4082).(21.28%)..........……-2269 (To 4831)
3 ->4…......…-1591 (To 4409).(27.12%).........……-1883 (To 5217)
4 ->5…......…-1299 (To 4701).(36.19%)….........…-1537 (To 5563)
************************************************** ***********
Several Ligier JS1 race cars were equipped with Citroen tranny in Maserati configuration
1969 - 1970 Ligier JS1 Ford Gallery Images - Ultimatecarpage.com
I suspect that they may have had some internal modifications.