What are the Citroen gear box limitations?

[MrDangerUS 108]

Well, the obvious limitation is CWP.

What is the next weak link?

I'm interested in proven fixes (not "opinions") and TQ achieved. How high one can go?

Thanx

[dsvitesse1 66]

Hi John,

I have heard, not seen any specs or data, over 400 BHP. I'm sure in combination of Quaife ATB and very gentile left foot, the gearbox shoul not have any problems with that .

cheers,

Harry Martens

[MrDangerUS 108]

That is impressive!

With Cryo-treated CWP-I assume? Otherwise it should be reported as a miracle...

BR

John

[Simon350S 192]

I'll be following your progress with interest as I'm looking at trying for 300hp

[MrDangerUS 108]

Simon,

What is your recipe for getting your engine to 300?

[MrDangerUS 108]

The next weak link is the input shaft,(Esprit/Esprit turbo C35 gearbox input shaft B085F4068F),

which I found here:

http://www.elanfactory.com.au/pdf/product_catalogues/Catalogue%20-%20Lotus%20Esprit%20parts.pdf

I'm wandering how much Harry is charging for something like this.

I heard the GTO Racing has couple nice gear box "fixes", (don't know if for C35 though).

Next on the list: ["Poland" marked] bearings must be replaced with quality SKF parts

Am I missing anything?

HOW TO MAKE IT BULLET-PROOF?

ANYONE?

Edited May 15, 2011 by MrDangerUS

[MrDangerUS 108]

C-35 Citroen box improvements:

-install Quaife LSD

-cryogenicly treat your CWP, crown wheel and pinion to improve strength

-replace bearings w/SKF parts (Harry Maartens, DS-Vitesse, Netherlands or in USA, Jerry & Sylvia Hathaway, who are extremely competent and helpful. SM World is a Citroen SM repair and restoration facility recognized by the Citroen factory:

http://infoweb.nl/smworld/)

If you wish to upgrade the gearbox using bolt-on parts w/o too much of a fabrication, search for a Renault UN1. V8 gearbox can handle up to 400lb/ft.

Here's an UN1 conversion to inboard brakes done by JAN HOEL.

http://www.facebook.com/photo.php?fbid=179165288761382&set=pu.178516808826230&type=1&theater

UN1 – 016 – 4 Cylinder G/Box – First variant of Lotus UN1– First used on X180 Introduction in 1988. This 'Box had rear cover with L/H shift lever.

UN1 – 026 – High Torque G/Box – Stronger Casings etc. introduced circa 1993. This 'Box had rear cover with R/H shift lever

UN1 – 027 – V8 Gearbox – Introduced in 1996 on V8 Esprit. This box was basically similar to 4 Cyl High Torque units with new Clutch.

Housing. It carried over the R/H shift lever. It had synchro on Reverse Gear. A higher 5th gear. The shift mechanism was changed to an improved version of the R/H mechanism from VIN W2272 – this requires a different shift master unit and cables.

UN1 – 028 – 4 cylinder G/Box for the Esprit GT3 (2.0 Litre) with a different Axle Ratio and Gear Ratios - this Axle Ratio is not suitable for 2.2 Litre Engine Torque.

In a nutshell the 026 & 027 Gearboxes are very similar except for the Clutch Housing, Synchro on Reverse, 5th Gear Ratio. The clutch Housings & Rear Cover (with shift lever) can be changed over easily. Minor improvements were introduced at the time of Sport 350 to improve durability.

The Lotus versions of the Box were very similar to Renault units at first sight. What people do not realise is that the Lotus versions had some very important differences. The main issue is the crownwheel & pinion. Although the Ratio is identical to some Renault vehicle applications the material is different. The Renault material will not survive the Lotus application (even the earliest non intercooled cars). Running on the approved oil is another critical item.

Do not forget to replace your weak clutch!