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WHAT TRANSMISSION COULD REPLACE UN1 ?

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122K views 188 replies 48 participants last post by  ragingfool35  
#1 · (Edited)
I would like to collect your thoughts on replacing UN1 with more durable and modern transaxle able to handle up to 400 lb-ft.
I'd like to start discussion by presenting an idea of using 6 speed Cayman S transmission.
I'm curious if anyone has installed one like this in his/her Esprit, yet?

California Motorsports Porsche 987 987c Boxster Cayman transmission section

http://www.californiamotorsports.net/987 Boxster 5 speed G8701 2005.pdf

178.33 MPH at 7000rpm, cable shift. They're modern technology; shift lightly and more quickly than the UN-1 and you could use/adapt a Porsche Boxster shifter.Getrag rates them conservatively at 380nm which is about 280 ft-lbs of torque. For road use, not drag racing, one might get away with 400 ft-lbs.
Also available in Audi Avant version http://www.advancedautomotion.com/product_info.php?cPath=69_52_143&products_id=29

TRANSMISSION SPECIFICATION

· Type: G87/01

· Original equipment for: Boxster 987 05-08; Cayman 987 07-08

· Description: H Pattern 5 speed manual transaxle with triple cone synchromesh (1st/2nd only) and synchronized reverse

· Limited Slip Differential: Not offered as optional equipment by manufacturer

· Speedometer: None

· Trans controls: Shift cables

· Clutch: Hydraulically assisted push clutch, single plate

· 1st gear 3.50

· 2nd gear 2.118

· 3rd gear 1.429

· 4th gear 1.091

· 5th gear 0.838

· Final drive 3.556
 

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#5 · (Edited)
G50's are bulletproof and ideal for high torque applications, but have to be turned upside down and fitted as they are orientated the wrong way round in the Porkers. GT40's and Ultimas use them ok as their chassis has better space/positioning, and they swear by them for the racing applications. The Esprit however is a tougher proposition and I only know of one that managed it at some very high angle for the CV joints. It was done in the UK for a track car, but the parts were sold on, and I think a guy in the States ended up with them

The other Getrag units, like those used in the Boxter/Cayman and later Boxter S/Cayman S, are not rated as highly but are a far easier fit for the Esprit. Their Audi variants have been popular with GT40 replica builders for a long time as they are far cheaper to obtain, and a few Esprits have also fitted variants of them (such as Andy Hills' Audi 4.2ltr V8 project) and I am in the process of trialing one myself with the tuned LS3. The one Advanced Automotion promotes is the old 01E FWD version, reputedly stronger than the newer ones like the 01X/0A2 due to its cast iron bearing carrier.
 
#6 ·
Not sure about fitting in the Esprit but as others have stated I know that Factory Five GTM car uses one to bolt up to a LS motor. Here is what they use off their website.
Other Components/Parts

Porsche Transaxle Parts from 1990-1998 2-wheel drive 911 models

Porsche G50 or G50 variant transmission including clutch disk, pressure plate, throw-out bearing, inner CV joints and starter
 
#8 ·
I'm in the process of fitting an Audi 01E to my LS3 powered 914. I sourced mine from Advanced Automotion. Because of HP for my application I used a custom 1-2 gearset and went with full WPC treatment. I also went with a Wavetrac diff which I can't wait to try. I think this trans would be a good candidate for an Esprit. If used behind a 4 cyl you could probably just use one without any mods.
 
#10 · (Edited)
That looks pretty nice. Only $2600!
I'm wondering if it'd clear Esprit trunk floor and the rr brace.
That one is too long as it is the 4WD version. You want the FWD that looks like this:

Image


It is short enough to fit the body length with an adaptor plate, but will require a custom cross brace as it is higher than the Renault UN1-2x series. (If you intend to use it with a Lotus engine, it may require a revised engine height/position to align the input/output shafts, therefore new mounts.)

As far as I know the 01E only came in these ratio sets:

1 - 3.50
2 - 1.89
3 - 1.23
4 - 0.86
5 - 0.67
6 - 0.56 (/0.60)

F - 3.85

or

1 - 3.75
2 - 2.14
3 - 1.51
4 - 1.17
5 - 0.97
6 - 0.82

F - 3.85


You would need to check if the power/torque characteristics of the engine you intend to use will work well with the longer or shorter set (although AA might offer some customised ratios.)
 
#14 ·
I admire you fella's techno. savvy.

Was on the Porsche Rennlist site for almost 9 years.
I hate to say it but it seems Lotus owners are more sophisticated and more 'keen' than the 928 owners.
I do NOT mean to over-state!
 
#15 · (Edited)
0A3 Trans = B6 S4, is rated 450Nm, but is hard to get. Quattro is too long for Esprit. Is the 2 WD tranny shorter than C35 or UN1?
 
#18 ·
I stuck with the Renault unit through many of my adventures with uprated Lotus engines, and never broke one. I still have a couple of them lying around somewhere. It's actually a very strong box given its original application. It was raced, and is still used in many uprated Esprits, as well as GT40 replicas etc.

However, engine power has marched on significantly, but I believe the old Derek Bell re-engineering of the UN1 internals is still available through GTO Engineering.

If added to the cryo-tempering and REM isotropic super finishing procedures becoming more available lately, I think it could easily handle any uprated Lotus Esprit engine - except perhaps the most extreme ones.
 
#20 · (Edited)
[/QUOTE]If added to the cryo-tempering and REM isotropic super finishing procedures becoming more available lately, I think it could easily handle any uprated Lotus Esprit engine - except perhaps the most extreme ones.[/QUOTE]

Cryogenic treatment vastly improves your load and longevity of metal parts. I see a lot of people rebuilding their motors and wonder why they dont have the liners, pistons, valves i.e. all internal parts treated.

There is a caveat! You must have someone really good do the treatment and VERY few in the WORLD use good cryo coolers and know how to heat treat after very well!

Shameless Plug:
We treat a lot of racing teams internals: Top fuels drag cars see six times the life from valve springs alone after cryo treatment.
I have attached an article for some interesting reading.

If you need any info I can help:
Bentzion (at) metal-wear (dot) com
 

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#21 ·
BTW,

Many companies that you may not be aware of already use cryogenics on their products. NASA, Weismann transmissions (built the McLafren F1 transaxel among other racing cars trannies.) Jerico transmissions, most of F1 and LMP car builders. Porsche used Cryo treated brakes on their endurance racers for years. They use a form of cryogenic treatment on cutting tools to cut the titanium for the F35. MAG who along with a another company is claiming 10 times the life on the tools and 35% faster cutting that results in huge cost savings. The government has given them an award for it!

Sorry for the rant. Most people put up a fight when we talk about cryogenic treatment. It is the single most advanced step that has been achieved in many years in materials treatment. The problem for the consumer is that manufacturers are very sort sighted and see a loss of revenue if they provide longevity to replacement parts...In racing and military it is considered absolutely necessary to save on costs and gain an edge whenever they can.
 
#22 ·
I read cryogenics treatment process many moon ago and read so many pros and cons. I sent a billet compressor, turbine wheels and turbine housing of a turbochargers to a company in Alabama that does this process. For the turbo to survive a heat that can reach as much as 1500 degrees, you need to find a turbine housing that has abundant properties of nickle. It's not cost effective to spend so much while the inferior product "made in china" turbochargers are flooding the market. Not too many cryogenic company out there and i'm sure the cost of this process is staggering. So, the availability and the cost of this process to regular enthusiast is unreacheable...for now!

For the meantime, until the government regulates/curve the fake-fraud made in china, i will not spend a dime.
Someday, I love to see "made in the USA" back in the shelves.
 
#27 ·
I have yet to see a con!!! Besides, how much do you think it costs to have a turbo done? I do entire engines for $1800! A turbo would only cost $150-200 max! If your buying a Borg Warner or Garrett charger I will guarantee that under normal use (non abusive and set up correctly) you will get at least 3 times the life. I will make you a deal, send us a piece that you want treated and I will do the first One on the house! We have plants in morresville NC, park city Il, Palo Alto Ca, and Camarillo Ca. Most cryo treaters are scammers have zero knowledge of how it all works and it has completely ruined the cryo industry. Our founders are metallurgists and scientist that do the r&d on house. My email is on a previouse post your always welcome.
 
#28 · (Edited)
Here is a bulletproof 500+ft lbs transaxle with great potential, but rather expensive.

Current Application:
EMCO designed the GA46 Transaxle expressly for the Daytona Prototype classification and for competition in 24-hour endurance racing. The GA46 first proved its reliability by flawlessly completing a 28-hour test at Daytona on November 6-7, 2002. Subsequently, the GA46 has run successfully in all the races of the 2003 Grand-Am Rolex Sportscar Series, including the Rolex 24 Hours of Daytona where it helped Multimatic capture the Daytona Prototype class victory.
By November 1st, 2003 the GA46 was in 9 of the 10 cars (3 of 4 manufacturers) competing in the final race of the Rolex Series including the Team Champion Bell Motorsports No. 54 Chevrolet Doran JE4 with its Driver Champion Terry Borcheller.
February 1st, 2004: The Rolex 24 Hours of Daytona overall race winner Bell Motorsports No. 54 Pontiac Doran JE4 shifted the GA46 to victory logging over 1800 race miles and over 12,500 shifts! All eleven Daytona Prototype GA46 customers competing in this grueling race combined for more than 13,000 trouble free miles over the course of the race.
More Information
GA46 - EMCO Gears, Inc.
 

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#30 · (Edited)
Except bold and pioneering installation by Mike Rodrigues, has anyone else installed ZF5-DS-25 series transmission in Esprit?

Apparently, wide range of gear ratios are available from this company: RBT Transmissions – Heritage and Performance
ZF requires a new bell housing, which is prototyped and available from NZ foundry, (contact mike R).
A group buy could be arranged if 10 buyers would commit to purchase.


http://www.thecarnut.com/Manuals/Bora_Transaxle.pdf

http://en.wikipedia.org/wiki/List_of_ZF_transmissions

http://file.seekpart.com/keywordpdf/2010/12/17/2010121716259640.pdf

http://www.spacecitypanteras.com/Technical/ZF Transaxle Requirements.pdf

Maserati Bora had 3.77:1 ring and pinions in them instead of the 4.22:1 that a Pantera uses!
ZF tranny was used in Panteras well into the 90's!