The Lotus Cars Community banner
  • Hi there! Why not register as a user to enjoy all of the benefits of the site? You may register here. When you register, please pick a username that is non-commercial. If you use a name that appears on any search engine commercially, you must pick another name, whether it applies to you or not. Commercial usernames are for supporting vendor use only. If you want to become a supporting vendor and grow your business, please follow this link. Thanks!

UN1-026/27 "Holloway" kit - GROUP BUY

46K views 171 replies 52 participants last post by  71type65 
#1 · (Edited)
UN1-026/27 single shaft upgrade kit - GROUP BUY

We met in November 2014 with the President of EMCO Gears, which manufactured the UN1-026/27 single shaft upgrade kit before.

EMCO is willing to make more kits, but the minimum production order would have to be at least 20 units. .
EMCO manufactures racing gear sets for INDY cars, Porsche, Ferrari, Lamborghini and other high performance cars, so they have a proven track record.

It would be great if we could find at least 10 people interested in acquiring this kit and be able to organize a "group buy". IF we identify 10 people interested in this kit, I will be in a good position to discuss arrangements with EMCO and work out the details.

Lotus did very little to upgrade the gearbox after the S4 model in 1991. The introduction of the V8 in 1997 placed a new amount of stress on the design, which is why the upgrade kit was developed. The only change in 1998 was the position of the external gear shift "translator" on the outside of the gearbox case. Nothing on the internals changed.

The upgrade kit addresses 3 weaknesses of UN1 tranny:
1. The primary shaft, which takes the power from the engine is a 1 piece design on the upgrade, versus 2 pieces on the OEM. All flex is removed.
2. The primary shaft has a larger diameter and 9310 grade alloy steel, which eliminates the potential for shaft breaking on the 5th gear overhang (a common failure on OEM).
3. All bearings have higher torque specs, plus gears 1 and 2 ratios are optimized to reduce the "step" between gears, allowing for better synchronizer functionality.

In the past, Derek Bell stated, that all these changes made gearbox internals well capable of 600+ ft lb of torque. Great insurance as a new gearbox would be almost impossible to locate should the OEM fail.

Please be aware that the EMCO kit is designed as a "drop in" kit for gearboxes with 52mm rear shaft bearing (hi-torque casing). 52 mm bearing was introduced starting with S4 model.

I am trying to see if we can find enough people interested in making their transmissions much stronger and eliminating well known issues.

This kit fits only:
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. Similar to 4 Cyl High Torque units with new Clutch
Housing. It carried over the R/H shift lever.

UN1-026/27 single shaft upgrade kit decreased first gear ratio focusing on addressing synchronization engagement issue. It did not drop the first gear ratio as extremely as Quaife/GTO kit. This makes EMCO kit more friendly for lower torque 4 cylinder engines.
NEW GEAR RATIOS:
Holloway..........GTO
1-st 3.0 ....... (GTO 2.66)
2-nd 1.94 ....... (GTO 1.75)

Cost of the kit $4,000 plus shipping and insurance.

This price is good till March 15, 2016

You will receive what is shown in the pictures.

10% down payment required to place your name on the list

Please MP me if you are interested and include your personal e-mail address. I will send you terms/conditions and updates.
Or, you may click on my avatar and go to "contact"-here is my email.
.
 

Attachments

See less See more
5
#3 · (Edited)
It is a fix and safeguard against higher cost alternative.
Small price to pay for improved tranny, comparing to the new one (if you can even find it).
There is one (02 V8) tranny on ebay for 5.5K, but how good it is if it still has the crappy shaft inside, see the difference, below.

Yes, there are 3 SKF shaft bearings included in the kit.

Neither synchro assembly nor ring are part of the kit.
 

Attachments

#4 ·
Funny thing is that no one ever advertises my favorite part of the kit. Yes, not worrying about breaking the dog teeth off second gear is good. Not worrying about shearing off 5th gear is good. Not worrying about having to machine this case is also good.

The thing no one talks about is the new ratios. I love the new ratios! With the stock box I found that sometimes on some roads, 2nd was too low and 3rd was too high. Now 2nd is perfect. Also having a longer 1st is also good thing that makes a V8 more enjoyable to drive.
 
#5 · (Edited)
All the UN1 Lotus Gearboxes are very similar. This is the 'simplified' history.
These changes included Revised Gearchange & Synchro on Reverse Gear. The introduction of the Esprit GT3 created another variant of the UN1 gearbox. This variant is only approved for the 2 Litre version of the Lotus Turbocharged engine. This version of the UN1 is designated UN1 – 028 and has a different Crownwheel & Pinion that is only suitable for use and validated for the GT3 engine. UN1- 028 is not recommended for use on the 2.2 Litre Engine.
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 and 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) w/different Axle &Gear Ratios - 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 realize is that the Lotus versions had some very important differences. The main issue is the crown wheel & 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.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The original UN1 design, although durable and lightweight, was not crafted for the high torque of a Lotus Esprit. The OEM gearbox possesses three weaknesses:
The primary shaft is two pieces connected by a weak spline configuration subject to breakage
The 5th gear overhang is tapered and poorly supported, creating a weakness
The primary shaft flexes under high torque due to its narrow diameter, again creating vulnerability
In addition to the weaknesses of the OEM design, the UN1 gearbox is nearing obsolescence. Parts are difficult to obtain and expensive. When it breaks, and it will, the Holloway Performance kit enables you to increase the UN1’s capacity.
Which model of Esprit? Those with 52mm rear shaft bearing, starting with the S4 model
What are the gear ratios? 1st/2nd are 3.00/1.94 (OEM 3.36/2.05)
What are the gear cuts? 1st is straight cut; 2nd is helical cut
Why change the gear ratios? To lower the “step” between gears, easing synchro transition
Is a different clutch plate required? Original clutch is used; no alterations
 
#6 · (Edited)
In many cases, these shafts have broken due to a fatigue failure caused by flexing of the shaft where it leaves the roller bearing. The crack starts at the step reduction in diameter exactly where the roller bearing ends, it then proceeds through the oil hole rapidly followed by failure.

Usually, 4 cylinder engines don't have enough torque to shatter the shaft, but if you have S4 /S4s or tune your engine, every day may bring a surprise, LOL.
Last two pictures show results when (460HP/450 ft lbs torque) tuned SE was driven hard, box lasted 10K miles.

In the upgraded kit, (3-rd upper pic), the shaft is larger in diameter, and there is no reduction in diameter of the shaft (an obvious stress raiser), as well as being made from a superior material.
Check discussion here: http://www.thelotusforums.com/forums/topic/72381-question-about-un1-strength-vs-engine/?page=1
.
 

Attachments

#8 ·
<SIGH> Wishing had the extra $.. I would so be in for this! Just to remove so often letting up on the throttle out of fear of trashing the transmission! Stupid obamacare screwed me on this...
 
#19 ·
A couple related newbie questions if you don't mind...

1- How "drop in" is this in practice?
2- Any idea on the expected number of hours for the job?

Here in Rochester, NY I believe we've lost all the expert tranny builders to retirement. Moreover, I am pretty sure any Esprit experts are 3-4+ hours away in Toronto or Northern NJ. (A challenge I figured I would live with a couple years from now).

Before I bought my '03 Esprit in October last year, gearbox reliability was the only nagging concern I had. Ultimately I hoped the possible abuse to my car could have only been "so bad" with ~5,500 miles on the odometer when I bought it.

So...
I'm pretty sure I too am in, but I'm also pretty sure I can't PM yet as my total number of posts are in the low single digits.

If you're willing to email me, I'm at "em-oh-elle-e-zee-9-3 at yahoo dot com."

Thanks- Scott
 
#20 ·
Scott, as mentioned above I used a different but very similarly configured kit on my 2000 V8. I had the work done; a lift is a big help. Engine does not need to come out; just the transaxle. I am not expert, just a happy customer, so consider as a guideline only. :smile2:

The transaxle removal allow about 4 or 5 hours. Tear down and installation of transmission internals say 4 hours or so. Allow another 4 or 5 hours to get it all back together.

Some items to consider / check / budget for / might come up / expect when doing the job include:


  • New clutch parts, bearings, etc. (~$2,500)
  • Quaife LSD, if you want one now is the time. (~$1,500 IIRC?)
  • Synchro hub / rings for the critical second gear. These are often needing renewal; if shifting is OK now you should be good. These parts may only be available good used or limited availability. ($800 to $1,500 as req'd?)
  • Basic gaskets, as required. JAE or the guys here should be able to help you with the details of what to consider lining up if you are going to a non Esprit specialist for the work. I think new seals for the output shafts for example. ($300 or so?)
  • The kit will include bearings for the new input shaft as it is different diameter than stock. Any other internal parts that look sketchy on tear down would probably be sourced locally by your shop from a transmission supply or from JAE. e.g. My local guy replaced some other bearings which I assume he just matched up as required.
  • There was a mount or something on the right side that commonly needs replacement; can't recall details but my Esprit guy ordered in as required before he started.

HTH. I would suggest buying the kit, even if you want to wait a season or two to figure out the installation, or drop the car off somewhere during a winter season to get it all done. Mine was a three day deal with a guy who had all the stuff to hand.

Stu
 
#21 ·
Thanks for the reply. Your points make sense. I can't tell if I have issues with the 2nd gear syncro or if it was user error and I *do* like the idea of adding a Quaife.

Once I'm already looking at a giant expense, what's another thousand or two...right? ;-)
[It seems like a couple places have Quaifes discounted a bit right now too]
 
#22 ·
Hi all,
I would like to ask if there's any chance that a Turbo SE can be rebuilt to use this kit?
Ihave read al of the above.
Byt, for example, is it possible to get the newer shifte from an 02' car plus the rear end of the tranny, and build that on to the 1990 tranny?
And is that enough, or are more parts needed to adapt this kit?
I guess it's only a matter of time, before mine breaks Down as well. Doing absolutely fine for the moment.
Or do I need to source an s4-s4s transmission complete?

This set sounds good, also with respect to the gearings.

Kind regards,
Redfox.
 
#61 ·
Hi all,
I would like to ask if there's any chance that a Turbo SE can be rebuilt to use this kit?
I have read all of the above.
But, for example, is it possible to get the newer shifter from an 02' car plus the rear end of the tranny, and build that on to the 1990 tranny?
And is that enough, or are more parts needed to adapt this kit?
I guess it's only a matter of time, before mine breaks Down as well. Doing absolutely fine for the moment.
Or do I need to source an s4-s4s transmission complete?

This set sounds good, also with respect to the gearings.

Kind regards,
Redfox.
Unfortunately, this kit would not fit earlier UN1-s, but there is a hope on the horizon!

Friend of mine, Peter Lenard, decided to independently develop a short ratio gear kit for his UN1-03. Although older, yes I believe UN1-03 new parts are quite likely to be a straight fit into the older SE boxes.

PM me, if you'd like to get more information.
 
#23 ·
Tuning

Since the V8 engine was de-tuned from roughly 500 to 350 hp due to the limitations of the oem gearbox, I assume that this upgrade would also allow for re-tuning the car back up to a higher hp?
What would that re-tuning entail? Is there an ecu chip for that, or is there much more to it than that?
 
#27 · (Edited)
INFORMATION ON SHIPPING CHARGES:

Domestic:
USPS Priority Mail $78 -80 (to the furthest point in California) or less + $55 insurance

Overseas:
Australia and New Zealand: $135 +$55

.
 
#28 ·
#32 ·
In case anyone is interested in replacing their 2nd gear syncro as needed or even as a maintenance. Jae has them in stock for $125 plus shipping.....This is just the syncro ring(or blocker ring) not the hub and sleeve (which usually don't need service unless severe grinding is has been an issue for a while). 1st and 2nd rings are the same may want to do both right away.
 
#34 ·
That is a "decent" price considering that PUK and other "usual suspects" want over 200 euros for one ring!
Are they original Renault, or cottage industry byproduct?
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top