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1985 Turbo Esprit with HCI mods & intercooler
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Thanks. The problem at the moment is how to transition from the stock female splines in an outboard Stevens hub carrier to a flanged Porsche CV930 half-shaft.
 

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2017 Evora 400
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Get the Stevens outer CV joint/spines and the P car inner CV joint/splines, take your measurements, send it all to the driveshaft people and they will make it for you.

Sorry I don't know what the outer hub is off of and I don't seem to have that in my database.
 

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1985 Turbo Esprit with HCI mods & intercooler
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The outer hub is off an '88 or '89. I also have the '88/'89 drive shafts with the male splines and outer bearing cartridge, which as far as I know, are unchanged across models through S4.
20210326_142219.jpg
 

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2017 Evora 400
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Then all you need is the P car inner and splined shaft and you'll have all the parts. That should be pretty easy to acquire.
 

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1985 Turbo Esprit with HCI mods & intercooler
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While waiting for the Renegade kit, I've ordered Wilwood brakes from Claudius-- 6-piston and 12.25" disks up front in anticipation of transitioning to 17" wheels. Meanwhile the car has been stripped for a full restoration, albeit with body on.

After agonizing about replicating an X180R-style cage, I read a nice piece about the increase in torsional strength achieved by Lotus circa ‘88 by stiffening the composite body. Apparently this was more significant than modifying the backbone. Since the interior of my ’85 is stripped, it would be relatively straightforward to strengthen the GRP into a monocoque a la F1. This could be done across the bulkhead, the roofline or roofline edges and corners, down the window pillars, and across the floor pan to the backbone. Perhaps the L & R upper corners of the bulkhead could be sufficiently layered up to support attachment of an X180R-style metal tube frame across top of the engine compartment to the rear uprights. The CF reinforcing shell inside the cabin could be layered up solid, or wrapped around thin alum tubing, thickened at the corner joints, and bonded to the existing fiberglass panels. So what we have here is basically a rigid CF bicycle frame all around the cabin and joined to the chassis via existing chassis bolts. The CF paneling could be laid up solid, or as a honeycomb sandwich, or wrapped around a foam core.
 

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.....
After agonizing about replicating an X180R-style cage, I read a nice piece about the increase in torsional strength achieved by Lotus circa ‘88 by stiffening the composite body. Apparently this was more significant than modifying the backbone. Since the interior of my ’85 is stripped, it would be relatively straightforward to strengthen the GRP into a monocoque a la F1....
Interesting. Where was the article? Did they provide any before/after quantitative analysis or measurements of torsional rigidity?

A bit difficult to imagine the FG buildup would be more effective than a properly designed and installed roll cage, either aluminum or steel, that triangulates all the suspension attach points. Welding the cage to the frame rather than bolting might help, although I'm not sure if that's practical. It's how I installed the cage in my Europa but that was a stripped out race car.
1286947

This approach shows additional tubes running to the lower front suspension attach points. I don't think the X180 version has those tubes (see below). Again, maybe not practical on a road car depending on comfort/performance tradeoffs.
1286951



The Esprit S model has 14 bolts attaching body to frame, expect the G model is similar. Maybe installing some additional attachment points and/or brackets between body/frame would help make the total structure more rigid.
1286948


I've also seen writeups that suggested reinforcing the backbone around the shift mechanism cutout.

Wonder if this approach adds any stiffness, or lightness 🤯
1286949
 
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if you decide to move forward with a 180 R style bolt in cage, I would be interested in a copy also. Perhaps some savings in building two at once. Not sure if the difference in years between our cars would be an issue.
 

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If I recall, the X180 had a rather simple reinforcement plate around the shifter opening that added a lot of stiffness.

In discussing the Europa frame design with my civil engineer friend who helped me design the Europa space frame I built, he said that the way they made the backbone was actually very good, and he used similar designs all the time. He suggested that torsional rigidity could be greatly increased by welding in a piece of sheet metal going across the inside of the backbone box, with a hole in the center no more than 1/3rd diameter to run the stuff through.
 

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What did the Esprit do for side impact protection? Just fiberglass doors?
 

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What did the Esprit do for side impact protection? Just fiberglass doors?
Yes why would you want/need any more :)

Actually I think there is a big metal box beam in there,.

@Dr.Hess

I am trying to envision what you are saying. Maybe I will load up a picture to see if I have it right. Does not seem that hard to do if you had the backbone on the floor completely stripped.

Thinking pull all of the hoses and lines out, 1/2" slot to slide the plate in. Weld the top, plug welds on the side and bottom.

I think we could actually calculate the increase in rigidity with a few assumptions and some measurements to see if it would be worth while.

Would you have to cut an access panel to get the hoses, cables and wires routed back through the 1/3 diameter hole?
 

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Don't know about the access panel. I thought of notching the edges for the coolant tubes, that is, run the tubes secured to the box and have the plate clearance for the tubes, but I didn't run that by my friend. Europas have 2 steel coolant tubes not really well attached that run down the backbone, that is until they rust out because English.
 

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1985 Turbo Esprit with HCI mods & intercooler
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The photos above came from another thread. I'm planning something of this sort for the '85. Of course for the Renegade conversion, there will be a Porsche Boxter S cable shifter inside...
 

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This rear Hatch....Dammit! could they not have produced these for sale - Esprit owners around the world would have been thrilled.

Lotus-Esprit-GT1-124603.jpg
 

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I think the beam is attached to the latch on one end, the catch for the latch on the body is attached to a structural piece of the chassis I believe.

The other end of the beam is attached to the hinges, the hinge mount on the body is also screwed into a metal cross bar that is inside the dash. That cross bar is connected to the strong bits.

Its kind of like a roll cage. Isnt the Elise the same way?

If I have time later I will post a pic from the manual where you can see how its all linked together.

I am sure its safe, back the Lotus was like - Safety first, then lightness, next on the list is aesthetics, and on down to ease of serviceability at the end. I may have the order wrong :cool:
 

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Hello all, I am a newbie to the forum and am posting so I can connect with any members that own a lotus esprit with a LS conversion (mine has a LS1) looking forward to meeting some peeps cheers Bujo007
 
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