MrFluffy
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| posted on 20/2/07 at 08:14 PM |
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Ive not given up yet you know...
If your a lotus esprit lover, turn away now!
I bought a engineless/transaxleless rotting rolling chassis S2 esprit (£28 on ebay guv'nor), and gave away the fire damaged shell, and now Im
left with a rolling chassis which at least gives me some uprights and wheels and steering gear etc. Along the way previously a donor rover v8 engine
has been procured and a 6-71 blower, and a Renault 369 transaxle and I have a megasquirt sat on the bench doing nothing so it'd be rude not to.
I did think I had an adaptor plate twixt v8->transaxle, but its turned out to be rover -> something else random adaptor after finding 3 renault
bellhousings, so Im going to have to make my own anyway.
Now, I still want to continue headlong in the plan to build a tube chassis for my nova kitcar, since the X form of the lotus isnt quite what I wanted
in terms of side impact and Id like rocker arm suspension instead of the falling rate of the lotus units, and various other bits n bobs and it would
probally be as much work to get rid of the tinworm in it than make a new one, but I plan on using the original chassis as a giant jig and lifting the
geometry from it mostly since by all accounts the esprit was a fine handling car. Now my problems start ...
At the front, its a double upper wishbone, but with a single lower wishbone, with a trailing arm back to the chassis in the form of the anti roll bar.
I think this should be improved to a pair of double wishbones with more rigidity in the chassis where they mount in the fore aft plane, which I can do
without changing radically altering the geometry and can still use the chassis as a appropriate jig.
At the rear, the S2 used the driveshafts as the upper member in the suspension, but that was with the citroen box and resulted in a lot of knackered
boxes from the side loads etc, and theyre not really good for more than 200hp and rare to find. The later Stevens-Esprit used a more conventional un1
transaxle with upper and lower wishbones, but there is a lotus specialist in the US called LPBC (lotus prepared by claudius) who offers a double
wishbone conversion for the earlier cars. I plan to replicate the conversion but perhaps incorporate some subtle changes to update. Oh and the earlier
cars ran inboard disc brakes, so no citroen transaxle currently means no rear brakes. That may take some thought.
So a cunning plan is forming, first job now Im home again has to be to measure up the chassis and get it into a cad package to play round with the
suspension mods, unless someone knows where I might lay my hands on a drawring of some description of the original lotus chassis.. I asked on the
esprit lists but there arent a lot of people needing the information and nobody was forthcoming...
Anyone spotted some nice lotus drawrings on their travels... Its still locost honest... 28 quid for a jig and uprights...
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rav
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| posted on 20/2/07 at 09:26 PM |
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Thats one of the craziest plans ever, even by locoster standards
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Browser
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| posted on 21/2/07 at 02:35 AM |
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quote:
Originally posted by MrFluffy
At the rear, the S2 used the driveshafts as the upper member in the suspension, but that was with the citroen box and resulted in a lot of knackered
boxes from the side loads etc, and theyre not really good for more than 200hp and rare to find.
Ah yes, the famed Chapman Strut, which worked fine on his formula 1 cars (Lotus 25/49 etc) but ws found wanting a little on heavier road cars
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TheGecko
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| posted on 21/2/07 at 05:12 AM |
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quote:
Originally posted by Browser
Ah yes, the famed Chapman Strut, which worked fine on his formula 1 cars (Lotus 25/49 etc) but ws found wanting a little on heavier road cars
No, nothing to do with the Chapman strut in this case. The Esprit just has double wishbone suspension with the half-shaft forming most of the
upper wishbone. That design was extremely common in Formula cars from the '50s through the early '70s.
A Chapman strut is (as the name implies) a strut suspension, used at the rear of the vehicle, usually with the transverse locating link being the
half-shaft. The problems Lotus encountered with struts in Formula cars had everything to do with stiction issues in the relatively small diameter
struts used at the time and nothing to do with the half-shafts. Modern struts are used very successfully in the rear suspension of many vehicles.
30+ years of strut development has helped.
Dominic
(building a middy clubman with strut rear suspension)
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macnab
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| posted on 21/2/07 at 09:02 AM |
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Pictures of this project would be nice, I alway liked the nova.
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TheGecko
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| posted on 21/2/07 at 09:40 AM |
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quote:
Originally posted by TheGecko
The Esprit just has double wishbone suspension with the half-shaft forming most of the upper wishbone.
After I wrote that I thought about it
some more and eventually did some research when I had time. The Esprit rear suspension is a large semi-trailing arm arrangement that uses the half
shaft as a locating link.
Sorry for any confusion.
D
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Bart-Jan
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| posted on 21/2/07 at 10:26 AM |
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If I understand it correctly, you are planning to mount a Renault 369 transaxle to a Rover V8? I'm very curious whether the gearbox would
survive. It's more wise, probably to use a UN1 box. In which case I could help you out with a bellhousing;-)
I intended to use a Rover V8 for my Midtec Spyder, but eventually decided to opt for an Alfa V6. So I don't need the bellhousing I allready
bought...
Oh, and I found a supplier for Ranault 21 Turbo UN1 boxes in The Netherlands. I don't know whether the guy's got more, but I could ask if
anyone's interested. Sending them over would be expensive though...
[Edited on 21/2/07 by Bart-Jan]
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MrFluffy
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| posted on 21/2/07 at 11:04 AM |
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quote:
Originally posted by Bart-Jan
If I understand it correctly, you are planning to mount a Renault 369 transaxle to a Rover V8? I'm very curious whether the gearbox would
survive. It's more wise, probably to use a UN1 box. In which case I could help you out with a bellhousing;-)
I intended to use a Rover V8 for my Midtec Spyder, but eventually decided to opt for an Alfa V6. So I don't need the bellhousing I allready
bought...
[Edited on 21/2/07 by Bart-Jan]
According to derek bells excellent un1 site , the 369 only differs from the un1 in the pitch of the threads that hold the end cover onto the box and
the reverse gear pattern, in fact I believe his lola box is a hybrid 369/un1 box that has been modified as such over the years and blowups.
The bellhousing is certainly the same since I have the 369 and some ex un1 bellhousings here already as I thought my adaptor plate relied on it being
a un1 housing which I was misinformed was a different pattern to the 369 one.
I know already that the rv8 fits in the esprit chassis in stock form, since Ive seen the conversion done a few places now. The headers are tight near
the rails unless you fabricate a tubular manifold, sounds ok to me! I run day to day a 3.5 efi rangey so Im quite familiar with the foibles of the
motor (Ive got both headgaskets changed down to a weekend now in situ on the RR) , and of course have amassed a load of spares as a result...
For the rear, yes its a semi trailing arm reinforcing the single wishbones, thats probally one of the other things that I want to get away from at the
rear too, as the wheel must describe an arc fore and aft in its vertical motion although the trailing arm is truly a huge lump of box section and is
never going to flex, it is mounted to the chassis with a weird rubber ball socket affair. Currently there is no section of the chassis in the right
area to support the lower wishbone anyway, since it originally mounted onto the citroen transaxle. un1 conversion to a s2 esprit involves fabricating
a new section to the chassis at the rear to carry the wishbones on..
Ill try take a few shots of the chassis, theres not a lot at all to one in fact. The guy who helped lift off the grp body from it afterwards said he
had always wanted an esprit, until he seen exactly how unsubstantial they were that day, and I can carry the bare chassis under one arm on my
own...
For the un1 site, its well worth a peruse for the information (and that lovely mainshaft conversion) and is at :-
http://www.un1.co.uk/history.htm
At the moment ive done very little to the shell since she was beetle based, I have however cut it into two sections, and will make the front and rear
segments flip up and removable. Before with the beetle chassis, the shell made it more rigid therefore needed to be one piece, which made engine
access etc a pain. Cut like this the roof must be raised to operate the flip mechanisms...
Theres another guy done this with a lotus chassis and a nova, but he used an europa one with no mods...
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MrFluffy
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| posted on 9/4/07 at 08:07 AM |
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This is the total sum of chassis and driver protection on a lotus esprit s2 bar the fibreglass shell...
The guy who lifted the body off when I disposed of it said he always wanted a lotus esprit, until that day when he seen exactly what protection and
side impact stuff it offered.
Im liking more the idea of using it as a jig and only modifying the rear in a major way as its needed. The front Ill restrict myself to making tubular
wishbones to replace the pressed steel ones, locating the lower arm better and making the shocks inboard using a linkage.
She'll be up on her wheels properly tonight with the engine located where it needs to be. I mated the box to the engine last night although the
plate Ive been given seems a little misaligned. More work needed...
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MrFluffy
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| posted on 12/4/07 at 07:42 AM |
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quick update
Hmmm, dontcha love mockups to check everything fits as youd expect...
Even got headroom with my 6'3 frame ...
Note distorted inner shell on one side from sitting on ground over time and wibbly rear wheels as I havent started the chassis mods proper yet. Well,
I had to make sure it was all viable before really...
Spend the rest of this week sawing out the bits of the shell that I dont need.
Does anyone know if a rearview camera setup in lieu of a rearview mirror is sva compliant? Im just going to have a durty big supercharger where my
rearview would go, so Id rather just build a firewall there if so...
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MrFluffy
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| posted on 12/4/07 at 08:20 AM |
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Ive posted the rearview camera question in the sva/legal section of the forum. Makes sense to ask it in the right place...
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