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Nitron 40mm NTR Fast Road/Track Day Suspension Kits now available for the Esprit


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35 minutes ago, Jacques said:

Sport300 is [...] with a stiffened chassis with gearmaster cut out bracing

A bit off topic but for your info the S4s is supposed to have that feature too if I am not wrong.

Edited by Giniw
removed the part about the engine brace as originally intended
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Hi Ian  The later S4s chassis rear spring mounts are different to the SE..   

@Jacques  I have a CAD drawing of my rear upper 2.5" spring perch adapter for my 89SE, and then the part number for the Energy Suspension spring isolators that I used.  You could talk to a local machi

or even send the drawing to Nitron and let them know it is required for the earlier chassis.

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No, it may have the stiffened cut out around the gearmaster, but no rear engine brace. That came only on the more track focused Sport300. Not even on the Sport350. I find it very relevant to know these extra data, as they are some of the reasons leading to the possibility to raise the springrate and possibly a bit firmer damping/rebound.

It wil be interesting to see how the new poly-gearbox mounts perform. I don't know the shore value. If slightly stiffer, one can contemplate if it does stiffen the rear end a bit and maybe even lead to twisting the middle of the chassis a bit (more), so the need for bracing may arise.

On another note, I'll try to stiffen the rear cross brace further than just the U-shape. More later on my own thread.

I suppose some of you have ordered the Nitron kit? I did some days ago, and I hope to have it before Christmas, so may be able to play a littel with it in the Christmas vacation. Anyway, I will not drive it untill the Spring is here with warmth, Sun and dry roads. But looking at what other users if the "new" Nitron set have said, it seems to be sporty but still very road compliant. No track day extreme.

Late V8 are supposed to have used a bit thicker tubing the for norman rear engine cradle, Sport350 style. Maybe someone can confirm this?

I have tried an SE with the complete Bilstein damper/Eibach Lotac developed set, and it feels like my own original dampers and springs (not original as in the original set - they have been renewed later on). I did not feel it enough firm. personally. I'd prefer something firmer.

Anyway, there are many assumptions in this. We'll need to try it out.

Kind regards,

jacques

Nobody does it better - than Lotus ;)

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Haha.. Yes, Chris, I am a Continental European Scandinavian and a firm believer in the metric system, as seen from the left side of the road ;) 

I did not read anything about the set you mention to be firmer or softer. And it's supposed to fit's right on to your Sport350, it was only the Esprit Turbo SE which need some bits turned on a lathe for adaptation of the more narrow springs rear compared to the ones installed on those cars.

We'll see if we need some other parts as well. It's not always that one can buy a plug and play set, but more often a plug and pray set.

Kind regards,

Jacques

Nobody does it better - than Lotus ;)

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33 minutes ago, Jacques said:

No, it may have the stiffened cut out around the gearmaster, but no rear engine brace.

You are totally right, I just quoted you badly, sorry, indeed I only wanted to quote the first part about the gear lever hole.

Edited by Giniw
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I have had a quick look but as I have nothing to compare it to I haven't really inspected thoroughly.

That part of the trimming is off on my car at the moment (well it has been for ... a while lol) so I can probably take at few photos if you need (but I am afraid I won't see the car before the weekend)

gearchange recess reinforcing plate 1.png

gearchange recess reinforcing plate 2.png

Edited by Giniw
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Yes, please if possible. I seem to remember that someon actually improved on this further.

The Sport300 has a further two bolts from chassis to body to stiffen it further (being ahand laid thinner bodyshell). That might be interesting to replicate. The Stevens bodyshell onwards is much stiffer than earlier Esprit's.

Reason being for all these small extra notes, that if it can lead to a stiffer car, then spring rates can be raised without twist/breakage/cracking.

MrDangerous mentioned in another thread, that chassis flex/twist exhibits a certain curve, meaning that up to a certain point, the chassis twist will not be actual flex in itself, but also for example the compression of bushings, bearings etc. From that point on, the flex is linear. But untill then there is a display of hysteresis.

Kind regards,

jacques

Nobody does it better - than Lotus ;)

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I'm fairly sure that extra plate around the gear change was to prevent cracking in the corners of the cutout rather than add any stiffness to the car. Metal right angle corners are prone to cracking quite easily, especially when the extra stiffening around the engine bay is factored in. 

88 Esprit NA, 89 Esprit Turbo SE, Evora, Evora S, Evora IPS, Evora S IPS, Evora S IPS SR, Evora 400, Elise S1, Elise S1 111s, Evora GT410 Sport

Evora NA

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I think that we've seen some "nice" pictures of that ;(

Worth thinking of, when stiffening the suspension. I think there are also pics of someone making round corners in the cutout.

Kind regards,

jacques

Nobody does it better - than Lotus ;)

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The gear shift aperture plate upgrade was added to increase the stiffness of the chassis. The flexing of the non-strengthened chassis was causing cracking in the corners of the aperture (which have crack stop holes rather than sharp corners). The stiffened chassis also allowed Lotus to increase the spring rates on the S4 and USA S4s.

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The 1991 X180R had a 20% increase in torsional stifness thanks to it's roll cage. It also seemed to have reinforced upper and lower widhbones and rear trailing arms plus 20% rise in spring stiffness (LEW). If someone have exact pics of those or can shed more light on that, I am interested.

I found this:

Front Suspension Rear Suspension
Model Color Code Rate (N/mm & Lbs/in) Free Length (mm) Static Length (mm) Color Code Rate (N/mm & Lbs/in) Free Length (mm) Static Length (mm)
S1 Orange 21.2/121 355 N/A Green/Green 27.5/157 347 218
S2 Orange 21.2/121 355 N/A Green/Green 27.5/157 347 218
Turbo Red/Red 21/120 366 191 Blue 27.5/157 347 218
S2.2 Orange 21.2/121 355 N/A Blue 27.5/157 347 218
S3 Red/Yel 19.3/110 354 191 Green/Yel 24.5/140 326 203
Turbo 85 Yel/Purple 22.8/130 369 203 Blue 27.5/157 347 218
S3 85 Yel/Yel 22.8/130 381 216 Green/Yel 24.5/140 326 203
Turbo HC Yel/Purple 22.8/130 369 203 Blue 27.5/157 347 218
X180 Turbo Blue/R/Wh 28.1/160 361 203 Green 27.5/157 347 218
X180 N/A Yel/Purple 22.8/130 369 203 Yel/R/W 27.5 & 157 334 205,7
GMP4 Inj. Yel/Purple 22.8/130 369 203 Yel/R/W 27.5 & 157 334 205,7
SE R/R/Purple 29.1/166 372 219 Green 27.5/157 347 218
Eagle Ch. Yel/Purple 22.8/130 369 203 Yel/R/W 27.5 & 157 334 205,7
SE 93 MY R/R/purble 29.1/166 372 219 Green 27.5/157 347 218
S4 Blue/Blue/W 41/234 N/A 214 Gr/Blue/Gr 45/257 N/A 227
Sport 300 White 45.4/259 208 290 Orange 49/280 N/A N/A
S4s R/Blue/W 41/234 N/A 214 Gr/Blue/Gr 45/257 N/A 227

Jacques

Nobody does it better - than Lotus ;)

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The S4 was fitted with the following combination of springs:

Prior 1995 MY --> front - yellow/blue/green  &  rear - blue/blue/yellow

1995 MY up to VIN 2030 --> front - blue/blue/white  &  rear - blue/blue/yellow

VIN 2031 on --> front - red/blue/white  &  rear - green/blue/green

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From memory, mine were 350ftlb all round. Surprised me as assumed the rears would be higher however I was very happy with the setup, certainly for road and light track use. I’d start there and if not happy go a little higher but really think you should try the recommendation first.

 

Trevor.

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I'll get around to it at some point.

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4 hours ago, Giniw said:

I can probably take at few photos

I just checked on my phone and I do have a few already but they don't show the plate very well and it's a bit hidden under another thin metal sheet.

The actual reinforcing plate you are looking for is bichromated as the rest around it, and from the photos it looks quite similar to the reproduced one which was for sale there:

s-l500.jpg

https://www.ebay.com/itm/Lotus-Esprit-Titanium-Shifter-Reinforcing-Plate-/333364319821

(How is the shift rubber gaiter attached when you don't have this plate on the car?!)

 

 

 

Edited by Giniw
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Definately. That's why I grabbed the Sport300 parts and will install later on, but it's a body off together with the engine brace.

Btw. what does people think about the titanium version sold on fleabay? Is it stiff enough? I don't know the type, 9 or 5 - 3Al2,5V or 6Al4V. How does it fare compared to steel in this particular purpose?

And if installed (this material) would it be doable to use titanium bolts? Or 8,8 or 10,4 steel bolts only?

Kind regards,

jacques

Nobody does it better - than Lotus ;)

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3 hours ago, Jacques said:

Or 8,8 or 10,4 steel bolts only?

The photo I have here is not very readable but I think I can read a 8, so most probably 8.8 grade on the original steel plate.

Edited by Giniw
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I am not familiar with the titanium bolts grades but as long it's at least a 8.8 equivalent it should be all right (rupture not before 8*100=800 N/mm²  and plastic deformation not before 800N/mm² * 0.8=640 N/mm² if I am not wrong)

Edited by Giniw
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