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CHANGES

412 BHP...THAT WILL DO NICELY......

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What a beautiful car Dave.

<swoon>

Where did you get the side splitters from, or is it an undertray?


I tempted fate...now my Esprit V8 IS in bits...(sob)

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Looks fantastic, love the centre lock wheels :wub:


A

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On 30/01/2019 at 18:15, CHANGES said:

Sorry for the slow reply but only recently done the full strip and check to confirm how things unfolded.  

It seems it was just the CWP that let go , the rest of the box is in tip top condition. Fortunately none  of the bits traveled into the main area.  

Looking at the torque capability of the 3.89:1 CWP. , it was only at matter of time , it was never going to hold the 450 ft lb for ever.     I came to the final conclusion it let go when it did because I had recently increased the mechanical grip with the new wheel tyre set up.  Aggressive acceleration would break traction in second and third before, this would release the torque from the drive train .  We now have to really power hard to twitch in second (in the dry only) ..   this increased grip transferred the higher / or complete torque load onto the CWP.   net result failure.   

The reason it did not go bang bang when I coasted or was towed was probably down to the state of the teeth on the pinion which were well chewed..  

IMG_20190119_105102804.thumb.jpg.518e65babe5a743117ef39244a1c4485.jpg

 

Where to go now.. ?   

 I will take this opportunity to try and solve the high ratio 1st problem by fitting a 4.11:1 CWP .  The figures look very promising..     I do have a high torque 4.11 in stock from GTO Racing , but with spike loads it could be bumping up against its limits..  GTO Racing say it will be fine, but looking at it , i'am unconvinced at the moment. :rtfm:   So at present I am looking into and talking with a gear specialist who can make a bespoke CWP well capable of handling all the projected loading's..   

 will advise.. :secret:

The magnet on the right looks like a nice Christmas tree, is that what you would expect the magnet to look like on any gearbox or is it just that this was bedding in or due to the failure (although I would only expect the bigger bits as per the other picture)? 

I'm asking because mine looked a lot like that shortly after the GTO upgrade a few years ago (but not many miles ago) and I was told it's normal but just checking. 🙂

cheers

-Chris

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23 hours ago, swindon_alan said:

What a beautiful car Dave.

<swoon>

Where did you get the side splitters from, or is it an undertray?

They are all a part of the aero kit (undertray)  , 

307427005_finishedesprit011.thumb.JPG.db0fcc8f596325cc4111244e115e4aae.JPG

 

 

3 hours ago, cweeden said:

The magnet on the right looks like a nice Christmas tree, is that what you would expect the magnet to look like on any gearbox or is it just that this was bedding in or due to the failure (although I would only expect the bigger bits as per the other picture)? 

I'm asking because mine looked a lot like that shortly after the GTO upgrade a few years ago (but not many miles ago) and I was told it's normal but just checking. 🙂

cheers

-Chris

That magnet is much as i would expect on any box strip, just a bit extra on this one due to failure.   You always seem get a fine deposit on them , nothing to be concerned about..      Any chunky bits or fine slithers is a different matter .  The stuff on the magnet when you wipe it off has a feel more like a graphite than iron filings..  when you rub it between your thumb and finger it should not feel lumpy.  ( which mine did in this case , but expected)....  Hope that helps put your mind at rest..  

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Mine had great big branches on it 😂

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Only here once

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Was the aerokit a factory option Dave? Sorry to persist but I don't think I have seen one before. Just wondering about a V8 version...


I tempted fate...now my Esprit V8 IS in bits...(sob)

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2 hours ago, swindon_alan said:

Was the aerokit a factory option Dave? Sorry to persist but I don't think I have seen one before. Just wondering about a V8 version...

As Barry said,  it was all custom made in the West Midlands specifically for this Esprit ..  

As a point of note the same design will fit any Esprit S4 onward's.. inc V8.  But there are also other unseen parts which accompany it to focus a designated air flow around the engine and exit of the radiator.   More of a package that creates ground effects with the front splitter and rear diffusers  also maintaining a more the focused air flow passed the engine at the same time.. 

1123225488_splitter006a.thumb.JPG.d7c5c95c1663a115d4eb41c17a029e02.JPG1447525207_splitter008.thumb.JPG.d95bb0b1fbdac1d4d3470ea867bd93fb.JPG 1212521085_IMG_20180325_163633081(2).thumb.jpg.08971501ed5eecbd002bc989887ba829.jpg

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Thanks very much for the pics Dave, that really is good work and it has got me thinking!

Just a point about your discs, they're on the wrong sides, the grooves should be pointing "backwards".

image.png.23b2ca0a60de9b005b18b7aa48d740ef.png


I tempted fate...now my Esprit V8 IS in bits...(sob)

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Fantastic news Dave,  sounds expensive but with 412 bhp going through it, a wise investment   :thumbup:


A

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34 minutes ago, silverfrost said:

Fantastic news Dave,  sounds expensive but with 412 bhp going through it, a wise investment   :thumbup:

If we were still at 412 bhp  I doubt we would have had such a problem.  We were only generating 365 ft lbs of torque at that point which is only slightly over the std V8 spec using same 027 box..   We started to run into g box issues when we went to 425 bhp and the 409 ft lbs torque,,  that is when it only took a short time to blow 5th off..   The GTO conversion fixed that issue and things seem to hold together well until the latest spec build..    The 461 bhp with 450 ft lbs that we have now is what exposed the power break point of the CWP.  This was not a spike load that broke this ,it was straight power run . So using this info we can say the spike load of the 3.89 CWP in the 027 box is > 450 ft lbs ..  I have been advised that the actual recommended load on the STD CWP is more in the region of 300 ft lbs.  This means it is being used well into its top loading with the V8's  as std.  This would explain why quite a few V8's blew the CWP out under power starts , where they could reach the spike loads especially with sticky tyres, or when snap changing into 2nd which creates a reverse loading that will fracture a lot lower down the scale.    What it does show us though is actually how durable the 3.89 CWP  is..  As long as it is not abused it takes quite a bit of loading over the recommended limits.     

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Crazy figures out of the four pot,  i love it,  Mr Chapman himself would be proud . :thumbup: 


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Our business based in California USA is now Cryogenically treating CWP for a lotus V8 owner.  Additionally we are also micro shot peening for increased surface tension but reduced drag.  

This should increase the strength of the pieces and reduce heat buildup.

 

 

 

Lotus Esprit V8 CWP.jpeg

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If the only thing constant is change, then why do we resist change the most?

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On 24/06/2019 at 05:27, Bentzion said:

Our business based in California USA is now Cryogenically treating CWP for a lotus V8 owner.  Additionally we are also micro shot peening for increased surface tension but reduced drag.  

This should increase the strength of the pieces and reduce heat buildup.

Hi Bentzion, 

That is probably the most cost effective way of getting a bit more out of the std CWP . and the rest of the gears come to that.  I would have probably looked into this as an option ,but as the 3.89 ratio was not right for my Esprit, it was time to develop a new stronger option.   This new CWP will also have the Cryo treatment with shot peening and REM treatment to finish off.. To try and make sure we don't get any further G/box issues, the rest of the box inc. the GTO  kit will be getting the same treatment. 

What will be interesting is to see how it effects the transmition loses , We managed to reduce them by 3.5% by using different oil,  So using the data we have and comparing with the post REM treatment etc should show how the lower friction factors can further reduce these loses..  I am also interested to see how it effects the transmition temperature.        

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