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

[cweeden]

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..  

 

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.    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.. 

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

[CHANGES]

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)  , 

 

 

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..  

[Barrykearley]

Mine had great big branches on it 😂

[swindon_alan]

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...

[Barrykearley]

Hand crafted in the West Midlands 

Great idea for a V8 - allows for easy collection of pistons and rods

[CHANGES]

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.. 

 

[swindon_alan]

Is the hand crafter you Dave or is it someone else who might repeat this awesomeness?

[CHANGES]

15 minutes ago, swindon_alan said:

Is the hand crafter you Dave or is it someone else who might repeat this awesomeness?

I am afraid it was me ,    A drawing board,  pencil , ruler , and imagination .     

This part was relatively straight forward to make, but had to be stiff enough not to distort at high speeds and also included some damping to prevent drumming noise in the cabin again at speed.. The real work was closing off the wheel wells so that air would flow constructively rather than just spill around willy nilly which would compromise the design...    Most important was all of these parts would restrict access so needed to be easily removable when needed.   Several years on they have been on and off many times without issue...    Pic's of other arch sections for info should anyone like to make their own..

 

 

When you get down to it there is quite a bit more that you don' see..  You must also remember the extra ducting and engine bay fans for when stationary to keep air flowing..  

[swindon_alan]

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".

[mike_sekinger]

They are correct for traditional straight grooves - outer of slot leading in terms of rotation:

https://www.apracing.com/Info.aspx?InfoID=39&amp;ProductID=976

[silverfrost]

Lovely work, just stunning 

[CHANGES]

Final Drive update

The good news is the new spec CWP has been settled on and ordered.   I have gone for a custom 4.3:1 not the 4.11:1 as previously mentioned..   This came about because the design /spec I settled on was different to the 4.11 racing version I had in stock and considerably stronger. .. As a result the costs were that of full development prototype regardless of ratio..    This gave the opportunity to  get the optimum 4.3 ratio rather than the closest option available which the 4.11 was.   The CWP along with the whole box will be getting the full treatment to isolate the weakness in this area.   The down side is the lead time is 12-14 weeks..  baring complications , which unfortunately means by the time i get it all back together most of this year will have gone by..  But is that not the way R&D goes..     

[silverfrost]

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

[CHANGES]

34 minutes ago, silverfrost said:

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

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.     

[silverfrost]

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

[Bentzion]

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.

 

 

 

[CHANGES]

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.        

[CHANGES]

Update 

Even though i have had the new high torque version of my Gear box back sometime, due to commitments on customers Esprit's  I have not even had chance to really look at it ..  But today i made time to whip the bell housing off  and get a look at the new CWP.    Pleased to say all looks as expected with the REM and super finish giving it a chrome appearance ,,  This treatment and finish process has been done throughout the whole box to insure it will take everything i throw at it...   There is other mod been done to help with the lubrication etc , which i will cover when i get round to putting it back in the Esprit.    But for now a few pic's  

 

  

[Barrykearley]

Looking forward to seeing you try and break it 👍😍

[cweeden]

Hi Dave,

Can you give an idea on the cost of such finishing processes if one was to undertake this? FYI I have the GTO strengthened internals and Quaife ATB. 

If it is deemed a rude question feel free to ignore it. 🙂

cheers

-Chris

 

[RichardJGC]

Don't let those customer Esprits get in the way of progress on this one! 😉

Looks fantastic and good to see it before its all hidden away.

[CHANGES]

8 hours ago, RichardJGC said:

Don't let those customer Esprits get in the way of progress on this one! 😉

Looks fantastic and good to see it before its all hidden away.

There we have it ,  from the horse's mouth 😱 , A customer saying the trader should come first.. .   But we know the customer will always come first,     it the way of the world..  Sorry Richard  yours is first ,  I will have to wait ..  

[Sparky]

Oooh, can't wait to put this one through its paces...

[CHANGES]

2 hours ago, Sparky said:

Oooh, can't wait to put this one through its paces...

You know you will be the first to test the limits.  'After me '...  As the only person  to have done any pre test driving on this , you are the only one that can give validated comparison feel data...  I can not wait to try the new ratio set up , 😀

[RichardJGC]

1 minute ago, CHANGES said:

.  I can not wait to try the new ratio set up , 😀

Neither can we. Go on...you know you want to!