Griffith Flywheel Weight
Discussion
stevesprint said:
What is the weight of a Griffith factory flywheel, 400, 430 & 500?
Thanks, Steve
Not sure if this will help as I can only really speak for the Chimaera side of things but one thing is for sure... all our cars have cast iron flywheels and none were fitted with steel.Thanks, Steve
The 4.0 litre cars unbelievably carry a standard Rover SD1 flywheel which weighs in at a stupidly heavy 32lbs. A 32lb flywheel may be ideal in a 1500kg 3.5 litre saloon car designed to waft four passengers through town as smoothly as possible, but in a 1060kg 4.0 litre sports car 32lbs is way heavier than needed and far from ideal
From the onset of the 4.0 litre capacity the bore size of all RV8 engines remained the same, so as we all know the 5.0 litre engine is merely a stroked 4.0 litre, which invariably meaning two things:
1: Its less willing to rev
2: It produces a significant slug more torque
Both these characteristics pretty much forced TVR to do something about flywheel weight so a bespoke flywheel was cast and fitted to all the 5.0 litre cars, this 5.0 litre flywheel is reported to weigh 22lbs but others have weighed theirs and found it to be just 19lbs.
The bespoke TVR 5.0 litre casting looks different to the Rover SD1 type, it has a kind of spoked arrangement as shown here...
TBH I'm not sure if the 4.5 Chimaera got the 5.0 litre flywheel too or just a machined down version of the 32lb Rover SD1/ 4.0 Chimaera one?
All I know for sure is when I took the flywheel out of my 4.0 Chimaera it was the ridiculously heavy 32lb Rover SD1 saloon car jobbie so I had V8 Developments machine it down to 25lbs which is what they consider the safe limit.
Slicing a full 7lbs out of my flywheel made a big difference, the kind of difference you could really feel and TBH there were no drivability issues with it whatsoever, the exercise of lighting my existing SD1 flywheel proved to be an absolute no-brainer.
If you have one of these SD1 millstones in your TVR I highly recommend you get it lightened but as already explained you can't really take it's weight below 25lbs or you'll be running the risk of it shattering
TVR clearly new this which is why they commissioned the bespoke casting for the 5.0 litre cars, so if you want to go lighter than 25lbs you either have to find a 5.0 litre flywheel or better still buy a new chromo steel one.
The steel one that's readily available for our cars comes from TTV Racing near Ipswich who are a renowned flywheel specialist, they offer a 15lb steel flywheel for the Rover V8 and hold them on the shelf.
http://ttvracing.com/flywheel-info/#
After the success of reducing my flywheel from 32lbs to 25lbs I actually felt I could go even lighter, so because I'm already on the limit of machining my SD1 one further I either needed to find a 5.0 litre TVR flywheel or buy the very light 15lbs steel one from TTV Racing.
I have a 4.0 litre producing 260 ft/lbs of torque so felt the 15lbs was going to be a bit too light given the way I like the car to drive and trying to find a TVR 5.0 litre cast flywheel for sale is obviously not that easy.
So my solution was to have a 19lbs steel one made by TTV Racing which by all my research and calculations should represent the ultimate sweet spot for my TVR and driving style.
More on the flywheel subject here....
http://www.pistonheads.com/gassing/topic.asp?h=1&a...
As for what the Griffiths got is anyone's guess but I'd speculate that all variants (except perhaps the 4.0 litre Griffs) had something lighter than the stupidly heavy 32lb SD1 one TVR fitted to the 4.0 litre Chimaera? We all know the 4.3 TVR RV8 was a sweet revving unit so it's possible the bespoke TVR cast flywheel I'm calling the 5.0 litre flywheel actually started out in the 4.3?
I've given you everything I know, so perhaps someone can fill in the gaps in my flywheel knowledge and share with everyone on this post?
Edited by ChimpOnGas on Thursday 5th November 11:00
Slight correction to the above!
I have just found my old post way back in 2011 where I started looking at all this and have seen the following figures were given to me at the time by Rob Robertson of V8 Developments.
Std Rover SD1/4 Litre TVR = 28Lbs (what I started out with)
V8 Developments machined & lightened version of the above = 21.5Lbs (what I have now - big improvement!!!)
TVR 500 = 20Lbs
Rob also confirmed the 4.5 Chimaera got the 28Lb millstone I had in my 4.0 litre.
http://www.pistonheads.com/gassing/topic.asp?t=995...
As already stated I have now gone for an all steel bespoke machined flywheel, this weighs exactly 8.5kg which is 18.74Lbs.
So along with going from cast iron to steel I've shaved a further 2.76 pounds off my rotational mass along the crank line. It's not much but it's where I feel the sweet spot lives and for the way I like the car to drive, I haven't tried it yet but I'm sure I'll notice the difference.
The important bit is that I can feel a further improvement in the way the car picks up revs over my machined down SD1 millstone but that I still retain the car's excellent drivability and town manners. I have spoken with two people that have fitted the even lighter TTV Racing 15lb flywheel and they both independently said that I may not like it as you do have to pick the revs up a little more than normal to get a clean departure from junctions.
Further evidence that my bespoke spun 18.74 pound chromo steel TTV Racing flywheel was the right choice, saying that I haven't installed it yet so I'm merely making an educated guess at this point.
Time will tell
I have just found my old post way back in 2011 where I started looking at all this and have seen the following figures were given to me at the time by Rob Robertson of V8 Developments.
Std Rover SD1/4 Litre TVR = 28Lbs (what I started out with)
V8 Developments machined & lightened version of the above = 21.5Lbs (what I have now - big improvement!!!)
TVR 500 = 20Lbs
Rob also confirmed the 4.5 Chimaera got the 28Lb millstone I had in my 4.0 litre.
http://www.pistonheads.com/gassing/topic.asp?t=995...
As already stated I have now gone for an all steel bespoke machined flywheel, this weighs exactly 8.5kg which is 18.74Lbs.
So along with going from cast iron to steel I've shaved a further 2.76 pounds off my rotational mass along the crank line. It's not much but it's where I feel the sweet spot lives and for the way I like the car to drive, I haven't tried it yet but I'm sure I'll notice the difference.
The important bit is that I can feel a further improvement in the way the car picks up revs over my machined down SD1 millstone but that I still retain the car's excellent drivability and town manners. I have spoken with two people that have fitted the even lighter TTV Racing 15lb flywheel and they both independently said that I may not like it as you do have to pick the revs up a little more than normal to get a clean departure from junctions.
Further evidence that my bespoke spun 18.74 pound chromo steel TTV Racing flywheel was the right choice, saying that I haven't installed it yet so I'm merely making an educated guess at this point.
Time will tell
ChimpOnGas said:
...so as we all know the 5.0 litre engine is merely a stroked 4.0 litre, which invariably meaning two things:
1: Its less willing to rev
2: It produces a significant slug more torque
Both these characteristics pretty much forced TVR to do something about flywheel weight...
Without wishing to appear argumentative - why would this be..?1: Its less willing to rev
2: It produces a significant slug more torque
Both these characteristics pretty much forced TVR to do something about flywheel weight...
The 2 points you highlight indicate to my laymans mind that the 5.0l is the engine least requiring a lightened flywheel...
A revvy engine, with less torque, that requires revs to make power (4.0l) is where I would have thought you wanted a light flywheel - easier for the (lesser) torque to accelerate quickly, to get up to rev band where it makes power...
A lower revving, torquey engine (5.0l) would have plenty of torque to move a heavier flywheel, and wouldn't be requiring reaching high revs quickly in order to make good power - so I would have thought a light flywheel was less a requirement here...
If the above is correct then I would surmise that the flywheel was added to give a more sportscar-like "character", rather than out of neccessity due to engine characteristics.
As said, not trying to be difficult - just wondered what your thought process was on this...
Dom
Dominic TVRetto said:
ChimpOnGas said:
...so as we all know the 5.0 litre engine is merely a stroked 4.0 litre, which invariably meaning two things:
1: Its less willing to rev
2: It produces a significant slug more torque
Both these characteristics pretty much forced TVR to do something about flywheel weight...
Without wishing to appear argumentative - why would this be..?1: Its less willing to rev
2: It produces a significant slug more torque
Both these characteristics pretty much forced TVR to do something about flywheel weight...
Dom
Because the 500 con rod big ends are further away from the centre line of rotation and therefore will carry more rotational momentum/mass and would be like having an even heavier flywheel. I therefore assume TVR reduced the flywheel weight because the 500’s are smooth enough at idle without the extra weight.
David (COG),
I agree, its the laws of levers and “TVR cannae change the laws of physics” not even Scotty. Thanks for your flywheel weights & links to the other side, interesting & good luck.
Steve
ChimpOnGas said:
We all know the 4.3 TVR RV8 was a sweet revving unit so it's possible the bespoke TVR cast flywheel I'm calling the 5.0 litre flywheel actually started out in the 4.3?
Sadly not, my 4.3 flywheel looks like a standard SD1 full fat flywheel. I’m kicking myself for not weighing my flywheel when I had my engine out while fitting my S10 (Tuscan T5 to normal people). (Dave, (sorry everyone else), I made my own offset gear lever by modifying the external linkage as you need the rubber bush to stop the heat, sorry back to business.)ChimpOnGas said:
As for what the Griffiths got is anyone's guess but I'd speculate that all variants (except perhaps the 4.0 litre Griffs) had something lighter than the stupidly heavy 32lb SD1 one TVR fitted to the 4.0 litre Chimaera?
I once had an old standard SD1 full fat flywheel that weighed 30.6lbs so 32lb could be correct.ChimpOnGas said:
Std Rover SD1/4 Litre TVR = 28Lbs (what I started out with)
Therefore sounds like TVR did shave 4 lbs off the SD1 flywheels.ChimpOnGas said:
V8 Developments machined & lightened version of the above = 21.5Lbs (what I have now - big improvement!!!) TVR 500 = 20Lbs
21.5lbs, is there any negative effect on idle particularly when pulling away from stationary? Please be really critical and picky, you're good at that . Do you “have to pick the revs up a little more than normal to get a clean departure from junctions” like with the TTV Racing 15lb? or have you just got use to it?ChimpOnGas said:
Rob also confirmed the 4.5 Chimaera got the 28Lb millstone I had in my 4.0 litre.
If the 400 and 450(Chimmy) flywheels are 28 lbs and my 430 flywheel looks standard full fat I doubt very much TVR machined a special for the 430 and therefore now assume the 430 flywheels are typical TVR’s 28lbs.ChimpOnGas said:
As already stated I have now gone for an all steel bespoke machined flywheel, this weighs exactly 8.5kg which is 18.74Lbs.
Therefore 21.5lbs must drive ok otherwise you wouldn’t go any lower, which answers my previous question above.Thanks for your thorough report, I concluded
| SD1 | 32lbs |
| 400/450(Chimmy) | 28lbs |
| 430 Assumption* | 28lbs |
| COG old | 21.5lbs |
| 500 | 20lbs |
| COG | 18.74Lbs |
(*Assumption is the mother of all f ups)
Thanks for everyone's input
Steve
ChimpOnGas said:
V8 Developments machined & lightened version of the above = 21.5Lbs (what I have now - big improvement!!!) TVR 500 = 20Lbs
stevesprint said:
21.5lbs, is there any negative effect on idle particularly when pulling away from stationary? Please be really critical and picky, you're good at that . Do you “have to pick the revs up a little more than normal to get a clean departure from junctions” like with the TTV Racing 15lb? or have you just got use to it?
There are no negatives whatsoever to taking a full 7lbs out of the original flywheel, as I've said may times fitting the lightened flywheel was an absolute no-brainer A TVR Griff or Chim is a very light car that produces excellent low end torque, the crank shaft itself is massively heavy so you can safely cut a big chunk of weight out of the flywheel and all you feel is the engine picks up revs massively better.. Do you “have to pick the revs up a little more than normal to get a clean departure from junctions” like with the TTV Racing 15lb? or have you just got use to it?I will be carefully weighing by V8 Developments lightened flywheel when it comes out in a few weeks time so I know exactly how much it weighs, admittedly I never weighed my original but I can tell you it is ridiculously heavy. I used to restore cars for a living and built many engines from Austin Healys to Jag XKs to Mk1 & Mk Ford Zephyrs, the standard Chimaera flywheel felt about same weight as that used on a Mk2 Zephyr which I do know is well over 33lbs and crazy heavy even for the big old Zephyr, Ford chose it to help smooth out the big old six and compensate for a distinct lack of gears, we routinely took a full 6lbs out of these flywheels and balanced the bottom end which resulted in huge improvements in engine responsiveness and smoothness with no real downsides in what is a big saloon who's owner still expected drivability and refinement.
ChimpOnGas said:
As already stated I have now gone for an all steel bespoke machined flywheel, this weighs exactly 8.5kg which is 18.74Lbs.
stevesprint said:
Therefore 21.5lbs must drive ok otherwise you wouldn’t go any lower, which answers my previous question above.
Honestly, trust me, it's perfect and I would recommend the flywheel weight loss diet to anyone with the stupidly heavy Rover SD1 millstone. In few weeks time I will be selling my V8 Developments lightened flywheel which I've absolutely loved from the day I fitted it, the only reason I'm changing it is because I feel I can still go fractionally (3lbs) lighter so I've had a custom chromo steel one spun by TTV Racing.It's a fine line though, both people I've spoken to that have the 15lb off the shelf offering from TTV Racing say you do need to lift the revs a bit to get the car off the line which is why I've chosen to have my custom 18.74Lbs made.
stevesprint said:
Thanks for your thorough report, I concluded
(*Assumption is the mother of all f ups)
Thanks for everyone's input
Steve
Well that sounds about right but I'm still not convinced TVR did anything at all with the standard SD1 flywheel. In any case it's all a bit irreverent because all you really need to know is this... | SD1 | 32lbs |
| 400/450(Chimmy) | 28lbs |
| 430 Assumption* | 28lbs |
| COG old | 21.5lbs |
| 500 | 20lbs |
| COG | 18.74Lbs |
(*Assumption is the mother of all f ups)
Thanks for everyone's input
Steve
If you have anything other than a 5.0 litre Chim or Griff you'll have a standard flywheel in your car, and if you have a standard flywheel you can easily slice 7lbs out of the back of it with no downsides only benefits that you'll really feel, benefits that will make you giggle every time you squeeze the throttle.
Do give me a shout if you want to buy my V8 Developments lightened flywheel before I put it in the PH TVR Parts & Plates classifieds.
Dave.
Edited by ChimpOnGas on Thursday 12th November 08:00
I have this behind my Rover it is Epic. rev's like a GSXR . you know it makes sense 
http://www.v8tuner.co.uk/product.php?id=855
http://www.v8tuner.co.uk/product.php?id=855
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