Diffuser for rear of Griffith
Discussion
sjpalmer1 said:
Why would you go to all that effort if it doesn't actually do anything.
For the same reason that a large number of modifications get done, I suspect: because it makes the car look and feel better in the owner's opinion. Whether it actually makes a significant difference to the car's performance is largely irrelevent in most cases.
The defuser designed for the Supercharged Griffith SC500 and seen on Mark Hockins car was evaluated during the second half of the Challenge series. Mark found the defuser improved rear end stability minimising lift and reducing the severity of breakaway, this enabling him to hold the car nearer the limit as the car became more predictable. Notably he would not take the defuser off after fitting. Since the end of the series the defuser has undergone some changes to improve laminar airflow.
For aesthetic reasons the defuser is best fitted closer to the rear body work, but we found significant improvement when moving the defuser rearwards, in effect lengthening the undertray. The downside is it doesn't look quite so good.
Our SC500 Griffith has just been repainted in it's new livery ready for installation of the front splitter and defuser, not forgetting the Supercharged engine, we hope to fit the defuser and centre exit exhaust directly after Christmas. I will post some photo's shortly, it does look good, is wholly functional and does not require any body mods. Hopefully you will agree the defuser enhances the overall appearance of the car, reducing the rear end lift for which the Griffith is known.
This defuser is part of the body kit offered by TVR Power early 2007. We opted to produce the defuser in GRP rather than carbon, as the defuser by virtue of its location is susceptable to minor abrasion and possible damage over speed bumps or when parking.
For aesthetic reasons the defuser is best fitted closer to the rear body work, but we found significant improvement when moving the defuser rearwards, in effect lengthening the undertray. The downside is it doesn't look quite so good.
Our SC500 Griffith has just been repainted in it's new livery ready for installation of the front splitter and defuser, not forgetting the Supercharged engine, we hope to fit the defuser and centre exit exhaust directly after Christmas. I will post some photo's shortly, it does look good, is wholly functional and does not require any body mods. Hopefully you will agree the defuser enhances the overall appearance of the car, reducing the rear end lift for which the Griffith is known.
This defuser is part of the body kit offered by TVR Power early 2007. We opted to produce the defuser in GRP rather than carbon, as the defuser by virtue of its location is susceptable to minor abrasion and possible damage over speed bumps or when parking.
Thanks for the info, sounds interesting when facts are added to the photos to stop speculation, where did you do the wind tunnel work or is it all track based. You don't mention anything about the mesh to the outside of the rear lights, does this actually do anything or is it cosmetic ?
Sorry about my spelling errors, but that's what happens after a night out and writing responses at 3.00 in the morning! The shape and form of the diffuser was generated using the latest computer technology, the overall package being limited by the existing car shape, ground clearance and rear wheel departure angles. For any diffuser to work, the standard rear exhaust configuration has to be changed to inline centre or side exit, minimising the turbulence generated by the exhaust. No specific load values yet as this is part of the overall package under evaluation. As with all (except F1) aero development, judgement has been gained by 'on track evaluation' over the past 2 seasons, let's see how many cars will be fitted with it next year on track. To achieve specific calculations the overall body form has to be digitised and modelled in the computer, this is time consuming and extremely expensive, therefore we are currently limited to track testing. Our front splitter has yet to be tested at max speed repeatable, but is designed to improve cooling by inducing higher air pressure in front of the intercooler/radiator package as the total core thickness is now 110mm. Sorry I can't be more specific.
We don’t intend to develop a similar package for the Chim due to requiring extensive rear end modification to become effective, but I guess it would be better than the standard Griff anyway due to the extended rear body. Perhaps someone can advise whether they have knowledge or experience of similar rear end lift in their Chim at high speed. Development of the aero bits is all linked in with the Supercharger installation for the Griffith, our Supercharged 4.5 and 5.0 litre Chims have not been driven to the limit yet to reach any judgement. These cars will be subjected to extensive track evaluations during the coming weeks.
SC500 said:
To achieve specific calculations the overall body form has to be digitised and modelled in the computer, this is time consuming and extremely expensive, therefore we are currently limited to track testing.
Modelling might help you understand why it works - or doesn't - but at the end of the day, the only thing that matters is the actual downforce in real-world conditions. And that's something that can be measured fairly easily without any horribly expensive equipment. Despite all the F1 technology you refer to, I'm skeptical that the downforce produced at 'public road' speeds is enough to be measure let alone be noticeable. Get well into three figure speeds and if it works, the effects could be enough to start mattering - but you would need attached flow through the extractor for it to work, and I think you will struggle to achieve that without an undertray.
SC500, you mention the development of a front splitter. Is this being developed along side the rear or afterwards ? Surely they need to be done together to get the correct overall package. What ever you do at the rear will effect the front and vice versa. You also mention ducting air over the cooling pack due to its thickness. The amount of air going through the cooling pack at high speed needs to be kept to the minimum to provide adequate cooling and no more. If you force too much into the nose of the vehicle or into the engine this will then provide front end lift and negate what the front splitter is trying to do.
sjpalmer1 said:
...If you force too much into the nose of the vehicle or into the engine this will then provide front end lift and negate what the front splitter is trying to do.
Doesn't this mean that it will in a worst case still be equal to a normal car with no aero mods? Given the small nose of a Griffith (compared to normal forced induction cars like Evo-suburu-lines) I think the SC500 is quite a challenge in terms of the rad/intercooling !
What I would fancy with this potential set-up is to add some mesh vents at the top of the bonnet to help suck air from the rad in addition to the normal (small) gap.
Few bags of sand in the boot and an Iron block in the front should have traction and stability sorted.
Good Adjustable suspension is alot more important (lower all round), mine is fine at Silly speeds - binned the crap splitter age's ago (well with lower ride height it will last 5 minutes!).
Ok it is a Chim but they were all designed on paper or by a dog with no aerodynamis or windtunnel in site. Just hang-on
Good Adjustable suspension is alot more important (lower all round), mine is fine at Silly speeds - binned the crap splitter age's ago (well with lower ride height it will last 5 minutes!).
Ok it is a Chim but they were all designed on paper or by a dog with no aerodynamis or windtunnel in site. Just hang-on
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