New Sportmotive chassis

[RichardD]

DonkeyApple said:

Jolly good stuff.

Thanks, great sharing of thoughts all the way up the modern TVR heirarchy imho

From that analysis document as linked to earlier, a rear hoop makes a reasonable difference as does a front hoop (23% above just the rear hoop) with the (even simple) cage givign another increase.

Also (and this may be a tangent), from that modelling pic, the rear upper wishbones do start with the outer part higher. Accelerate, add in some cornering and bumps and the this effect exaggerates, so they can reach quite exteme angles - doing strange things to the geometry.

[gifdy]

saxon said:

Can I say that what concerns me when driving my Griff is not the stiffness of the chassis but the complete absence of side intrusion protection sitting that low down behind a flimsy fibreglass door and a bit of carpet and with a backbone girder on the other side.

I applaud any attempts to make the chassis better, but I think my main concern as a keen driver, Dad and husband is safety, not shaving a couple of seconds off a lap at Brands.

The main thing that makes me occasionally look at selling the Griff is the thought of replacing it with something rewarding to drive but safer - Honda S2000? Toyota GT86? heck even an MX5 or a 2.8V6 Saab 9-3 convertible chipped for 300BHP. The other thing that makes me consider selling it is its lack of usability when the weather turns foul - poor demisting, heating, wipers etc.

Saxon

Fascinating discussion but this post sums up my own view perfectly. If someone came up with a modified chassis which gave some side-impact protection without having the inconvenience of a full cage, I'd rip their arm off.

[DonkeyApple]

gifdy said:

Fascinating discussion but this post sums up my own view perfectly. If someone came up with a modified chassis which gave some side-impact protection without having the inconvenience of a full cage, I'd rip their arm off.

This is doable but you'd have a steel bar across the inside of the door. I guess this is why some small cars have very high sills.

What you'd need to do is reshape the inside of the doors so that the lower 8 inches or so are scalloped in and then build up the shell to create a much higher sill within which is located framework. This is how it is done on my car but the framework at this point is CF and honeycomb bonded front and rear to the CF across the ends of the spine and incorporating the cage sections.

[Zumbruk]

Chilliman said:

Also, will I need to get the sump baffled so all the oil doesn't go to one side of the engine when I'm taking the roundabout at the end of my road at, hang on while I work it out, umm, ah yes, 150mph?

All joking aside, yes. Several of the TVR sprint championship competitors cars have had severe oil starvation problems caused by surge, despite baffled sumps, and at least one is having his car dry sumped after a number of engine failures.

[GTRene]

does a small cage like this ads some chassis stiffness?



this guy also uses a 5.4 rover engine

http://www.ridedrive.co.uk/articles-griffith-jeffs...

here are more pictures of such roll cage system...it was made that way so that you still had a clear rear view.

http://www.neilgarner.co.uk/gallery/category/Curre...

this one looks more rigid, a full cage I guess welled in?

http://www.racecarsdirect.com/listing/28079/tvr_gr...

also uses a strange dash...

but I guess with such cage you can't use the roof system?





edit to ad a thread about roll cage in say Griffith/Chimaera >>

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Edited by GTRene on Wednesday 10th October 12:06

[jwoffshore]

OK, somebody asked to see a few pics, so I may as well. This is still a work in progress, so it's not all pretty and shiny.

Front end with LS engine in. You can see how much more room there is around the sides of the engine, so easy to get the exhaust manifolds down the side of the block. That saves space in the front of the engine for other stuff, e.g. remote oil filter, Accusump (for those not wanting oil surge). Also it takes a lot of heat out from under the bonnet. More bracing around the front end and shock top mounts relocated/beefed up.



Looking down the side, you can just see the heavy duty engine mounts which originate from 4x4 offroad competition vehicles. They are much stronger than the Rover style mounts.



Here's a look down the backbone. You can see the rear shock mounts improved similar to the front and more bracing tubes.


Rear & front uprights. The wishbones are still being fine tuned, so can't show those yet.


There is also more room to get the exhaust past the T56 gearbox. We are using the latest T56 Magnum which is the closer ratio version. With a standard axle ratio, 1st gear is good for about 50mph, through to 5th gear for 160+ top speed. 6th gear is a 200mph overdrive, for more relaxed cruising.

[Bluebottle]

that does look good how does it compare with a std bare chassis for weight?


I want one..just for those hubs!

Edited by Bluebottle on Wednesday 10th October 12:39

[500dread]

jwoffshore said:

this topic has now drifted so far into Roger Irrelevant territory that I don't think it's worth the bother!

Happy you changed your mind. They're interesting pics. Disagree about 'Roger' though. Thought we were all pretty much on topic and have been all along.

[jwoffshore]

Bluebottle said:

that does look good how does it compare with a std bare chassis for weight?

Thanks for the positive comment. I don't know the weight really. It is bound to be a few kg heavier in the frame, because we have extra bracing tubes and also the bottom rails are a thicker gauge of steel. However, some weight will be saved with the ally uprights vs the old steel ones. The lighter uprights should help the suspension work better too.

I forgot to mention, we are going with the Subaru steering rack as per the car build by Steve SSPPGG, so no more leaky TVR racks to worry about.

[grahamw48]

Can you please open a factory once the prototype is completed and marketable ?

[jwoffshore]

grahamw48 said:

Can you please open a factory once the prototype is completed and marketable ?

Yeah, there's some Russian rich kid we could get to help us....

[Bluebottle]

jwoffshore said:

Bluebottle said:

that does look good how does it compare with a std bare chassis for weight?

Thanks for the positive comment. I don't know the weight really. It is bound to be a few kg heavier in the frame, because we have extra bracing tubes and also the bottom rails are a thicker gauge of steel. However, some weight will be saved with the ally uprights vs the old steel ones. The lighter uprights should help the suspension work better too.

I forgot to mention, we are going with the Subaru steering rack as per the car build by Steve SSPPGG, so no more leaky TVR racks to worry about.

Would be good to get an idea of the additional weight, maybe when it goes for powder coating/galving it could be weighed?
re: hubs, It alsways helps reducing the unsprung weight

[grahamw48]

jwoffshore said:

Yeah, there's some Russian rich kid we could get to help us....

Noooooo!!!

[RichardD]

Bluebottle said:

...

For those really obsessed with shiny things .

(It is a diff by the way (which looks a bit like the head of a Cyberman!)

[900T-R]

jwoffshore said:

grahamw48 said:

Can you please open a factory once the prototype is completed and marketable ?

Yeah, there's some Russian rich kid we could get to help us....

[sportmotive]

err no Russians are getting involved in my chassis!

...hmmm factory you say

[Bluebottle]

RichardD said:

Bluebottle said:

...

For those really obsessed with shiny things .

(It is a diff by the way (which looks a bit like the head of a Cyberman!)

Have you seriously billet machine a new casing for you diff!?

[sportmotive]

Its not ours no Richard is just teasing you with it, its made by the company that are machining our uprights....although we could use it...

[Chilliman]

I'd like 10% off the price of my new windscreen for starting this thread

[DonkeyApple]

jwoffshore said:

OK, somebody asked to see a few pics, so I may as well. This is still a work in progress, so it's not all pretty and shiny.

Front end with LS engine in. You can see how much more room there is around the sides of the engine, so easy to get the exhaust manifolds down the side of the block. That saves space in the front of the engine for other stuff, e.g. remote oil filter, Accusump (for those not wanting oil surge). Also it takes a lot of heat out from under the bonnet. More bracing around the front end and shock top mounts relocated/beefed up.



Looking down the side, you can just see the heavy duty engine mounts which originate from 4x4 offroad competition vehicles. They are much stronger than the Rover style mounts.



Here's a look down the backbone. You can see the rear shock mounts improved similar to the front and more bracing tubes.


Rear & front uprights. The wishbones are still being fine tuned, so can't show those yet.


There is also more room to get the exhaust past the T56 gearbox. We are using the latest T56 Magnum which is the closer ratio version. With a standard axle ratio, 1st gear is good for about 50mph, through to 5th gear for 160+ top speed. 6th gear is a 200mph overdrive, for more relaxed cruising.

Does this mean that if you fitted a RV8 you could run the pipes straight down and out?