Bentley Speed 8 replica

[Mick Ridley]

Hi Joey,

That a very intresting project you have, and I wish you the best of luck with it. Im building an alloy mono chassis for my GT40, and can appreciate the amount of work you have done, to get your car to its present stage.

As you are building a replica of a modern LMP car, have you considered useing the engine/gearbox as a semi stressed part of the chassis, and mounting your wishbones, and suspension units to the engine/gearbox.If you were to do this, your chassis could finish just behind the rear roll hoop, and would save a lot of work

That is what I have done for my car here is a link to my build log http://www.gt40s.com/forum/gt40-build-logs/36067-gt40-aluminium-mononcoque-chassis-3.html#post415073 there are pics of the engine gearbox on post 43 and on post 51 it explains how im going to attatch the engine/gearbox to the chassis. It will be mounted in a similar way to the Maclaren M20

Here is a pic of what I have done. Im useing a Rover V8 with a Renault UN103 gearbox, I inverted the gearbox so I could get the engine as low as possible in the chassis without having too much angle on the driveshafts. Your top shock mount would need to be lower than mine, because your body work is much lower, but you could use a link system and have your shocks mounted inboard. I have studied your rear wishbones and mounts, and think it would be much better to use a more conventionall set-up

 

[Robert May Eng.]

run away screaming. Chassis is not very well done! As practical as tits on a boar hog!

:laugh:

Nice concept but that thing would not even get down my drive. The thing that worries me with these "reasonably priced" starter packages is they are normally a sprat to catch a Mackerel. Trick glass,suspension packages,lights and wheels would probably put that a long way from the initial costings. A bit like the cobra I built that was buildable for under £12k that cost me £25k or my brothers ultima that ended up at over £40k.

Bob

 

[joelee]

Thanks for technical advice above, I'll think about that way.
as you required, here re some pic about the a-arms uprights. Can I beg Michel to post some pics about the tube chassis covered with carbon panel ?

 

[Michel]

Hello Joe
Thanks for these pics

Concerning that famous chassis I built ;
It was a VBM gt I built for le mans 1998 but never raced because the engine manufacturer failed delivering one engine one month before préqualifications
I will try to dig out some pics as soon I found some in my archives
This is what shape that car had ; ( very gt40's inspired LOL remember this was in 1998 !!! since that year seems some inteligent manufacter copied ideas !!)

Ok now coming back to your project ( I do not like to hack other's threads !!)

One of my interrogation about your rear suspension it is the unusal angle of the shock absorber and spring unit !!!
Have you done a cinematic simulation on drawings or whatever to evaluate this unit is taking as loads in extension and max compression ?
to my private expertise there is arange of sharp angle not to reach and where the springrate start to decrease terribly and suddenly in case of big bump on curve or with a big gaz acceleration !!!
Until you do not reach total stroke you will not feel any effect and suddenly the car goes
oversterring and badaboum !!!!!
Hope you did some good cinematic drawings and that am wrong just watching pics

 

[Michel]

Hello Joey
In your site on the prices page there is on optional extra

" 5 parts spoiler" at 1200 euros = what is this part ?

As front spoiler is included in the bodywork pack is it the rear wings wirh all flanges ????

Thanks for any information on that

I noticed to day that your channel is avaible again !! perfect ; there are plenty of interesting video where we can watch more details on your project
Thanks

 

[Gabriel Von Wahl]

Joey,

Any way we could trouble you for more pictures of the interior of the LMP?

 

[Gabriel Von Wahl]

All, if anyone is interested Joey sent me some cool pics of the interior (bare and basic) but he seems to be incredibly straight forward and "one of us" when it comes to the enthusiasm behind the project.

I wonder if the chassis could handle a Bentley W12tt...

 

[Bobi]

Hello guys, this is my first post here. My name is Bobi and I'm the chassis and suspension designer behind this project.

Here the good news are coming. Both, the chassis and suspension, are being revised/redesigned to provide extra strength and able to take considerably higher power and braking forces. There will be no problem to handle up to 2000HP with this setup!

I was also reading the comments you wrote on all 3 pages, and below I will try to reply them:

First, about the engine. The initial choice of engine was driven by two reasons:

(a) As Joe already mentioned, this project was privately funded and therefore the budget was not unlimited. You know, we all have that desire to have the best possible components in our cars, but in the real life everything cost huge money and we must consider where to use the funds allowed at higher priority.

(b) The space under the engine cover is not as big as on other cars, and as such, it will not accommodate any unit. Most OEM engines are either too high or require extensive and expensive work to be able to mate with proper transmission. Risks to obtain a engine and transmission combo that eventually would be too big and unusable in the car were too high, and not good for the budget. But now that the chassis is already tested and free space in the engine bay measured and considered as enough for even bigger engines, there is an AUDI engine option in the list that will allow some better performance figures.


As for the chassis and sispension design, there were many things to consider while designing them the way you see them. The main goal was to achieve simple, light, yet strong and affordable chassis that will allow easy installation and access to components underneath the body.

Then, it had to allow wider range of engine and transmission options, thus the area between the rear suspension is a proper frame instead of using the engine as a structural member. If we were doing the latter, that would limit the engine and transmission choice to only one unit, and eventually making it necessary to design custom rear half of the chassis for other customers who would like to use different drivetrain. That would also lead to extra expenses on the customer's side, and longer time required to development and delivery.

The chassis is designed to use 2mm thick steel sheets on the floor, plus 1mm thick sheets all around the cockpit area. All sheets are not whole pieces attached next to the tubes, but separe pieces instead welded inbetween the tubes, thus providing much higher load capacity and reducing weight. This design will unload huge forces from the tube welds as well, due to the separate pieces acting as an extra support to the frame.

The body itself will lay down directly on the chassis, as the latter is closely following the body shape in most areas. This also provides extra rigidity to the body.

There must be two X-braces above the drivetrain area, and two other X-braces behind and above the driver, and several other reinforcements at the front end as well, that were not yet installed on the prototype chassis. However, all future chassis will feature this as a strandard. There will be no compromise with the safety. Most of these were not used initially as a concern if there will be enough room in the cabin, but now that the car is built and there is plenty of room inside, that will allow to use the full potential of the safety cell.

Although it's showing an older version of my chassis design, the following video may help you better determine the main shapes of the chassis and suspension, as I know CAD images with their bright colours and clear outlines are easier to understand than real photos.
[ame="http://www.youtube.com/watch?v=w0s21_V28B8"]http://youtu.be/w0s21_V28B8[/ame]
Upon release of the first customer chassis I will upload a new detailed overview video with the much improved new design of chassis and suspension.

If you have any questions regarding the design and why something is "made this way, no other way", don't hesitate to ask me.

Thank you for your time!

Bobi


PS: I also replied some more questions on another forum, so you may want to read them as well.
Aeromotor, yes this is Grassroots: Grassroots Motorsports forum: Grassroots Motorsports Magazine

 

[Michel]

Hello
Many thanks for all these informations
There will be a lot of questions to ask to understand why you did so choices for your upright design , your wishbone constitution, the clevis bolted to the chassis to hold suspension , the rollbar welded on middlle of tubes and not going to the floor etc etc etc
I think it's not the place to have long and complicated discussion about all these
choices as probably you have very good reasons to have done in 2013 such tecnology ( very old fashion)
don't you think that with such an exceptional work on the bodywork ( I personally told to Joe that it was excellent!!!) it was smarter to draw modern suspensions? Cost was similar as upright can be done by laser cutting but much more lighter , choice of others bearing from specific car allowing to have a central wheel nut modern fit etc etc
Again I do not want to be at all critical upon your work ; only helping this project to find the right market !!! This is the absolute first question to ask

If I was one of your future customer I will first wonder ......
Why and for what purpose do I need to build such Replica ?
Track day car ?
Show car ?
School driving car ?
Etc ETC
Then each use will havequestions and answers you are asking for


Good luck to this project

 

[Ron Earp]

Fellows, there is no advertising allowed on GT40s.com by non-vendors. Bobi and Joey you'll need to decide if you wish to be a vendor on the site and sign up as a vendor if you wish to continues posts like these. Thanks,

Ron

 

[Bobi]

Thank you for the notification, Ron Earp. I'm not affiliated with the company and the sole reason to register here was purely to reply some technical questions regarding my design that few people asked in the topic. But I understand what you mean and sorry if I accidentally violated some rules. I can't find "edit post" button, otherwise I would delete my YouTube video and announcement of improved chassis design in my first post if this was considered advertising. In the future, if anyone have technical questions send me a PM as to avoid my new postings in the topic. Thank you.

 

[Ron R.]

Ron,

I understand your position.

Is there any way affiliates can answer questions posed by the peanut gallery without violating policy?

It would seem a shame to kill this thread, or have to have all responses by third parties who start with..."according to sources...."