Help with Saturn Chassis Back End
 

Im struggling to work out the rear end of my saturn MX5 based chassis.
I have uploaded a drawing on my blog http://2.bp.blogspot.com/-_mpP1kf8gv.../s1600/BE2.PNG of the back end and will hopefully try and explain what i mean.
I cut d11, d12 & 13 to the new sizes and tried to fit them in place as show in the guide but it doesn't work out. It appears that d11 should be cut as original and fitted in the original location but the guide has d12 labeled as d11. Looking at d12 and 13 cut from the guide they don't fit where the existing d12 & 13 fit. the angles shown are the wrong way and according to the drawing i have done are the wrong angle on 1 end.

On the drawing it also shows that d11 (12 on the drawing) doesn't follow the line of plate cp7 on the shock / roll bar mount assembly. should it follow the angle? it still doesn't follow it if i sit it on the corner of the tube and not the diff plates as show.

I also couldn't find a drawing of rp1 & rp2 but i think they are listed as grp1 & grp2 in the cutting list at the back.

Sorry if this doesn't make sense. i have confused myself trying to work it out and more so trying to writing it down.

If anyone could take a look at the dimensions on the drawing on my blog and offer any advice it would be gratefully received.

Many thanks

Andy

I think it depends on whether you're planning to use the Saturn (or is it NTS now?) GRP rear tub, or an ali rear tub.

RP1 and RP2 are only fitted if you are going for an ali tub.
Whereas GRP1 and GRP2 are used if you're going for a GRP tub.

I made my the top diagonals follow CP7 (but it might be better to trim CP7 to make it follow the diagonals?)
You can just about see the way I've done here:

https://lh4.googleusercontent.com/-E...0/S5033022.JPG

Good point on the grp1/2 referring to the rear end used
I'm going to be using a grp so ill use the grp tubes.

does your d12 sit on top of the dif plate or on the corner?

Andy

D12 does indeed sit on top

that makes more sense thinking about it. Ill have another look at the pieces later.
Trouble is when drawing it is that the easiest way is to use a frame generator, only a sketch is drawn and tube assigned to the sketch lines ( see second pic down) http://bamaroadster.blogspot.com/201...r-chassis.html.
These are then trimmed and mitered to suit. this leads to problems when overall dimensions are not easy to work out or just tube lengths are given.
but it does make things easy to change just by inputting a new dimension to change the position of the line.

Like vmax says - it sits on top of the diff plate.

Little tip - it's easier to drill the holes in the diff plates before you weld in D12.

I hopefully have sorted the rear end for the mx5 based chassis. Its all tacked or clamped but before i fully weld it can anyone confirm that the dimensions i have are correct.
http://bamaroadster.blogspot.com/201...imensions.html

Also has anyone got any measurements for the mx5 based fuel tank. i have access to the tig welder at work for a while and would like to have a go at building one. i wouldn't know where to start measurement wise as i have no body work or knowledge of what else is in that area of the car.

Many thanks

Andy

Hi Andy,
Iv'e built a fuel tank for my MX5 build out of ally with swirl pot and flange for MX5 sender. I have kept it within the dimensions of the SSC back end and the book. If interested it's on my Photobucket and if you like I can draw it up this weekend and send it to you on Autocad (I believe you have Inventor?) I've got it roughly drawn but without the flange...
The fuel tank we have made uses the sender/fuel pump without any mods but does slightly go over the diff plates.
Just let me know if this is of any use.... Johno

http://i1199.photobucket.com/albums/...0122011297.jpg

Hi Johno
Any drawings you have would be a massive help thanks and any details regarding the filler neck, swirl pot and pump would be a massive help. I could come up with something myself but without knowing any details of the sender / pump it would be pretty pointless. seems a shame to not have a go at least whilst i can use the tig welder at work. unfortunately i'm going to have to make it from steel as we don't use aluminum as work. i have read about people using stainless which is an option and would polish up quite nicely. obviously heavier though.
Do the rollcage rear braces have any imact on the fuel tank size? i seem to remember reading that this fixes to the bottom of the chassis around that area.

Many thanks again for your offer and help

Regards

Andy