Month: August 2011

More tower building

After a few hours of round the house, mowing lawns etc, I got stuck into the car again.

Today was continuing with the front strut towers.

First was to finish the passenger side by adding an an extra bar, and connecting the main rollcage tube to the new strut top.

I tacked welded in some temporary some bracing between the front caster rod mount and the existing from chassis rail (the funny cross in the bottom right of the pic above).  This was to give it enough strength to hold it in place when I cut out the sheet metal around the old towers.  This metal is going to be replaced, but with a series of flat panels that are much easier for the to make 🙂  The front sections will be replaced as well, but for now I need them to stay lined up so that they can be used as reference points as I build the replacement sections.

I added in the final bars to complete the main cross section that joins the left and right strut towers together.

Then started working on the drivers side, copying all of the same tubes and other pieces as the passenger side, then cut away all of the inner tower sheet metal on this side as well.

I then needed to make to top cap for the towers, for the front suspension to bolt onto.  I have designed a top to give me the same camber adjustment that I used to have, but with one less layer of metal than I had previously.

I’ve cut out the outer circular shape for the other side, but have not yet cut out the inner slots – so that’s the next job when I get another chance to get back into the shed.

New towers

Got another 2hrs of work done, this time the front end tubing up to the top of the strut towers.

I machined up the larges rings for the top of the towers, cut out the standard strut top and tack welded the new one in.  Then I made the tubes that run from the strut top to the other parts of the car.

This large ring will have a top welded onto it, where the top of the suspension will mount.

Half of the original strut top mounting plate won’t be used with this new mount, as I’ll be integrating two of the parts into a single piece, without losing any adjust-ability.  The joys of a specific build – rather than having to contend with ‘standard / mass production’ parts and way’s of doing things.

 

Another view

 

So next job tomorrow is to do this same thing to the other side of the car, connect up the last few bits of chassis tubing on the other side, then make the new top plates.

Good days and bad days

Had a good day on Wed, got home early from Targa West recci and so got a few hours in the shed!

I was going to make this front section a bolt-on affair, to make getting the engine out easier.  It was going to be hard, and not very light, and then I had a brain wave (yes, they happen once in a while) and have come up with an easier way to get the engine and gearbox out easily, in one peice.  More on that later…

So, with that instead of having to make complicated mounts, I could just weld everything in.

There are still a few bits that I have left to do, once I buy another small bit of moly tube.

All the front end is now all nicely tied together, all the way up to the new strut top mounts that I’m going to make.

Some more angles…

Then it was onto building the mounts to hold the steering rack in.  It’s all adjustable in both dimensions, so that I can adjust bump steer as well as akerman angle.  This made it a little harder to make than it should have been, but…..  I can’t wait until I can get a mill, cause I could have made the brackets out of alloy a lot faster and nicer than the steel ones that I’ve done.

I made such good progress in these hours – was a good day.

Thursday got home from recci day two early as well – things only got worse from there, so no more progress to report.

Until next time…

Mounts, mounts and more mounts

Yesterday was some cleaning up around the yard, making a new vegi patch, doing retic, planting seeds, then fertilizing all the fruit trees, all the gardens and the lawns.  By that time the day was nearly over, but managed to squeeze in a couple of hours on the car.

Got the lower a-arm mounts made, and gone one of the tacked onto the frame in the required location on the chassis.

There are three mounting locations available for me to test out when its all running again.  The lower most hole is at the same location as the modified mount that I had on the original sub-frame.  This now gives me the option to go higher than that point to test out how the car feels with these different roll centers.

Got a good chunk of car time today were I continued with the suspension mounts.  This time it was on the caster arm mounts.

Once I’ve added the last chassis bars to this mount, I’ll profile it to remove the excess material (like the lower a-arm mounts have been)

I then started preparing the mounts for the steering rack.  I’ve cut out the profiles that are needed to mount the rack, so they will fit tightly over it locking it into position.  Didn’t get a pic of these, so you’ll have to use your imagination 🙂  These will bolt onto the main sub-frame that will run across the engine bay.  These bolt locations will be adjustable up and down, as well as for and aft via some shims.  This will allow me to make changes to help take out any bump steer and also to change the amount of Akerman angle that the steering has during a turn.

Next on the list was to build the sub-frame to hold the steering rack mounts into place.  I didn’t have the metal I needed, so I spent some time trying to work out what the framework in the front end will look like.  I used some high tech masking tape to mock it up :).  I’ve tried to set the bar work up so that it will be easy to change to work at its best once I have changed the front suspension over to double A-arms – rather than the MacPherson strut setup that it has now (A-arms are a much better race suspension, but the mount at a different location).

Pic on the left is taken from above, the second one taken from underneath.

The framework is going to be quite extensive, so to determine how I was going to get things like radiators and intercoolers to fit I put them in.

The whole assembly will be moved back a little bit from the photos here, as I have now removed the coolant swirl pot and I’m going to mount it on the side of the motor.  This gives me another 100mm to move the radiator and intercooler back.  Also on the list is to cut off the outlets of the intercooler and radiator and rotate them around to point them in the right direction to suite their new homes.

I made a few adjustments to the proposed frame after this fitting, to make better use of the tubes and to reduce the size of the mounts that will be needed to hold the rad and cooler in place.

I’ve taken the measurements of all these tubes, now I just need to work out the tube sizes required so that I can buy a couple of them tomorrow.  I need to analyse the forces on the tubes in order to select the right tube size to make it strong, but also very light.  A tube that is put into compression needs to have a larger diameter to take the forces.  A tube that is purely in tension can be a much smaller diameter (ie lighter), but may need a higher wall thickness.

Until next time…

See my 9 inches of glory

Started work on the front suspension last night, and have the right front mocked up in place to start designing the mounts for the suspension arms and the steering rack.

As an experiment, I put the old rear rims and tyres (255 wide tyre on a 9inch rim) on the fronts, and they actually clear the struts with the current setup.  So I put on the 25mm wider guards that Neil got a hold of, and it actually all sits very nicely in there 🙂  I previous had 8″ rims with a 240 width tyre – this extra rubber should mean a good deal more grip.

The wider guards actually looks quite nice, the extension of width is quite subtle.

Ohh yeah, nice and FAT!  JC – I’m coming for ya!

Now, to find some 10 inch rear rims, so that I can get some 280 or 300mm wide tyres on the rear 🙂

More soon I hope…