870c project

[Bugle]

Thought i'd finally update this thing.

Found after the first run that the front bulkhead cap had cracked where the upper deck attaches, so I got another bulkhead cap, did 1 lap and it had broken in the same spot. So I machined one out of delrin. Ran it in the 2010 NSW state titles which were held at St Ives. Ended up BQ'ing then DNF'ing the final due to the servo saver loosening off and jamming the steering, only positive was that after 2 rounds of qual at the regrade I was in the top 10 which is unusual for me, too bad I couldn't hold it.

This is what it looked like then

Then the shorty lipo battery came out, and I realised I could do what I wanted to do from the start but couldn't due to NiMH cells being obsolete, make a 4+2 1989 world titles chassis, just with a shorty in place of the 4 cell and ESC on the other side. The weight distribution is a bit out of whack with the front right and left rear being heavier than the other sides, but it seems to handle better. Turns in much better, used to understeer alot mid corner with the original chassis.

[Bugle]

Then I broke it

[Bormac]

Great pics of it out at Snives Thomas

[Bugle]

Yeah look at all the people standing around admiring it Nah those were taken during the concourse.. Unfortunately the best looking car can't win if it doesn't have a fancy paint job

Hopefully will get around to making a 7075 billet front bulkhead soon.

[littleVETTE]

looking good frank! it looked like your rear end was a bit soft. the front wheels are tickling the dirt while the rear was getting busy.

[Asso_man!]

A nice upgrade would be to use a longer top deck that bolts right into the front and rear bulkheads instead of only into the top caps. Just use some small tubes to catch up with the gap.

Very nice car and great machining work too, I would be all over two delrin caps

[fakiee]

A nice upgrade would be to use a longer top deck that bolts right into the front and rear bulkheads instead of only into the top caps. Just use some small tubes to catch up with the gap. :

I did this with a works 91 with the RPM bulkheads (designed for the 870c with no top deck). It was probably a bit too stiff, but I thought it looked great!

[Mr. ED]

Same problem here with those topdeck fixations in the bulkhead covers.
Maybe you could turn us little inserts for the small scrwes that go into the magnesium part?
Fixing the topdeck to the shocktowers doesn't sound like the best idea to me: I've heard a couple people talking about the magnesium part breaking at the point they're screwed together with the towers. (As happened to you.)
I think that 'd happen more frequently if you connect the towers to the topdeck.

Pitty of this weaknesses as this car has been one of those few I could drive pretty descent with my limited driving skills.

[jwscab]

yeah, it would be nice to see a bulkhead cap machined with ears, or at least a placement for a small angle bracket so that the tower attaches to the bulkhead and cap at the same time.

[Bugle]

The rear suspension is really stiff, no.2 piston, blue springs and 40wt oil is wayy stiffer than I run on any other car. I would've tried the rear swaybar but I can't find the thing. Guess i'll have to make one.

Yeah the top deck that goes through the other holes is a good solution, you used some brass tubes and super long m2 screws? The delrin caps solved the problem too but are a bit harder to make than a new top deck.

I think the problem with the bulkhead breaking was that the aluminium angle I used to attach the shock tower to the bulkhead cap had bent. The rear end must've had some hard hits too because the shock tower has snapped above where it screws to the bulkhead cap but hadn't broken the bulkhead. I'll machine a stiffer pair of front shock tower to bulkhead cap braces rather than using plain angle alloy.

Since I have to make a new rear shock tower i'll make some 89 worlds replica ones, which seem to be pretty much 91 works towers.