On Tue, 19 Nov 2002, Shane Ingate wrote:
> Mike Munson asked:
>
> > How is the motor coming? Are you going with the 2.7 liter up grade? What
> > pistons will you use?
>
> Block is overbored 0.11". Hepolite pistons for the Mazda 626 work.
> Alternatives are Miata E pistons. Both require a bit of machining to the
> wrist pins. They are nice and light pistons that will easily survive up to
> 11:1 compression.
>
> Jury is not yet in on the head gasket. Options are copper, or asbestos.
> I'm leaning towards asbestos because it does crush. The copper gaskets are
> sourced here in the US, and asbestos in Oz.
I can't address crush or tell you that asbestos is nasty stuff... but if
the motor is going to be subjected to teardowns, copper is def. the way to
go. Plus with copper you can message the gasket to fit your new HUGE
"holes". :-)
> While I have all your attention, what is the list's wisdom about
> foam-filled, steel-can encased fuel cells?
I like Al better. They look cooler.
> By mounting one in the spare-wheel well, I can lower the CG, but it is moved
> further back and is perhaps more exposed in event of a rear-end accident.
> It does have the frame rails on either side, but backing into a tree would
> go straight into the cell.
This is where I've mounted my cell. It fits "real nice".
If you are concerned about backing into things, you could build a cage
around the cell. Most of the SCCA road racer types extend the rear braces
for the main roll hoop to the back of the car... it wouldn't be that much
more work to hang the cell from those braces.
If you're not building a cage, then you could still build some stiffening
in the boot area in case of a rear impact.
> I know that the auto-racing sanctioning bodies require fuel cells, but there
> is an interesting fact: statistically, more cars burn in competition with
> fuel cells than with stock fuel tanks after an accident that impacts upon
> the tank.
Well - the question is not about burning in and of itself. It's about
survivable impacts. If you have a cell, the leak rate should be faily slow
(assuming a ballistic bladder inside a metal container). THus if the cell
is compromised, you should be able to get out of the car without getting
burned. Sure the car might burn, but you can get out before the entire car
turns into an incinerator.
Contrast that to the cells that you see in _a lot_ of "race cars". Like
plastic container (dense polyethelyne) cells with _no metal_ and _no
bladder_. Compromise one of those babies and we're talking BOOM with a
capital B. And it won't take an overly large impact to compromise one of
those tanks. And fuel will spray everywhere in a large shunt. This is not
fun. And in a race car, things get REALLY HOT so there are lots of
ignition sources for that fuel that is now everywhere.
So, I'm not surprised by this fact, but I'd like to see detailed numbers
(broken out by sanctioning body, for example). I'll bet the drag race guys
have some really bad fires.
FWIW - don't skimp here. Spend $1000 for a fuel cell installation or
you'll be sadly dissapointed in the results.
> Cheerio,
>
> Shane Ingate in Maryland
regards,
Bob "Nomex" Lang
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