In reply to a message from marksawatsky sent Tue 5 Apr 2011:
For short bars try speedway engineering… They sell hollow bars
whatever length and arms of either steel or aluminum… Bending
aluminum arms is hard to do safely, especially double bends which
are needed to allow full turn radius. Steel bends much easier but
winds up adding weight over aluminum…
Where is your roll center? I wouldn’t begin to do sway bars and
springs untill that number is known…In general I’ve found that
softer springs and stiffer sway bars work easier to turn plus
traction is improved if the suspension can be more compliant…
My XK-E V12 Race car had a surprisingly high roll center for as
low as it was… Your track width (I know stock MGB’s track is right
at 50 inches) is likely narrower than mine so that puts your roll
center even higher… Plus you had a roof and a full cage while I
didn’t. My roll cage consisted of a single hoop over the driver
only… (Vintage racing allows that) and then tubing to pick up the
body. Look at Group 44’s XK-E for example…–
The original message included these comments:
only 75 lb/in spring rate but it’s enough to put my car into
understeer. Since making those calculations, my weight balance has
changed and now my car is softer in the front, I will need a front
bar as well. My chassis had a torsional stiffness of 1600 ft/lbs
per degree and since then I have seem welded it and added braces so
I’m not very worried about chassis stiffness. I also have only 2
1/2’’ of compression on the suspension and the natural frequency is
2.5 Hz, it’s pretty stiff. The front bar is going to have to be
very short so I need to find a good source of custom bars, but
first I need to drive the car and see where I’m at.
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In reply to a message from Kirbert sent Wed 6 Apr 2011:
Kirbert;
That’s what autocrossing is… some big flat parking lot someplace
with cones laid out for the track…
Tight twisting turns and corners… no straights to speak of and
relatively low top speeds. 60 mph is considered fast…
One car at a time and the event lasts maybe 1 minute or so…
It’s drag racing for those who like to corner… Every major city
seems to have groups of them meeting a couple times a year in some
parking lot someplace… The BMW club,the Porsche club,etc. it’s
really cheap racing (er,… affordable) Plus it’s ubber serious
since the race may come down to the tenth or even 100th of a
second…
It’s a combination of car and driver… unlike drag racing which
tends to be mainly drag racing or top speed events which is
completely the car…–
The original message included these comments:
Only if they’re running on a flat surface, no dips or bumps. Running
springs stiff enough to eliminate the need for sway bars on a road
course would be stupid, might as well eliminate the suspension
Many race cars run very small sway bars, but that’s because their CG
is about six inches off the ground, they don’t need much. For the
stiff indeed. When you run tires wider than 8’’ or so, sway bars are
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In reply to a message from marksawatsky sent Wed 6 Apr 2011:
If you want to road race your car look at Chump Car racing or
LeMons racing.
Those groups are for $500 cars… however rollcage, safety, Wheels
tires and brakes are exempt. Plus both groups have a soft spot for
British cars. Jag V12 motors are often available for a nominal
price… and the basic body is worth extremely little in the shape
the pictures show… The only area’s of concern might be the spring
shock units. and guages… If I recall you bought those off E-bay
for a nominal price didn’t you?
Go back to full thickness brake rotors. This is endurance racing.
There are 2 events here at Brainerd… both twin 7 hours…(7 hrs on
saturday & 7 on sunday) mid June and late July I think…
Your car would be blindingly fast…
There are other events scattered around the country…Up to 24
hours of nonstop racing…
The good news is you have to have at least 4 drivers (up to6) …
they offset the costs of racing. If your car doesn’t breakdown you
would have a great chance at winning the bags of nickles… ($2200
worth of nickles) Second place is about 1/2 that and they pay back
to third place… Since technically it’s a business you can take a
tax break if you shouldn’t happen to win… They tend to be held
on short tight tracks… No contact rule in effect if you contact
someone you are black flagged and have to come in and discuss
things with the chief steward (about a 5 minute penalty) that
prevents it from being a demolition derby… (even though a lot of
the cars are very tough looking)…
Ask for details.–
The original message included these comments:
In reply to a message from Kirbert sent Tue 5 Apr 2011:
D Modified and E Modified are SCCA Auto-x classes and there is a
Yahoo discussion group for them. I guess cars in these classes are
not conventional because only some run even one sway bar. Many race
cars resist roll with stiffer springs and only small sway bars to
adjust balance.
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In reply to a message from MGuar sent Wed 6 Apr 2011:
I have around $12,000 in parts alone in the car so maybe Chump car
is not for me. I belong to a club that road races but these guys
mostly have cars worth maybe $3000 and they bang fenders a lot. I
will do lapping days but that’s about it, although my brakes and
cage are easily up to the task.–
The original message included these comments:
If you want to road race your car look at Chump Car racing or
LeMons racing.
Those groups are for $500 cars… however rollcage, safety, Wheels
tires and brakes are exempt. Plus both groups have a soft spot for
British cars. Jag V12 motors are often available for a nominal
Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !
In reply to a message from marksawatsky sent Wed 6 Apr 2011:
I was going to race an XJ-S V12 with twin turbo’s ( homemade turbo
set-ups are called ghetto charging) in their races. Ran everything
by the various officals and got their blessing… Now safety gear
and allowed stuff totalled more than $6500 with the car free and
only $235.00 spent on the twin turbo set up… Safety gear (seat,
seatbelts,fire extinguisher,fuel cell, rollcage,etc.) all fall
under the heading of safety gear.They don’t count. Wheels as long
as they aren’t more than twice as expensive as the original wheels
(I note your MG originally had wire wheels and they are close to
$500 ea so the wheels need to cost under $1000 apiece., brakes
again double the cost of the original’s, so your calipers don’t
count… tires are open, anything you can buy (except they have to
be street tires with a wear rating above 170)
Here’s the bottom line… If the car looks like it could be made
inexpensively (and your’s does) it’s OK, If I recall you got a good
buy on the coil overs, the rest of the suspension mods are allowed
as long as the material you made them with could have cost under
the $500 limit… Since your car is old, British, and definately
home made they would be very, very, easy on you… Oh, they might
assign you some penalty laps for the shocks which would pretty
well prevent you from winning but on a per lap basis that sort of
racing is the cheapest around…
However I was going to make carbon fibre Bonnet and trunk plus
fenders which I actually can do under the $ limit the way they
calculate stuff… (see my article in the archieves on how to make
cheap carbon fibre parts) My problem was the stock XJ-S V12
weighs 4200pounds… gutted out for racing but with a roll cage
etc… it’s hard to get weight down under 3000 pounds. Carbon fibre
would have allowed me to get close to 2500#s When the new rules
were published for this season requiring stock hood and trunk I
couldn’t figure out how to get the weight down low enough to make
it all work…
That plus none of the people who wanted to co-drive with me could
come up with the required money. A couple had lost their job, one
had a big health issue and well the money never came, preventing
completion of the car…
So I have a semi complete race car with no place to race it…
With the twin Turbo’s Vintage won’t have me. Without them unless I
dump money into the engine I’m stuck around 300 HP. I should be
able to modify it to around 500hp for about $5000 without the
turbo’s) Then since it’s a 1976 it’s too new for most of the
vintage clubs so I’m stuck with a handful of places it can race and
track days… Since I like wheel to wheel racing as compared to
simply lapping It wouldn’t seem worthwhile to me… Like as not I’d
be racing against Trans Am cars, Corvettes, and replica Cobra’s.
PS if they bang fenders make some out of Carbon Fibre. it will
mash their fenders but leave you relatively unscathed… Carbon
Fibre is cool stuff!–
The original message included these comments:
I have around $12,000 in parts alone in the car so maybe Chump car
is not for me. I belong to a club that road races but these guys
mostly have cars worth maybe $3000 and they bang fenders a lot. I
will do lapping days but that’s about it, although my brakes and
cage are easily up to the task.
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Sadly, the V12 stopped running when the thrust bearings fell out of it and lost oil pressure. I sold off the custom intake manifolds, bellhousing,flywheel and almost everything V12 related. The car now has a turbocharged 4 cylinder that makes nearly 400 hp and 400 ft/lbs of torque.
