STAGED HANDLING IMPROVEMENTS FOR THE 240 TURBO Version 1.0
by Paul Schuh
Our assumption here is that handling improvements include anything that will
improve:
- the maximum cornering forces your car can generate
- the speed with which your car will negotiate a standard slalom.
These two goals really cover all of the bases because they represent your car’s
handling performance in both steady state and transitional situations. Almost
all real world handling can be broken down into these two basic components.
As you should know your car’s factory handling represents a compromise
primarily between handling performance, ride quality, and cost. Most of us who
desire improved handling are willing to sacrifice ride quality to some degree,
as well as spend a little bit of money. Cars that handle extremely well and
also offer a comfortable ride have the benefit of extremely sophisticated multi-link
suspensions. When you start with the unsophisticated 240 suspension design and
shoot for performance, your ride quality will not survive. To put it another
way, the more money you spend, the more your car will begin to ride like a go-kart.
(But go-karts handle great!)
First consider all of the components that have an effect on your car’s
handling: wheels, tires, tire pressure, steering mechanism, suspension hard
parts (control arms, etc.), suspension soft parts (bushings), shocks, springs,
sway bars, alignment specs, body rigidity, weight, weight distribution, aerodynamics,
and, most importantly, driver. None of these should be overlooked in your quest
for ultimate handling.
(Note: Although this discussion is written specifically for the 240T owner,
much of it is applicable to other Volvos as well.)
STAGE 0:
Stage 0 for handling modifications is different from engine modifications.
Stage 0 of engine modifications begins by bringing your car back to factory
specs. But when we begin to improve handling, it is primarily by wholesale replacement
of parts rather than modifying existing parts. Since parts to be upgraded will
generally be replaced, there is no need to bring your suspension back up to
factory specs. Therefore we’ll start with the least expensive modifications;
those which are free.
DRIVER:
Unlike engine performance, where the driver has only a small impact, handling
is greatly impacted by the actions of the driver. In fact, this is the area
where most people will see the most practical benefit. It is no coincidence
that a world champion rally driver driving a stock 240 could beat most of us
around any given course in our high performance TBrick. Looking at it from another
perspective, driver skill could be worth 100hp, maybe more.
Start by reading. There are a number excellent texts which should be available
through your library (remember we said “free.”) and are definitely
available through most of the automotive book mail-order catalogs. Piero Taruffi
wrote an excellent one in the 50’s and many others have been written since
then. Learn the basics. Then practice them until they become second nature.
I know I said free, but for those of you who have the money, go to a professionally
instructed high performance driving school. Been there, done that, got the polo
shirt, definitely worth the money, if you have it. It’s nothing you can’t
learn from reading but it jump starts you on the process, and being at a race
track, gives you lots of room to make mistakes that you don’t get on the
public roads.
Also not free, but fairly low cost: join a sports car club and go racing. For
those in the States, join SCCA and start in the SOLO 2 program (autocross).
It’s cheap and there are lots of experts who are more than willing to help
you out with free advice. You will wear out clutches, tires and brakes faster,
but the rest of your car is very unlikely to be damaged, so you don’t have
to worry about ruining your daily driver.
The bottom line is this: Your mind and your reflexes are the keys to real-world
handling improvements. Unless you are a trained racing driver, your car is already
capable handling that would surprise you.
TIRE PRESSURE:
The key word here is to experiment. As a rule of thumb, higher pressures create
stiffer sidewalls and therefore more precise handling. All high quality tires
will can be used at pressures slightly higher than those listed on the sidewall,
at least for short periods of time. Increased pressures also offer less rolling
resistance. However, if pressure is too high you will reduce the contact patch
and decrease the grip of your tire.
STAGE 1:
OK, so you’ve memorized Taruffi’s book, you can find and hit the
apex of an off-camber decreasing radius turn every time, and you’re running
your Yokohama’s at 40psi, what next? Stage 1 starts with the lower cost
upgrades to your car.
SUSPENSION BUSHINGS:
Many, (but not all (yet)) of the rubber bushings in your front and rear suspensions
can be replaced with polyurethane units. These are available from IPD as well
as other sources and most can be installed by the typical owner in an afternoon.
Some of the rear pieces (trailing arm bushings, etc.) will require the help
of a shop with a press, but this is not expensive. Poly beats rubber in every
respect unless you’re after a luxury car ride (in which case you wouldn’t
have read this far).
ALIGNMENT:
A performance alignment will help your handling as well. The 240 has a limited
number of adjustments, of which toe and camber are of most interest to you.
You must first realize that any alignment settings you request that are not
factory spec will probably not be done by a dealer and may not be done by a
neighborhood tire shop. Finding a knowledgeable performance tire and alignment
shop is well worth the hunt. Discuss your handling desires with the senior technician
and ask for recommendations. If they seem unwilling or unfamiliar, keep looking.
One alignment setting with great potential to help correct your nose-heavy,
understeering 240 is a bit of negative camber. As in all things, a little is
good, too much is very bad. 1-2 degrees should provide a noticeable improvement.
Negative camber will change the wear pattern of your front tires but we’ve
already agreed that tires are consumables. A little negative camber in the rear
might be nice too, but it is not easily adjustable on your car (it would require
custom suspension pieces (see below)). A tiny bit of toe-out is also usually
recommended for sharper handling. Talk to your technician.
Note that the exact relationship between the top of your strut tower and the
sides of the hole in the top of your fenderwell is a little different on every
240. It is very likely that you may not be able to push the top of the strut
inward far enough to get negative camber before it hits the lip at the inner
edge of the hole. Those who are serious about their handling will use a die
grinder/rotary tool to enlarge this hole as necessary to accomplish the camber
change.
BODY RIGIDITY:
The less flex in your body structure the better your car will respond to steering
inputs. Being a sturdy design, the 240 is a fair handler right out of the box,
but there is much room for improvement. Front strut tower braces are the most
common improvement and come in several different types. These braces allow less
flex in the front subframe (which includes the front suspension) by tying it
more directly to the body and to itself.
Upper and lower “triangulation” bars are available at low cost from
your Volvo dealer. These provide more connection from the sub-frame to the body
(to the firewall above and to the underbody below). The top bars are a direct
bolt-on (15 mins) and the lowers are just a little more complicated, requiring
some drilling. Have the dealer look on the microfiche for the ‘79 242GT
to locate these parts.
Crossover strut tower braces tie the strut towers together at the top and do
not allow them to flex relative to each other. Unfortunately, it is very difficult
to find a crossover brace that will clear the stock B21FT intake set-up. If
you have converted to a B23 intake, you have several choices. If your intake
is stock, keep looking. They are rumored to be available or under development
from various sources.
Other stiffening of the body may be possible but would require custom work.
Besides being expensive, it could easily add weight that would be detrimental
to both performance and handling. Proceed carefully. A 240 with a fully braced
front-end is plenty stiff.
WEIGHT and WEIGHT DISTRIBUTION:
These topics are inseparable. If you make any change in the weight of your car,
you will also change the weight distribution. In general, of course, weight
is bad for performance and handling, but performance generally is only affected
by absolute weight, whereas handling is affected by weight distribution as well.
The general principles are these:
- Remove weight from your car anywhere you can: Look in your trunk, under
your seats, in the glovebox and anywhere else. How much of the junk you carry
around really needs to be along for the ride? Look under your car. Any mud
packed under your frame from a recent off-road excursion? What about under-coating.
Some of you need it where you live and some of you don’t. Now start to
think more radically. Do I really need all of these accessories, like carpeting
in my trunk and mudflaps? Now think more radically, do I really need air conditioning,
power steering and that 30 pound muffler??? (Here’s a hint, if you drive
a Turbo with a catalytic converter, you really don’t need that muffler.)
How about replacing your spare tire with a can of “flat tire inflator”?
Stop when you get to something you can’t live without.
- Especially try to reduce unsprung weight, that is weight outboard of the
spring. Unsprung weight is the most detrimental to handling. Primarily what
240 owners can do here is use lighter wheels and drilled brake rotors (and
remove disk backing plates). Expensive. (But if you’re going to replace
your wheels anyway, go as light as possible without sacrificing strength.)
The only other options are custom made, exotic metal axles and control arms.
Very expensive.
- Use your “unremoveable weight” to your benefit. Move it closer
to the ground to lower your center of gravity. Distribute weight evenly about
the car’s center of gravity, front to rear and side to side. Not many
things can be relocated, so this is hard. The battery is where most people
start. Move it to the rear, as low as possible. The only drawback to this
is the extra weight of those long battery cables you’ll have to install.
Most things are tradeoffs. You might be able to find a lighter battery as
partial compensation. The biggest weight shift comes, of course, from lowering
your car closer to the ground. This is accomplished with a set of “lowering
coils” available from IPD and other sources. These are easily installed
in an afternoon by the owner if you have, or can borrow, a spring compressor.
Besides lowering your center of gravity, they have a higher spring rate (i.e.
they’re stiffer) so they will sharpen your turn-in as well.
SWAY BARS:
These are a proven performer on 240’s and are a must for all serious drivers.
IPD sells good ones for the 240 Series but others may be available. If you haven’t
already switched to the poly sway bar bushings, do it now. These are another
easy installation that the typical owner could do in an afternoon. All gain,
no pain.
STAGE 2:
SPRINGS:
Better springs are a great idea and were covered under Weight in para 4 of Stage
1.
SHOCKS:
240 Turbos come with Boge Gas shocks that give adequate performance and can
be used with lowering coils. However, for ultimate performance, the specially
valved Sport Bilsteins are hard to beat. Once available from IPD, they may now
only be avail direct from Bilstein or from overseas sources (SAM?). The normal
Bilsteins are probably no better than any other high performance gas shock.
TIRES:
Like most everything else on your car, tires are a design compromise, in this
case between ultimate grip (dry traction), wear and wet traction. If there were
no rain and we could afford new tires every month, we’d all be driving
on racing slicks which offer no compromise dry performance. If you drive in
the rain you need some type of channeling to carry off water and prevent aquaplaning.
If you have a budget, you need some hardness to the rubber compound to increase
tread life. That being said, buy the softest tire with the least tread depth
you can get away with for maximum dry performance. If you are willing to live
with some compromises, Goodrich, Yokohama, Hoosier and other manufacturers make
special road racing and autocross compound tires that are street legal. Sidewall
height (as a percentage of tire width) gives tire series, which is typically
expressed as 60, 55, 50, 45, 40 etc. The smaller the number the shorter the
sidewall, the crisper the handling. Your 240 Turbo comes with 60 series standard
and will easily accept 55 or 50 series with some loss of speedometer accuracy
and no rubbing problems if you don’t go too wide. There are too many excellent
brands and models available for us to recommend a specific tire. Read the magazine
reviews and shop by price and specification.
WHEELS:
Your standard 15 inch Turbo wheels are a good start and do not necessarily need
to be replaced. Going to a larger size (16, 17, 18, ... inch) will improve handling
by allowing an even smaller sidewall without losing overall diameter. Larger
size wheels also tend to have wider and longer wider contact patches (but also
increased frontal area and increased weight) for increased adhesion. So bigger
is generally better, but sizes over 17 inches are VERY expensive and hard to
fit on a 240 without some rubbing. Once you pick a size, go with the lightest,
strongest wheel you can afford.
AERODYNAMICS:
Most of the world considers aerodynamics and the Volvo 240 an oxymoron, but
what do they know. Although aerodynamics will have more effect on your car’s
top speed, aero is important for high speed handling as well. The primary factors
here are coefficient of drag and generation of lift; you want to reduce both.
- Drag, as they say, is a drag. It is not as important to handling as cancellation
of lift, but it should not be ignored. Contributors to drag include frontal
area and non-laminar air flow (turbulence). There is not much you can do reduce
the 240’s substantial frontal area, but suffice to say every square inch
helps (or hurts). If you need to maximize speed, fold in your outside mirrors.
Some changes you might make to improve other areas of handling will actually
increase your drag. Wider tires and deeper chin spoilers both improve handling
but increase frontal area and therefore reduce your top speed. Turbulence
can be tamed somewhat by smoothing your car, including your underbody. If
you don’t have a deep chin spoiler, the Volvo belly pan helps. Other
lightweight underbody panels could be fabricated (carbon fiber or fiberglass
sheets) to smooth the underbody, especially from rear axle to rear bumper.
On top of the car, first make sure it’s clean. Dirt = drag. Spoilers
and vortex generators, if properly designed, will reduce the vacuum behind
your car and cut drag as well. Beware: all spoilers and aero kits are not
created equal. Research what you buy. Was it wind tunnel tested?
- Cancellation of lift on a car is accomplished by generation of downforce
(negative lift). Downforce will improve high speed handling by increasing
the pressure between the contact patch of your tire and the road. Unfortunately,
there is no free lunch. Lift of any kind, including negative lift, is a form
of drag. The warning from the last paragraph applies here as well. Be careful
about selecting an aero kit, most of which are for looks only. Most increase
drag, so unless you’re sure they also reduce lift, you may end up lowering
your top speed with compensating benefit.
STAGE 3 :
SUSPENSION HARD PARTS:
These include everything else we haven’t covered yet, including control
arms, links, trailing arms, panhard rods, rear axle, etc. Modification or replacement
of these parts is difficult and rarely done. Some very expensive lightweight
pieces based on Group A Turbo parts are available from aftermarket in Sweden.
However they would yield significant performance improvements because almost
all of this is unsprung weight. An additional benefit of custom pieces include
the ability to design in increased adjustability. A cost no object suspension
upgrade would include replacement of the solid rear axle with and independent
design similar to today’s modern sports cars, with unequal length control
arms, struts and multiple links.
STEERING MECHANISM:
Your 240 came from the factory with an excellent power rack and pinion mechanism
that is responsive in both high and low speed maneuvers. There is little that
can be done to improve it. It is possible to convert the equipment you already
have to a manual system or to replace the entire rack with one from an earlier
240 Series without power steering. The benefit of this is the weight loss in
the front end (see Stage 1, para 4) and more free space under the hood. This
will of course increase the steering effort at low speeds, although you may
gain some quickness at higher speeds if you find a rack with a faster ratio.
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