Lotus Elan

Suspension Upgrades, was wheels and tires

PostPost by: jcocking » Tue Jun 29, 1999 2:42 pm

With the talk of staying with original sized rubber unless upgrading the
suspension to take advantages of the newer tires, What suspension upgrades
are available? Are there levels of upgrade (i.e. better road use,
autocross, full track, modified so Colin would not recognize it, etc)?

jeff






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PostPost by: Lawrence King <lawrenc » Tue Jun 29, 1999 5:16 pm

Hi Jeff:

Hmm... Suspension upgrades, been there, done that. Here are a few of my thooughts, you may have different beliefs ;-)

Colin did a wonderfull job of designing the Elan suspension, he really knew what he was doing. For Auto crossing I stiffened the springs to reduce the body roll in corners (necessary with modern sticky tires), add adjustable shocks, and otherwise leave it alone.

I thought that the stiffer springs would make for a miserable street ride but I was wrong, it is a little bumpy but acceptable. After driving it in a dozen autocross events I think I need to stiffen the front anti-roll bar a little tiny bit since the back end has "come around" on me on two occasions (in about 50 runs). Other than that it is great.

For street use I wouldn't recommend anything other than new springs and shocks.

Dave Bean has 3 levels of springs (normal, stiff, full race) and a couple of types of shocks (standard, and adjustable), he also has adjustable suspension links (so you can change the castor, and camber). On the subject of adjustable suspension components, I believe Colin was right when decreed that "if is is adjustable the users will just mess it up".

Hope you find my "thoughts" interesting.

Lawrence King Ottawa Ontario Canada
http://www.promobility.net/lawrence
Is boneless chicken considered to be an invertebrate?
Lawrence King <lawrenc
 

PostPost by: "Erik V. Berg" » Fri Jul 02, 1999 8:48 pm

Also in the category of not_what_God_and_Colin_Chapman_intended,
but definitely worth considering for any specification Elan where it
would be legal, be it road, rally, race, autocross, etc, is a Spyder
frame. I would say this should be one of the first upgrades to be
considered, for any Elan which the owner does not mind modifying.
(Unless applicable rules do not allow....)

The difference in handling is remarkable, and among other things
the motor mounts work much better, and the diff strut rod mountings
are greatly improved. There is no down side that I'm aware of,
except for a small weight increase.

Andres you wrote:

1. Replace "Silentblock" bushings with nylon or similar.
-and-

4. Install Spyder tubular A-arms at the front <snip> Install nylon
bushes on these.
-and-

5. Replace rear A-arms (probably dented by a previous owner) with
more carefully built alternatives. <snip> Nylon bushes again.

I found it interesting that your implication here is Nylon (or possibly
Teflon, or Delrin?) bushings are a good setup in a road car. I've heard
others say that stiffer bushings should not be considered except possibly
for seriously competitive race cars, because of the resulting tendency of
the suspension to beat itself apart, and the remarkably good accuracy of
the suspension location with stock bushings on Elans.

I've heard, for example, people recommend that with rod-end outboard
links on the rear A arms, stock (or at least rubber) inboard bushings
should be used, to retain some shock isolation and avoid hammering the
suspension unduly.

Comments?

Regards,
Erik Berg







"Erik V. Berg"
 

PostPost by: "A. Sta. Maria" » Fri Jul 02, 1999 9:01 pm

Jeff,

You requested contributions to the following query:

"What suspension upgrades are available? Are there levels of upgrade (i.e.
better road use,
autocross, full track, modified so Colin would not recognize it, etc)?"

Perhaps one approach might be to chronicle my type 45's progression in this
area over three restorations in a period of some 20 years:

Absolutely stock components will result in the classic Elan ride and
handling, and are what God and Colin Chapman intended. However, if you must
modify:-

1. Replace "Silentblock" bushings with nylon or similar.

2. Install Koni, Spax, or other adjustable dampers. Externally
adjustable rears if you have extra cash.

3. Install stiffer springs (80 lbs/in rear and 120 lbs/in front to
start).

4. Install Spyder tubular A-arms at the front (heavy and will twist
turrets in a crash, but look good -- they match the rear tubular A-arms;
Dave Bean doesn't like these.) Install nylon bushes on these.

5. Replace rear A-arms (probably dented by a previous owner) with more
carefully built alternatives. These look the same as the originals but have
more accurate geometry with slight toe-in. Nylon bushes again.

The foregoing will result in a good road car, perhaps slightly faster that
the stock version. But if the desire to modify further cannot be
restrained:-

1. Replace rear springs with narrow 2-1/4" diameter springs to clear
wider tires and rims. This will require modification of spring perch and
top mount. While at this, you might also:

o Change the upper rubber mount (Lotocone) with a spherical bearing
mount for more precise location;
o Install adjustable spring perches.
o For the heck of it, swap the rear aluminum hub carriers for
magnesium hub carriers (this is expensive!).

2. Replace the standard cast hubs with special hubs to take aluminum KO
spinners and 26R wheels. This has the added benefit of aluminum bronze
front hubs which are light in weight and look good to boot. As noted
before, the rear hubs can be obtained in "narrow offset" specification, so
as to clear stock fenders. The aluminum spinners actually float in water.

3. Install 5-1/2" or 6" 26R wheels -- magnesium if you are truly in the
fringe group and don't mind scrimping on other things like food and
schooling. Aluminum if common sense prevails. Use lightweight aluminum
valve stems (available at Ferrari dealers).

4. Install a slightly thicker front bar.

I would stop here, but if you are racing or have some other excuse, then:-

1. Replace the upper front A-arms with 26R replicas with adjustable rod
ends. Replace the lower A-arms with matching 26R replicas, nylon bushed.
These will lower the ride height and give better geometry. Your suspension
will also look like it is on steroids.

2. Replace the rear A-arms with 26R replica arms. These have adjustable
rod ends at the inboard ends and sphericals at the outer ends. A more
modern version has the rod-ends outboard; these are more "high-tech" in
appearance and easier to adjust (but are not "original"),

3. Install fatter, more modern externally adjustable front dampers with
250 lb/in 2-1/4" springs.

4. Install 150 lb/in 2-1/4" springs at the rear.

Now you have a race car that you probably cannot use on the road!

Regards,

Andres
Manila
Philippines








"A. Sta. Maria"
 

PostPost by: David Shiers <david at » Sat Jul 03, 1999 8:27 pm

I have just purchased some new shock absorbers and springs from Tony
Thompson, England. Although he advocates using stiffet springs and

adjustableshock, he maintains that the original rubber type bushes
should be used. This is on a hillclimb and sprint car. I do drive it on
the roads but only to events.
Will let you know how the new set up works.

--
David Shiers
David Shiers <david at
 

PostPost by: "A. Sta. Maria" » Mon Jul 05, 1999 1:57 pm

Hello David,

I sought advice from Tony last year when I was setting up my Elan and
mentioned I might use the car for the occasional hillclimb. Apparently, the
requirements for hillclimbs are different from the settings for a circuit
car. I recall he advised 120 lbs/80lbs front/rear springs for hillclimbs,
because of the standing start and short period of race time involved, but my
memory is hazy on this. We ended up with a 250/150 lb combination with 26R
arms (with rod ends).

An English mechanic in the U.S. whom I met (and who sells modified arms for
the Elan) advised against hard bushings for the lower front arms when rod
ends are used in the upper arms, because of fear of suspension binding in
the event of some misalignment of the arms (the more compliant rubber
bushings are more forgiving). Tony didn't make the same comment, but only
advised that we check that the suspension (installed without springs and
dampers) swings through its arc without binding. In fact, all the arms he
supplied me have either rod ends or nylon bushes. We call our races either
"sprints" -- for races of about 10 laps -- or "enduros". Your sprints are
probably different.

Incidentally, when I was using the 120/80 lb combination with nylon bushings
all around (and spherical bearing rear top mounts), all from TTR, the ride
did not deteriorate dramatically and I thought was actually acceptable. But
I admit not to having used it on the road much. In my opinion, this set-up
should be the absolute limit for a road car and that, as you advised us,
rubber bushings are preferable in most instances.

I had hoped to use springs just a bit more stiff, but apparently there is a
no man's land between 120/80 and 250/150, if one does not want to have to
compress springs before fitting. My springs now just slip in without
pre-compression.

Tony is an excellent guy and very helpful, with obviously more experience
with Elans than most everyone. He has been unstinting in his support for my
small, amateur effort. Not a mean feat considering the distance involved.
He truly loves Elans.

Regards,

Andres
Manila
Type 45 DHC
"A. Sta. Maria"
 

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