This section will detail some general advances in the
design and functionality of the car to enable other forms of motorsport
to be enjoyed beyond only drag racing.
(Click on pictures to see larger version)
Enabling manual gear selection on the automatic transmissions
The existing automatic setup was great for drag racing and normal
driving on the street but did not allow manual downshifting which
limited the use on any form of driving where manual gear selection would
be paramount for both engine braking and corner exit gear selection.
To resolve this issue I purchased a TCI Streetfighter
ratchet shift. This would allow manual shifting of the transmission
from D into 3,2,1 and of course 1,2,3,D in a simple forward\backwards
motion similar to a sequential manual gearbox. Although this will
not have the same responsiveness as an actual manual gearbox it should
suffice to enable the car to do motorsport events where manual gear
changes are required.
The TCI shifter before installation, it's quite a nice
piece of engineering design.
Once installed in the car it looks much nicer than the old Daewoo
shifter that was there previously.
Installation however didn't go quite as smoothly as hoped since asking
if this was specifically compatible with my 4T40E tranmissions and being
told yes, I (stupidly) assumed that the correct connection parts would be
included. Despite the kit containing the appropriate adapters for
loads of transmissions there was nothing for my model or indeed any FWD
I had to fabricate a plate to hold the linkage cable in place and also
modify the supplied shift plate to fit correctly onto the transmission.
Somehow (mostly luck) I managed to get one of the other plates modified
on the first attempt after some gental (ie abusive) filing followed by
welding and filing again to fit.
Before, nowhere near the correct alignment:
This was a fun job trying to get a plate made up to hold the shifter
cable and be able to drill
the existing bracket in place without taking this bracket off.
Result at the end though, successfully selects all gears. Just
need to work on the rear one next which will take a bit more design
Balancing the water cooling systems
Cooling the rear engine has always been problematic, with various
enhancements around the airflow into the rear compartment and the fan
ducting it isn't too bad but will eventually overheat (or as a minimum
have the fan on constantly trying to cool the rear radiator) if driven
5+ miles with both engines in use and quicker if on a track.
Initially I had though to share the water between the two engines but
had concerns that this may cause flow path issues and then had an idea from a
combi boiler to use a water heat exchanger. This would share the water cooling
from the front engine with the rear without the actual water being
shared and hopefully enable more stable temperature control on the road
at least to start with. I dont't think this will allow full track sessions
the front cooling system will be unable to cope with that amount of
extra heat dissipation currently (i'm going to try and get some more
radiators in there somehow) but it should be at least sufficient for
shorter sprints and hill climbs for now without worry.
This is the new heat exchanger, it's a 210kw unit so should transfer the
heat fairly well to assist the rear cooling.
I have also added an extra radiator (actually quite a large heater
matrix from a ford of some derivative) into the front corner of the
passenger wing area. Still needs to be boxed in to force the air through
from the front at this point and there should be another one fitted in
the driver side. Hopefully with the addition of these extra rads
the cooling will be much improved since the two of these smaller rads
are about 75% of the existing front primary radiator but double the
thickness and double the density of cooling fins. Added a 6" fan
also to the new little rad which is controlled along with the primary
Heat exchanger installed and piping currently through
the car with insulation installed to stop it heating the inside of the
car too much like it used to do many years ago. Heat exchanger
seems really efficient so will look forward to testing it out on the
road for a long distance twin engine trip which used to be impossible
for more than about 5 miles due to the excess heat build up at the rear.
Still likely not up to full track sessions just yet as think it will
require another rad added to the front setup to cope and also some oil
Think i'm getting into fan overload up front, might need
an extra circuit to power this lot soon when the next rad is added lol
The original rear engine water hose that connected to
the back of the water pump was replaced since the 2 outlets were too
small to ensure good coolant flow from the heat exchanger. This
new copper one uses 15mm connections so much better than the old one which
was 8mm bore.
After a few sessions at Curborough and also the hill
climb at Shelsley Walsh I found it quite hard to get a good responce to
steering in the corners due to quite bad torque steer and also being
generally very heavy. Once the manual quick shift is installed I would
need to be able to hang on to it with one hand and that would be quite
unsafe as currently a small change in camber under heavy acceleration can yank the
steering even with 2 hands quite harshly. The power steering from
a Corsa B should resolve this issue and make the car much easier to hang
Rather than try and make the Corsa setup fit from
scratch (which would have been cheaper, DIY would come in at around
£100, a complete kit was £300) it was easier to purchase a ready made kit to save much time and
possible errors adding yet more delays. This retrofit will also provide an
opportunity to strengthen the mount point for the steering as it just
didn't feel solid enough for me when used with a lowering bracket.
Finally all installed, it's adjustable via a control
knob on the steering column. Still to test on the road but in the
garage you can turn the wheel with one finger when on max and it barely
feels like there is any assistance on minimum so should be good once
i've got used to the correct assistance setting for each type of
driving. Had to modify the mount point instructions on the kit due
to the fact I had slightly moved the steering rack so the side
strengthening bracket wouldn't how originally intended but it's more
solid than before.
Eventually I may replace the manual assistance control
by using the speed outputs from the transmission which would enable the
assistance to vary automatically based on speed but manual will suffice
for now. Was really good on first trial, although you do lose a
little of the feedback through the steering to detect traction loss it
is so much easier to control the torque steer under heavy acceleration
with slight camber changes in the surface and also snatch when exiting
Bigger Front Brakes
For drag racing and the shorter sprints the metro turbo
8.4" 4 pot brakes have been ok but for longer sprints\hillclimbs these
really start to struggle due to the increased weight of the car with 2
engines and heavy automatic transmissions.
I had been looking around for upgrades to the 8.4" discs
and was thinking about creating something myself from adapting various
parts from other cars to increase the disc size. This would have
been the cost effective option but to save time have decided to go for
an off the shelf conversion from ZCars as this would give me 270mm discs
and lightweight calipers. Also since braking is very important
from a crashing perspective though it a better idea to have
professionally machined components rather than something I cobbled
Brake kit to be fitted
Disc comparison Metro Turbo and ZCars, just a bit bigger
The Metro turbo disc actually wasn't 8.4" but more like
8 4/16ths" so in reality more like 8.25". The ZCars discs are
10.2" so should provide much more efficient braking.
Weight wise there is a small saving there too on
unsprung weight, the Metro setup was 7.7Kg with the ZCars being 7.2Kg.
Unfortunately the bigger discs will actually increase rotational mass
when accellerating in the lower gears but shouldn't be too bad.
Fitted into place to check the clearances (which all
I have also now removed the twin brake cylinder
arrangement that was used originally and returned to a single master
cylinder and pressure bias valve for the rear. I would have used
this option in the first place but with the throttle bodies there
wouldn't have been clearance for the master cylinder however with the Evo
inlet there's plenty of clearance. This has also enabled the servo
assist to also be used at the back to which should improve braking
Following some road testing the new brakes are in
another league compared to the original 8.4" ones, not just in coping
with longer amounts of braking effort without heat issues but in the
general feel, responsiveness and progressiveness. I think that the
servo needs to be changed back to a lower ratio as with a 3:1 servo the
brakes are now just too sensitive. Will likely fit a spare 1.5:1
servo that I already have spare from a previous setup. Really
looking forward to testing these at the track.