Skoda Estelle Tuning
Disclaimer:
This webpage is only meant to be advisory, what's published here is what we have learnt over the years from rallying the beasts.
It should go without saying that the rest of the vehicle should be fit for its purpose, make sure that it handles and brakes well before you start tuning the engine. There is no point in tuning engines for more power if they aren't working properly beforehand. Be especially careful if you are looking at tuning high mileage engines, a rebuild will almost certainly be necessary, check cylinder compression, oil pressure and any untoward rattles. Be aware that power tuning engines may result in a reduction of reliability......
Refering to a Haynes or similar type manual should also answer any questions that would be regarded as FAQ....
Any information on this page is provided in good faith, but neither I (Ian Jones) nor "Team Bouncing Czech" will be responsible for any problems you may have whilst attempting to following these notes.
Updated sections shown in Green.
Last Update 30/01/02: After reading the correspondance on the "Skoda Rescue" forum - additional notes about downdraft carbs......
Front Suspension
Front Suspension: The front suspension is a double wishbone setup, the coil springs can be uprated and lowered. Dampers can be replaced with Spax or Koni, if you are going Stage or Road rallying then it makes good sense to reinforce the wishbones by plating the face where the damper bracket mounts to as well as plating the underside of the upside down "U" sections that form the arms, creating a "0" section instead.
Making reinforced bottom damper mounts will ensure that you won't suffer any more breakages of a noted rallying weak spot. Note that there are two different track widths depending on whether it is an Estelle 1 or 2, the difference in track is caused by wishbones of differing length, the two are not compatible.
Unless you want 15 degrees of negative camber.
Rear Suspension
Comes in two flavours, Swing Axle or Semi-Trailing Arm.
Swing axles were fitted to the 105 and 120 models in the UK and much has been written about the questionable handling that swing axles can give. Once you've fitted stiffer dampers and uprated springs to the rear then the car will handle a lot better. Just make sure that you don't lift off too suddenly mid corner if you are driving like a loon....
When the Skoda 130L was introduced, it came with semi trailing arms and driveshafts derived from the 120 Rapid (Now there was a contradiction in terms) and much more pleasant handling.
The rear springs were softer in rate than the swing axled cars, but were a fair bit longer. Don't try to use a 120 Spring on a 130 back end in an effort to lower the car as the wheel will collapse into the arch and look silly. The 120 spring rate is rather too high as well. The standard 130 spring is rated at 120lb/inch, going higher than 150lb will result in rather nervous handling more akin to its swing axled sibling. We once tried a set of 180lb springs at a very greasy, icy Cadwell Park. The driver aged about 10 years that day......
The trailing arms can be reinforced by welding strips of 6mm steel strip into the channels of the "I" section if you are stage or road rallying.
As with the front suspension, the semi trailing arms come in two different track widths depending on whether it was 120 Rapid or 130L, 130 & 136 Rapid derived.
If the talk of swing axles has scared you, then the semi trailing setup can be bolted on to the swing axled car providing that you change the following items.
Brakes
If they aren't broken, why fix them. They are good as standard. 2 and 4 pot calipers available, 4 pots on 130's and Rapids. Uprate pad material on front, if you can find any. Ermintrude currently runs Skoda 4 pot calipers with "Carbon Metallic" pads from an MG Metro caliper. They are great once warmed up but the temperatures required mean tarmac stage use only, no good for either forest stage or road use. For these purposes, Mintex list a pad for the Metro in M1144 compound, part number MLB65.
Use good quality standard shoes on rear, not your £5 compressed camel dung specials. I also have 19mm bore rear cylinders fitted.
A certain amount of play can be adjusted out of the braking system by fiddling with the little spigot beneath the master cylinder. Don't go mad though, as too much adjustment results in your car grinding to a halt with the brakes locked on..........
Engine
What's available?
105 - 1047cc of crazy power. 5 port (2 inlet/3 exhaust - like
BL "A" series)
120 - 1174cc low and high compression available (Head as above)
130 - 1289cc 5 port, high compression (9.5:1)
135 - 1289cc 8 port single point injection catalysed engine
fitted to the 135Ric Rapid only.
136 - 1289cc 8 port carburetted engine fitted to the 136 Rapid.
If you can get one, go for the 136 Rapid engine. The 136 Favorit fits, according to "Skoda Dave" but you will need to replace the spigot bearing in the end of the crank. Apparently, the holes for bolting the Estelle mounts to are already drilled and tapped. I'm still not sure about the manifolds though.
As for bigger bores, I'm told that 1340cc and 1400cc kits are available in the Czech Republic. I do know that the new Fabia has a 1400cc pushrod engine in its "base" model - Would that be a 140 motor then? Same bore as 1289 but a stroked crank, the man at the dealers said sonmething about a reinforcing cradle in the block as well.
Carb: Junk the Jikov - Fit Weber 26/28 DCD or
32/36 DGAV. In the case of the DGAV, I ran
mine without the autochoke, the choke flap and all associated
gubbins was removed. A couple of pumps on the gas pedal before
starting sufficed. It even worked when the carb was put on a
standard road car following failure of its Jikov. The
aftermarket replacement carb that Weber supply for the Estelle is
good only for standard engines, this carb seems sensitive to revs.
As in bits on carb shake loose
sensitive. All the above carbs have the same stud pattern
as the Jikov, you just have to open up the inlet manifold to
match.
An inlet manifold was available for a single Weber DCOE /
Dellorto DHLA from SK distributors for both the 130 and 136
motors. It might not fit under the engine cover of a Banham
Spyder kit car though.
The 136 Rapid inlet manifold takes the same carbs as the 130.
I've noticed a twin 40 set-up on a 136 engined Estelle in the
Skoda Owner's Club pages. Manifolds appear to be cast aluminium
and are also available in the Czech Republic, according to "Jay"
I've had a couple of queries about jetting carbs. I'll have to admit that I haven't kept notes of what size jets I used, so I can't really help there - All I can say is that no two engines are ever the same and that so long as when you fit the carb, you get a decent idle mixture, take the car down to a decent rolling road. Let an expert solve the problem of jet sizes. It's money well spent.....
Filtration is vital. These are rear engined cars and where do you think that all that crap and dust goes from the back wheels on dry days? Straight into the engine bay.
Case History: In the first TBC rally Estelle.
We ran a Weber DCD carb with a K/N pancake filter on top.
The first few events weren't a problem as they were generally all
tarmac affairs. It wasn't until we did a dry forest event that we
noticed a drop in power as the day progressed, culminating in the
engine cutting out and refusing to restart. The K/N had become so
clogged that it just wouldn't allow any more air through. In K
& N's defence, it has to be said that the only filter that
would fit between the top of this carb and the bodywork was only
2" (50mm) high, so it probably didn't have enough filtration
area to start with.
We wouldn't recommend foam filters, certainly not un-oiled.
On Ermintrude, I use a K&N filter on the DCOE carb. If it's dusty then I have an oiled foam cover supplied by K&N to fit over some monstrous V8 airbox. This is then wrapped around the filter to provide additional protection.
Exhaust: Ashley do a one box Group "A" system that fits onto the standard exhaust manifold, but it gets noisy pretty quickly. Might not be a problem on the road, but it's a bit of a ball ache when you take the rally car to the noise test before an event. BTB Exhausts can also supply a one box system.
Cam: Piper 285 good choice. Nice and tractable. They'll need your cam to grind. Also tried....
Compression Ratio: Take care if trying to raise compression by skimming 130 heads. The pistons are domed and if you take too much off the head then the pistons will contact the bottom of the combustion chamber.
Cast iron cylinder heads crack (105,120,130): If you suffer what appears to be a blown head gasket & fit a new one, only for it to fail again, it's probably the head at fault. You will normally find the crack emanating from the exhaust valve seat area.
Keeping It Cool
On my stage car "Ermintrude," I modified the thermostat by removing the centre from it, thus creating a simple blanking plate. The 'stat can't seize shut now.... Make sure that the hose between the 'stat housing and the expansion tank isn't blocked. Also make sure that the spigot on the expansion tank that takes the hose from the 'stat isn't blocked either. As long as you have these parts clear, you can't get an airlock in the cooling system. Always use a decent antifreeze........
As a result of all this, Ermitrude runs at 60 degrees on road sections and goes up to 70 on stages. Mind you, the heater output isn't brilliant!
A wise old man (Well, he did run a Skoda service centre) once advised me that 105, 120 and 130 Estelles always need gasket sealant on their head gaskets. And that the published torque figure for the head bolts was too low. So sealant and 50 lb ft it was then.
A word of wisdom, if you go and look at a car for sale that just has water in the cooling system and no sign of anti freeze - Just walk away. This evidence would normally indicate that the engine has a leak in the cooling system or worse, headgasket trouble and the owner can't be bothered to fix it, so what other corners has he or she cut in maintenance?
Transmission
Not much choice I'm afraid. You're stuck with a choice of 4 or 5 speed gearboxes. 1st, 2nd and 3rd are the same on all boxes, 4th on a 5 speed is lower than 4th on a 4 speed. The best choice would be a 5 speed box which has the lower 4.2:1 final drive fitted. Don't forget that you may need to recalibrate the speedo if you've changed the final drive.
If you're really lucky, you'll have a 5 speed Straight Cut box. You'll be lucky because they are as rare as hen's teeth. At least I'm lucky at something then. These transform the car. From quiet and refined to unbelievably frantic. Mine is good for 95 mph @ 6000rpm. Good for acceleration but absolutely no fun on the motorway. Suitable for rally cars and masochists only.....
Clutches, The later large diameter clutch would be the one to go for. Any reputable make should do. Don't expect blistering take off's though. If you manage one, expect acrid burning clutch type smells.
Slack in the gear linkage can be taken out by using the later "Dog Bone " type linkage, packing out the joints with washers.
Just out of interest, I have a theory about crownwheels. I have a feeling that they're only good for about 80hp at the wheels, before they start shedding teeth. At least if the experiences of two of my teammates are anything to go by. Has anyone out there noticed the same? Let me know, email address below......
As I said at the beginning, all the above is advisory. I have no control over how you build your car, or for that matter, how you treat it. Ermintrude isn't caned mercilessly all the time so I seem to have had reasonable reliability.
Just enjoy what you do......
Ian Jones