tuning advice

[hawkeracing]

I'm a former Estelle and S110 coupe owner whose thinking of going back to a RWD Skoda as a toy for sprinting and hillclimbing. I have some ideas in my head and I'm looking for about 100+bhp in the lightest car.
I really want a 130RS replica, but no one ever seems to sell....second choice is an Estelle or Rapid coupe. I ideally want the 130 or 136 non swing axle suspension for the handling and the best engine available.
Was the Felicia engine a cross flow head design. From Memory the 136 rapid had an 8 port head but it doesnt appear to be cross flow from the photos Ive seen? Is there a manifold available to fit twin 40s (or throttle bodies) to the 136 type engine?
Lastly......am I mad or can this be done fairly easily?? (where could I go to look for parts/help)

[skorob2007]

Hi,
You caould try John Shelley at www.skofast.com, he's a rear engined tuning guy with masses of knowledge and although based near the factory, he does bring parts to the UK frequently.He also has a GP.B Ex John Haugland rally car 130LR.He can answer any of your questions.
Also, try CPMS in Peterborough, my mate Chris Pepper runs it, another Skoda enthusiast with over 20 years experience.He sells new and used parts for all Skodas from the 60's onwards.01733 324251.

[Dor]

Hmm, 100bhp eh, tricky but not impossible.

If i remember corerctly the works cars ran about 120bhp but has some fairly trick internals.

If you want it as a sprint car or hill climber then perhaps consider a lower ratio final drive for greater acceleration? the 120 has a lesser ratio and would i beleive fit on the 136 box.

As standard the 136 was i think 63bhp? with the standard Jikov single choke carb. Certainly a Weber 40 goes on, but yes, i think you need a custom manifold for twins rather than just an adapter plate for a single 40. I *THINK* the works cars on ran a sigle 40 anyway.

The 136 head was indeed 8 port.

A few things to consider then:

Skim the head.
Tubular manifolds (the exhaust one as standard is rubbish and rots)
Rip of the old exaust and replace with a 'OEM restriction free' lookalike or go custom like the works cars.
Balance the crank (the standard balance was pretty good anyway though)
For 100bhp you would undoubtably need a reground higher lift cam
You can't bore it out. Its out to the liners already.
You probably need an electric fuel pump to replace the mechanical one.

The std seats (very comfortable!!!!) weigh a lot.
The doors and bonnet are extremely heavy. Perhaps go with a fibreglass or equivlent repacement?

The brakes on the 136 were acually 4 pot! But repalce the pads as they could fade quite a lot.

Get a fan overide switch in the cockpit for when the thermostat breaks (if it hasn't already!!!)

Hope tihs helps.

Chris (Owner of old rally navigation spec'd 136)

[hawkeracing]

Thanks, if I'm doing it, the engine will be getting professsionally built - lightened, balanced, head, cam and a custom tubular exhaust......so from what I'm hearing 100bhp should be relatively easy.

[rigsby]

Originally Posted by Dor

As standard the 136 was i think 63bhp? with the standard Jikov single choke carb.
)

All estelles and rapids came with twin choke carbs as standard, what are called up and over manifolds are available for the webber side draught carbs, put a post on the international skoda forum for one ( tends to specialise more in rear engine skuds)

[StevenP]

Originally Posted by hawkeracing

Thanks, if I'm doing it, the engine will be getting professsionally built - lightened, balanced, head, cam and a custom tubular exhaust......so from what I'm hearing 100bhp should be relatively easy.

Agreed! Have you considered using aftermarket fuel injection like Omex/Megasquirt and running throttle bodies on a custom inlet manifold? A chap on the S.O.C. has a Favorit with this kind of setup and is producing around 115bhp the last time I read up about his project. May well prove easier to tune depending on your experience in the world of carbs! An aftermarket Ashley exhaust system should suffice!

The 135/136 8 port head isn't crossflow. You'll also want to use a Felicia Mpi head as it's better flowing with bigger valves (and a few other minor differences)

[KenONeill]

Easy peasy Japanesey.

Ported head and inlet manifold, Weber compound, slipper pistons and a 3-branch manifold (5-port head) should give you 100bhp.

If you can find a manifold, twin DCOE40s should see 120.

Or go with SteveP's suggestion of a Megasquirt or Emerald EMS, and throttle bodies on stub manifolds. Which will also let you ditch the dissie for a fully electronic ignition.

[Tenman]

find some way of dropping an SR20DET in it.... 200BHP straight away

[KenONeill]

If you're going to get silly, how about an RN26DET then? Up to 1_000bhp or so!

[Tenman]

hehe, be expensive getting 1000BHP out of an RB26... not impossibe though...

[hawkeracing]

Needs to be the original engine for class regs. I intially thought fuel injection, but I'm now favouring webbers to keep the cost down and keep the project simple. As I intend to have the engine rebuilt the Felicia MPI head sounds like a nice easy mod....will it bolt straight on or does it need modding?
Is the old banana single webber manifold still available? Thought a nice single 45 would give good results. Does anyone know where I might get a twin carb manifold?
Finally...how much does a Rapid weigh as standard?

[Dor]

Originally Posted by rigsby

All estelles and rapids came with twin choke carbs as standard, what are called up and over manifolds are available for the webber side draught carbs, put a post on the international skoda forum for one ( tends to specialise more in rear engine skuds)

Lol, yes meant dual choke. Mines still sitting in he garage. The Jikov was bit complicted though. A fairly basic Weber dual choke tended to work better as standard.

Are the up and over manifolds that readily available? (apart from fabricating your on of course)

Rgs

Chris

[KenONeill]

The main reason for using the up and over is to get the carb away from the exhaust manifold. These days it may be simpler and cheaper to use exhaust wrap?

As for how much a Rapid weighs as tandard; lots more than it does after you take out the sound deadening, underseal and bumper re-enforcements (total mass about 100kg).

Oh and I was joking about using a Nissan turbo motor; they're way too heavy and in the wrong place unless you're building a mid-engined silouette racer.

[Tenman]

aye, an RB would be a little bit heavy and way too long, I'd imagine that if you could get a gearbox to work with it though an SR20 or a CA18 would be fine to go in a Skoda, they certainly aint gonna be any heavier than a Fiat/Lancia Twin cam...

[KenONeill]

I'm dubious about the FIAT/Lancia twincs as well. The standard units are alloy block aren't they?

[Tenman]

the SR20DET is an alloy block, the CA18DET isn't... the RB's aren't either... as the CA's are basically RB's with 2 cylinders lopped off

edit:... apologies for hijacking this thread, just realized how bad I did that here..

[KenONeill]

Ok. I'm not really into Silvias, or Pulsars for that matter.

[lewist123]

weight wise and handling wise is it a big NONO to stick a heavy lump in there?

I have had my eye on a 2.6 audi engine and transaxle to turn round and plonk in the back! it will fit (I think) but it will weight a huge amount compaired to the stock engine. will that totally mess up the 'handling'?!

[KenONeill]

I think that would be even worse than the CA18 mentioned earlier. Not only is it a big old lump of engine, but I think you'd be moving the powertrain CoG backwards and upwards, shifting not only the static weight distribution, but also the rear roll centre, for the worse.

[Tenman]

how well would the standard lump stand up to forced induction? I imagine sorting engine management out would be a bit of a pain, but is the engine strong enough to cope with it as long as you lower compression slightly.