[Australia] Vauxhall Astra 4S Replica

[ant]

I am building a replica from the ill fated Group S WRC Category that was left high and dry with the banning of Group B in 1985.

A short History lesson:

Opel and Vauxhall built 4 proto type rally cars, 3 Opel Kadett Rallye 4x4.. 2 went on to do the 1986 Pari to Dakar and 1 Vauxhall Astra 4S that was entered and finished 4th in the Audi Sport rally on 11th Oct 1986 in the hands of Andrew Wood/Mike Nicholson. After this one of the Opel Dakar cars went to John Welsh to compete very successfully in the English Rallycross Championships.

I have found references to 4 configuration engine in the car:

2.4L Manta N/A Engine: 250HP
2.4L Manta Supercharged Engine: 325HP
2.4L Manta Turbocharged Engine:400HP
1860cc Zakspeed Cosworth Turbo Engine: 500HP

This was mated to a 4WD gearbox called Xtrac System. Mike Endean Formed Xtrack and designed a 4WD gearbox that could be changed by hand while competing from 28:72 (front:rear) drive stepless to 50:50 by a hydraulic system.

This was all packed into the humble Opel Kadett GSi and is reported one version was as light as 850kgs. The car retained the floor and roof and pillars of the cokpit and the rest was space frame and sheeted in fiber glass and kevlar.

Here is a walk around John Welch's Autocross car to show some of the features of the 4S.

Johm Welch 4S Overview

The Replica I am going to build will be the "Andrew's Heat for Hire" Sponsored Vauxhall Astra 4S as it was presented for the Audi Sport Rally in 1986.



This will be the 325BHP 2.4L Manta Supercharged engined version. This was, as all Manta/Ascona performance engines a Diesel 2.3l block re-bored to 2.4 and fitted a Cosworth twin cam 16v head. The Supercharger was a Sprintex and was fuel injected.



This was, as all Manta/Ascona performance engines a Diesel 2.3l block re-bored to 2.4 and fitted a Cosworth twin cam 16v head and fuel injected. This was then supercharged with a Sprintex Supercharger.



For more info about the history of the car you can look at my unfinished wesite with plenty of info and pics. Plus some of my others cars and some more on the Opel Kadett GSi rally car as well.

http://www.ynet.com.au

[ant]

Re: Vauxhall Astra 4S Replica

Mick G started his thread HERE and has acquired many of the original panels and molds. So the biggest thanks goes to Mick for unearthing these parts and making it possible to build a replica of the car.

Before I built my Opel Kadett GSi rally replica post HERE I was collecting information on the 4S but ended up giving up on the idea after I realized the difficulty of the external fiber glass/kevlar shell and the 4WD system. So seeing Mick's post got me excited beyond words.

So looking at the speck of the car there are 2 main things to consider.

1st a 2.4l 4 cylinder twincam 16v engine. This is not as easy as it sounds. The best I could come up with is in Germany guys are making Manta replica engines from using a old 2.4l block from the Frontera 4x4 which is a cast iron block but not that easy to get a hold of. But even harder is a C30SE twincam engine that is a 6 cylinder and cutting 2 cylinders off and making a 16v head... they do it and it works a treat... but well it's a lot of effort.

I searched for ages and considered Saab engine bored out which actually only gives you just over 2.3l but very powerful. Then one day I found that the Ecotec engine we all know and love has a 2.4l VVT version made in America only... so this is it problem solved.



As you see above my 2.4l VVT Ecotec I have a M90 Supercharger adapted to GM's tricky water to air intercooled inlet manifold making the need of a front mount intercooler obsolete. A few other things where needed like lower compression from 10.4:1 down to 8.5:1 and H beam rods ect to give me an expected 350BHP.

2nd thing is the 4WD system. It has to be north/south engine config and be able to handle upto 400BHP. This left no doubt a Skyline 4WD system would be the best and cheapest.

Recently I took delivery of a Nissan R32 Skyline GTR. This I will strip and use all the running gear including the front and rear Multi Link Suspension system and including the 4 piston front and 2 piston rear brake setup.



So along with the Daewoo 15i shell I also have... I have the parts to start the build. All I need is the fiber glass panels from the UK and I have all the bits.

For traction I will retain the ATTESSA 4WD System from the GTR... So it will launch like a GTR but weigh 500+ kgs lighter and the Supercharged 2.4l will have no lag and heaps of torque.

[ant]

Re: Vauxhall Astra 4S Replica

Engine:

Standard Engine Specifications:
GM Powertrain

Type: Ecotec 2.4L I4 VVT
Displacement: 146 cid (2393 cc)
Compression Ratio: 10.4:1
Valve Configuration: Dual overhead camshafts
Valve Lifters: Hydraulic roller finger follower
Firing Order: 1 - 3 - 4 - 2
Bore x Stroke: 88 x 98 mm
Bore Center: 95.48 mm
Bore Area: 243 cm2
Fuel System: Sequential fuel injection

Horsepower: 173 hp (129 kW) @ 5800 rpm (preliminary)
Torque: 167 lb-ft (226 Nm) @ 4500 rpm (preliminary)
Shipping Weight: 273 lb (124 Kg) Dry

Block: Cast Aluminum
Cylinder head: Cast Aluminum


My Engine Specifications


GM 2.4L VVT Ecotec M90 SuperCharged


Type: Ecotec 2.4L I4 VVT
Compression Ratio: 8.4:1
Induction: M90 Supercharger @ 12Psi
Rods: LSJ Forged
Pistons: 8.5:1 CR Forged
Valve Springs: Dual Springs
Valve Seats: Titanium
Head Bolts: Replaced with Head stud & nut kit
Injectors: Seimens 689 cc/min
Intake Manifold: Intake with Inbuilt Intercooler

Horsepower: 350+ hp (expected)



Here is my engine sitting in Melbourne awaiting internals from the US before it will be stripped and rebuilt. The build has been managed by Ecotec Marine and with advice from Ray Bates From the US who worked with GM Motorsport and did development on this engine. The engine is designed to run well into the 500+ BHP figures but to go the extra mile from the mid 300's I would have to start flowing the head and buying cam shafts but also there is a limit I can run the Supercharger and at this point we will be running 12psi, well within the safe limits of the M90 but I will have pulleys up to 18psi ready for "tune day".

[ant]

Re: Vauxhall Astra 4S Replica

Suspension and Drivetrain:

Nissan R32 Skyline GTR

Gear Ratios

1st: 3.214
2nd: 1.925
3rd: 1.302
4th: 1.000
5th: 0.752
Final Drive: 4.111

Brakes

Front: 324mm ventilated, 4-piston calipers
Rear: 300mm ventilated, 2-piston calipers


Front Suspension

Green:Anti Roll Bar / Stabiliser Bar + Drop link (further up)
Blue: Tension Rod
Yellow: Front Lower Arm
Red: Upper Camber Arm



Rear Suspension

Red: HICAS steering rack replaceable with a lock bar
Orange: Anti Roll Bar / Stabiliser Bar
Cyan: Rear Camber Arm
Yellow: Subframe bushes (aka Pineapple rings)
Pink: tension rod / steering rack rod
Grey:anti roll bar link arm
Blue: traction control arm
Green:track rod end

[Harvey]

Re: Vauxhall Astra 4S Replica

Fantastic project, plenty of pics during the strip and build please

[Dario]

Re: Vauxhall Astra 4S Replica

Nice Anthony!!! Cool info and pictures!! I do hope U get this project finnished One question about the engine, the 2. litre ecotech, is this engine a north/south mount only or could this engine be placed as "normal" in a Opel Kadett Gsi as well??

[ant]

Re: Vauxhall Astra 4S Replica

Thanks Harvey will do for sure... I already have an overwhelming amount of information already... so I will put up as much as I can. I have gathered a mountain of information on the R32 Attessa 4WD system and how to control it either electronically or manual control the hydraulics for the front to rear drive split... for example.

Dario... the 2.4L VVT Ecotec is mainly a front wheel drive Like in the Cobalt SS. I think there are rear wheel drive in some US sports cars. I don't know what gearbox they use though.

One interesting thing for a GSi project... you might notice the inlet and exhaust is oposite to C20XE which gives you more room to fit ram inlet manifold like some BTCC cars run.

[Dario]

Re: Vauxhall Astra 4S Replica

yeah, I noticed the opposite placing of the inlet and exhaust and that caught my attencion How much does these 2.4vvt eco engine goes for, without the supercharger system?

[ant]

Re: Vauxhall Astra 4S Replica

I paid $3000 AUD for a low km engine.

[Dario]

Re: Vauxhall Astra 4S Replica

ok, that`s about the same price as for a C20Let in Norway, a fair price for a newer engine and that`s likely to be in better shape too... Hmmm... maybe I`ll check out for a engine like this next summer then. I really want a 2.4 litre 16valve n/a engine in my Kadett, with throttle bodies.
But enough off topic now, sorry for that m8te.

Back to topic, when will you start working on the car and modify it to a 4s replica? Will you start with the suspension and axles first? Fitting the mechanicals or bodywork first?

[Dario]

Re: Vauxhall Astra 4S Replica

And some questions about the history of 4s....
Two were used in Dakar rally with n/a manta 400 engines, one of those were bought by a man in the x trac system right?? And the other were sold to John WelchThis car was later wrecked and sold to a Swede who used the x-trac 4x4 system on his Audi.. Also heard rumours that John Welch build another 4s himself after the crash? Is this true?
Then there is the "heat for hire" car, wich is right now i Vauxhaul Heritage senter.
Opel in Germany have a "Bastos" painted n/a 400 powered in their Museum. Is this the car that originally had the Ford Zakkspeed engine?

[ant]

Re: Vauxhall Astra 4S Replica

I am waiting to get the engine built which should start as soon as the parts arrive from the US... so I hope to have a running engine in the next few months. By then I will have the engine removed from the GTR Skyline and have an adapter made to bolt the ecotec to the GTR gearbox.

The plan is to have all the running gear sorted with the engine tuned and the 4WD System modified and test run in the GTR shell by the end of the year. At this point I would have stripped the Daewoo shell and plan the swap over, build the roll cage etc..

As far as I know and mick g might be able to help here...

The Opel Kadett 4x4 with the Zakspeed Ford engine is held by Opel in Germany.

The "Andrews Heat for Hire" is as you said at the Heritage Center.

John Welch got both Bastos cars and crashed one then was sold to Tommy Kristoffersson and he remove the Xtrac 4WD gearbox for his own Rallycross Audi Coupé S2 and the other was returned to Mike Endene... who restored the car back to it's Bastos Dakar livery and still owns it.

I can only guess that the car sold to Tommy Kristoffersson was rebuilt. Unless as you said they changed the original Zakspeed car which I wouldn't think they would do. Well unless they are still embarrassed over the scandal of having a Ford engine in their prototype.

I don't know if John Welch built a 5th car and if so where it would be.

[mick g]

Re: Vauxhall Astra 4S Replica

The car Opel have is the first prototype, with the Zakspeed engine which it still retains. Tommy has the car john wrote off which was a Paris Dakar car,the shell of which is rumoured to be stil around. I'm certain John had Gartrac either spaceframe a new shell or spaceframed the other Paris Dakar shell. He did say they were very heavy in Dakar trim at over 1100kg. Having crawled all over the car at the heritage centre there is very little of an Astra shell left, the floor is certainly all fabricated to accomodate the gearbox and rear diff/suspension setup..

[Dario]

Re: Vauxhall Astra 4S Replica

I am waiting to get the engine built which should start as soon as the parts arrive from the US... so I hope to have a running engine in the next few months. By then I will have the engine removed from the GTR Skyline and have an adapter made to bolt the ecotec to the GTR gearbox.

The plan is to have all the running gear sorted with the engine tuned and the 4WD System modified and test run in the GTR shell by the end of the year. At this point I would have stripped the Daewoo shell and plan the swap over, build the roll cage etc..

As far as I know and mick g might be able to help here...

The Opel Kadett 4x4 with the Zakspeed Ford engine is held by Opel in Germany.

The "Andrews Heat for Hire" is as you said at the Heritage Center.

John Welch got both Bastos cars and crashed one then was sold to Tommy Kristoffersson and he remove the Xtrac 4WD gearbox for his own Rallycross Audi Coupé S2 and the other was returned to Mike Endene... who restored the car back to it's Bastos Dakar livery and still owns it.

I can only guess that the car sold to Tommy Kristoffersson was rebuilt. Unless as you said they changed the original Zakspeed car which I wouldn't think they would do. Well unless they are still embarrassed over the scandal of having a Ford engine in their prototype.

I don't know if John Welch built a 5th car and if so where it would be.

I`ve also heard that the germans have the zakkspeed powered 4s hidden away. But a german bloke on this forum posted a picture from the Opel museum with Bastos paint and a 400 n/a engine. So I do wonder a bit about it being the zakspeed car..

[mick g]

Re: Vauxhall Astra 4S Replica

Here is the Opel car which you can clearly see the Ford based zakspeed engine still in it...

There are more upto date pictures in the German rally magazine, rallyemagazin.de as they have just done an article on it, im trying to translate it..