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As some of you may know from this question i am currently rebuilding my car. The plan is to rebuild it from scratch. An important part is the engine. At the moment there is a 1.4l 8V petrol engine with 60HP(44KW?). This is, of course, a bit too little for the effort this project is going to have (IMHO). So i plan on getting a bigger engine.

The biggest engine in this model is a 2.0l 16V petrol engine with ~150HP. But i think this will also be too little. Unfortunately i have no specific plan on which engine(power) to use. I could think of about 400-500HP at the end. The normal weight of the car (from the papers) is about 980kg.

There wasn't an official 4x4 version of this model, only a few (1-5 maximum) self-made versions. So i can't simply get the base of a 4x4 one. But from this i know it is possible to build it.

The problem is that i have little to no experience with AWD or 4x4, but i would like to learn more about this in general. I already learned a bit about the differences between 4x4 and AWD from this question. I am primarily interested in the use of 4x4 or AWD on the street.

Main Problem

The main reason for this is, if there will be traction problems because of the power/weight ratio. There is no use for a 500HP engine if the car can't go forward anymore.

So when will the car benefit from a 4x4/AWD modification? What aspects do i have to take in consideration (for example HP, Weight, nm, cost...)?

What is the 'best' behaviour for street use? full/part 4x4 or AWD or...? The car won't be used off-road.

Addition to make the Q less broad

What specific parts do i need to change in order to build AWD in a car whose series never had a performance version with built-in AWD? Apart from the AWD system and the modifications on the bottom of the car to install the AWD system properly.

Addition

I am aware of the fact that for this increase in power, there are many more things to do (improving the brakes, chassis, landing gear and some things more) but that is not the question here.

I know the cost is an essential part of this project, but the cost is not the problem here.

If there is need for more informations please tell me. I will then add this as soon and good as i can.

Edit

As i expected the question. The car i'm talking about is an Opel Astra F CC from 1995.

By landing gear i mean the summary of parts for the connection between the vehicle and the undergrounde. I don't know the exact english term. The german term is "Fahrwerk". Here a wiki link. I hope thats helps.

  • It would help to know what model of car you are building. Also, not sure what you mean by landing gear. I realise that 500+ bhp will make it a flying machine. – Steve Matthews Apr 20 '16 at 10:11
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    You need to watch Project Binky. You'll then have an appreciation for what it takes to put an AWD system into a vehicle which never came with it. Also, this might help you think outside the box, which I think is needed here to attain your goals. – Pᴀᴜʟsᴛᴇʀ2 Apr 20 '16 at 10:32
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    I'm pretty sure by "Fahrwek", the English term would probably be "suspension" ... but my German is beyond rusty, so I had to use other methods. @SteveMatthews may also be correct. This website shows the term "Fahrwerkuntersuchung" to mean "chassis analysis", which may lead us to even a better understanding. – Pᴀᴜʟsᴛᴇʀ2 Apr 20 '16 at 10:47
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    You are doing better than I would in german. Mein Deutsch ist scheusslich! – Steve Matthews Apr 20 '16 at 11:05
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    @SteveMatthews - Haha! Mein Deutsch ist Strudel! – Pᴀᴜʟsᴛᴇʀ2 Apr 20 '16 at 22:14
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My first thoughts, given the car is question, would be to check to see if there is a performance version of the car which features four wheel drive.

For road use, if you have over 300bhp going through the front wheels, things can get difficult. A friend of mind had a 320bhp Seat Leon Cupra (Front wheel drive) and sold it to buy an Audi S3 (same basic chassis setup but four wheel drive) as he was struggling to get the power down in the Leon.

Now, in the UK your car was sold as the Mk3 Astra and was out at around the same time as the Calibra which was a sports coupe based on the slightly bigger Cavalier chassis. It appears that the front suspension from a Calibra can be fitted to your car very easily. You simply need to change the top mounts and enlarge the holes the strut tops sit in very slightly.

However, the rear is a more complex proposition. You can fit the entire Calibra 4x4 system but you need to cut out the boot floor and centre tunnel of your car and weld in place the Calibra items.

Your best bet is therefore to try and locate a scrap / crashed / damaged Calibra Turbo 4x4 which will give you everything you need for the conversion (including the all important brakes). Apparently the engines in these cars are good for around 420bhp with serious modification. On the plus side, I'd assume once you've found a suitable Calibra to use for parts for the conversion , it wouldn't be particularly expensive.

One final thing I would say though is, try and find a GSI 2.0 16V version of your car in standard form and drive it. You may find that this provides enough power to make you smile.

  • I don't know a performance version of my car. Only self-made by other crazy car freaks :D. I know the problem with the 300+bhp from an experiment with a Ford Fiesta XR2I. The problem was in fact that they hat no more traction and therefore where unable to move. I know the trick with the Calibra in sense of engine. Thanks for the hint with the AWD. I thing this will be the way to go. Luckily i don't have a deadline so i have plenty of time to gain knowledge and material. But it is not that easy to find a Calibra and Astra GSI in good condition for a reasonable prize. – Requion Apr 20 '16 at 11:15
  • I'm sure you'll find a Calibra if you keep looking. Join your local owners club, very worth while. In the UK at the moment there is one Calibra Turbo 4x4 for sale, here gumtree.com/p/vauxhall/… however this car is probably far too good to cut up. I'm sure you will find one in the end though. – Steve Matthews Apr 20 '16 at 11:18
  • Oh, turns out there was a performance version of this car available in South Africa called an Opel Astra 200t S - details here; carmag.co.za/road_test/from-the-archives-ope-kadett-200-ts – Steve Matthews Apr 20 '16 at 11:21
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Before you start, I'd have a good read of the rules applying to it - I seem to remember that Germany is very strict on heavily modified cars, so you might well find there are restrictions on what you can do to it - modifying the monocoque (chassis/bodyshell) to allow the fitment of a propshaft and rear drive axle might well be restricted, or involve huge amount of tedious and expensive paperwork to get TUV approval...

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    Thanks for this reminder. In fact, the car modifications i plan are only possible with a (tedious and expensive) single-approvement of the car by the TÜV. But even with this in mind it is perfectly possible to realize the mods. For example there is a street legal Kadett 4x4 in my hometown. So this should only be a question of cost. But that's another problem i will have to handle :D – Requion Apr 20 '16 at 12:21

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