Astra and Ford Focus engine suitability (Oz build)

[200bhp]

Having longed to build a kit car for years with no money or space when I was in England, I now find myself with some spare cash and a massive workshop so the time has come to build something interesting.

I really want to build something from the ground up, including my own chassis so have been looking at Locost type builds. Road registration down here requires a little more effort than the UK with the whole build needing to be signed off by an engineer - Luckily I'm on the list so that'll be easy I'm looking forward to seeing if there are any refinements to be made to the basic locost chassis through chassis FEA and dynamic analysis which is what I do for work most days.

The biggest stumbling block when building a kit down here seems to be parts availability.

Most rear wheel drive donors are either big heavy V8 Commodores (think Vauxhall Monaro) or the Ford equivalent. A tired MX5 will cost 7 or 8 times more than it would in the UK.

So I've been thinking of what other engines to use and one car that is available cheaply is the MK4 Astra 1.8. These cars are all built in England and the engine is the same as a UK car. The other related option would be the 2.2 from an early Astra Coupe.

Also very cheap would be a Focus (approx 2003 vintage) with a 1.8 or 2.0

Thoughts and comments welcome.

[ugg10]

Sorry can't help with the Astra other than Westfield used the corsa vxr 1.6 turbo engine in their cars a bit ago. The 2.2 may also have been used in the omega (commodor?) so there may be a rwd gearbox available. 2.2 was used in the Vauxhall vx220 but in fwd format.

For the focus, the easiest fit will be the st170 as that is basically a zetec engine so has the right bell housing pattern for the type 9 and mt75 boxes. There is a guide on locost builders forum to get this engine running on the OEM ecu.1.6 sigma will need a bespoke bell housing or there is a guy on turbosport forum (freddy686868) and uk eBay who sells an adaptor for a Mazda rx8 box (also does a zetec version, not sure about a duratec version though). Depending on the age of the car 1.8 and 2.0 could be zetec or duratec, lots of info on fitting these engines to sevens, duratec will need bell housing or can be used with the mx5 mk3 box but I think they sit at an angle.

If you want to build your own chassis have you looked at the midlana, basically a rear engine seven, buy the book of plans, you can then use the fwd engine and box outright, just need a second set of front uprights. (Looks similar to the Sylvia R1ot).

Hope this helps.

Edited by ugg10 on Saturday 9th July 09:18

Edited by ugg10 on Saturday 9th July 09:20

[Tony427]

Why not look at getting a "half cut" from Japan. Basically it's a car cut in half with the roof off so that you get the front half with the engine and box, ecu, steering, pedal box, brakes etc so you only need to sort out a rear axle.

Something Supra-ish should be available quite cheaply and would make an excellent powerplant.

Cheers,

Tony

[dai1983]

ugg10 said:

If you want to build your own chassis have you looked at the midlana, basically a rear engine seven, buy the book of plans, you can then use the fwd engine and box outright, just need a second set of front uprights. (Looks similar to the Sylvia R1ot).

Hope this helps.

Edited by ugg10 on Saturday 9th July 09:18

Edited by ugg10 on Saturday 9th July 09:20

The Midlana uses early mx5 hubs/calipers etc and steering rack. You can use any FWD engine and gearbox combination you like but the original used a turbocharged Honda h24. Others I've seen have used anything from duratecs, GM and even 12v v6 Alfa engines as you can widen or narrow the chassis.

The book is more expensive that the Haynes books but there are seasonal sales on Lulu to knock a bit off. If you look on the forum there is an Australian who's done a CAD build and is doing a "real life" one too. The nosecone is only available in the states which means you make your own or modify another to suit.

I've got a Ford Puma that I'm toying with using due to its cheapness and light weight drivetrain. Problem is I keep changing my mind and consider just prepping the puma for the track. It will be cheaper and take less time but then I think "it'll still just be a puma" so look at doing something different.

[pigeondave]

Regarding the chassis
I found this thesis on the net years ago. Could be a good starter for 10

https://www.google.co.uk/url?sa=t&rct=j&q=...

If the link doesn't download try googling "luego sports cars chassis thesis" its the B version that you want.

Keep us updated on the chassis i find it an interesting read.

[200bhp]

ugg10 said:

If you want to build your own chassis have you looked at the midlana, basically a rear engine seven, buy the book of plans, you can then use the fwd engine and box outright, just need a second set of front uprights. (Looks similar to the Sylvia R1ot).

Now that does look interesting!

I really like the idea of a rear or mid engine car, one of the biggest problems with a 7 type car here would be the heat from the engine cooking my legs in the summer - Keeping everything behind me would greatly reduce that problem.

[200bhp]

pigeondave said:

Regarding the chassis
I found this thesis on the net years ago. Could be a good starter for 10

https://www.google.co.uk/url?sa=t&rct=j&q=...

If the link doesn't download try googling "luego sports cars chassis thesis" its the B version that you want.

Keep us updated on the chassis i find it an interesting read.

Thanks for the link, his thesis shows us that people like Lotus actually know what they're doing doesn't it! haha.

Before seeing that I'd had some discussions with my colleagues about doing exactly this. One thing that's not covered in that thesis is how the panels are attached to the frame. Riveting, gluing, welding all have their advantages but I think there are pros and cons for each method. Not much point in stiffening the chassis with panels if they're not actually rigidly attached to the chassis - That's the biggest thing with FEA analysis, making it actually represent the real world.