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AWD rolling chassis BEC

zakeen - 30/8/16 at 11:11 PM

Im interesting in building an AWD BEC and would rather buy a rolling chassis then to build my own. Is anyone aware of a company selling them or know someone who has made one in the past?

Thanks.

ReMan - 31/8/16 at 05:47 AM

No-one currently makes one I'm aware of
Nothing wrong with waning or doing, but what is the goal?
Bear in mind BEC And an extra 50kg of 4wd transmition don't normally sit well together
You also don't say what style of vehicle your thinking, a 7 alike or a off road buggy type?

jelly head - 31/8/16 at 07:10 AM

May well be making this up but didn't a company once build a twin engined 4wd BEC? Z cars maybe?

adithorp - 31/8/16 at 07:46 AM

quote:
Originally posted by jelly head
May well be making this up but didn't a company once build a twin engined 4wd BEC? Z cars maybe?

There's been a few one offs but don't think there's ever been a kit available. All the ones I've seen have had issues of some sort and the complexity and additional weight don't make it worth the effort IMHO. Think z-cars went bump this year.

micksalt - 31/8/16 at 07:57 AM

I believe it was Z Cars, using an Ultima GTR as the base vehicle and two Hayabusa engines, one driving the front wheels and the other the rear. Must have made for some interesting dynamics if the engines ever fell out of balance.

Schrodinger - 31/8/16 at 08:02 AM

Tiger did do a Six with 2 bike engines but from memory that was rwd.

mcerd1 - 31/8/16 at 08:04 AM

^^^ http://www.tigerracing.com/model/tiger-z100/

[Edited on 31/8/2016 by mcerd1]

Ugg10 - 31/8/16 at 08:06 AM

The Dax Rush was available with cosworth 4x4 running gear - badged the quadra iirc. Also there was a 4x4 cobra replica using the Granada running gear (Realm engineering IIRC). But these days I think you will be building from scratch or modifying a stock locost frame.

[Edited on 31/8/16 by Ugg10]

mcerd1 - 31/8/16 at 09:37 AM

quote:
Originally posted by Ugg10
The Dax Rush was available with cosworth 4x4 running gear - badged the quadra iirc. Also there was a 4x4 cobra replica using the Granada running gear (Realm engineering IIRC). But these days I think you will be building from scratch or modifying a stock locost frame.

when I was buying my rush (cica 2005) I asked DJ's how many quadra versions they had sold - they reckoned it was only about 25 at the time - 2 or 3 of which had RV8's grafted into them

and I know that at least one locost was built using a similar setup and maybe a couple of others that were being built

the sierra/XR4x4/cossie running gear does the job but it adds alot of weight (never got an exact number but have had estimates over 100kg extra) and the permanent 4x4 has much higher transmission losses than 2wd setup (something like 25% rather than 10 to 15% )

DJ's told me they had effectively given up the quadra development in favour of RWD BEC cars as they were significantly quicker round the track and reckoned the 4x4 only gave any advantage in 0-60 time and bad weather
they particularly pointed out the extra weight making it harder to carry speed through a corner and how the 4x4's ability get the power down again quicker was never quite enough to make up for this...

red22 - 31/8/16 at 09:58 AM

LINK

This chap made AWD work. Interesting read if you've not come across it before. Seems to have moved on since the last time I checked it out. Looks like he's making several different cars and an attempt at Pikes Peak now.

nick205 - 31/8/16 at 10:10 AM

quote:
Originally posted by Ugg10
The Dax Rush was available with cosworth 4x4 running gear - badged the quadra iirc. Also there was a 4x4 cobra replica using the Granada running gear (Realm engineering IIRC). But these days I think you will be building from scratch or modifying a stock locost frame.

[Edited on 31/8/16 by Ugg10]

That's the AWD 7 type car I recall too although not a BEC. IIRC DAX have since gone out of business (or no longer offer the Quadra).

I'd think the difficulty with an AWD BEC would be differentials and engine placement. IIRC the Quadra made use of the AWD Sierra's N/S front engine and differential systems. I'd also imagine you'd want (or need) the torque of a car engine to get the best from an AWD system.

Starting with an AWD donor (Imprezza?) may be the way forward, but would still require a fair amount of engineering work.

nick205 - 31/8/16 at 10:22 AM

A quick Google on Imprezzas shows the engine in front of the front axle line. This would make the tin top version nose heavy and not be ideal for a BEC type car (IMHO). Thinking back to Group B rally cars they tended to be mid or rear engined - better weight distribution I assume. To do this though many had custom or fancy centre differential arrangements. The Peugeot 205 T16 was cebtre engined and IIRC used a Citroen differential in the centre to split the power fornt/rear.

nick205 - 31/8/16 at 10:31 AM

Peugeot 205 T16 transmission image for reference. Expensive and rare!

An Audi quattro car may be a way forward, but I'd think others would have done it by now if it was really worth it.

Ugg10 - 31/8/16 at 11:16 AM

quote:
Originally posted by nick205
A quick Google on Imprezzas shows the engine in front of the front axle line. This would make the tin top version nose heavy and not be ideal for a BEC type car (IMHO). Thinking back to Group B rally cars they tended to be mid or rear engined - better weight distribution I assume. To do this though many had custom or fancy centre differential arrangements. The Peugeot 205 T16 was cebtre engined and IIRC used a Citroen differential in the centre to split the power fornt/rear.

I also thought about the Audi but again that is a transaxle with the engine in front of the front axle and a rear drive out of the back. Note Audi have 2 Quattro system, the A3 (golf) uses a transverse engine as in the picture above, the A4/5/6/7 (Passat) uses the longitudinal and transaxle arrangement.

The Dax used the Sierra arrangement as it has a side take off the gearbox and a second drive shaft coming forward to a separate front diff which made it easier to mount. Looks like the Suzuki vitara has a similar arrangement. Also Toyota used this type in the supra and estima I think. So there are a few option that would allow a more conventional seven arrangement but with a diff in between the front wheels but will need a wider tunnel.

[Edited on 31/8/16 by Ugg10]

adithorp - 31/8/16 at 11:28 AM

None of the tin-top set-up really work with a BEC though as the engine and box are integrated in the bike motor. Somehow you need a stand alone transfer box that you can link the bike output shaft/sprocket to.

OP, why are you thinking of bec4x4?

coyoteboy - 31/8/16 at 12:05 PM

I considered both BEC4x4 and twinnyBEC before I ditched both - too complicated and would end up heavy, defeating the point unless you have a lot of cash and time to throw at custom transfer boxes, carbon prop shafts etc. DP did it well. Tin top hardware doesn't translate well. Any of the tin top 4x4s have the engine way out in front which is accentuated in a light car.

obfripper - 31/8/16 at 12:09 PM

A suzuki sj/jimny transfer box might suit this, i don't know what it's torque limit is though, but it would also give you high/low reduction gears, and various ratios are available.

Dave

CNHSS1 - 31/8/16 at 04:43 PM

Yep I'd be looking at one of the puny 4x4s, fiat panda or similar, SJ 410that sort of thing.
Alfa romeo used an electrically engaged rear diff on one of their 80s cars (badged Parmalat at the time). Maybe summat trick like only having the extra diff engage when wheels pin detected? Most decent aftermarket ecus will run a bike engine and will read wheel speeds to switch it in and out. I doubt you really need 4wd all the time in a BEC other tan for launch and the odd over enthusiastic cornering manoeuvre...

james h - 31/8/16 at 10:13 PM

Here you go:

awd bec 1

awd bec 2

From THIS site.

I like the idea of a 4WD BEC using a sprag (one way bearing) clutch ala the Palatov cars in a previous post. The issue as mentioned would be parasitic losses and weight - make your car lighter and add a turbo and you should claw back any disadvantages!

zakeen - 31/8/16 at 11:18 PM

quote:
Originally posted by adithorp
OP, why are you thinking of bec4x4?

Wow, what a great response and so much information! Thanks! Its mainly because of the weather conditions of where I live, we have a lot of snow in the winter and why only have fun half of the year?

From what I have seen so far maybe it might be best to buy one of the rolling chassis of a buggy and convert it more towards a road style.....

nick205 - 5/9/16 at 09:33 AM

quote:
Originally posted by zakeen

quote:
Originally posted by adithorp
OP, why are you thinking of bec4x4?

Wow, what a great response and so much information! Thanks! Its mainly because of the weather conditions of where I live, we have a lot of snow in the winter and why only have fun half of the year?

From what I have seen so far maybe it might be best to buy one of the rolling chassis of a buggy and convert it more towards a road style.....

Would a cheap 4x4 not suit you better? Be warmer with a roof, windows and a heater.

mangogrooveworkshop - 15/10/16 at 04:44 PM

I can sell you a set of plans for the buggy
awd bec 2
I was going to make a road going one however a divorce threw a spanner in the works. �30 quid

My mate in the Netherlands built two Caterhams in four wheel drive

I also have two small differentials from four x four quads available for �80 quid each that would work in a buggy.

I will post the details later

[Edited on 15-10-16 by mangogrooveworkshop]

TRX - 1/1/17 at 03:07 AM

> Peugeot 205 T16 transmission

Oooo....

That's basically an Audi / Toyota / old Beetle / Rentault / Porsche engine/transaxle turned sideways, with a really tall final drive as the center diff and tall end diffs.

As long as you could juggle the gearing to come up with a useable final drive ratio, that looks DIY-able.

jeffw - 1/1/17 at 07:51 AM

quote:
Originally posted by Ugg10

I also thought about the Audi but again that is a transaxle with the engine in front of the front axle and a rear drive out of the back. Note Audi have 2 Quattro system, the A3 (golf) uses a transverse engine as in the picture above, the A4/5/6/7 (Passat) uses the longitudinal and transaxle arrangement.

[Edited on 31/8/16 by Ugg10]

The system in the Golf/A3/TT platform (quattro with a small q) is a Haldex system and therefore in not full time 4WD, most of the time it makes like a FWD car. The A4/A5/A6/A8/R8 platforms all have the space to run Quattro systems which have Torsen centre diffs and (with the exception of the R8) engines in front of the axle as per the original Audi Quattro Group B rally car.

The Palatrov D4 is a AWD BEC engined car http://www.palatov.com/cars/d4/

http://www.palatov.com/wptest/wp-content/uploads/2016/01/20150520_093731.jpg
[Edited on 1/1/17 by jeffw]

[Edited on 1/1/17 by jeffw]

mark chandler - 1/1/17 at 08:57 AM

I suppose you could chop up a 4wd quad, you really need a bias diff front to rear.

coozer - 1/1/17 at 02:23 PM

quote:
Originally posted by obfripper
A suzuki sj/jimny transfer box might suit this, i don't know what it's torque limit is though, but it would also give you high/low reduction gears, and various ratios are available.

Dave

Got a Jimny in the garage ATM, scrapman coming for the body tomorrow..

Problem I see for a 7 is the diffs in the axles are offset to the os and the front prop runs under the engine. That means the rear prop would be in the drivers foot well...

However there has been a few sj's done with bike engines and the transmission is well suited to using whatever you like.

coozer - 1/1/17 at 02:27 PM

coozer - 2/1/17 at 04:48 PM

And here is what the transmission looks like on the chassis. As you can see the 4x4 box is totally independent and can be used for all sorts of stuff!!