Tank Mike

What are the laws on these. A number of people have said they can never be road legial and others say its fine as an electric/hybrid are technically twin engine'd.

Cheers

craig_southampton

ive seen a twin engine nova that was road legal

RickyLee53

Not to drive on both engines it wasn't.

IIRC the engines have to be mechanically linked so they form 1.

vroooom ptssssh

even if it's not legal, just have 1 engine running for MOT....your only 'carrying' the other enging around when Mr Pold comes along....

just bump start the rear engine when you want to run both

vaughant

iTrader: (1)

Always fancied a twin engined mr2 turbo as you could put a Celica gt set up on the front which should be RELATIVELY straightforward and the rear setups already done for you.linkages should make sense as their essentially the same box just one operates in reverse of the other so I'd guess that's not impossible to link up.

I'm assuming if it passes biva or at worst sva it should be fine.petrol tank mounting would be an issue along with maybe fuel lines/exhausts I would say.

BLACKCOS

did not karl norris have a twin engined festa years ago? I have seen a few twin engined vw golfs think dubsport did them

bluntys1rsturbo

There is still ian nixons ex europarts twin engined r5 gt turbo going as well also has 4wd.

Roscco

Do the engines have to run in perferct symmetry? Otherwise wouldn't 1 be holding the other back?

craig_southampton

ever seen this
http://www.youtube.com/watch?v=phQfA5-DL1I

Tank Mike

I can't see it being a massive problem. Might make the power delivery feel irratic if there not perfectly sinced but I can't see it being to much of an issue

Big Will_

No, it's a common misconception. But, if you think about how the engine rotates the flywheel and the clutch drive plate, which in turn drives the input shaft in the box, through the gear ratios, output shaft into the diff and the into the driveshafts, to the wheels and tyres - now imagine that happening both at the front and rear of the car. Now imagine the car free wheeling down a hill in gear and that process reversing...

If the front engine and the rear engine experience different loads, the car will still accelerate and one engine will rev faster than the other - imagine two identical cars doing the same speed, one in 2nd gear, one in 3rd - the only effect would be the engine rpm.

The throttle bodies need to be capable of opening in unison and the gear linkage needs modifying to operate both gearboxes at the same time. It's generally easier to use two seperate engine looms and ECUs to allow each engine to run independantly, as i mentioned above in terms of load.

Some top end ECUs such as Pectel SQ6, Motec M800/M880 and Life Racing F88R/RS are capable of operating two drive by wire throttle bodies with an offset delay so you could iron out any hesitations etc.

Chip

iTrader: (3)

Ive seen many twin engines cars, and none ever that handled well. What do you intend to use it for Mike?

In the 60s BL did a load of twin engined mokes that they were trying to flog to the army (redundancy is good for reliability)


Im not convinced on this law people keep mentioning on forums about only driving on one engine, as ive yet to see a proper reference for it? can any of the people mentioning that please state where they are getting the info from, ie what law published what year etc (road traffic act presumably?) or are you all just repeating stuff you've heard and taking it as gospel?

Chip

iTrader: (3)

Depends what for, straight line acceleration its pretty much totally irrelevant, they can be massively different and its still no issue, in fact off the line for a launch you would probably want about 4 or 5 times the power to the rear that you have to the front.

For handling though, massive issues trying to balance the throttle through the apex if the two ends are slightly different.

Tank Mike

Mr shark boy wants another puma engine. And we all fancey the task of getting it in and running, even if it is just the technical exercise. Why don't they handle well? Is it purly the weight or is it the hold geometry set up? I would expect the cars weight to rise by 3-400kg but 90% of that weight will be mounted in the middle of the car.

Gaz 88

Ived seen a caddy van with two audi turbo engines in!

Gaz 88

http://www.pipewerx.com/pw2_project.html

timrud

Chip the Road Traffic Act wouldn't cover things like this, it would more likely be the Road Vehcles Construction and Use Regulations 1986 (or other revisions).

Mk1-stu

Read this

could be pub talk, it is a forum after all, but either way still worth a read

JK12

iTrader: (1)

cool! Wonder if 5th gear paid for the new engine??

XRT_si

iTrader: (2)

There have been many twin engined cars over the years, some worked a lot better than others it seemed.
The first Dubsport twin engine VW (the blue Rallye) used a 2.8 and a 2.9 VR6 engine. As Will stated, the engines will match themselves to each other.

I remember reading before an interview with the owner of the twin VR6 turbo engined Mk3 Golf who tried describing it as imagine a big guy and a little guy pushing a broken down car. One is probably doing more work than the other, but it still works better than one.

With regard to laws; I had a rear engined Fiesta that I was looking to put two engines in as I've always been fascinated by them, still seen no law stating it isn't allowed, as the forum above seems to confirm.

Marvin_hagler_

in the old days you could get minis with two engines fitted,they were called twinnys.
it was the sort of thing that your typical car and car conversion enthusiastic reader did for a laugh.

have a look at this twinny race car

http://webcache.googleusercontent.co...&ct=clnk&gl=uk

Tank Mike

It seems it is legal then. Find out when i suppose if we get a book chucked at us.

I'm quite interested in the handling point that chip made. If anyone could go into some more detail that would be good!

Mk1-stu

surely the simplest solution, would be to contact an SVA / VOSA center and just ask them ?

JamesG

Guy who works at my place built this. twin vauxhall 2.0 16v engines. Still early days in the development but it has run 7.9 0-100 and a 11.6 1/4 mile.

Chip

iTrader: (3)

Well if people are saying that its legal to build it with twin engines and MOT it etc, then it wouldnt be the construction side of things surely, so I thought it might be RTA, but like I say, my own opinion is that its just myth anyway, so wont be either, lol

Chip

iTrader: (3)

I know Mike really well, in fact it was me that first suggested to him to move to auto on one of the boxes to improve its quarter times.
Superb car that!

Chip

iTrader: (3)

Ive not driven them myself so dont know for certain, but would imagine that the problem is that you will struggle to hold both engines on a balanced point at the apex given the differing grip front to rear.

tabetha

I personally know of two twin engined cars, 1 a 5GT turbo, the other a skoda 130 rapid, both mot'd, the 5gt is owned by a mot tester, though he doesn't mot his own car.
tabetha

Chip

iTrader: (3)

Tabetha, that counts for fuck all though, my nova is legally MOT'd as it was built before the rules changed but if you built and identical newer car up now it wouldnt be legal to just MOT you would have to put it through single vehicle testing.

Martin-Hadland

iTrader: (2)

Don't do it!!! They drive very badly.

Tank Mike

When you say drive badly, what part of the drive is bad?

The extra weight? The cornering? Having unsyinconised engines?

As I say, its more of a technical exersise than anything. Just need something a bit harder to keep the brain awake. But if were going to do it, i would like to try and iron out some of the problems people sugest.

timrud

Good times from the mini

Chip

iTrader: (3)

Thats just on really average road tyres as well mate, pradas IIRC, so nowhere near even 888s let alone the sort of tyres most people putting in good times are running.

That car has SO much potential, I think Mike will see it well into single figures by the time he has finished with turboing it etc, especially if he puts better rubber on it.

david 100

My uncle has a Ford DDD, thats 2 Fordson Major's tractors with their front wheels removed and then joined together, i guess that dont count.

Chip

iTrader: (3)

In terms of twin engined CARS like this thread mentions then no I dont suppose it does, lol