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Twin engined bec pics wanted
CraigJ - 27/2/09 at 05:26 PM

as title, as many as possible mid mounted bec pics needed. just want to look at all my options and get the best ideas on how to mount and run the engines.

Thanks.


Tiger Super Six - 27/2/09 at 05:30 PM

Do a google search on the Tiger twin engined 7 - there is quite a bit on that incl pictures.


CraigJ - 27/2/09 at 05:32 PM

ive seen the tiger but its not much use to me as im building a mid-engined car.

It is a nice car though.


tegwin - 27/2/09 at 05:35 PM

I love innovation... but...

Why do you want to use two engines?

Thats twice the weight of gearboxes, twice the weight of coolant....twice the weight of exhaust...

Would you not be better off spending the money on a turbo for the zx10? Or a little supercharger if you are desperate for more power....


Two engines would be a PITA... not impossible... but a lot of effort for minimal gain IMHO!


CraigJ - 27/2/09 at 05:48 PM

quote:
Originally posted by tegwin
I love innovation... but...

Why do you want to use two engines?

Thats twice the weight of gearboxes, twice the weight of coolant....twice the weight of exhaust...

Would you not be better off spending the money on a turbo for the zx10? Or a little supercharger if you are desperate for more power....


Two engines would be a PITA... not impossible... but a lot of effort for minimal gain IMHO!


I just like a challenge lol.

The ZX10 is the older one and only has 137bhp de-restricted. The engine is 20 years old so will be down on power a bit. The VFR engines are a lot newer 97-98 and produce 100bhp in standard form before any tuning. Weight, the ZX10 i think weights in at aroung 50-60 kgs, i can pick it up and hold it a chest height quite easy. The VFR is lighter to start with so will only be adding maybe 30-40 kgs to the total weight. Thats maybe 430 kgs with 200bhp, the standard mongoose that onyx built weighed in at 430kgs and only had 100 bhp and that was quick. The 2 VFR's weight less than a k-series and its gearbox.


jacko - 27/2/09 at 05:56 PM

Look at Martin Keenan web site he has photos of a car with two engines in the back
Its in his projects section

[Edited on 27/2/09 by jacko]


progers - 27/2/09 at 06:02 PM

Don't bother doing it, its a PITA to get twin engines working properly together and you tend to end up spending far more than you think to get it working.

There are several engineering issues to solve (how do you combine outputs from the engines, changing gear, cooling etc) and you are unlikely to get 2x the power of a single engine once all the losses in the system are added up.

Far better spending a bit more money on a newer more powerful engine and tweaking it if necessary. I've just bought a ZX12r for £1,250 and with a bit of simple work that will give 180+ bhp.

I knew the owner of a twin ZX9r tiger, engines were dirt cheap but the cost of the build was anything but.

You have been warned!

Paul


froggy - 27/2/09 at 06:03 PM

my car is 650kg and makes 200hp at the wheels.its a lot of work and there are problems getting the clutches and throttles to work together. going the turbo route would be easier but not cheaper ,have a look on mk engineering,s website under projects to see how martin keenan did my car. i run nitrous on mine too so i can add another 150hp if needed, it drivees a lot more like a car engine now it has 160lb/ft of torque so i can cruise along at 70 without wanting to change up a gear. if i can crack my synchro problems with my clutches it would be driveable on the road but for now its a track car only. i stuck with my v twins as they sit well in the car and are light and cheap.

i spent some time on a hub dyno and the autograss style drive system i use showed that running both engines onto a fixed shaft didnt affect the output as i ran each engine separateley and they made the same power as each other and when run together the output doubled so the losses remained the same the coolant is linked through both engines but they never get above 80c so its not an issue. i wouldnt do it again but im happy with the results for what its cost me

[Edited on 27/2/09 by froggy]


cheapracer - 27/2/09 at 06:16 PM

Z Cars have a twinny Ultima on their website but the seperate engines run the seperate ends (4WD).

By the way, If it was easy everyone would be doing it.

I always thought one way you might do it simply is to run the first motor to a spring loaded drive shock absorbing shaft as you find on some shaft drive motor bikes and some farm equipment. Maybe a car tailshaft rubber donut universal joint in a shaft to seperate them may do it too. The point is to lessen the torque shock (for want of a better description) of each motor affecting the other.


stevebubs - 27/2/09 at 06:31 PM

Rossbost has one engine per rear wheel

www.furorecars.co.uk


Simon - 27/2/09 at 07:13 PM

Look for pics of an SR8 I saw at Brighton last couple of years.

Talked to the builder who said it was easy

Power from both engines via chains to common layshaft, the to diff.

ATB

Simon


Robertf - 27/2/09 at 09:40 PM

Not much help, but the guy who used to run the Alfa specialist I used to use had a twin engined alfa 164. Twin 3.0 V6s but one at each end, and only connected at gearlinkage.

While it would probably have been easier to get 400 bhp from a single engine than getting the twin engined car to work, it was a fantastic car, and the noise with both engines at full chat was spectacular so I can see the appeal of a twin engine car!


cheapracer - 28/2/09 at 05:21 AM

This is the latest kid on the block...

http://www.youtube.com/watch?v=f7o88PMGFSw&feature=related

A number of people have tried twin engine for serious purposes and commonly have 2 problems, they break cranks and unpredictable traction events as the engines fire together or not.


russbost - 28/2/09 at 09:46 AM

Here's a few pics of the Furore


[img]http://
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[img]http:// tw eng rear
tw eng rear
[/img]


[img]http:// eng bay
eng bay
[/img]

First pic shows (up to a point) what i feel is one of the hardest things to resolve, the fact that you finish up with a very short driveshaft on the nearside (this obviously applies only if you are going to drive the wheels separately rather than driving 2 engines onto a jack shaft & using a chain drive diff)

If you look at the 2nd pic you'll see that the driveshaft disappears behind the black ali cover, this is about the point that the inboard cv boot starts gives you an indication of how tight it all is & also of the substantial width taken up by a 2 litre "straight 8"

The 3rd pic shows how little room there is between the 2 engines, you really couldn't package them significantly tighter, more modern engines like the R1 or new ZX10 might give you a touch more room.

Don't let me put you off ifyou want to go ahead with it - perfectly willing to share the knowledge I've gained from doing mine - it's "doable" but the engineering is a PITA. However I don't think i could have got a 150kg 270BHP powerplant for less than a grand any other way, & once it's working properly is fantastic power with plenty of torque.