robertwa
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| posted on 3/2/08 at 05:39 PM |
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AWD BEC
I've seen the posts before on twin engined BEC's and their somewhat complicated drivetrains and controls.
The engine in my car is a Yamaha FJR1300, a bigger bored, shaft engined cousin of the R1. I have a spare engine on the bench which I am considering
turbo-charging. While stripping this engine, I noticed that it has a counter shaft assembly below the transmission which drives the 90 degree shaft
drive. It is called the middle drive assembly. Think of it as similar to the R1 but with an extra shaft below the sprocket output. This extra shaft is
the reason that the drive rotates in the opposite direction, the reason why my rear axle is flipped upside down to compensate.
Anyway, this middle drive assembly runs the complete length of the engine, and has a side cover on each side of the engine casing. The assembly can be
easily removed by taking off both side covers and pulling it out.
My idea is to fabricate a longer middle shaft with splines on either end, and machine new side covers with bearings and oil seals.
This would allow the engine to be mounted longtitudinally like most BEC's but with a drive output facing the back and the front of the car to
enable a AWD drivetrain. I believe there is also room at the rear to fit a small centre diff where the rightangle drive unit currently is.
But I guess the question is - would it be worth it? Would there be much of an advantage in the AWD setup apart from bragging rights of course?
These engines go for peanuts on ebay since they are not that popular with the usual groups. I saw two go for US$300 last month.
Looking forward to your opinions
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worX
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| posted on 3/2/08 at 05:44 PM |
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It would definitely be worth doing it (for the bragging rights alone )!
In all seriousness, I think that part of the fun in these cars lies in the RWD aspects of the drive.
Having said that, if I were you, I would be doing it just because I could! It would be an excellent project and a very good achievement.
It might be worth doing it to the turbo'd engine though, as you will suffer from extra weight and additional transmission losses (obv)...
All the Best!
Steve
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stevebubs
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| posted on 3/2/08 at 05:49 PM |
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Weight would have to be the biggest consideration for a project like this.
One of the reason BECs are so quick because they're light. Adding 4WD removes this benefit.
If you're turboing at the same time, however, will the extra horespower outweigh the mass penalty?
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bob tatt
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| posted on 3/2/08 at 06:36 PM |
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was very fortunate to go in the tiger z100 with two yamaha 1000 engines in all i can say is i will never go in anything so fast again in my life and
the noise was something else totaly amazing off the line and in gear as well go for it i say
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Rogue Se7ens
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| posted on 3/2/08 at 07:01 PM |
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This sounds like an idea that would at least be worth exploring. Others like dp cars, have pursued 4wd with a bike engine, and I would say if the
engine already lends itself to being able to be converted then I would want to give it a try and may even do so if I could get a hold of one. Let us
know what you do.
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Paul TigerB6
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| posted on 3/2/08 at 07:39 PM |
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One thing you might want to consider is the clutch. With all that additional traction of the 4 wheel drive would it last many standing starts
especially with the huge extra torque a turbo will add??
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