Ugg10
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| posted on 15/4/25 at 04:44 PM |
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VFR1200F Rear Diff ?
So, doing a bit of brain storming for a potential new project.
I really like the idea of using the VFR1200F engine - v4 engine sound, 170 crank HP at 10k, 95ftlb at 8750 (90% from 4k), it can be mounted in the
same orientation as in the bike so possibly no need for new sump/baffles etc, comes with 6sp manual or DCT gearbox (might be interesting), some come
with a reverse function, complete bikes available cheaper than ZZR1400, Huyabusa, ZX10, R1 etc. Looks a compact unit.
Now the issue - it is left hand side shaft drive, so drive shaft goes anti-clockwise making use of standard Mazda/Sierra/Freelander diffs impossible
unless you run them upside down (lots of debate as to whether this is advisable of not). The alternative is to make a reverse transfer box or use the
Quaife reverse box permanently in reverse (again suggestions that this is not advised).
Then I stumbled on the front diff from a BMW X5 (and others) and noticed that the splines in the CWP are machined in the opposite direction to
something like an English CWP.
BMW
English
So, does this mean that the BMW is designed to run anti-clockwise when mounted in the rear of a RWD (sevenesque) car or am I getting this totally
wrong ?
If it is, then this looks quite interesting as it is available in 3.07 and 3.15:1 rations which are better for use with high revving bike engines that
have a primary reduction gear built into the gearbox. Quaife also seem to do an ATB for them (at a price). However, as it is for the front drive is it
man enough for a bike engine car given that it comes out of a big, heavy SUV with more power and considerably more torque even if reduced down by the
front/rear power split ?
Also looks quite a compact unit with four nice mounting holes but you will obviously have to get drive shafts made up to suit the rear uprights. These
diffs can also be picked up quite cheaply on ebay and are plentiful plus service kits are readily available.
Anyway, I'd be interested in thoughts on this as a potential solution or happy to be told I am barking mad (not the first time !). I guess if it
does look promising it could be a solution for other shaft drive engines (BMW K1600 ?) that are predominantly on the left hand side of the bike.
Thanks in advance for comments.
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1968 Ford Anglia 105e, 1.7 Zetec SE, Mk2 Escort Workd Cup front end, 5 link rear
Build Blog - http://Anglia1968.weebly.com
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adithorp
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| posted on 15/4/25 at 06:37 PM |
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Seems a reasonable plan.
Even with the motor in the same orientation as in the bike, it will experience oil swill. It doesn't in the bike, as the bike leans in corners
keeping the oil where it should be. In a car the vornering forces aren't counteracted by lean.
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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nick205
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| posted on 17/4/25 at 10:04 AM |
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Do any other car 4x4 front diffs behave in the same way as the X5?
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Minicooper
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| posted on 17/4/25 at 05:21 PM |
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I have the vfr1200 dct version sitting in my garage, you need a rear diff that rotates the opposite way as you have worked out. I found many audi rear
diffs to be suitable, great ratios as well, quaife atb diffs are available to suit but a bit more expensive than the usual ford stuff.
Never heard of a built in reverse for the vfr1200. Any information?
As for being small not really they are a big lump. I know they use certain tricks to make it narrower in the rear cylinder area, I think I have seen
an overlay of the VFR800 engine and the vfr1200 appears to be quite a bit smaller, but my vfr1200 looks massive?
The vfr1200 has a semi dry sump design as standard with a sealed crankcase, meaning it has the advantages of a dry sump with a compact wet sump tank
I'll see if I can find anything on it. just remembered it has a oil tank above the engine in the valley of the cylinder heads to provide tank of
oil ready to use, It is also fly by wire throttle system which makes it that bit easier to place anywhere you want
Cheers
David
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Ugg10
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| posted on 18/4/25 at 10:40 PM |
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@minicooper,
Thanks for the info, will look into Audi ones.
About the reverse, may be incorrect, I think I saw this on a late model BMW K1600 and got mixed up with the VFR.
Also, thinking about it, steering column may be an issue as the engine will sit towards the diver side. Nice engine but the cons are starting to mount
up.
The KTM 1290 is also interesting, dry sump, vtwin, 170hp and a decent amount of torque but quite pricy. Also it has a race engine mode that switches
off the abs and traction control. Might go well in a rear mid engine car bolted directly (via Cush) to a freelander diff. The old MEV Sonic 7 might be
a good candidate, I think they are still being made.
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1968 Ford Anglia 105e, 1.7 Zetec SE, Mk2 Escort Workd Cup front end, 5 link rear
Build Blog - http://Anglia1968.weebly.com
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