cosworthspeed10
|
| posted on 25/8/10 at 03:32 PM |
|
|
MNR Vortx Propshaft Damage !!!
Hi Guys, I have a MNR with a Busa engine in that keeps snaping propshafts on the universal joints. I have taken the shaft back to Dunning &
Fairbank today who said that the propshafts are only rated to 160 Bhp Max (1100 series) and that I need a 1300 series propshaft to cope with the Busa
power (180 Bhp), the shaft would then be good for 350 Bhp. The problem is that the Universal joints will be bigger in diameter and I would need a
larger diameter bike sprocket adapter to connect to the 1300 series prop.
Is anyone else breaking props like we are and are there any other alternatives?
[Edited on 26/8/10 by cosworthspeed10]
[Edited on 26/8/10 by cosworthspeed10]
|
|
|
|
|
Bluemoon
|
| posted on 25/8/10 at 03:35 PM |
|
|
go CEC?
|
|
|
RazMan
|
| posted on 25/8/10 at 03:37 PM |
|
|
Have a word with GB Engineering - they custom make driveshafts etc to your spec and they might be able to suggest something.
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
|
|
|
tomgregory2000
|
| posted on 25/8/10 at 03:40 PM |
|
|
i would be worried about them giving you specs in BHP as BHP does not break things torque (the twisting force) does the damage
|
|
|
Mal
|
| posted on 25/8/10 at 04:04 PM |
|
|
You may have a problem caused by the flanges that the ends of the shaft connect to not being parallel to each other.
|
|
|
cosworthspeed10
|
| posted on 25/8/10 at 04:04 PM |
|
|
quote:
Originally posted by tomgregory2000
i would be worried about them giving you specs in BHP as BHP does not break things torque (the twisting force) does the damage
Yes I agree, but i suppose it would be hard to put a torque figure on the shafts as it would be dependant upon traction and engine power. I dare say
that when you drop the clutch with a set of slicks on the back at 10,000rpm it will put some serious strain on the propshaft and this is normally when
the prop breaks.
|
|
|
coyoteboy
|
| posted on 25/8/10 at 04:16 PM |
|
|
It still makes more sense to spec shafts for torque as power has sod all to do with it. I see this all the time, with things like performance clutches
specified for power figures rather than torque. Walk away and find an engineering company that knows the difference.
|
|
|
Johneturbo
|
| posted on 25/8/10 at 04:31 PM |
|
|
Hmmm thats what killed my last car
broke at the uv joint engine end, car was a total loss
ETA did you get the propshaft supplied with the kit?
[Edited on 25/8/10 by Johneturbo]
|
|
|
interestedparty
|
| posted on 25/8/10 at 04:32 PM |
|
|
quote:
Originally posted by coyoteboy
It still makes more sense to spec shafts for torque as power has sod all to do with it. I see this all the time, with things like performance clutches
specified for power figures rather than torque. Walk away and find an engineering company that knows the difference.
I expect they are already well aware of the difference, but find it more meaningful to the average customer to give a figure in BHP that might bear
some relation to the torque.
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
|
|
|
cosworthspeed10
|
| posted on 25/8/10 at 04:42 PM |
|
|
quote:
Originally posted by Johneturbo
Hmmm thats what killed my last car
broke at the uv joint engine end, car was a total loss
ETA did you get the propshaft supplied with the kit?
[Edited on 25/8/10 by Johneturbo]
Yes the prop was supplied with the kit. I suppose MNR should not supply this prop if the manufacturer says it's not suitable?
|
|
|
DRC INDY 7
|
| posted on 25/8/10 at 04:42 PM |
|
|
Have a word with danny keenan at mk sportscars he runs a holeshot tuned busa engine in his race car no probs with the propshaft
https://www.facebook.com/groups/462610273778799/
Puddle Dodgers Club
|
|
|
Johneturbo
|
| posted on 25/8/10 at 04:44 PM |
|
|
Thing is though a bike engine like say my R1 on the bike is around 170/180bhp but only 90ftlb of torque
i think the zzr1400 is 198hp but only 117ftlbs
busa would be about the same?
|
|
|
Johneturbo
|
| posted on 25/8/10 at 04:48 PM |
|
|
quote:
Originally posted by cosworthspeed10
quote:
Originally posted by Johneturbo
Hmmm thats what killed my last car
broke at the uv joint engine end, car was a total loss
ETA did you get the propshaft supplied with the kit?
[Edited on 25/8/10 by Johneturbo]
Yes the prop was supplied with the kit. I suppose MNR should not supply this prop if the manufacturer says it's not suitable?
What have mnr said about the max power of said supplied propshaft?
i thought i was just unlucky when mine broke but maybe they arn't a good make after all.
i think Andy from ABperformance uses Bailey Morris
|
|
|
paublo999
|
| posted on 25/8/10 at 06:21 PM |
|
|
Due to my combination of sticky tyres, 100lbs ft torque and a nasty vibration I went to a top spec Bailley Morris prop. Not a place to skimp on guys
as this thing could kill you.
The dunning prop IMO was not up to the job I needed it to do. I decided not to sell it on eBay for that reason.
My videos http://www.youtube.com/user/ninjabogeyracing
|
|
|
cosworthspeed10
|
| posted on 25/8/10 at 06:34 PM |
|
|
I have not spoken to MNR yet but I will contact them tomorrow. If the prop manufacturer says its not up to the job then they should not be sold with
the kits. As has already been mentioned when a prop blows it can cause massive damage, on my car it has torn a hole in the floor and ruptured one of
the 10mm fuel lines. It could have been very nasty!
The universal joints on the prop are GKN which are supposed to be good joints. D&F don't make the joints they simply assemble and cut the
prop to length.
[Edited on 25/8/10 by cosworthspeed10]
|
|
|
cosworthspeed10
|
| posted on 25/8/10 at 06:59 PM |
|
|
quote:
Originally posted by Johneturbo
Thing is though a bike engine like say my R1 on the bike is around 170/180bhp but only 90ftlb of torque
i think the zzr1400 is 198hp but only 117ftlbs
busa would be about the same?
The power figures listed above is what the engine can develop, the torque developed when you drop the clutch from 10,000rpm with sticky tyres will be
much more with all the inertia from the engine when the clutch engages.
Did your prop fail in motion or when doing a fast start?
|
|
|
procomp
|
| posted on 25/8/10 at 07:07 PM |
|
|
Hi
So how then do the CEC's manage to use the small joints and run 180FtLb. 
Use a decent prophaft supplier who uses new parts throughout the build of the shaft.
Cheers Matt
|
|
|
daviep
|
| posted on 25/8/10 at 07:17 PM |
|
|
quote:
Originally posted by tomgregory2000
i would be worried about them giving you specs in BHP as BHP does not break things torque (the twisting force) does the damage
I wouldn't be worried at all, torque at the propshaft is completley different to the torque produced at the flywheel due to the mechanical
advantage of the gearbox and also the primary reduction on a bike.
Horsepower and propshaft speeds are what you need to calculate torque on the propshaft.
So if you know the speed range the propshaft will operate in (most automotive applications will be similar dependant on wheel size and diff ratio)
then all you need to know is the engine BHP to calculate whether the prop is strong enough.
Davie
“A truly great library contains something in it to offend everyone.”
|
|
|
cosworthspeed10
|
| posted on 25/8/10 at 07:22 PM |
|
|
quote:
Originally posted by procomp
Hi
So how then do the CEC's manage to use the small joints and run 180FtLb.
Use a decent prophaft supplier who uses new parts throughout the build of the shaft.
Cheers Matt
Matt do you know for definate that the CEC's run the 1100 series joints? I don't think they do. The reason they use them on the
BEC's are because the bike sprocket adapter is very close to the clutch slave cylinder (on the Busa motor anyway) and there isn't really
any room for a bigger joint
Also CEC's may have different ratios on the rear diff. My car has a 3.14 rear diff.
|
|
|
daviep
|
| posted on 25/8/10 at 07:24 PM |
|
|
quote:
Originally posted by coyoteboy
It still makes more sense to spec shafts for torque as power has sod all to do with it. I see this all the time, with things like performance clutches
specified for power figures rather than torque. Walk away and find an engineering company that knows the difference.
Spoken with conviction but still a load of rubbish apart from the bit about clutches which is irrelevant.
Davie
“A truly great library contains something in it to offend everyone.”
|
|
|
BobM
|
| posted on 25/8/10 at 08:11 PM |
|
|
Having had my prop fail twice on my Busa powered Fury I discovered the reason was that the nut holding the adapter onto the gearbox output shaft was
fouling the prop yoke and preventing it from seating properly on the adapter. We ended up grinding down the nut a little bit and it fits nice and
flush now.
What was happening was that the bolts were trying to bend the end flange on the prop which then meant either the UJ failed or the flange snapped.
Worth checking.
Not very Locost but very BEC 
|
|
|
Johneturbo
|
| posted on 25/8/10 at 08:18 PM |
|
|
quote:
Originally posted by cosworthspeed10
quote:
Originally posted by Johneturbo
Thing is though a bike engine like say my R1 on the bike is around 170/180bhp but only 90ftlb of torque
i think the zzr1400 is 198hp but only 117ftlbs
busa would be about the same?
The power figures listed above is what the engine can develop, the torque developed when you drop the clutch from 10,000rpm with sticky tyres will be
much more with all the inertia from the engine when the clutch engages.
Did your prop fail in motion or when doing a fast start?
mine failed in motion i was doing 40mph then went into a 60phm zone and floored it in second then bang! it snapped it a fuel line cought fire and was
a total loss within about 10mins
lucky me nor the otherhalf were injured.
here's the old thread
http://www.locostbuilders.co.uk/viewthread.php?tid=96533
 
Description
 
Description
 
Description
[Edited on 25/8/10 by Johneturbo]
|
|
|
mangogrooveworkshop
|
| posted on 25/8/10 at 11:00 PM |
|
|
ALL THE BETTER REASON TO PUT SOME PROP CATCHERS ON when we look at the above posting by Johneturbo
|
|
|
Johneturbo
|
| posted on 26/8/10 at 12:49 PM |
|
|
i did a search on props and found a thread
that had some info on UJ's
taken from the thread.........
Dave Mac propshafts in Coventry
I just ordered a new propshaft from them today to do a gearbox change.
They charged £95 plus vat and do a 24hr turn round. It will be all new, painted and balanced, 1140 series UJ's* (rated for
continuous 400Nm or 50% possible overload to 600Nm), ford rocket spline to english axle flange.
*Bigger UJ's would be more expensive; 1300 series are rated for 556Nm continuous and 1000Nm max possible, but are bulkier and
might not fit the tunnel"
i know you said about the 1100 and the 1300
|
|
|
cosworthspeed10
|
| posted on 26/8/10 at 07:55 PM |
|
|
quote:
Originally posted by Mal
You may have a problem caused by the flanges that the ends of the shaft connect to not being parallel to each other.
Looks like you may have hit the nail on the head there!
When I spoke with Dunning & Fairbank today they asked if the prop flanges were parallel to each other. The flanges ideally need to be parallel
(Horizontally and Vertically) for the Universal Joints to work well together, in the Horizontal plane because the engine is rotated 10 degrees in the
chassis the prop flanges are not parallel to each other but they are in the vertical plane. I think you can have flanges that are not parallel to
each other but this need to be specified when selecting the prop as the Universal Joints need to be angled differently from one end of the prop to the
other to allow for this. My prop is designed for parallel flanges (as may all the MNR BEC props) and MNR may not have taken into consideration the
unparallel flanges.
Does this make sense?
|
|
|
