Straight-cut competition gearbox - Lancia Beta or Montecarlo

Non-engine, eg: aerodynamics, gearboxes, brakes, suspension
Post Reply
Snakeman
Posts: 52
Joined: Wed Jul 12, 2006 2:24 pm
Location: Bedfordshire
Contact:

Straight-cut competition gearbox - Lancia Beta or Montecarlo

Post by Snakeman » Mon Sep 23, 2013 1:44 pm

Hi All,

I have been circuit racing my Lancia Montecarlo for a few years now where I am at the stage of looking to upgrade my transmission from and OE box to an Involute straight cut gear set with dog engagement, preferably also with straight cut final drive gear.

The eliminated shaft thrust from helical gears and helical final drive can only serve to provide my torque to the road wheels. I am also hoping it survive longer than the syncro box's I've used

I am aware of a gear & shaft conversion in Italy (Kit RCE15 by Bacciromano or Carenini), but this particular kit seems to retain the syncromesh engagement. I am also aware that Cololli also offer a kit - T.171

Has anyone ordered any of these gear kits and successfully installed them? I am slightly nervous of ordering these items direct from Italy because there will inevitably be questions about bearings used, installation guidance etc. and my Italian speaking is limited to beer and coffee purchasing (!)

Alternatively, and my much preferred option, has anyone commissioned a UK company to manufacture a straight cut gear-set for a Lancia Beta or Montecarlo?

Thanks
Geoff W

Guy Croft
Site Admin
Posts: 5003
Joined: Sun Jun 18, 2006 9:31 am
Location: Lincoln, UK
Contact:

Re: Straight-cut competition gearbox - Lancia Beta or Montec

Post by Guy Croft » Tue Sep 24, 2013 10:42 am

You're right to be circumspect about this Geoff.

Years and years ago John Day raced with a Colotti box he'd built and it never misbehaved. Paul Brace got a set for his MC and it slipped out of mesh over and over and never ran right.

If I were you I would talk to Quaife

http://quaife.co.uk/shop/search/results ... 619?page=2

I'd ask them the nearest equivalent non-Lancia transverse box they have and see if it can be adapted. This may seem a frightening proposition!

It may be that they can buy in Italian stuff and build it up. I would not be surprised if they can.

Member Rich Ellingham (that is his username) has a Bacci gearset in his Tipo, he may be able to help here. He is always very helpful - pm him.

G
Guy Croft, owner

Will01
Posts: 558
Joined: Mon Nov 26, 2012 3:50 pm
Location: Dumfries, Scotland
Contact:

Re: Straight-cut competition gearbox - Lancia Beta or Montec

Post by Will01 » Tue Sep 24, 2013 11:36 am

If it is the same John Day which i suspect it is, he works for Days & Whites garages in Kent round the back of Brands Hatch. John is a really nice chap and we have had discussions in the past including some of his racing. They are Alfa Fiat Lancia specialists in the south east and i wouldn't be surprised if they could help you with orders from Italy as they order many of their spares from there.
Pretty sure they were building up a MC a few years back for racing, but i may be mistaken.
I have used them for parts and servicing in the past and they are highly recommended from me.
GC_21

Guy Croft
Site Admin
Posts: 5003
Joined: Sun Jun 18, 2006 9:31 am
Location: Lincoln, UK
Contact:

Re: Straight-cut competition gearbox - Lancia Beta or Montec

Post by Guy Croft » Tue Sep 24, 2013 12:50 pm

Yes that is John

G
Guy Croft, owner

Snakeman
Posts: 52
Joined: Wed Jul 12, 2006 2:24 pm
Location: Bedfordshire
Contact:

Re: Straight-cut competition gearbox - Lancia Beta or Montec

Post by Snakeman » Thu Sep 26, 2013 7:57 pm

Following email correspondence with Quaife, they will only do a gear kit for a minimum quantity of 30 units, so that's a non-starter.

Stay tuned...

tmvolumex
Posts: 165
Joined: Fri Jul 07, 2006 12:43 am
Location: USA
Contact:

Re: Straight-cut competition gearbox - Lancia Beta or Montec

Post by tmvolumex » Sun Sep 29, 2013 1:03 am

In your post you mentioned

"The eliminated shaft thrust from helical gears and helical final drive can only serve to provide my torque to the road wheels."

This is true but:
The final drive is subjected to the most torque and thus would generate the most power loss with anything but straight cut final drive gears.
Your Monte has essentially straight cut final drive gears in the final drive now. I say essentially as they are cut at a slight angle to reduce gear noise as in done in FWD cars.
On a rolling road dyno the correction factor for CRANK BHP vs rear wheel BHP is quite a bit different for FWD cars vs RWD cars.The reason is, most FWD cars use essentially a straight cut ring and pinion final drive gears (as in your Monte) versus a 90 degree hypoid gear set up in a front engine RWD car. A ring and pinion with all gears turning one plane (all in one plane) has a much higher efficiency than a hypoid (90 degree) set up. I would doubt if the reduction is losses, thus more power to the rear wheels, by going to a straight cut gear tooth set up, would be worth the expense. RWD losses are 15 - 20 % because of the hypoid final drive. FWD and transverse RWD is maybe 5%
Usually straight cut gears are used in a gear boxes because they are stronger and can accommodate a dog mesh system which allows additional gear width, created by eliminating the syncromesh. Dog mesh gear boxes can be shifted without the clutch, much faster than a syncromesh box if you are skilled and dont mind higher maintenance.
Tom
GC_31

Guy Croft
Site Admin
Posts: 5003
Joined: Sun Jun 18, 2006 9:31 am
Location: Lincoln, UK
Contact:

Re: Straight-cut competition gearbox - Lancia Beta or Montec

Post by Guy Croft » Sun Sep 29, 2013 10:51 am

the att dyno curve of Geoff's (with respect) shows the actual loss on his MC...

it's a lot more than 5% and not linear..


GC
Attachments
Goeff Ward dyno data.jpg
Goeff Ward dyno data.jpg (289.05 KiB) Viewed 1459 times
Guy Croft, owner

tmvolumex
Posts: 165
Joined: Fri Jul 07, 2006 12:43 am
Location: USA
Contact:

Re: Straight-cut competition gearbox - Lancia Beta or Montec

Post by tmvolumex » Sun Sep 29, 2013 3:17 pm

I believe that most chassis dyno shops do not change the correction factor for different final drive types in the car they test on a chassis dyno. The correction factor usually set in the software program is for a hypoid final drive, not a spur gear set up like the Monte has.
Tom
GC_31

tmvolumex
Posts: 165
Joined: Fri Jul 07, 2006 12:43 am
Location: USA
Contact:

Re: Straight-cut competition gearbox - Lancia Beta or Montec

Post by tmvolumex » Sun Sep 29, 2013 3:23 pm

The only way to determine actual drive train loss would be to compare engine dyno test data with a chassis dyno test data.

On the other hand, when it is all said and done, it is the power and torque to the rear wheels (or front wheels, or all 4 wheels) that is the important factor.
Tom
GC_31

Guy Croft
Site Admin
Posts: 5003
Joined: Sun Jun 18, 2006 9:31 am
Location: Lincoln, UK
Contact:

Re: Straight-cut competition gearbox - Lancia Beta or Montec

Post by Guy Croft » Sun Sep 29, 2013 3:27 pm

sorry Tom, Geoff's FW figures of torque and power from Northampton Motorsport rr correlate exactly with my own bench dyno data and have every time someone with one of my engines has gone there - to within a few bhp, which is why I recommend them almost exclusively.

Beyond that I am not really qualified to add anything useful (assuming that was...!)..


G
Guy Croft, owner

Post Reply

Who is online

Users browsing this forum: No registered users and 1 guest