LocostUSA.com

Learning how to build Lotus Seven replicas...together!
It is currently March 19, 2024, 2:15 am

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 14 posts ] 
Author Message
PostPosted: January 5, 2020, 1:31 pm 
Offline

Joined: January 2, 2020, 8:16 am
Posts: 4
Hello, all.

I' new to the forum (although I been a reader for years now). I'm mechanical engineer and work as suspension engineer in a auto supplier. I finally decided to put in motion my intention of designing and building a BEC Locost. Wanting to make it as light as possible (OfC) I'm researching components.

Can you guy give me suggestions for IRS differentials with aluminum casing, preferably with LSD available as OEM of aftermarket?

Thank you,


Top
 Profile  
Reply with quote  
PostPosted: January 20, 2020, 8:17 pm 
Offline

Joined: January 2, 2020, 8:16 am
Posts: 4
Hi Folks,

Doing a lot of surfing and researching I came across Audi Quattro vehicles differentials. I found several applications like A4, A6 and A8.

I will check in more details about ratios, splines, etc, but can you guys give me an opinion if there is any reason these differentials are not suitable for a Locost?

Did anyone considered or succeeded using them?

Thank you,


You do not have the required permissions to view the files attached to this post.


Top
 Profile  
Reply with quote  
PostPosted: January 21, 2020, 8:45 am 
Offline
We are Slotus!
User avatar

Joined: October 6, 2009, 9:29 am
Posts: 7651
Location: Tallahassee, FL (The Center of the Known Universe)
I used a Ford 8.8 IRS out of a Mustang Cobra. Swapped the cover for one off an Explorer, which has big "ears" that made for a better mount. If I had it to do over, I'd just get the Explorer unit to begin with, but when a friend gives you one out of a Cobra, you go with it... :mrgreen:

_________________
JD, father of Quinn, Son of a... Build Log
Quinn the Slotus:Ford 302 Powered, Mallock-Inspired, Tube Frame, Hillclimb Special
"Gonzo and friends: Last night must have been quite a night. Camelot moments, mechanical marvels, Rustoleum launches, flying squirrels, fru-fru tea cuppers, V8 envy, Ensure catch cans -- and it wasn't even a full moon." -- SeattleTom


Top
 Profile  
Reply with quote  
PostPosted: January 21, 2020, 10:52 am 
Offline
The voice of reason
User avatar

Joined: January 10, 2008, 4:47 pm
Posts: 7652
Location: Massachusetts
The Ford diff Gonzo mentions is a good choice. It has a lot of parts available for it, multiple types of limited slip from multiple manufacturers.

I did what Gonzo suggests, be aware that the diff case determines the halfshafts that you use with it because of things like oil seal diameter. The diffs are identical ( sort of ) but the cases are not.

I thought the Explorer parts were big and heavy but when I measured them they were not, I think they are the standard 100 mm CV joints, but I don't remember right now.

_________________
Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.


Top
 Profile  
Reply with quote  
PostPosted: January 21, 2020, 7:52 pm 
Offline
Automotive Encyclopedia
User avatar

Joined: December 22, 2006, 2:05 pm
Posts: 8035
Any diff that accepts standard porsche/vw cv and axles is way ahead of anything else imho. Allows you to buy off the shelf half shafts. Best to have matching uprights.

I'm not aware of any fords using standard cv joints but it looks like the audi's do and I know they have in the past.

Use a hardened steel driveshaft adapter to replace the hardened steel sprocket on the bike output shaft.


The longer the driveshaft, the larger the od should be, not necessarily thicker walled.

You can use fwd or rwd uprights if they accept a cv that matches the diff.

While the diff case is light alloy, the spinning insides are not as light as smaller ring gear applications.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12


Top
 Profile  
Reply with quote  
PostPosted: January 23, 2020, 12:18 pm 
Offline
The voice of reason
User avatar

Joined: January 10, 2008, 4:47 pm
Posts: 7652
Location: Massachusetts
Well I welcome some talk here because it's an area I need to stop being stalled at in my Car9 build. At the light end we have the Hitachi R160 from Subaru at 55 lbs. Then there is the Miata at 65 and the Big Ford diff at 75 lbs. My guess is the Audi is in the 65+ lbs. area.

Thomas, if the diff in the picture is on your garage floor, that's a petty big plus. Pay some attention to where the mounting holes are when you design that part of your frame. All of the drivetrain torque shows up on the diff mounts.

The Ford diff doesn't come with stubs for VW/Porsche style joints, but everything is available for that diff. It would be nice if the world choose a smaller Ford diff, but they didn't. They adapter stubs cost about $750, so not cheap or maybe I'm wrong on the price. When I measured the balls and cages etc. in the Ford halfshafts they were the same stuff as the moderate size Porsche units. I imagine they are basically world standard. They are one size bigger than the VW base stuff on my Formula Ford's transaxle.

So the stuff from the Ford Explorer IRS that looked so big and bulky really wasn't when I measured and weighed the parts. Overkill for many of our cars but not the turbo or V8 ones. Where I got lost was in the details of things like oil seals and also uprights. THe Thuderbird stuff is good but I resent they charge more for it now. It seems like you could mix and match the halfshaft parts but I haven't gone far down that road.

Along with this there is the possiblities of the stuff the off road folks use which is sometimes referred to as micro-stub ( ? ). This involves making your own upright with a bolt on bearing assembly. SOme catalogs sell a dozen variations on parts for this...

_________________
Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.


Top
 Profile  
Reply with quote  
PostPosted: January 24, 2020, 8:06 am 
Offline
We are Slotus!
User avatar

Joined: October 6, 2009, 9:29 am
Posts: 7651
Location: Tallahassee, FL (The Center of the Known Universe)
Quote:
It seems like you could mix and match the halfshaft parts but I haven't gone far down that road.
With Ford stuff, you can. I have "hybrid" half shafts on my car, with the splined inner piece from an Explorere (matching the diff) and the outer one from a Cobra axle. Dis-assembly of an old greasy CV is a job best done in latex gloves on an old piece of plywood, while wearing a shirt you plan to throw away afterwards...

:cheers:
JDK

_________________
JD, father of Quinn, Son of a... Build Log
Quinn the Slotus:Ford 302 Powered, Mallock-Inspired, Tube Frame, Hillclimb Special
"Gonzo and friends: Last night must have been quite a night. Camelot moments, mechanical marvels, Rustoleum launches, flying squirrels, fru-fru tea cuppers, V8 envy, Ensure catch cans -- and it wasn't even a full moon." -- SeattleTom


Top
 Profile  
Reply with quote  
PostPosted: January 24, 2020, 11:13 am 
Offline

Joined: January 1, 2015, 1:55 pm
Posts: 327
I've used the aluminumC5 Vette diff in a few applications. I had an input shaft machined that allowed me to eliminate the transaxle and run a drive shaft. I had a thick aluminum plate machined that bolted to the front of the diff, provided for a support bearing. The plate bolted into my chassis.

I think the late model Camaro uses an aluminum diff.

I had 4 of the diff to driveshaft conversions made. I have 2 extra.


Top
 Profile  
Reply with quote  
PostPosted: January 24, 2020, 9:38 pm 
Offline

Joined: August 26, 2010, 7:12 pm
Posts: 287
Location: Minneapolis
The Audi diff turns backwards from other diffs


Top
 Profile  
Reply with quote  
PostPosted: January 25, 2020, 1:06 am 
Offline
The voice of reason
User avatar

Joined: January 10, 2008, 4:47 pm
Posts: 7652
Location: Massachusetts
Quote:
The Audi diff turns backwards from other diffs


Well sometimes we have people ask for that too! You can see the driveshaft is offset a bit towards the driver's side.

_________________
Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.


Top
 Profile  
Reply with quote  
PostPosted: January 26, 2020, 1:03 pm 
Offline

Joined: August 26, 2010, 7:12 pm
Posts: 287
Location: Minneapolis
Unless you want to go really fast backwards.


horizenjob wrote:
Quote:
The Audi diff turns backwards from other diffs


Well sometimes we have people ask for that too! You can see the driveshaft is offset a bit towards the driver's side.


Top
 Profile  
Reply with quote  
PostPosted: January 27, 2020, 12:11 am 
Offline

Joined: July 6, 2009, 11:50 pm
Posts: 177
slappynuts wrote:
Unless you want to go really fast backwards


Seems like the perfect solution if you want to do a front engine rwd setup with an older Honda engine (B, H, D, or F series) since they spin backwards.


Top
 Profile  
Reply with quote  
PostPosted: January 27, 2020, 8:54 am 
Offline
The voice of reason
User avatar

Joined: January 10, 2008, 4:47 pm
Posts: 7652
Location: Massachusetts
Also some shaft drive bike engines might use this...

_________________
Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.


Top
 Profile  
Reply with quote  
PostPosted: January 27, 2020, 6:56 pm 
Offline
Automotive Encyclopedia
User avatar

Joined: December 22, 2006, 2:05 pm
Posts: 8035
There are some bike motors with right side sprockets that would work with that. I think Honda shaft drives would also.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 14 posts ] 

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 5 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
cron
POWERED_BY