locked / welded Diff?

T

TED HEINRITZ

Well-known member
With a front drive car, what are the disadvantages of a locked / welded Diff?

At some tracks I get a little to much wheel spin, inside tire spins, reducing the acceleration.

Now if I had a little more power, it wouldn't help if I am getting to much wheel spin now.
 
I'm sure Ogren will chime in sometime, but the quick jist is that you can't turn unless you're on the gas. get the car woah'd down, then nail the gas and turn.
 
Well that is how I normally drive it anyhow, I did hear it can increase the steering effort.

The problem is when I turn in and give it gas, at some tracks I just get to much wheel spin. At Watkins Glen, not to much of a issue, but at Mid Ohio and VIR, I am starting to give up to much with the wheel spin. Now if I could put the power down on both front wheels and not just the inside one, that could help.

With a better motor this will just get worse.

Not sure if a good limited slip diff is available for a ford escort gearbox, which is what I now run in the Fiesta. The gearing is better, although being a 5 speed I have 1st blocked out, making it easier to stall it in the pit area, and harder to get it onto the trailer. Limited prep only allowed 4 gears....
 
Yes, most of the VW crowd runs a spool or welded front diff. It's great in the dry. Pulls from the inside wheel, since it's traveling the shortest distance. It's just difficult to turn 90 degrees in the paddock, and DON'T even try to turn while backing up.

You'll like the "Popeye" forearms too
 
Contact Tony Ingram about a quaife or tran-x for your application. Welded just sucks in FWD, You will save on broken parts with a good diff.

TONY INGRAM [[email protected]] Send him an email
 
First drive around the paddock the steering wheel will try to break your wrists. After you get used to or scared of that, the thing will be fun in a straight line and coming out of the corners. It will take a different driving style. I installed one years ago in a customer's rally-X car. He said it was great in the dirt. Seemed to do OK on flat tracks like TGPR until it broke axles. It seemed like everytime that thing hit the track it would break axles and the car would instantly shoot off track. Quite odd. You are better off spending the money on a good limited slip like a Quaife, Peloquin, Wavetrac, etc.
 
So if it were to break a axle, it can then become a hazard. I didn't really consider that.

I wrote to Quaife to see if they currently make a unit for my transmission. I adapted a ford Escort transmission, I think it came out of a 1997 Escort, it's a 5 speed with first gear blocked out. Being limited prep only allowed 4 gears.

The axles are custom Moser made units, might be stronger than OEM, but something could still break.

Seemed like welding up a diff would be simple enough, but nothing in racing is really free.....

So now the real question is just how much more money do I throw at this old car, or start over with something else, which would of course just cost even more....
 
I've broken a couple of CV joints the the last 2 years, but that's because I didn't have enough "plunge" in the 1/2 shafts. Mainly the outer one that binds and then the cage fails. Once it breaks, it does tend to want to pull to one side or the other.
 
Welded is faster than the Quaife. It makes more lateral grip for some reason- maybe like TIm says the vectors are higher toward the inside of the turn. It is a pain in the paddock.
If the car is neutral without the locker, it will need a lot less rear stiffness with it locked.
That is how drastic the lateral front grip goes up.
It is faster even if you are not spinning the inside tire. I dont know why. I did not believe it until i locked my first VW.
I use the quaife for the Chumpcar and rentals
MM
 
You probably would be faster swapping to an MTX75 transmission if at all possible. There are tons of options for that gear box. Yes, you would get hit with an alternative box weight, but the availability of LSDs, gears, dog kits, etc are well worth it.

You could try and Eckerich diff if no one else makes one, however, expect a long wait. A clutch type diff would give you the benefit a locker without the problems, because you can get the preload much higher than the Quaife. However you are probably very limited in your options since its an odd transmission.

Another thing to consider is car tracking when both front tires encounter different traction conditions under braking. Add to that the unequal length axles you are running and I would expect some pretty harsh characteristics.
 
We tried a lot of diff options in Mathis and Albin cars over the years. We all run welded today.
Quaiffe type needed so much preload to not spin the inside that they were at a one weekend life expectancy.
The wave track type with a more aggressive friction disk were not faster than welded, and Chris liked it less in the rain than welded.
A truly adjustable clutch type might be able to be set up faster, but I have a lot of other places to spend that money first.
 
The ford ESCORT box that I am using looks to be a MTX5, same or similar to what was used in a Mazda 626.

Quaife does list a diff for a Mazda 626, so that could be a option.

But not sure if that is a ideal solution if it won't last very long.

To make the conversion to the Escort gearbox, I have Moser custom axles, I assume these are stronger than stock OEM. Also the Tempo hubs are much stronger than fiesta OEM.

Being the off season, there is time to sort out the options..... Replacing the tired engine with a better one will only increase the possible wheel spin, so need to do something to fully take advantage of a new engine.

thanks for all the feedback.
 
I'm pretty sure Jason runs an OS Giken limited slip.

Seems like most of the VW guys I know like running a locked diff, where as most of the Honda guys I know prefer to run some type of limited slip.
 
Greg Gauper":2dpsvltn said:
I'm pretty sure Jason runs an OS Giken limited slip.
Click to expand...

Yep OS Giken Super Lock LSD.

And if they make one for a Yaris they must have something that will fit a Ford trans. :lol:
 
So I'm wondering if adding a front sway bar would help with the wheel spin? Also is the Quaife ATB with the helical gear any better than the LSD with clutch plates?

You'll like the "Popeye" forearms too[/quote]
getting my anchor tattoo next week :lol:
 
Well, most of the the VW folks that run an LSD, don't run any front bar, and have 2 rear bars.
 
Every time so far, adding a front bar increases the inside wheel spin. The bar adds roll stiffness by picking up the inside tire along with the outside tire.
test / Try it bothways. Add front spring rate to reduce load transfer through reduced body roll. Usually adding spring rate works better than roll bar. ( front)
Add rear spring rate and or sway bar . I like to add rear sway bar until the rear tire comes up about 4in on most turns. If the tire comes up, it adds most of that weight to the inside front tire. If I add sway bar and the car gets too loose, I reduce spring rate until the balance allows me use enough bar to get the tire up.
Rear toe out also helps the inside tire by tracking the rear tire outside of the front tire,reducing the dynamic loading of the front tires. I use the Dynamic Rear Steer( DRS) as much as possible also to increase the rear steer effect, adding lateral potential to the front. It is simply optimized rear axle bushings that allow the rear axle to move a little under lateral loading, steering the entire axle alittle .

I will have to look into the OS diff. The welded does not like trail braking and I feel that braking well into the turn is crucial at this time. SM has improved us as drivers IMHo
 
What would be a good way to determine the right starting point for spring rates and I assume you can go to high with your spring rate?
 
VWs can use about anything from 350 to 800# front springs. It all about balance . Softer may have more grip as long as you have camber control. If you loose camber than you need more rate.
I would start about 400 and balance the car in the rear with maybe 250 plus a BA bar.
 
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