Anyone else ran a locker in a rwd rally car?

I was talking to gene awhile back about his 210 days and he told me that he ran a Detroit locker and loved it. Said it gave him full turn in capability of an open diff but full power to both wheels coming out.

So i was wondering if anyone else had ever tried them and what their thoughts were on them for on stage.

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"Rally racing makes a heroin addiction look like a vague craving for something salty"

Really no one other then gene has ever ran a locker in a rally car.

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"Rally racing makes a heroin addiction look like a vague craving for something salty"

I ran one, Duane Bender ran one, Dale Beard ran one,Brian Cooperran one, Janice Damitios brother ran one but since they are old farts and not on here......



Edited 1 time(s). Last edit at 09/19/2011 01:37AM by heymagic.

Yeah, what current RWD cars running today to they make a locker for?

I would suspect it works fine in something low to medium power.

Why not just weld it up?

There are helical gear locker style diffs that were stock on vlovos called the G80, I was going to get one, but got warned off. There are some weird things about them, they have a centrifugal weight in them so they only lock up at low speeds (?) that volvo hotrodders remove. They are out there for like $100 used. Thinks naturally go wrong for me so I just went with the welded diff to reduce the number of moving parts...



Edited 1 time(s). Last edit at 09/19/2011 03:45PM by alkun.

Quote
phlat65
Yeah, what current RWD cars running today to they make a locker for?

I would suspect it works fine in something low to medium power.

Why not just weld it up?

That there is a very good question. Both rally and certainly the RWD cars have changed since the 90s. I'd guess they still make lockers for most Toyota diffs, prolly most trucks that are on the market. Certainly the Ford 9" and most Jeep offerings. We used the center section (cheap gears) and lockers for a Datsun 620 pickup. You could get anything from 3.5X to 5.3X fro shopping at the junk yard. They fit the 200 SX disc brake rear ends. None of which are around today I'd guess.

Lockers are pretty tough and hold lots of horsepower. The difference between other diffs is pretty amazing on gravel. When you let of the gas the car turns like an open diff, no pushing at all. When you hit the gas it locks, push plus..be pointed where you want to go. You can hold a perfect arc, tail out thru any corner by feathering the gas ever so slightly.

Welded diffs like to push, the better the traction the more the push. You can certainly manhandle them and many do. I've seen video of Mssr. Lane having the Volvo push terribly at Pomeroy, I think he had to backup on an acute corner because of the push. That doesn't happen with a locker.

LSDs are very smooth in comparison. you really don't notice them when they work. Lockers 'talk' to you. They are a bit brutal on tarmac where LSDs aren't.

Another feature of a locker is they allow a car to ride on top of berms and ruts where weldeds dont. Probably not a huge concern with todays smoother stages.

If I built another RWD today I would figure out a way to put a locker in it. I believe they were largely responsible for my ability to take a 120 hp Datsun and keep it at the top of the pack against more powerful Mazdas, Toyotas and even most Talons and GTXs back in the day.

Quote
phlat65
Yeah, what current RWD cars running today to they make a locker for?

I would suspect it works fine in something low to medium power.

Why not just weld it up?

Any Volvo, any Volvo running a Toyota rear end. I realize there aren't a ton of rwd stuff out there but it seems the old timers hang around here and if anyone was to give it a try it would be them.

I have ran a welded diff and even though it was predictable i didn't like it going into the corners. I also ran a supra LSD and even with it pre loaded more it would still do the one tire fryer

And actually Detroit lockers are pretty stout. Drag guys use them, big motored big tired rock crawlers use them. Probably live a easy life in my little car.

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"Rally racing makes a heroin addiction look like a vague craving for something salty"

Quote
heymagic
If I built another RWD today I would figure out a way to put a locker in it. I believe they were largely responsible for my ability to take a 120 hp Datsun and keep it at the top of the pack against more powerful Mazdas, Toyotas and even most Talons and GTXs back in the day.

That's all that the endorcement I need.

Thanks Gene

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"Rally racing makes a heroin addiction look like a vague craving for something salty"

Bumping this back up.
We switched from a welded diff to a Spartan Locker in the d30 on the Volvo rally car after breaking 2 or 3 axles in a row after having no issues for 15+ events. Maybe new motor, maybe less care taken while making tight corners on pavement, who knows.
The locker has done 2 events so far (OTR and Oly), with only one broken axle... which was an axle that had been raced for a few stages with the other side being broken at PFR. We were able to drive the car out of the stage at a decent clip and all the way to service with the broken axle, and the locker stayed "locked" the entire time.
For $225, it's a fantastic upgrade to a stock Volvo diff. Way better handling on stage. No banging noises or anything weird. Stays open on turn in, and locks up on acceleration.

My only experience with lockers is in my LR Disco II. Its an off road toy, but not a trailer queen. We use a Detroit locker in the rear axle, and a Detroit Tru-Trac in the front axle. The LR guys who only trailer in and out use Detroit Lockers front and rear, but because I drive road and highway as well, I was recommended by the tech people at Detroit to use the Tru-Trac in the front when building the truck.

I could not believe the difference once the lockers were installed. I have had both axles at complete opposite articulation, with only two tires grabbing, and walked in locked low thru HumVee training grounds without once ever losing forward momentum. I have also had the truck rolled onto its side damaging almost all the sheet metal, but because one tire had traction, I was able to pull it out in reverse without having to hook up the winches.

I have front, rear, and side winches; and the truck is over 6,000 pounds when fully rigged in expedition gear. But once the lockers were installed it became a whole different machine. In a low weight rally car, anything Detroit makes would prove to be a huge upgrade, I would believe.

Did you know that you can get an ex-NASCAR locker for under $200 shipped?



Frickin' work of art inside, it is, compared to the production-car Detroit Locker on the right. Only downside is that they are 31 spline axles (this is a downside?) and they require a 3.25 bearing case for your Ford 9".



Upside is, most of the inexpensive aluminum cases are 3.25", so it all works out...

Ron Sutton makes different springs to make it easier or harder to unlock. I went for the second-lightest option.

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Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.

That is a work of art. You are going to make RX have an ultra-modified class next season, Pete.

It's not, not really. I just got tired of bending, breaking, and generally wearing out increasingly hard to find rearends. Like Gene alluded to about Nissan rears way upthread (years back...), playing with old Japanese steel means you can't just junkyard the parts you need anymore, you need to get inventive.

Really should get off my butt and go put gas in it so I don't have to do it on the way to work tomorrow.

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Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.

Quote
Robert Culbertson
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We switched from a welded diff to a Spartan Locker in the d30 on the Volvo rally car after breaking 2 or 3 axles in a row after having no issues for 15+ events. Maybe new motor, maybe less care taken while making tight corners on pavement, who knows.
The locker has done 2 events so far (OTR and Oly), with only one broken axle... which was an axle that had been raced for a few stages with the other side being broken at PFR...

Huh.....curious to see if you still occasionally break an axle even with that locker.

I thought one of the benefits of going rwd was not having to deal with constant broken axle shafts..
Or is the dana 30 weak in this application?

Or can you upgrade shafts?

Besides ratio availibilty is this another reason people go toyota rear axle?

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You can definitely break axles with RWD.

A locker should be a lot easier on axles because only 100% of the torque can go through one axle.

Let me clarify that statement. A welded diff/spool will not let the wheels turn at different speeds. If you are going around a tight corner and you're not under enough power to spin the inside tire, then, you can have one wheel that is being "dragged". That is negative torque on the wheel. That torque gets transmitted to the other tire. You can have 200% torque on one wheel and -100% on the other wheel, or any other figure you wish as long as it adds up to 100%. (The total torque has to be positive otherwise you won't be accelerating)

So, simplified, a Detroit Locker is a spool with a ratchet so that you can never have negative torque applied on a wheel. Therefore, the torque to the other wheel can never exceed 100%. This will make life easier on axles.

Less simplified, there can and will be just enough negative torque to cause that side's side gear to ride up the ramps against spring pressure and disengage. This is where the different spring rates come in. Stronger springs mean it takes more negative torque (in real numbers, not percentages) to disengage. So the less grip you have available, the lighter the spring you will want to have if you want it to disengage properly. Stock is generally something like 70 or 90lb. Ron Sutton sells springs all the way down to 25lb. I opted for 40lb as a starting point, since the stock springs felt like about 200ft-lb of breakaway torque on the axle and I wanted to go lighter than that.

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Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.



Edited 2 time(s). Last edit at 05/21/2017 09:24PM by Pete.