Google is your friend...

"In the IRL everyone uses an IRL mandated transmission, whereas in CART the transmission is a unique design by each car manufacturer to maximize car performance. In addition, a CART transmission case is made from light weight Magnesium, whereas the IRL unit is an aluminum case. The differential on a Champ car is a limited slip unit. On ovals they are fitted with a spool. The IRL car runs a spool for all races."


http://www.autoracing1.com/MarkC/200...RLCloseFar.htm

Hell while I'm at it I'll piss everyone off. Carroll Smith says to throw the Detroit Locker in the dumpster. Yeah, some of his ideas are dated and the book that comes from is dated, but if it belonged in the dumpster then where does it go now? I really don't care. This discussion just got me thinking and doing some re-reading. I'm just stirring the pot. :D

Re: Detroit Lockers
 

Check your rulebooks. I believe both NASCAR (on roadcourses) and TransAm by rule MUST run Detroit locker diffs. Why? I don't know and it doesn't matter; thems the rules.

For your NASCAR reasoning are you going to convice me a carbuerated pushrod V-8 is also the most perfect racing engine or do they run them because that's what the rulebook tells them to do? Never make the mistake of saying "So and so does it so that means it's the best". All racecars are products of the rules under which they are required to compete. You think guys building Formula Vees are just inherently dumber than everyone else and haven't figured out that wider tires and some power would make those things go a hell of a lot faster? Insisting that NASCAR uses Detroit lockers because they are the "best" is folly. NASCAR competitors use them because the rulebook tells them they have no choice.

I haven't checked the schedule but NASCAR still only races on 2 roadcourses a year? And 50+ oval races I think? Maybe NASCAR has no real desire to encourage teams to develop even more new parts for only 2 races and instead enforces a "spec" rule on the diffs used?

I said that.

He doesn't get on the power and lock the diff until he is ALREADY in the turn. It's initial turn in where it tends to unsettle the car. You also don't get the chance to change your mind. Once the car is turned in and set if you back out of it for any reason you could possibly be in for problems.

Your taking my point of view as some sort of attack. Detroit lockers are not pieces of shit but like any other device they have their own set of problems. Only people running them in modern days that I know of are those that are mandated by their rulebooks to do so. Detroit lockers don't suck but there are better alternatives IMO.

As for Shelby I respect him but when's the last time he built a real racecar??? If you're going to tell me 'ol Shel would step up today and put Detroit lockers in new Shelby Cobras he planned to take racing I will have to turn my back so you don't see me laugh ;)

If you wish to see what modern technology is doing look no further than F1 and and especially 4WD rally cars over the past 5 years or so. The rules have fluctuated in both to at different time allow computer control of diffs and at other times insisted on pure mechanical devices. Damn near everything has been tried again and again recently.

The good qualities a Detroit locker diff has are cheapness and robustness. It by no means has any inherent performance advantages and in fact has quite a few limitations due to it's operating characteristics. Hence people tend to use other designs that can be made just as tough and yet perform the limited slip differential function better. I ask you, isn't THAT what any racer asks for?

Every oval track car runs a spool in the rear. Sprints on dirt or asphalt, CART on ovals, IRL on ovals etc. If you have any kind of diff at all then you have no use for tire stagger... It defeats the purpose of running stagger.

CART only runs diffs on road courses.


Anything can be made to fit if you're willing to build it. The FD guys think a Kaaz makes some racket, they'd freak if they had a Detroit locker! They basically sound like they are trying to grind themselves into pieces anytime they are not locked.

LOCKED SPIDERS
 

Hey this thread has got you people thinking, and that really what it here for. To make you think. I never said the detroit locker was the best for all race cars. I only stated who was useing them and how strong they are. A person who races gathers over time a list of things in his head, that works for him. This cam co, this clutch co, this locker co, etc,etc. This is the way it should be. Racing is hard enough, without changing vendors every race. Run what you want to. Its a free country. The orignal post was asking about welding spiders in his RX-7 circle track car. Thats all he asked. What we've done is re-invent the wheel for him. To answer the orginal post, all I can say is do it. Its done every day in the USofA, and will keep on being done every day we race. As for a locker in a RX-7, well do like we did, use a 8" or 9" ford like every one else did and still do. Factory told us to. From RX-7 street stock to CART/IRL in one day. What a trip!!!! What can we re-invent tomorrow?

Tricky Dick Elliott

Re: LOCKED SPIDERS
 

Any relation to Bill?


-Ted

Re: Re: LOCKED SPIDERS
 

Only when I'm trying to get a freebe out of a vendor. Otherwise no. If I was, I wouldn't live in Arkansas.

An aritcle from noted racecar engineer Mark Ortiz on pros/cons of various diff designs can be found here.

Mark's aricles are also listed in our Suspension and Handling links:

Chassis and Suspension Tech Articles! A wealth of knowledge is featured in this UBB forum! Features many chassis topics from Mark Ortiz along with Brian Beckman's Physics of Racing series of articles. When you get serious, this is the place to read up.

For a short oval track, you would want to keep it an open rear end or LSD at the most because you are cornering more at a short track (bristol) then a superspeedway (Taladega)

No. At a short oval track you keep the spool and run more tire stagger.

Re: LOCKED SPIDERS
 

I learned from this.

My .02 On this one...

Close friend in High School ran a Detroit Locker in his Shelby Mustang GT-350. Pure Race car.. not street.. Was Beautiful.. Till he was on a caution lap in the light rain.. and eased gently on the power coming out of a corner expecting the locker to do just that.. and when it locked the expected slide started.. and he goosed the wall. NICE car bent. Fixed.. but bent. They changed I believe to a Auburn after that.. It was a clutch pack style.. smoother engagement for Road racing.

My RX-3 I ran (Formerly Sharkey's RX-3 for those in CFR) had a welded rear diff. AND After breaking 3 axles.. and really not having much fun coming out of the horseshoe at Daytona sideways through 3rd and 4th... every time.. I switched to the clutch style from a 1st gen.. and it made WORLDS of difference.. the car ACTUALLY handled out of corners.. It didnt just leap sideways when you applied power.

IF you can at all do it.. DOnt weld it.. Try to get some sort of LSD...... BUT.. if it comes down to Weld.. or Not racing.. Weld the fooker..

Thinking of welding mine used mostly as a drag car but see's some street use. I know you guys are going to hate me but it's sbc powered

Im just worried about breaking an axel.

"For your NASCAR reasoning are you going to convice me a carbuerated pushrod V-8 is also the most perfect racing engine or do they run them because that's what the rulebook tells them to do?"

hahahahaha. lol, nascar suxx ass.

hey i have a question..... can you weld up a rearend out of a second gen NON LSD rearend, or does it have to be the LSD rearend?

I can be an open diff. Doesn't matter.