Any racers out there race/drive with a welded diff or a spool before? Does it work well, or is an LSD "safer"?

Go around a corner with a welded diff....


Oh wait!! you cant.....

You need a limited slip for anything other than drag racing.

Me personally, Im tired of laying down 1's ee's and not 11's....

With a spool you get exactly the same drive on both rear wheels which is okay until you need to turn a really sharp corner a speed and then the car will really have a bad push. Another down side is if you break an axle on one side the car will usually turn very quickly towards that side with a loss of control.

here we go again...

a lot of top cars in top series will run a spool.
it takes a different driving style and inherent "butt sense" to throw the car into a slide in each corner and then catch it on the exit.

one common comment is that a locked diff helps under braking. my belief is that its not so much about the breaking, but more about the speed that you scrub on turn in. It takes a while to learn how to drive this way comfortable, but once you do you will be able to enter a corner faster than anyone else!

So the locked diff really is faster on the first part of a corner, but it is slower on the 2nd half (exit) part of the corner. I think for a super high powered car like a new GT3 or RSR you can oversome this track out because of the abundance in horse power. For a teener with a realistic motor you give up something on track out for turn in speed.

I'm faster overall with my locked diff... but like all things its a compromise.

I've run a locked diff for I believe 4 seasons now.

brant

Hmmm.... I'm pondering the spool/locked diff idea. Maybe I will try it eventually, but we'll see. I ask this because I've been driving my shifter kart around quite a bit lately, and of course, they don't have diffs, so you just have to make it go around the corners. I've been very used to it, so it doesn't bother me, as it is pretty much second nature for my driving style.

There are race cars out there that use a welded diff, ie: I've heard of 917's using them. Just wanted to see if anyone here uses it with sucess in our "low powered" cars

mine is welded...

I should mention, that they aren't so great on a dirty track or in the rain. This because you are balancing on the very edge of traction, and you purposely throw the car into a drift and then catch it by flooring the throttle when you feel you've drifted enough to make the corner.

so, in a low traction situation, the tires don't like to
"Re-Catch" themselves or stop their slide and this technique doesn't work so well.

I know of multiple 914 race cars that have run welded diffs. In fact, my race shop sells them for I believe 100$

I choose to buy one, since I certainly didn't want to trust my own welding skills.... and since I do trust my shops

brant

Brant makes a good point and he is "used to it" which can take some time I imagine. A couple of years ago at am HSR-West race at Willow Springs there was a yellow 356 with a spool diff and the car was very interesting to watch going around turns 8 and 9. I followed it for several laps and it reminded me of a crab as it seemed to want to go sideways and the driver was constantly making little turn corrections where others were rounding the turns smoothly with little steering input. They finally parked it and it was latter sold and the spool was removed I think? Personally I like the feel of my GT limited unit when turning tight corners like I have in the Mexico races.

I have a welded diff if anyone wants it...

Rich

rich, is it still inside of a box or pulled out.
I tried to buy that from you about 3 years back so I could build a 2nd box.

did you ever try it out (and dislike it?)

brant

tried it,,,tookit out.

So, its out of the case..ready for you or I was thinking about a cool desk lamp.

Rich

dang....
out of the box requires resetting the R/P

(part of the value of having it in the box was saving the money of resetting the R/P)

It took me about 5-10 track days to learn how to drive it.
I'm a slow learner, but it definitely is not something that you would initially like the first time you drive it.

The entire driving style is different.
and the car set up/tuning is different also.

reminds me a lot of driving a tail happy (911 like) car.
you turn the corner by throwing the car sideways and having the rear rotate. Then -sorta like a 911- you pull the car out of a slide by standing on the gas.

its like an exagerated 911.
kinda dukes of hazard fun though

and after I finally learned how to drive it, my lap times at my favorite track were the quickest I had ever driven even though I had the same exact set of old used tires on it.

I think that the reason I was faster was because my braking points had all gotten 20feet deeper, and not because I really needed the traction of both wheels accelerating!

Its that last 1-2 car lengths entering a corner where I can catch the competition.

brant

Thanks for the info Brant.

I've done a few races with the spec miata, with an bad LSD. But of course, driving my shifter kart is about the same as driving with a spool. I don't really throw it in the corners since the steering it setup really sensitive already, but I do stand on the gas to exit correcting all the way. I don't think I've ever exitied a corner with the steering wheel pointed the correct direction. All in all, I see myself as a maniac driver. haha. I gotta stock up on some fenders and suspension parts I guess....

Rich, I might be interested in it... just to try it.

Thanks

Andrew

QUOTE (Terrance @ Nov 7 2005, 03:54 PM)

Thanks for the info Brant. I've done a few races with the spec miata, with an bad LSD. But of course, driving my shifter kart is about the same as driving with a spool. I don't really throw it in the corners since the steering it setup really sensitive already, but I do stand on the gas to exit correcting all the way. I don't think I've ever exitied a corner with the steering wheel pointed the correct direction. All in all, I see myself as a maniac driver. haha. I gotta stock up on some fenders and suspension parts I guess....

Terrance,

With your shifter kart, the front end geometry is what allows it to turn by unloading the inside rear wheel as soon as you turn the steering wheel. Otherwise, it would simply go straight. OTOH, a suspended car with a spool acts somewhat differently.

Andys

QUOTE (Andyrew @ Nov 7 2005, 04:54 PM)

Rich, I might be interested in it... just to try it. Thanks Andrew

have fun setting pinion depth

QUOTE (Aaron Cox @ Nov 7 2005, 05:16 PM)

QUOTE (Andyrew @ Nov 7 2005, 04:54 PM) Rich, I might be interested in it... just to try it. Thanks Andrew have fun setting pinion depth

Yeah.. what Aaron said.
not a trivial thing you can just try out in an afternoon
think of it as a 5hundred dollar "Test"

brant

QUOTE (brant @ Nov 7 2005, 05:18 PM)

QUOTE (Aaron Cox @ Nov 7 2005, 05:16 PM) QUOTE (Andyrew @ Nov 7 2005, 04:54 PM) Rich, I might be interested in it... just to try it. Thanks Andrew have fun setting pinion depth Yeah.. what Aaron said. not a trivial thing you can just try out in an afternoon think of it as a 5hundred dollar "Test" brant

almost went through this myself....this weekend.

your better off buying a KNOWN good case with r/p and welding that dif.

that being said, i have a SideShift case with diff, and shafts....no gears. swap yours on and weld the diff. perfect time to go with an H gear... oh wait, i know someone who has one they want to sell also....

Ya ya aaron...

I know.

But I have other plans that have not yet been discussed publicly

And limitations from the 901 just dont suit me...

I was just curious what my car would be like, might be easyer to get around an autox track.

it is not for autox....it sucks in autox...dont try it in autox unless you have 200 hp or more...

you push into any corner...and you need to have enough hp to wag the tail at command, and under control...

on a track I see the benefit, but autox not...

Rich

rich...

I have 290hp... soon to be over 350

and tq on command (200ft lbs at 1.5k?)

but setting the R&P does not sound like fun...

Yet... I have 2 spare trani's that I want to play with.

I agree with Rich.
A locked diff would really only be used on a big track.
definitely not an autox item.

and I believe that the correct way to weld a diff includes removing it from the box. Welding it with bar stock inserted between teeth, and then reinstalling it into a box and resetting the R/P

The benefit of a locked diff is on fast corners (60mph+).
Not slow ones.

brant