You might want to rethink your trash talking to me by telling me I'm wrong and giving false info. Where is your info? I can name a few reputable shops and a really succesful import racing team that would agree with me that the LSD is more stressful on the tranny, as well as the type-r tranny is not the best suited for drag in FI vehicles.

I do know that an Open Diff creates less stress on the tranny and drive axles because it lets the power through more rather than the LSD giving a jolt to the synchros cause it grabs them both harder.

simple like this. the spider gears are pushing on both drive gears and one of them offers lots of resistance (tire sitting on pavement) and the other side offers no resistance (up in the air, or sitting on a patch of ice), then it will find a happy balance where both sides are receiving almost no torque at all. All the rotational energy is guided to the side with the least resistance. In the end, that side spins very fast and the pressure on each drive gear is the same.. Almost no torque is needed to spin one wheel, and therefore almost no torque is going to the other side as well.

Now, when an LSD is added into the equation. It is just like say you have a set of slicks on your open diff. You get way better traction thus creating a larger jolt to your transmission and drive axles. Why do you think a lot of the times people snap axles and break tranny's?? Too good of traction, thats why. An open diff can help to alleviate that stress because it decreases the amount of damage that can be done on daily driving or racing.

Yes I agree an LSD is good for drag and can help your times. Yes a type-r tranny is excellent for a vehicle that is more NA than anything. Though the LS tranny has longer gears, thus longer time in BOOST and less shifting. The type-r tranny means one more shift which makes another episode of short turbo lag and shift time.
Thanks for your agreeing on that issue carl_aka_carlos

Y80 Tranny (B18B1 tranny)
1st: 3.230
2nd: 1.900
3rd: 1.269
4th: .966
5th: .714

S80 Helical LSD (B18C5 tranny)
1st: 3.230 [same]
2nd: 2.105 [shorter]
3rd: 1.458 [shorter]
4th: 1.107 [shorter]
5th: .848 [shorter]

Its just plain simple, More shifts means less time in boost. Why do you think that the fastest cars use a powerglide tranny? Less shifts=better times.

I stick with an LS tranny cause it keeps me in boost longer and I never have to shift into 5th.

sidenote: An open diff can be more beneficial for cornering (autocross/road race)



[Modified by xrtdac, 1:08 AM 10/3/2002]

 

bah, i don't believe it.

Theory makes sense, if you were comparing the tranny in an 18 wheeler to an LS Integra's. I'd go for the LS's since it's got taller gears compared to many many short gears on the truck.

So what if you "stay in boost longer." A car can stay in boost longer by downshifting one gear at 60mph , allowing the turbo to really spool for a long while, slowly winding out the tall gear.

Same car can downshift 2 gears and allow gearing AND boost to get out of there at a faster rate.

I suppose if you're a half assed slow poke shifter, and all you're worried about is drag racing *yawn*, maybe the best thing to do would be an LS tranny since you're worried about shifting so much.

But if ya think about it...both trannies require 4 upshifts down the 1320, unless you're trapping *well* over 100mph.

sidenote: what the crap? Do you even autoX? Oh yeah, I'm really flying thru those tight corners with my open diff and inside tire hopping and spinning madly.


[Modified by Jesse H, 3:37 AM 10/3/2002]

 

I'm no expert on boost, but based on the discussion I would have to agree with Jesse. I would prefer to wind out my shorter gears while on boost than to "stay in boost longer" on a taller gear.

Correct me if I'm wrong, but as typically seen on an NA car, most of the peak horsepower on an FI car is also at the high spectrum of the RPM scale. I'd prefer to keep the RPMs up there, as opposed to slowly climbing in RPM to "stay in boost".

My 2 cents.

 

ONE word for you MattyMatt and Jesse: POWERGLIDE
hmmmmmmm....2 gears. Tons of record holding racers run them. Less shifts??? Hmmm, you think they may have figured out forever ago that LESS SHIFTS EQUALS FASTER TIMES.

examples: AEBS focus, osofast eclipse

Why would you want to stay in boost longer?? MORE HORSEPOWER FOR A LONGER PERIOD OF TIME. Rather then continually shifting and having to build back up to full boost. Notice in a FI vehicle, you are not at the same amount of boost prior to shifting as you are after a shift. You get LAG and then full boost. So again you want longer gears to keep you in boost longer.

Why would you want to shift more? MORE SHIFTS MEAN MORE DEAD TIME. It doesn't matter how fast your shifts are, its just common knowledge.

Now on to the differential questions.
With an lsd it will still do that but that inside wheel will have more power.

HERE IS THE PROVEN KNOWLEDGE.

Differentials reduce tire wear and help a car turn more easily by allowing
the rear wheels to travel at different
speeds while turning corners. The inside wheel must slow down (smaller
radius turn) while the outside wheel
speeds up an equal amount (larger radius turn). To balance the drive torque
at each wheel, more torque is
applied to the outside wheel, speeding it up, while less torque is applied
to the inside wheel, allowing it to
slow down.

LSD:
The spring pack pushes the side gears against the clutches, which are attached to the cage. Both side gears spin with the cage when both wheels are moving at the same speed, and the clutches aren't really needed -- the only time the clutches step in is when something happens to make one wheel spin faster than the other, as in a turn. The clutches fight this behavior, wanting both wheels to go the same speed.
-howstuffworks

If the LSD wants both wheels to go the same speed, then you are being pushed or pulled straighter due to the differences in the speeds the wheels are traveling on the different radius' in the corner.

I am trying to prove the physics of this matter.


[Modified by xrtdac, 7:55 PM 10/3/2002]

 

Actually dude , what you say is correct about how an open diff will turn better, but an LSD is an open diff if you think about it. lets look at the 3 types of diffs

Locked - used only on high end drag cars (Funny cars) Wheels always Spin at the same rate. (only 4 drag, or mayby Tractor- pull 4 you hicks )
LSD - allows some slip and some grip. Grips only when wheel spin in detected. Go to the AutoX forum and ask those guys if an LSD is better for getting out of a corner, and im sure they will tell you YAH. and also
Totally open - GSR, Ls - Will still allow one wheel to spin freely. In fairness to you, what the other guy said about a GSR tranny having one wheel hopping is not true, unless youre a retard and are under full throttle.

But bottom line is that an LSD does not behave like a locked diff. It is meant to be the best of both worlds. (If ur makin mad turbo ponies then ya, you might **** one up, but he's prolly not)
Peace

 

Yes I am making good turbo ponies. Thanks for the help.
I agree with that. The physics of the matter though is the LSD will still make the car want to go straighter in the corner cause once one wheel goes slower the lsd will sense the change and try to correct that by making it go the same speed as the other wheel. thus causeing the vehicle to want to go straighter.


[Modified by xrtdac, 8:10 PM 10/3/2002]

 

I give up.

I know enough about powerglide and drag racing ho hum bullshit that:

FOR ALL OF US HERE, an ITR tranny will yield better 1320 times over an LS tranny. That was the original statment.

Slap on a powerglide which consists of 2 long gears that will allow the car to reach the end of the track w/out bumping the revlimiter on anybody's turbo car here and it_will_be_slower. Gearing.

Is anybody here running so much boost and trapping such high mph's that they're in 5th gear at the end of the strip? If so, by all means go for the powerglide if your car is a dedicated drag racer or LS tranny.

But jeez man, whatever applies to some pro drag racer that weighs 2K lbs, with a big *** turbo making 400 fwhp isn't always gonna apply to our street cars. Got it?

Well no freaking duh. Being pulled straighter in relation to the tires...not in relation to where the car is pointed in the corner. Thus you have a car that has a better chance of going to where it's pointed.


[Modified by Jesse H, 10:59 PM 10/3/2002]

 

Jesse do you know that you basically just agreed with me about FI and a longer geared tranny.

Yeah Im real damn close to needin 5th gear, I just haven't turned up the boost yet to stress it. But if I had a type-r tranny I would be in 5th gear cause I max out 4th on my ls tranny at the end of the run. If I shifted into 5th Id lose time cause of not being in full boost for that short time.

HERE IS MY ORIGINAL STATEMENT if you wanna be picky about it:
That was my own words. See the keywords: "DRAG RACING" and "FORCED INDUCTION"

DID anyone here say your car or his car is going to run worse with an ITR tranny?? No. I said, He would be better off with an LS tranny if he is going to add FI to it later on and is focused on drag racing.

"Being pulled straighter in relation to the tires" Exactly because if it is being pulled straighter in relation to the tires then the whole car is going to go straighter, therefore your whole point of not in relation to the car makes no sense.


[Modified by xrtdac, 10:33 PM 10/3/2002]

 

by the way this is all becoming one big *** argument. The only thing I can guess is that we are not really able to express our views as clearly as we would like through this. therefore we may continue battling this until our views are as clear on here as they are in our heads.

Care to just end this battle? Or no? I know my thoughts and knowledge, you know yours.

 

I understand that. It's just that you seemed to imply that anybody with a turbo car and 250 fwhp is going to benefit from something with longer gears. If you're almost crossing the line in 5th gear, obviously you're damn fast. Much faster than the typical boosted Honda that isn't going to benefit from taller gears. That's the point you failed to mention, causing everybody (alot of uninformed) that if you've got a turbo car you best be using the tall LS tranny. So I've got nothing else on that issue.

With LSD. I and every autoXer and roadracer will prefer to run with a limited slip.

 

exactly ...!