a couple of newbie questions

[96conv]

What is limited slip differential? Did it come standard in late 80s Carreras or was it an option? Should I look for this feature or is it something that would just be nice to have?

What does dyno testing mean? Is this something that should be done during a PPI for a daily driver?

I know these are basic questions but I can't seem to find definitive answers. Thanks.

[RickM]

I'm not an expert on either subject but simply put....

Limited Slip Differentials (LSD) was an option on Carreras of the late 80s. It helps distribute power to the rear wheels evenly...instead of allowing one wheel to spin. There are different styles of LSDs and they can be retrofited into an existing car....for a price.

A dyno is a piece of equipment which measures the power (HP and Torque) of a car. This can be done in different ways as the format of the machines may differ. One type of dyno has rollers that the drive wheels will turn while another type will hook up to an engine on a bench or stand. There are many variables that can influence the results of any dyno test.

Didn't they do dyno testing in Jurassic Park?

[91C2wrencher]

'96conv, LSD are always an option as they serve a specific function that not drivers want or need. An "open differential" allows only one wheel to spin(that being the one with the least traction) this is good for daily driving in moderate climates and provides a reduced stress on the drive train, particularly in tight turns. A LSD provides drive to both wheels and is desired in high performance cars to get the power down and aid in decceleration control(60/40 or 80/20 LSD reffering to the amount of slip between the two rear tires during accel. 40 and deccel. 60 slip). FWIW an open differential cars rears wheels will spin in opposite directions if checked while both rears are off the ground and one wheel is turned. A LSD rear wheels will turn in the same direction.

Dyno testing - put your car on a stationary dynometer and run it through the gears to measure hp and torque. No it not usually part of a PPI and usually never done except to verify engine modifications.

[91C2wrencher]

Jeez, the "boss" called and I'm late with the post! carpe e deim!

[TMH]

Yup, factory LSD was kind of an EXPENSIVE option, so I haven't seen too many cars with it. My understanding is that it really helps control the car in cornering situations in wet/slippery conditions. I can't wait to check this out this winter as the '87 I just got came with factory LSD. The way to tell if a car has LSD (other than looking at the option codes - but then again it could have been added later): Jack up the car so that both rear wheels are clear of the ground. Turn one wheel and if the opposite wheel turns in the SAME direction you have LSD.

Tom

[EDIT] D'oh - 91C2wrencher beat me to it!

[Eugene at Pelican Parts]

My SC was optioned with an LSD. You can test if yours has one by jacking up the rear and spinning a wheel. If both wheels turn in the same direction, you have limited slip. The test may not be accurate if your LSD is excessively worn.

Oh, and LSDs wear out because they use clutch disks to transmit torque. As you may know, anything that operates using friction eventually wears out.

[91C2wrencher]

The option code for a LSD is 220, IIRC. find it on the label under the front hood.

[Face]

Dyno is short for dynamometer - and it works as previously stated...

[Eugene at Pelican Parts]

Originally posted by TMH
Turn one wheel and if the opposite wheel turns in the SAME direction you have LSD.

Tom

[EDIT] D'oh - 91C2wrencher beat me to it!

EDIT: TMH beat me to it!

[91C2wrencher]

Right! dynamometer. Not a dynometer which was used up through the Jerassic period to measure the output of your Wholly Mammoth.....

[nostatic]

Originally posted by Mark Wilson
Didn't they do dyno testing in Jurassic Park?

I thought they were testing synthetics...but the older Raptors started leaking.

Originally posted by nostatic
I thought they were testing synthetics...but the older Raptors started leaking.

Obviously these were flat six powered raptors...

[nostatic]

Some of the older ones were flat fours. Boy, when the genetic engineers brought out the newer flat six Raptor, you should have heard the purists shriek. It also didn't help that the body shape changed.

We don't want to even talk about what happened when they evolved to warm (water) blooded...

[91C2wrencher]

Originally posted by Mark Wilson
Didn't they do dyno testing in Jurassic Park?

Ya, that's when they found that seals have been leaking since the beginning of time

[Eugene at Pelican Parts]

Originally posted by 91C2wrencher
Ya, that's when they found that seals have been leaking since the beginning of time

When my seals leak, I club them, and then they go AR! AR! AR!

Bad seals!

[91C2wrencher]

When my seals leaked I replaced them with Walrus..coo-coo-ka-choo

Have any of you guys ever blown a seal? I haven't but I do suspect some board members have.

[91C2wrencher]

Originally posted by Mark Wilson
Have any of you guys ever blown a seal? I haven't but I do suspect some board members have.

No, but I've eaten a lot of tuna!

[96conv]

Thanks to those with the serious responses. For the rest of you guys, get back to work!