Ok I searched and I know there has been threads on this topic. Just most of them didn't answer what I was looking for.

Here are my questions I would like answered (refer to the jack test):

Some LSD's like the type r/helical will go oppoisite ways while in gear correct?

What EXACTLY does a car do in the test if it DOES NOT have a lsd?

A car HAS to have an lsd if -in gear- both wheels spin the same way?

Is the only real way to tell if you have an LSD is to take out your axles and see if you can see through with no bar?

Thanks a lot

Miles

 

they spin the OPPOSITE ways. when u spin one side wheel forward, the other whould spin backward. in gear of course. if it does not do this, then ur lsd is crunked. (only front wheels)

 

So if you have an lsd... when in gear you will always be able to spin opposite ways? (Not only in reference to a type r)

 

No, an open diff will do the same (turn opposite). One way to tell if you have an LSD other than looking at the case for markings or pulling the axles is to do a burnout and check for two markings. Well, you can also make a tight turn and accelerate hard. If the inside wheel doesn't spin and/or the car pushes then you have LSD.

Why not take it to the track and find out? That is where the car belongs anyway.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by markpaco &raquo;</TD></TR><TR><TD CLASS="quote">No, an open diff will do the same (turn opposite). </TD></TR></TABLE>

I guess the Helm's manual is wrong then.

 

One of the other threads said that the burnout wasnt effective as a stock si did it and laid 2 even dark marks.

What do you mean look at the case markings?

 

Could someone also answer the questions directly (like one after the other) then I think I would understand completly

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1GreyTeg &raquo;</TD></TR><TR><TD CLASS="quote">I guess the Helm's manual is wrong then.</TD></TR></TABLE>

No, the Helm's manual isn't wrong. It is just an indication of an operational differential; open or LSD type.

You had me wondering if I was wrong but I remember my old RC car had an open diff and the wheels would turn opposite. I did some searching and this link: Differential Operation gives some differential basics.

It reads:

"An open differential allows for some slippage to occur between the two sides of the axle so that the tires do not rub the ground. With both tires left off the ground, put the transmission in neutral and with your hand turn one of the wheels. The other wheel should spin in the opposite direction with an open differential. If the opposite wheel does not spin, the differential may be damaged."

To answer the other question about the two skid marks on the Si. The Si probably exceeded traction on both wheels. That is why a straightline burnout may not be the best way to test for LSD. However, if you lay some water/lubricant under one of the wheels then it may be easier. Just make sure that one tire has grip and the other doesn't.

As for markings, you may see markings such as 'J4D LSD'. See image below:




I did notice one difference though. The HELM manual tells you to put it in 1st gear and spin the wheels. Whereas the link above says to leave it in neutral. Does it make a difference? I don't know for sure but I don't think so.


Modified by markpaco at 7:13 AM 5/17/2005

 

You need to do it in gear.

 

Ah ic... Where would that marking be? I'm guessing the underside of the tranny? (Just making sure cause me and a buddie are gonna see tomorrow)

Also if you guys could answer these..

What EXACTLY does a car do in the test if it DOES NOT have a lsd?

A car HAS to have an lsd if -in gear- both wheels spin the same way?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1GreyTeg &raquo;</TD></TR><TR><TD CLASS="quote">

I guess the Helm's manual is wrong then.</TD></TR></TABLE>

read closely.

 

if your that worried pull out the axles and look.